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January 3

Quantum Electrodynamics

I suspect I worked out the special relativity version of the Schrödinger equation. I want to check it, but I want another stab at it if I was wrong.

Is it some variation of $-\left(\hbar {\frac {\delta \Psi }{\delta t}}\right)^{2}=\hbar ^{2}c^{2}{\frac {\delta ^{2}\Psi }{\delta x^{2}}}+m^{2}c^{4}-U^{2}\Psi ^{2}$?

I'm pretty sure it's on the Schrödinger equation equation page, but I can't look myself for obvious reasons. If I just flipped a sign or something, go ahead and tell me the answer. But if it's completely wrong, don't.

While I'm at it, I have another question. I was trying to work out how the whole nothing -> particle + antiparticle thing works. Is nothing made up of particle-antiparticle pairs? That would require that, for example, the binding energy of positronium is about one MeV. I'm pretty sure it's supposed to be a quarter of a Rydberg energy or something like that. Does the weak force make another ground state when they're really close to each other or something? — DanielLC 02:03, 3 January 2011 (UTC)

The Dirac equation (don't look) page says "... the necessary equation is first-order in both space and time ...", so I don't think yours is correct. For the second part of the question, you may be interested in Dirac sea 157.193.175.207 (talk) 12:33, 3 January 2011 (UTC)

I don't think the Dirac sea thing helps. My problem is that there's three dimensions for each particle, so if you added a particle antiparticle pair, you'd add six dimensions. I'm pretty sure the laws just give how to change the amplitude of a given point in configuration space. You can't have it change the number of dimensions. Not unless you use the Copenhagen interpretation, and there has to be a better answer than that. — DanielLC 22:14, 3 January 2011 (UTC)

changing the QM framework to allow for creation and destruction of particles was historically a problem that was solved using Canonical quantization, especially second quantisation. 157.193.175.207 (talk) 12:27, 4 January 2011 (UTC)

If you drop the U, what you've come up with has a fair amount of similarity to a one-dimensional version of the Klein–Gordon equation, but there are a couple of important differences. I think you might as well just look at the article, since I think the Klein–Gordon equation isn't really all that important of a stepping-stone toward QED anyway, mainly because it describes a spin-0 particle, so it's not worth knocking yourself out over. Red Act (talk) 19:10, 3 January 2011 (UTC)

Size of Casimir effect vs observed dark energy

One thing the Casimir effect page seems to be missing is a comparison vs the observed Dark energy level. So do the microscopic and cosmic measurements about "the state of nothing" agree or are they vastly different? Hcobb (talk) 06:18, 3 January 2011 (UTC)

The Casimir effect vastly increases at distance scales shrink, whereas dark energy is in the biggest size scales and seems to increase as size increases. They are very different. Graeme Bartlett (talk) 08:09, 7 January 2011 (UTC)

Recording sound from a moving car?

Ordinarily, of course, one hears relatively little from the window of a moving car, since the background sound of rushing wind is so loud. But is it possible to design some sort of microphone pods that completely avoid turbulence, or cancel or filter all white noise, so that if they were connected to speakers inside the (well-soundproofed) car you could hear everything around the car while moving at highway speed as if you were parked? Wnt (talk) 06:50, 3 January 2011 (UTC)

Yes, but everything would be doppler shifted. Ariel. (talk) 08:40, 3 January 2011 (UTC)

Noise-canceling microphone, Anti-noise, and Noise-cancelling headphones may be relevant. Perhaps with well-chosen locations of several microphones and the right circuitry, you might be able to cancel out much of the motor, tyre, and wind noise and be left with the car-less noise. 92.15.31.128 (talk) 13:54, 3 January 2011 (UTC)

I don't think that approach would work well, here, as such systems require a way to distinguish between the noise to be canceled and the sound to let through. When listening to music from the radio, is straight-forward, the sounds coming out of the radio are the ones to keep and the rest need to be canceled. However, in this case, the noise from wind turbulence around the car probably sounds identical to that from wind blowing through the trees. Reducing the background noise, by streamlining the car, would assist you, as would putting a (streamlined) microphone outside the car and driving as slowly as possible. StuRat (talk) 16:02, 3 January 2011 (UTC)

Well it could do if the target is well separated from the vehicle. Adding noise in antiphase to cancel it requires pickup mics close to the noise source (ie the engine, tyres, body) and the target to be away from the car. Noise cancelling mics work by rejecting noise from the rear and sides. This is going to work best if the mic is on a boom pointing away from the car, or at least pointing out the window. Not terribly practical for an everyday vehicle, what's your intended application? some kind of espionage? SpinningSpark 16:57, 3 January 2011 (UTC)

Nay, just curiosity during a long drive - though I was thinking that if an answer existed it might be based on some existing spy tech perhaps for airplanes. I understand that the Doppler shift would be noticeable, but that is just part of the curiosity. The noise cancelling approach is interesting, but I think that any air turbulence directly at the microphone would be unique and could not be cancelled against any other microphone. Though the engine and tire noise could be dealt with so, I was supposing that a well insulated stalk on a microphone could do the same. The real question to my mind is whether a moving object can be designed aerodynamically so that there is a region of perfect laminar flow over part of it, which can be insulated acoustically from the rest, and whether a microphone membrane can be placed there so as not to interfere with the airflow but which can pick up the sound. Wnt (talk) 17:45, 3 January 2011 (UTC)

Streamlining can be far better than it is now, but it requires compromises like less ground clearance and passenger room. Also, the radiators we use now that rely on air smashing headlong into them have to go. Instead, a larger radiator along the inside of the hood might make sense. Windshield wipers and door handles also need to go (or at least should be covered up when not in use). Instead of being open at the bottom, the car must have a panel underneath. Then there's the gaps between body panels. A single shell that's lowered onto the frame (and driver) would fix that. StuRat (talk) 17:58, 3 January 2011 (UTC)

The usual idea for microphones in wind is not to encourage laminar flow, but rather to break it up to something less energetic. This is the reason for the fur covering seen on microphones used by outside broadcast crews. See here also. SpinningSpark 18:40, 3 January 2011 (UTC)

It's essentially impossible. If you know the spectral characteristics of the signal you want to receive, you can amplify in a way that focuses on that spectral range, but because white noise covers the entire spectrum and is completely unpredictable, you will still pick up the part of it that overlaps with your signal. If you don't know the spectral characteristics of the target, it is completely hopeless. (As StuRat said, the noise-canceling principle can't be applied in this situation.) Looie496 (talk) 19:50, 3 January 2011 (UTC)

I don't think the OP really means white noise, I am reading that as merely a substitute for all the various sources of noise found in a vehicle. SpinningSpark 20:37, 3 January 2011 (UTC)

I think what you are wondering is if you can make the car "slip" through the external sounds, so they would flow around the car and you wouldn't hear them. This would only happen if the local section of air was traveling faster than the speed of sound - and that would be quite noticeable due to the sonic boom. A concorde is quieter to its own passengers because it outraces its own noise. Ariel. (talk) 20:42, 3 January 2011 (UTC)

I am skeptical of the statement that the Concord was quieter because it was outpacing its sound. Sound from aircraft engines is easily conducted through the aircraft itself. Googlemeister (talk) 21:01, 3 January 2011 (UTC)

Some sound is, but most isn't. A jet engine is extremely loud (over 140db) - if a lot of sound was conducted you'd need ear protection on flights. Also a lot of noise is turbulence from the wings and other surfaces, and that noise is generated slightly removed from the wings. Ariel. (talk) 21:34, 3 January 2011 (UTC)

Edit: I tried to find a ref for it. The best I info I found was a forum post that said that the back of plane was much louder than the front ('And the very back of the cabin was dubbed "rocket class".'[1]), but otherwise the sound level was mostly normal/typical. Apparently they also worked hard when designing it to minimize sound, so it's hard to separate that from speed of sound quietness. Ariel. (talk) 21:47, 3 January 2011 (UTC)

where did all the mass go?

If the infant universe had infinite volume and infinite density, then it must have had infinite mass (since density is a function of mass and volume). However, our present universe does not have infinite density, so where did all the mass go?thank you. —Preceding unsigned comment added by 117.201.161.237 (talk) 11:05, 3 January 2011 (UTC)

This question has already been answered above. --Plasmic Physics (talk) 11:12, 3 January 2011 (UTC)

Where? And to answer your question, it did not have infinite volume. It was a singularity, so it was just a point with infinite density. When it rapidly expanded, it didn't have infinite density anymore. --T H F S W (T · C · E) 18:28, 3 January 2011 (UTC)

Here [[2]]. As I understand it infinite density is a backward extrapolation of the expansion of the universe we have observed. If this is true our observable universe started as a infinitesimal point, but we do not know how big the whole universe are and if it is infinite it is possible that the volume was infinite even when the density was infinite. The obvious answer to the question is that the mass is outside the observable universe and that every volume has expanded an infinite number of times so the density can be finite. --Gr8xoz (talk) 21:48, 3 January 2011 (UTC)

Theory of everything

Haven't electromagnetism and both nuclear forces already been unified? Why is it still so hard to unify gravity with a single force instead of three forces? --75.60.13.19 (talk) 15:03, 3 January 2011 (UTC)

Because gravity isn't even well explained by itself, never mind how it fits into a possible Theory of Everything. One of the key problems with gravity is that it is ignored by the standard model, which holds that forces are propagated by Force carriers; that is particles which transport the "force" between the things so affected by the force. EM is mediated by photons, the strong nuclear force by gluons, and the weak nuclear force by the W and Z bosons. There has not yet been any confirmed existance of a graviton, or even a consistant theory which predicts its existance, beyond the "the other forces have one, so gravity must too". General relativity gets around this problem by making gravity a pseudoforce, much like Centrifugal force; that is gravity represents objects moving in straight lines at constant speeds (and thus, unaffected by forces), but doing so in a curved 4D spacetime, a concept known as Geodesics. The problem is that, so far, both General Relativity and the Standard Model are really good, working theories, but they resist incorporation with each other. --Jayron32 15:30, 3 January 2011 (UTC)

Have you (the OP) read our article on the modern theory of everything? Electricity and magnetism were united as they were researched during the enlightenment forming electro-magnetism. Electro-magnetism and the weak force were united between 1979 and 1983 forming the electroweak force. There are several (related) theories to unite the electroweak force and the strong force forming the grand unified theory, however they are not fully resolved. Once this is done, the next stage is to unite GUT and gravity, forming the theory of everything. On a tangential note, special and general relativity explain how large objects move at speeds approaching the speed of light, and quantum mechanics explains how very small objects move. However, there is no working relativity and quantum mechanics theory to unite them. CS Miller (talk) 00:10, 6 January 2011 (UTC)

Coloured light

I know that if I look at, for example, a picture of a yellow object on my monitor, what I'm really looking at is nothing yellow, but instead little red and green lights packed so closely together that my eyes can't tell the difference and think they're seeing yellow. But if I'm looking at an actual physical object that really is yellow, am I correct that the light coming into my eyes really is yellow?

This caused me to imagine a situation where this blending of different-coloured lights didn't exist. We could only see pure hues of the entire spectrum, at different brightnesses. An easy way to simulate this is by loading a picture in your favourite graphics editor and setting the saturation in the entire image to 100%. I tried this on a couple of photographs, and it didn't look that much unrealistic. JIP | Talk 19:25, 3 January 2011 (UTC)

Our eyes and brain interpret colors by the amount of stimulation received by the three types of cone cells in our eyes. Light that is true yellow, that is say about 580 nm wavelength, will tend to equally stimulate the "red" and "green" photoreceptors roughly equally. However, so won't light which is 50% red and 50% green; the result is that we cannot actually tell the difference between "spectral yellow" and "non-spectral yellow". See also Color vision and Spectral color for more. --Jayron32 19:39, 3 January 2011 (UTC)

"So won't"? Do you mean "so will", or what? JIP | Talk 19:44, 3 January 2011 (UTC)

So will. --Tagishsimon (talk) 20:31, 3 January 2011 (UTC)

Sorry, "So won't" is part of my New England dialect. The "positive negative" is a regionalism present in that area. It means the same thing as "So will". --Jayron32 20:40, 3 January 2011 (UTC)

I could care less about that.  :) -- Jack of Oz [your turn] 21:19, 3 January 2011 (UTC)

Is that just a New England thing? I had no idea. From here in Connecticut, when I saw JIP's objection I thought "What's the big deal? It means the same either way." APL (talk) 23:07, 3 January 2011 (UTC)

It certainly doesn't mean the same here in England. "So won't" is not idiomatic here in any meaning, but it never occurred to me that it might mean "so will". --ColinFine (talk) 00:08, 4 January 2011 (UTC)

The negative form of will is will not, for which the contraction is won't.[3], literally woll not where woll is an obsolete or dialectical form of will.[4] Cuddlyable3 (talk) 21:57, 4 January 2011 (UTC)

Obviously. However, This side-discussion was about the specific construction "Something will verb, so won't something else" which (in some regions) is identical in meaning to "Something will verb, so will something else", despite the literal meanings of the individual words. "So don't" is occasionally used for "So do" as well. I suppose it's wicked confusing to people not from this area. APL (talk) 23:12, 4 January 2011 (UTC)

Having the same (apparent) color, but made up of different combinations of frequencies is called Metamerism. If you want to see the pure color in your photo, use a magnifying glass. Just changing the saturation won't do that because the ratio between the colors stays the same. Ariel. (talk) 20:39, 3 January 2011 (UTC)

Many objects that you believe are "really yellow" are just reflecting similar amounts of red and green light, plus frequencies in between, but very little blue light. I don't think I can distinguish between "true yellow" and normal reflective "yellow" (except in the extreme cases such as sodium lamps where the frequency range is very narrow), though looking at "pure red" and "pure green" objects by the reflected light should enable an estimate of the range of frequencies being reflected. I remember doing an experiment nearly fifty years ago, in which I held a pure red filter to one eye and a pure green to the other, and could see yellow perfectly normally, proving that it is in the brain that the signals are combined.Dbfirs 22:04, 3 January 2011 (UTC)

But I thought Binocular rivalry proved that each eye is separate! Maybe it only applies to shape and not color? (It mentioned something called "binocular colour rivalry", although without details.) Or maybe only if the images are very different? Ariel. (talk) 22:45, 3 January 2011 (UTC)

Some anaglyph images are "true color" in the sense that all the R information comes in one eye and the G and B data comes in the other eye. It never feels quite right, but it's close. APL (talk) 23:10, 3 January 2011 (UTC)

I think the brain always tries to combine the images, but can be forced to concentrate on just one set of signals, either at will, or involuntarily if there is a big discrepancy. The variation in density of cones and pigment suggests that we all see colour differently, but we adjust our perception to match that of others, so there is an enormous amount of pre-processing goes on in the visual cortex before the conscious mind "sees". Dbfirs 09:08, 4 January 2011 (UTC)

Another practical example involves the so-called "white light" emitted by fluorescent lamps, which is actually made up of various bands of color. Many things don't really show the proper coloration that they would under genuine sunlight, or a good natural-frequency incandescent bulb for that matter, because they aren't reflecting or absorbing real yellow light. Wnt (talk) 14:51, 4 January 2011 (UTC)

Chimney drought or draft

The article on Chimney drought or draft (Chimney#Chimney_draught_or_draft) confused me a little. It says that "the combustion flue gases inside the chimneys or stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That causes the bottom of the vertical column of hot flue gas to have a lower pressure than the pressure at the bottom of a corresponding column of outside air."

I'm confused by the claim that the hotter air would be at a lower pressure. Wouldn't the pressure be higher, because it's hotter? 65.92.7.244 (talk) 20:27, 3 January 2011 (UTC)

In a closed system, hotter air would be at a higher pressure, assuming the same sized container and the same quantity of gas. The deal is, the chimney is open at both the bottom and the top, so it isn't a closed container. As the hot air rises out of the chimney, this creates a lower pressure at the bottom of the column of air in the chimney, essentially because as the warm air leaves via the top, it removes air faster than it can be replaces by cold air at the bottom. What you have in this case is that the quantity of air is actually lower, proportionally, than the temperature of the air is higher. Mathematically, considering the ideal gas law PV=nRT, the "n" term is droping faster than the "T" term is rising, resulting in a lower overall "P" term. --Jayron32 20:31, 3 January 2011 (UTC)

The missing link in your description is that you havn't explained why hot air is less dense than cold air. Hot air has faster-moving air molecules which ricochet off each other and their container and spread out the same mass over a larger volume, and hence has lower density. Edit: reading it again I don't think its true: "as the warm air leaves via the top, it removes air faster than it can be replaces by cold air at the bottom" - its only a chimney, not a jet engine! The cold air should have no problems entering the chimney easily. The warm air rises like something lighter than water floats upwards from the bottom of the sea. 92.15.22.77 (talk) 20:46, 4 January 2011 (UTC)

This is how hot air balloons work. 92.29.114.99 (talk) 20:53, 3 January 2011 (UTC)

Is there an equation that would tell how much thrust (downward) a chimney generates if the volume of air intake, and its temperature and pressure is known? Googlemeister (talk) 20:55, 3 January 2011 (UTC)

I'm sure their is; its a question of fluid dynamics, however I have a background in chemistry, and not chemical engineering. A chemical engineer would likely be able to work out such a problem, and/or have an equation at hand. --Jayron32 20:59, 3 January 2011 (UTC)

If the chimney is in a steady state, then the volume and average density of the hot air in it will be constant. The difference between the mass for that volume of hot air, and the same volume of cold air, should allow you to calculate the force involved. At least that's my guess - its a long time since I did A-level physics. Edit: I understand the thrust is to do with the net momentum difference between what's entering and what's leaving. At a steady state the mass entering and leaving should be the same. If you knew the amount by which the cold air expanded its volume into hot air (although the pressure should be nearly the same since the hot and cold air are interconnected), then you could calculate the relative speeds at which the air entered and left the chimney, and thus calculate the net momentum and therefore thrust. Or you could use smoke to estimate the speed of the entering and leaving air directly. 92.28.251.68 (talk) 00:25, 5 January 2011 (UTC)

Right, thanks. 65.92.7.244 (talk) 00:04, 4 January 2011 (UTC)

I do not think there would be much or any difference in pressure, at least in a cionventional chimney, at the hot and cold air is in contact and would share the same pressure. Rather the hot air is less dense than the cold air as explained above, and so floats upwards. 92.28.242.164 (talk) 15:00, 5 January 2011 (UTC)

moons

Where might I find out the dates of various phases of the moon for the period June-February 1593? No lunar calendar I have been able to find online goes back anywhere near that far.

79.74.213.144 (talk) 21:00, 3 January 2011 (UTC)

The time between full moons is 29.530589 days. You could probably back-calculate from a known full moon to find the dates of the full moons in that time period. --Jayron32 21:24, 3 January 2011 (UTC)

I use a program called "stellarium" which shows you how the sky looks at any particular time and place and allows you to fast forward or rewind time. I've never tried to go back centuries though, not sure if it will accurately go back that far. I'm at work so can't check. It's free and easy to install if you want to give it a shot. Vespine (talk) 21:35, 3 January 2011 (UTC)

If you do the calculation yourself, don't forget the change from the Julian calendar to the Gregorian calendar. Dbfirs 21:48, 3 January 2011 (UTC)

I just came to write that. But that was 1582 which is before the 1593 date requested. But if you do go back farther be careful of that. Ariel. (talk) 21:50, 3 January 2011 (UTC)

Implementation of the Gregorian calendar varied by country (at as late as 1917), but in Western Europe the change was in 1582. Googlemeister (talk) 22:19, 3 January 2011 (UTC)

That's only correct for a few countries. Most Catholic contries changed within a few years after 1582, but most Protestant countries waited until the 18th century (1752 for Britain and its colonies, for example). See details here. --Anonymous, 07:04 UTC, January 4 (Gregorian), 2011.

List of 16th century lunar eclipses says that in 1593, partial lunar eclipses occurred on May 15, June 13, Nov 8, and Dec 8. Since lunar eclipses can only occur when the moon is full, this should do a pretty good job of pinning it down, assuming the dates are correct. Looie496 (talk) 22:49, 3 January 2011 (UTC)

The site you want is Fred Espenak's eclipse pages at NASA, and specifically the Catalog of the Phases of the Moon going back over 4,000 years (and almost 2,000 years into the future), and under that, specifically this page for the years 1501-1600. Note that he uses the Gregorian calendar beginning with the end of 1582, and assumes that all years start on January 1; if that's wrong for the location you're interested in, you need to correct the dates accordingly. Also note that times are given in UT; for dates of phases of the moon at some location other than the Prime Meridian, you need to correct to local solar time according to the longitude of the place at a rate of 15°/hour. For example, if it says "Jan 17 01:27", the date is January 16 for any location west of longitude 1h27m x 15°/hour = 21°45' W; if it says "Jan 17 23:27", the date is January 18 for any location east of longitude 0h33m (time until midnight) x 15°/hour = 8°15' ). --Anonymous, 07:17 UTC, January 4, 2011.

(The reason for "15°/hour" rather than using time zones, of course, is that they didn't have time zones in the 16th century.) --Anon, 10:58 UTC, January 4, 2011.

Aspirin

hey all. Over the holidays I was over at my grandparents' house and my grandfather has high blood pressure. He explained to me that he takes aspirin to reduce his risk of heart attack. I'm only in pre-med, but I'm curious: how does this work? I've heard that if you think you're having a heart attack you should chew an aspirin but I assumed it was a blood thinner. Wouldn't regularly taking a blood thinner be dangerous, though? Thanks. 24.92.70.160 (talk) 22:28, 3 January 2011 (UTC)

See the "Prevention of heart attacks and strokes" section of our aspirin article and also our Mechanism of action of aspirin article. You're right that it can act as a blood thinner, but that may be the lesser of two evils (the other being having a heart attack) and may even be a direct benefit (reducing clotting or other flow inhibition that can lead to heart attack). DMacks (talk) 22:29, 3 January 2011 (UTC)

Asperin does thin the blood, yes. There are dangers to taking blood thinners, but it is a standard treatment for some heart problems. A aspirin a day is a very common prescription. If that isn't enough, Warfarin is taken for heart problems to thin the blood. --Tango (talk) 00:05, 4 January 2011 (UTC)

I haven't heard about chewing an aspirin if you think you are having a heart attack. In the movies they take nitroglycerin at the onset of a heart attack. At Nitroglycerin it states Nitroglycerin is also used medically as a vasodilator to treat heart conditions, such as angina and chronic heart failure. It is one of the oldest and most useful drugs for treating heart disease by shortening or even preventing attacks of angina pectoris. Nitroglycerin comes in forms of tablets, sprays or patches. Dolphin (t) 07:22, 4 January 2011 (UTC)

See Myocardial_infarction_management -- aspirin is a well known treatment for acute heart attacks as its antiplatelet activity can reduce the degree of thrombosis and potentially decrease the severity of the ischemic damage. --- Medical geneticist (talk) 12:24, 4 January 2011 (UTC)

Pet peeve - aspirin does not "thin" the blood; your blood does not somehow become more dilute with the ingestion of acetylsalicylic acid. Aspirin serves to reduce platelet aggregation; that is, it reduces the "clumping" action of platelets. While the meaning is generally understood, you'll note that our article carefully avoids the use of this phrase. Matt Deres (talk) 14:26, 4 January 2011 (UTC)

Moreover, the prescribed daily dose of aspirin for preventive antithrombosis is generally the baby aspirin -- 81mg BID (or QD). DRosenbach ^{(Talk | Contribs)} 04:17, 6 January 2011 (UTC)

Light speed

I'm assuming that time and speed are inversely proportional. On that, I can predict the reason light speed can never be met is that you can't add more acceleration because you can't have a "0" time. Is this correct? Albacore (talk) 22:50, 3 January 2011 (UTC)

That doesn't make sense to me. I read your proposal as implying speed of light is infinite. That's obviously not true, it has a definite and measurable speed, so there is certainly time there for any given distance travelled. The light-speed problem is that you simply cannot reduce that time below a certain level. DMacks (talk) 23:00, 3 January 2011 (UTC)

(ec) No. Massive objects can not reach light speed, because as they accelerate arbitrarily close to light speed, it takes an increasingly larger amount of energy for each incremental unit of acceleration. This means that it would require an infinite amount of input energy to reach a finite velocity. It has nothing to do with "subtracting time", although the mathematical formulation of the Lorentz transform can be used to model the effect known as time dilation. Nimur (talk) 23:01, 3 January 2011 (UTC)

Note: I believe that when Nimur wrote "massive objects", he meant "objects with mass" and not "really large objects, like Jupiter". Comet Tuttle (talk) 23:05, 3 January 2011 (UTC)

Correct. I meant "objects with non-zero rest mass." That is, pretty much everything except photons. Nimur (talk) 00:10, 4 January 2011 (UTC)

Yeah you're talking about time dilation, and I'm not a physicist but I think this is one way you can look at it. Another factor to consider is Length contraction. I remember reading some mind bending stuff about how the universe is actually stationary in time from the reference of a photon, or any photon. So from a photon's perspective it's actually everywhere at once, or it's actually only one photon everywhere at once, or something like that, don't quote me I've probably got it wrong, but it was pretty far out. Vespine (talk) 23:34, 3 January 2011 (UTC)

Time dilation at light speed is infinite, which basically means time doesn't make sense for a photon. You could say that, from a photon's point of view, a photon is a line through spacetime rather than a point. If exists simultaneously at every point along its worldline, since without a concept of time everything is simultaneous. Mathematically, though, we just say the proper time for a photon is undefined and leave it at that. --Tango (talk) 00:10, 4 January 2011 (UTC)

Actually, what physicists say is that photon's do not have a point of view; that it is literally impossible to consider light itself as a reference frame, and thus it is nonsensical to even consider what the posibilities are. You generate far to many real paradoxes when you try to do so, it becomes kinda impossible to even think about it in those terms. --Jayron32 03:49, 4 January 2011 (UTC)

January 4

Lines when you squint at a bright light

When I squint at a bright light, I see long lines the same colour as the light eminating in many directions from the light. Why is this?--92.251.255.15 (talk) 00:56, 4 January 2011 (UTC)

It's diffraction from your eyelashes. Ariel. (talk) 01:47, 4 January 2011 (UTC)

I do not believe that is correct.--Gr8xoz (talk) 10:42, 4 January 2011 (UTC)

Nevertheless, it is correct, or at least by far the most likely explanation, though I might add eyelids.--Shantavira|^{feed me} 11:24, 4 January 2011 (UTC)

Relatively invariant.

I'm reading the appendix, entitles Physics and Perception, of David Bohm's "The Special Theory of Relativity". Bohm uses the term relatively invariant a lot, but I'm not sure what he means by it. I'll give you an excerpt of the opening paragraph: "Throughout this book we have seen that in Einstein's theory of relativity, the notions of space, time, mass, etc., are no longer regarded as representing absolutes, existing in themselves as permanent substances or entities. Rather, the whole of physics is conceived as dealing with the discovery of what is relatively invariant in the ever-changing movements that are to be observed in the world, as well as in the changes of points of view, frames of reference, perspectives, etc. that can be adopted in such observations. [...] [Einstein] was led to make the revolutionary step [...] of ceasing to regard the properties of space, time, mass, etc., as absolutes, instead treating these as invariant features of the relationships of observed sets of objects and events to frames of reference. In different frames of reference the space coordinates, time, mass, energy, etc. to be associated to specified objects and events will be different. Yet there are various sets of transformations (e.g., rotations, space displacements, Lorentz transformations) relating the many aspects of the world, as observed in any one frame to those as observed in another. And in these transformations, certain functions (such as the interval [does he mean space-time interval?] and the rest mass) represent invariant properties, the same for all frames of reference, within the set in question."

Can anyone shed some light as to what he means by relatively invariant? I can quote more of the book if needed. 65.92.7.244 (talk) 01:03, 4 January 2011 (UTC)

Invariant literally means not changing. Most measurements in relativity are relative i.e. they change depending on how you look at them, but the invariant ones don't change no matter how you look at them. Ariel. (talk) 01:46, 4 January 2011 (UTC)

What Bohm is talking about is the revolution in physics which changed what "invariant" properties were. There was a time when concepts like "distance" and "time" and "mass" were considered invariant, while concepts like "speed" and "density" were considered infinitely variable. Einstein flips everything on its head, showing us that distance and time are relative; but even in Einstein's physics, there are certain things, like "rest mass" and "speed of light" are invariant. Bohm's point is that there are still invariants in physics, its just that what we consider "invarieant" has changed as a result of special relativity and general relativity. --Jayron32 03:47, 4 January 2011 (UTC)

He's talking about Lorentz covariance. In particular, scalars are Lorentz invariant, and Lorentz covariant equations are also sometimes called "invariant". Red Act (talk) 04:18, 4 January 2011 (UTC)

How will Black & Decker get a Hydrator to work in just 4 years?

See http://backtothefuture.wikia.com/wiki/Hydrator

You see, on Back to the Future II, a 4-inch dehydrated pizza takes a few seconds to grow to 15 inches, ready to consume.

Allegedly, this Hydrator is supposed to be found in a typical kitchen in just 4 years.

What would it take to invent a real-working hydrator, and what are the prospects of making it happen by 2015? --65.64.191.135 (talk) 03:17, 4 January 2011 (UTC)

There's lots of food which is dehydrated and then able to rehydrated later. It normally doesn't take anything more than water to do so. The idea that you could dehydrate and the rehydrate a food as complex as a pizza, and get the results obtained in the movie, is pretty much as realistic as the Replicator in Star Trek. That is, it is complete bullshit invented for the movie. Actual food dehydration and rehydration is covered in the overview article Drying (food) and links that follow from there. --Jayron32 03:43, 4 January 2011 (UTC)

The reason is that there are one-way chemical processes which happen during dehydration, and they can't be reversed later on. A raisin soaked in water does not become a grape, for example. Depending on the food, the rehydrated version may be recognizable, perhaps even edible, but rarely is it exactly the same as the original. StuRat (talk) 04:45, 4 January 2011 (UTC)

I wouldn't worry too much about Black & Decker getting it right in time. If they don't, you can always hop on your hoverboard and pick up a fresh pizza yourself. HiLo48 (talk) 07:42, 4 January 2011 (UTC)

Uncited nutritionists wearing white coats and horn rimmed spectacles have perfected a recipe for the super thin pizza of the future that can be delivered by Fax. Cuddlyable3 (talk) 21:31, 4 January 2011 (UTC)

I heard it is extremely high in fiber. Googlemeister (talk) 21:42, 4 January 2011 (UTC)

Phosphenes!!!

I have always enjoyed watching phosphenes. Except my eyes have never been able to focus on them properly. Why?

Also how can I induce them? One time I was lying down to enjoy some mondo-radical phosphene bodaciousness, dude and I was getting some pretty chill phosphenity going on and then SOMEONE decided to turn on the lights and then I turned them off and I couldn't see crap in the sea of eigengrau. What gives, bro?

ZigSaw 03:49, 4 January 2011 (UTC)

You can't focus on them because they aren't actually objects. They are basically stimulations of your retina due to pressure fluctuations in the Vitreous humour of the eye. It happens behind the lens of your eye; the lens is the thing which does the focusing, so you're never going to be able to focus on it. The article you link gives some causes of them. --Jayron32 03:55, 4 January 2011 (UTC)

Well, Wilhelm Reich suggested an apparatus...... :) Wnt (talk) 06:43, 4 January 2011 (UTC)

Active Stealth

Other than plasma stealth are there any other technologies that can actively stealth an aircraft? ScienceApe (talk) 04:12, 4 January 2011 (UTC)

There is white wave technology, which is possibly used on the B-2. It sends out an exactly opposite wave to the radar hitting it, cancelling it out. I'm not sure if we have an article one it. --T H F S W (T · C · E) 05:47, 4 January 2011 (UTC)

See electronic countermeasures. Nimur (talk) 15:14, 4 January 2011 (UTC)

Number of cell in a human body -- a contradiction?

Human flora#Bacterial flora currently states: "Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 10¹⁴ versus 10¹³)" (the reference, Microbial Ecology of the Gastrointestinal Tract, gives those numbers), but Gut flora states: "The human body, consisting of about 100 trillion cells, carries about ten times as many microorganisms in the intestines" (references not publicly & freely viewable), and Cell (biology) states: "Humans have about 100 trillion or 10¹⁴ cells" (unreferenced). Approximately how many eucaryotic animal cells comprise the average human body? -- 119.31.121.89 (talk) 05:41, 4 January 2011 (UTC)

Wolfram alpha gives 1e14, [5]. It gives no references so I do not know how mush it should be trusted. Other sources gives figures between 1e13 and 1e14, [6], [7], [8] non seem to be really reliable. --Gr8xoz (talk) 10:34, 4 January 2011 (UTC)

This is obviously a pretty difficult question to answer, but considering that the 10¹³ claim is referenced to a review that is more than 30 years old, I'd be inclined to say that that article is wrong. The question has been asked here before e.g. here and here and the consensus both times was that it was somewhere between 10¹³ versus 10¹⁴ This press release by the Nobel Prize Committee (I hope they know what they're talking about) says that there are approximately 10⁹ cells per gram of tissue, so for someone skinny like me, that would work out as ~7x10¹³ which is nicely in the range (fat cells are really large and you supposedly don't grow new ones as you get fatter, so this rule won't hold if you are overweight). This based on a project at MIT says there are ~6x10¹³ Looking at other less reliable websites from a google of "number of cells in a human body" it looks as if the general consensus is that 10¹³ is definitely too low, and the lower limit is 5x10¹³. SmartSE (talk) 10:20, 4 January 2011 (UTC)

Our article on red corpuscles says that the average adult human body contains 2–3 × 10¹³ of them, and these should be about the easiest cells to count, so it seems likely that 10¹³ is too low. (The article also says that red corpuscles make up about a quarter of the cells in the body. All in all it seems likely that 10¹⁴ is in the right neighborhood. Looie496 (talk) 19:17, 5 January 2011 (UTC)

Hammer and feather

The article Newton's law of universal gravitation states:

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is directly proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses.

So, why do we say that without an atmosphere, all objects would fall at exactly the same speed towards the Earth regardless of their weight? (i.e., why do we only take into account the "Earth mass" and not "the two masses"?). Newton's law seems to imply that a hammer, being more massive than a feather, will increase ever so slightly the "product of the two masses" and so fall a tiny bit faster.

Is my reasoning wrong? Leptictidium (mt) 07:17, 4 January 2011 (UTC)

The force of attraction on the hammer is proportional to the mass of the hammer, but the acceleration of the hammer when allowed to fall in a vacuum is inversely proportional to its mass (Newton's 2nd Law) so the mass of the hammer cancels and the result is that a hammer, and a feather, and anything else in a vacuum at the Earth's surface, will accelerate at the same rate, namely about 9.8 m.s^-2. If the hammer is not falling in a vacuum there will be resistance caused by movement relative to the air and this resistance will slow the rate of acceleration. However, the air resistance will be a much smaller proportion of the weight of the hammer than the air resistance on a feather so the hammer will accelerate in air more rapidly than the feather. Dolphin (t) 07:28, 4 January 2011 (UTC)

You are not wrong, basically while the earth moves the hammer toward it, the hammer causes the earth to move toward the hammer. But the difference is so small, i.e. the earth moves so little, it's unmeasurable, so it's ignored. Also if you do actually drop a feather and a hammer at the same time, they will both cause the earth to move, so they will both hit at the same time. What I mean is that the hammer does not fall faster because it's heavier, rather the hammer causes the earth to move, which makes the distance slightly shorter. Ariel. (talk) 07:29, 4 January 2011 (UTC)

You are wrong in using the phrase "ever so slightly". We do take into account the two masses. The force of gravity on the hammer is thousands of times the force of gravity on the feather, but then, so is its mass (in the same proportion), so the acceleration is the same. (as explained by Dolphin. I'm still thinking about Ariel's moving earth - what happens if the "earth" is just twice the mass of the "hammer"? Dbfirs 08:28, 4 January 2011 (UTC)

Db, when you say that "ever so slightly" is wrong, you are missing Ariel's point.

Sorry, yes, I was replying to Leptictidium about the forces and the incorrect reasoning, and didn't have time to think through Ariel's reply. Perhaps Leptictidium was implicitly considering the movement of the earth in the question, but I didn't read it that way. Dbfirs 21:55, 4 January 2011 (UTC)

Let's do this algebraically. Say the earth has mass M, the hammer mass H, and the feather mass F. Then the hammer feels a force GMH/r², and by Newton's Second Law it accelerates at (GMH/r²)/H, which is GM/r². Similarly the feather accelerates at (GMF/r²)/F, which is again GM/r². They both accelerate at the same rate (if there is no air friction).

But the Earth also feels a force of GMH/r² for the hammer and GMF/r² for the feather. Therefore it will accelerate toward the hammer at (GMH/r²)/M, which is GH/r², and toward the feather at (GMF/r²)/M, which is GF/r². Since M is hugely greater than H or F, these numbers are ever so tiny in comparison with the hammer or the feather's acceleration of GM/r². But they are not quite zero. As Ariel says, the hammer (dropped on its own) will hit the Earth ever so slightly sooner than the feather (dropped on its own), because the Earth will come up to meet it ever so slightly faster. For all practical purposes this can be ignored, so we usually do ignore it. By the way, r is also changing ever so slightly while the object is falling; this too can be ignored for practical purposes, and it doesn't affect the conclusion in any case. --Anonymous, 11:12 UTC, January 4, 2010.

Oh, good. I was worried there for a moment that all objects everywhere might be attracted together at the rate of a falling hammer, which would have got uncomfortable quickly. 81.131.22.240 (talk) 11:20, 4 January 2011 (UTC)

So, even if there is a tiny, insignificant difference, there is some difference? Leptictidium (mt) 13:56, 4 January 2011 (UTC)

Yes, there is a tiny, almost insignificant difference. Not because the hammer accelerates faster (it doesn't), but because the Earth accelerates faster. — Sam 63.138.152.135 (talk) 14:34, 4 January 2011 (UTC)

The Earth falls as quickly toward a pound of hammer as a pound of feathers. And vice versa. A pound of feathers is bigger, and could experience more tidal force in free fall, but overall a spherical object of any size, whether made up of hammer or feathers, acts like all its mass is concentrated in its center in a uniform gravitational field. Now of course the Earth's gravitational field is not uniform, and I think this leads to a slight difference on this basis. For example, a pound of feathers of the spotted astrasphinx consumes a volume a light year in diameter; when such a ball just grazes the Earth's upper atmosphere, a small region of it undergoes a noticeable gravitational attraction - I think this will contribute more force than is experienced by a pound of hammer half a light year from the Earth, though I'm not sure. Wnt (talk) 14:41, 4 January 2011 (UTC)

Fearsome though the astrasphinx is, the OP isn't asking about a pound of feathers, but about two objects of different mass ("a hammer, being more massive than a feather...") 213.122.31.229 (talk) 16:07, 4 January 2011 (UTC)

Aha! but if you used a pound of gold against a pound of hammers, the earth would accelerate more from the hammers then the gold. Googlemeister (talk) 17:02, 4 January 2011 (UTC)

The usual conditions for the thought experiment on this are to have the hammer and feather dropped simultaneously side by side in vacuum. Under those circumstances both hammer and feather will hit at the same time, even after taking account of the immeasurably small movement of the earth due to the combined mass of hammer and feather. SpinningSpark 14:55, 4 January 2011 (UTC)

The thought experiment implicitly takes place in the reference frame that keeps Earth stationary. In any other non-privileged (equally valid) reference frame, Earth and the hammer accelerate towards each other at 9.8... m/s². But for the purposes of practicality, we consider that specially constructed reference frame that is centered at Earth. In this frame, all objects accelerate toward Earth; and because dependence of the gravitational force on the other object's mass cancels out the "F = ma" in the object's acceleration, (in other words, the gravitational mass and the inertial mass of the test-particle (hammer or feather) are always exactly identical). Acceleration is equal to F/m, which is proportional to m_{gravitational}/m_inertial, which is exactly one; therefore gravitational acceleration is a constant for all test particles (hammers, feathers, the Sun, and so on), when viewed from the stationary, inertial reference frame of Earth. This exact equality between inertial mass and gravitational mass is one of the interesting observations that led to Einstein's understanding of gravitation in nonprivileged reference frames. Nimur (talk) 15:08, 4 January 2011 (UTC)

Nimur, what you wrote isn't accurate (assuming you are still comparing a heavy hammer and light feathers). The earth and the objects do not accelerate toward each other at the same rate - the hammer accelerates faster, and it doesn't matter which reference frame you use. If you use one centered on the earth, then the motion of the earth toward the hammer is not felt by you, but it makes it appear that the hammer is accelerating faster toward you. If you use one external to both, then you see the earth accelerating toward the hammer, and it does that faster than toward light feathers. So the net acceleration between them is higher. Ariel. (talk) 21:11, 4 January 2011 (UTC)

I don't agree. The gravity constant g, as observed near Earth, is the same for all objects, irrespective of their mass. This is a basic tenet of gravitation. In other words, the hammer and the feather both accelerate toward Earth at the same rate. The weight force depends on the mass of the test-particle; and the acceleration of the test-particle is inversely proportional to the same mass, so the acceleration is a constant for all objects. Nimur (talk) 22:05, 4 January 2011 (UTC)

You are ignoring the fact that the earth is simultaneously accelerating and moving toward the hammer. So if you measure acceleration by simply checking the distance between the object the acceleration is higher for heavier objects. Ariel. (talk) 22:12, 4 January 2011 (UTC)

So the correct answer to the question is that the apparent acceleration of gravity, in the obvious reference frame of the ground under your feet, is not constant, but varies "ever so slightly" with mass, not because of the "product of masses", but because it depends on the sum of masses: g = G(M+m)/R² Dbfirs 22:42, 4 January 2011 (UTC)

Let me re-read reduced mass, mess with some equations on paper, and get back. You may be correct. In any case, we all agree that the practical difference in accelerations between hammer and feather is minuscule, if not identically zero. Nimur (talk) 22:57, 4 January 2011 (UTC)

Ok, my maths is pretty weak but I'll give it a crack. The force of gravity acting on a 1kg hammer is about 10 newtons, acting on a 1g feather is 0.01 newtons. The earth rounded up is 6 x 10^24 kg. Since F=MA ;the earth will accelerate A = 10/10^24 = 1x10^-23 meters per second towards the hammer and 1x10^-26 towards the feather. Rounding to orders of magnitude, the diameter of an atom is in the order of 1x10^-10, an electron is about 1x10^-15, so it's much less then that, but a Planck length is 1x10^-35 so the earth would definitely move a non zero amount. I have possibly made a fundamental error in working this out. Vespine (talk) 00:03, 5 January 2011 (UTC)

The most relevant response of the Earth is not via the center of mass motion of the whole Earth. The Earth, obviously, won't react as a rigid body when the masses are released. If you imagine standing on the Earth inside a vacuum chamber and holding a mass, then your feet are depressing the surface a bit. If the mass is released, there is a sudden rebound of the surface. This generates a shock wave that travels through the Earth. The moment the object hits the surface, another shockwave is generated. The surface waves of that first shockwave will cause the mass to hit the ground later or sooner than computed without taking the response of the Earth into account. This effect is many orders of magnitude larger than the center of mass motion of the Earth. Count Iblis (talk) 01:33, 5 January 2011 (UTC)

lol, of course, unless you've only done high school physics and everything is still perfectly smooth, rigid and frictionless. *facepalm.. ;) Vespine (talk) 05:38, 5 January 2011 (UTC)

Ok, hang on! I've just had another thought, perhaps to redeem myself: If that hammer originally came from the ground, and was lifted up to whatever height and then dropped, wouldn't the sum of all the vectors just cancel out to zero anyway? No net effect? Vespine (talk) 05:46, 5 January 2011 (UTC)

• Look, you guys have completely obfuscated the real answer here for the OP. The reason that the hammer and the feather fall at the same rate (at least, within the range of human perception) is because the earth is SO FREAKING HUGE compared to the difference in mass between the hammer and the feather that we cannot detect the difference between the rate that they fall. It's a problem of significant figures more than anything else; there is a real calculatable difference, it is just insignificant on any standard measuring device, so we ignore it. If you take the other extreme, and look at two hammers in space and two feathers in space, and look at the acceleration at which the two hammers will be pulled together, it will be much greater than the two feathers. But you only notice that difference because of the similarity in mass between the objects. Once you start working on differences of 10²⁴ in mass, it becomes silly. Does anyone here have a stopwatch accurate to 24 digits? I thought not... --Jayron32 05:49, 5 January 2011 (UTC)
  • Don't forget to account for the mass both objects lose in potential energy at E=mc² on their way down! --Sean 16:15, 5 January 2011 (UTC)

Spring

can spring be considered as a link.what kind of link . rigid,etc? —Preceding unsigned comment added by 59.93.130.219 (talk) 07:32, 4 January 2011 (UTC)

A carabiner with a spring gate is sometimes called a spring link. SpinningSpark 12:15, 4 January 2011 (UTC)

The question isn't about chain-type links, it's about links in a linkage. So far as I know, springs are modeled as forces rather than links. In any case, they wouldn't be a ridid link, as that's sort of the opposite of a spring. Andrew Jameson (talk) 16:57, 4 January 2011 (UTC)

there are three kinds of links ..rigid.fluid and flexible link(belt,rope).it seems springs can also transfer motion in one direction only.. can it be a flexible link —Preceding unsigned comment added by 59.93.130.68 (talk) 17:27, 4 January 2011 (UTC)

Not necessarily - a compression spring can transfer in all directions. An expansion spring is flexible in one direction, but rigid in the other. Ariel. (talk) 21:28, 4 January 2011 (UTC)

The Importance of Science

What is the importance of science??--Marcella Shine Michael (talk) 13:10, 4 January 2011 (UTC)♥

I gave your question a heading (hope I did it right). 213.122.31.229 (talk) 14:29, 4 January 2011 (UTC)

(ec) Science is important because it provides us with a way of understanding how things work. Matt Deres (talk) 14:31, 4 January 2011 (UTC)

Science is the antithesis of ignorance. -- œ^™ 15:04, 4 January 2011 (UTC)

It's something to do with "the grain in the stone" and "the hidden structure", according to The Ascent of Man. 213.122.31.229 (talk) 15:29, 4 January 2011 (UTC)

If you lean toward Primitivism and yearn for the Golden Age, then science does not have much value. If you use a computer and think it valuable for finding answers to questions, thank science. SemanticMantis (talk) 15:38, 4 January 2011 (UTC)

Science provides us with continually improving explanations of how stuff works. It allows the human race to better adapt to its environment, which is one of humanity's strongest traits. HiLo48 (talk) 17:43, 4 January 2011 (UTC)

Agreed. It prevents us from moving backwards, into believing incorrect things, as happened when much of the science of the Greeks and Romans was lost in the Middle Ages, due to rise of organized religion and suppression of science. StuRat (talk) 18:20, 4 January 2011 (UTC)

Breathing underwater

Why can't our lungs extract oxygen from water like gills can? If the lungs were filled with water, naturally the body would die from lack of oxygen, but would they be able to extract any oxygen into the blood at all? How close are the structures to something that could function as gills -- given several million years in a water-filled Earth, could we evolve the ability to breathe underwater with just a few dozen mutations? — Sam 67.186.134.236 (talk) 13:13, 4 January 2011 (UTC)

I looked at Artificial_gills_(human), which links to this: Why don't people have gills?. The mutation to breathing water would require us to either develop very large gills, or else to need less oxygen somehow. This doesn't really answer the main thrust of your question, the matter of whether lungs would function as gills if we had the lower oxygen requirements of a fish. 213.122.31.229 (talk) 13:51, 4 January 2011 (UTC)

Lungs encounter some problems with trying to breathe liquids, even ones that are highly oxygenated. See liquid breathing. Googlemeister (talk) 14:14, 4 January 2011 (UTC)

Bit more information at Drowning, where it says that fresh water in the lungs is absorbed into the blood by osmosis and leads to bursting of the red blood cells. So if we're going to become fish, looks like the best option is to be salt water fish. 213.122.31.229 (talk) 14:21, 4 January 2011 (UTC)

What about Amniotic fluid? I've always wondered how it is that a fully-formed fetus can 'breathe' liquid one minute, be born, then breathe air as an infant the very next minute. -- œ^™ 16:01, 4 January 2011 (UTC)

The fetus does not oxygenate blood via amniotic fluid. Oxygen is transferred from the mother's blood to the fetus via the placenta. One thing that makes this possible is that fetal hemoglobin holds on to oxygen more strongly than adult hemoglobin and can therefore extract the oxygen that diffuses into the mother's bloodstream. The rather instantaneous change from being dependent on the maternal circulation to requiring lungs for oxygenation is indeed spectacular, and it involves closure of the ductus arteriosus shortly after birth. During fetal development, breathing of amniotic fluid plays an important role in lung maturation; see pulmonary hypoplasia for a discussion of how lack of amniotic fluid can cause problems during development. The infant rapidly inflates the lungs with the first breath, and the remaining amniotic fluid is either reabsorbed or coughed out. --- Medical geneticist (talk) 17:16, 4 January 2011 (UTC)

Some concepts:

1) There's more oxygen in air than in water. Thus, lungs can be less efficient than gills at extracting oxygen.

2) One difference is that gills often have a continuous flow direction, while we reverse the flow direction of air as we breathe in and out. This leads to mixing of good air and bad, and thus reduces efficiency. StuRat (talk) 18:17, 4 January 2011 (UTC)

The fact that gills are a countercurrent exchange but our lungs are not is also relevant, as the diagram in that article shows, we can only ever absorb 50% of the available oxygen in the air, whereas fish can extract close to 100% of it. SmartSE (talk) 23:41, 4 January 2011 (UTC)

Well, even if we could extract the oxygen from the water, our lungs would still be crushed from the amount of water breathed in Crimsonraptor | (Contact me) Dumpster dive if you must 20:58, 4 January 2011 (UTC)

And not only do we need to get O2 in, we need to get CO2 out. Googlemeister (talk) 17:26, 5 January 2011 (UTC)

Yes, but that's a lot easier, as nothing needs to be in the air or water for you to extract. StuRat (talk) 19:49, 5 January 2011 (UTC)

I tried to figure out what problems Googlemeister was alluding to with the link to Liquid breathing, and it seems the viscosity of PFC (and water, it is implied) makes it hard to dissolve CO2 into it (something about the pressure of CO2 in the blood being too low) meaning that you'd have to breath unfeasibly hard. I was going to mention this, but got confused by the image of the mouse breathing PFC while floating in it (a ubiquitous pop science image, as hard to escape as that picture of the frog levitating in a big magnet). If the mouse doesn't need mechanical assistance to get its CO2 out of its lungs, why would a human? Maybe the task scales badly. 81.131.14.88 (talk) 15:04, 6 January 2011 (UTC)

Humans may be able to breathe liquids (though not water). I read it in New Scientist awhile ago, (found online link here but you can't read most of it without a subscription) and apparently if the liquid has a large amount of oxygen in it (more than normal water) it is physically possible to breathe it. Application is available to divers (as per article!) as having liquid breathing means problems such as the bends can be avoided. Rumours are the US military has tried it, although they faced problems, due to the fact that humans really aren't used to breathing anything but air! Chipmunkdavis (talk) 05:42, 7 January 2011 (UTC)

I believe another possible application is for a patient with a collapsed lung. StuRat (talk) 05:52, 7 January 2011 (UTC)

mesons

How do mesons containing up anti-up or down anti-down quarks exist.i mean shouldn't they annihilate each other — Preceding unsigned comment added by Raky rough (talk • contribs) 15:15, 4 January 2011 (UTC)

You are right. They do not exist for long! [[9]]Zzubnik (talk) 15:41, 4 January 2011 (UTC)

See meson. The longest lifespan of a meson is about 10^-8 seconds. Mesons themselves are basically gluon transporters; they basically are little taxicabs that carry gluons between different nucleons in the nucleus, providing the nuclear force. Another way to think of mesons is as the particle form of the energy needed to shuttle gluons around the very short distances between nucleons. Given their job, its not much of a surprise they exist for a very short time indeed. --Jayron32 21:14, 4 January 2011 (UTC)

Blackbirds falling from the sky

There have been reports of thousands of birds falling dead from the sky simultaneous with thousands of fish dying in Arkansas. The state wildlife commission has given glib and unconvincing explanations such as "some disease killed the fish" and "the birds were scared to death by fireworks" while some necropsies find "massive physical trauma" in the birds. When people have attempted to kill or drive away nuisance collections of birds by shotgun blasts or noise from loudspeakers, the birds just shrug it off. Other explanations are the thousands of birds "were killed by hailstones" (which somehow did not pile up on the ground as did the dead birds) or "they were struck by lightning" (which somehow simultaneously covered a 1 mile diameter). Mightn't it justify its own article, beside the brief mention in the article for the Red-winged Blackbird and for Beebe, Arkansas, since other species also died, and a similar dieoff occurred shortly afterward 300 miles away in Louisiana? From 1968 to 1975 the Smithsonian hosted the Center for Short-Lived Phenomena. Did their records include similar mass trauma killing of thousands of birds over a 1 mile area? Is there a listing of historic mass bird dieoffs? I expect domestic turkeys to run around in a panic and die when there is a disturbance, since they are not bred to have any common sense, but wild birds generally have not seemed so prone to fly around in a panic and die when there is noise, by crashing into each other, trees, houses, or the ground as some have suggested.. They have had millions of years of natural selection operating in a world where there is lightning. Edison (talk) 17:30, 4 January 2011 (UTC)

You seem to have citations from a couple of independent sources. A new article would seem valid, but do steer away from conspiracy theories. New Year celebrations and holidays can delay good responses from authorities. Just present what those media reports have told us actually happened. And be prepared to update it as further news comes to hand. HiLo48 (talk) 17:41, 4 January 2011 (UTC)

I could not gain any insights from that website, but if there were an official coverup claiming updrafts or hail, perhaps someone would be savvy enough to make sense of the data there. The rising barometer would be generally disproof of extreme weather events in the place at the time of the thousands of bird deaths. Edison (talk) 01:29, 5 January 2011 (UTC)

The mass dieoff in Arkansas may have motivated the media to publicize a later smaller dieoff in Louisiana. The species included other than redwing blackbirds, although they seem to be most numerous in the two cases this month. An article collecting unrelated dieoffs might be WP:SYNTHESIS or WP:ORIGINALRESEARCH, but not if CNN and other news media link the incidents in one article. Conspiracy theories? Christian Science Monitor specifically discussed these dieoffs in relation to such theories on January 3. Edison (talk) 18:01, 4 January 2011 (UTC)

The hailstone theory sounds reasonable, and the stones would then melt in short order, if temperatures were high enough. If this was in an isolated area, then people would likely discover the birds only after the stones were gone, especially if it happened when everyone was asleep. Volcanic gases could also kill off a flock of birds, but this would be obvious. As for fish, in addition to disease, there can be water quality problems, such as incorrect pH or a lack of oxygen, which can cause massive fish kills. StuRat (talk) 18:07, 4 January 2011 (UTC)

FWIW, there was a news report on this on the UK's BBC Radio 4 within the last 90 minutes - I think on the 17:30-18:00 PM programme - in which the senior veterinary official for Arkansas (can't remember his exact title) was interviewed. His general thesis was that fireworks had startled the roosting redwing blackbirds, which being unable to see at night then blundered into buildings and structures, injuring themselves. Other witnesses reported hearing loud bangs "like cannon fire" after dark and then seeing the birds flying into obstructions. 87.81.230.195 (talk) 18:59, 4 January 2011 (UTC)

There is a BBC report here. Ghmyrtle (talk) 19:09, 4 January 2011 (UTC)

Fireworks is rather unconvincing since the tens of thousands of other fireworks that are shot off each January 1 and July 4 don't kill thousands of birds. Googlemeister (talk) 19:34, 4 January 2011 (UTC)

Check out raining animals; this week's birds and fish might merit a mention there (but a special article sounds like a good idea to me). Robinh (talk) 19:50, 4 January 2011 (UTC)

Wouldn't WP:NOTNEWS apply? Googlemeister (talk) 20:16, 4 January 2011 (UTC)

OR, but it's worth noting that at this season of the year, red-winged blackbirds tend to flock in huge numbers. My guess is that a flock of them got caught in a strong updraft inside a thunderstorm, which could easily have carried them to an altitude of 20,000 feet or higher, where they would have died of suffocation and cold, and the bodies would have been scattered over a pretty broad area. If this is what happened, then I think there should be signs of it that are visible at autopsy. Looie496 (talk) 20:31, 4 January 2011 (UTC)

This isn't the first news item I've seen about a flock of birds falling down dead - here's one about 76 dead starlings in Somerset: [10]. Here's one about several hundred mysteriously inebriated parrots: [11]. It's all very Fortean. This one [12] is about 200 dead seagulls in Perth, and mentions a previous incident of 5000 dead birds which was established to be lead poisoning. This story in Pravda [13] from four years ago says that "Doctor Scientist Oleg Kiselyov" (presumably not this Oleg Kiselyov) estimates 2 million birds fall dead from the sky every month, and for some reason he blames them all on bird flu. 213.122.29.106 (talk) 20:38, 4 January 2011 (UTC)

The problem is, multiple bird species were affected. There's the red-winged blackbirds, but also starlings and grackles. I agree with the IP above me that this seems very Fortean indeed, but I would see what the autopsies say to get a clue on what on earth happened. Crimsonraptor | (Contact me) Dumpster dive if you must 20:53, 4 January 2011 (UTC)

Sounds like a job for Centre for Fortean Zoology if the Arkansas wildlife officials are not forthcoming. A weather updraft which carried thousands of birds to 20,000 feet, or which dropped so much hail that it killed the birds (but did not strike cars and things on the ground) should have left weather radar evidence. I am reading that a) the birds flew into trees and houses and died, and b) they were taken up in a windcurrent to 20,000 feet. It seems unlikely that both happened. Also they fell in a 1 mile square area or larger, rather a large distribution for the inhabitants of one or a few trees startled by a nearby noise. How many skyrockets and explosives would a town of 4,930 fire off on New Year's Eve, especially if there was some massive lightning storm and hailstorm? I didn't hear but a few firecrackers in my own larger city. It is easy to find present weather radar for any locality, such as Beebe, Arkansas, but I cannot find a way to scroll back and see the weather radar for that location on December 31. Anyone know how to access such historical information? One site shows nothing unusual there (in nearby Searcy, 16 miles away) on New Year's Eve, just scattered clouds, 52 degrees Fahrenheit. Precipitation for the day was 0.01 inches, none after 9 AM. Notably, the barometric pressure was rising all afternoon and evening, atypical for turbulent weather moving through. Edison (talk) 21:23, 4 January 2011 (UTC)

Edison, you might start looking at NOAA's NEXRAD RADAR Mosaic archive. It's sort of "low resolution" for your needs, and I seem to recall much higher-resolution NEXRAD data archive somewhere on the NOAA website; (maybe the RADAR Resources / Free Data Products page); so try clicking around on that page and/or web-searching the NOAA site. (I'll take a look later as well). Worst-case, you can email a NOAA scientist at the National Climatic Data Center contacts page... Nimur (talk) 00:28, 5 January 2011 (UTC)

Aha, here. NEXRAD Data Inventory. Though, you may need to be a bit of a WSR-88 enthusiast to interpret this stuff, (even the "Level III data products" are still very technical compared to ordinary weather maps you see on TV). But NOAA does make a lot of very useful software and source-code available, here's their data access tools page. You're pretty tech-savvy, but lemme know if you need assistance. Nimur (talk) 00:35, 5 January 2011 (UTC)

I could not gain any insights from that website, but if the "official explanation" is "Amazing Upcurrents" or "Rain of Hail" or "Lightning Blasts," perhaps that data can disprove it (unless it gets "tweaked") . Edison (talk) 02:02, 5 January 2011 (UTC)

In case anyone has any concerns about notability, this news has now reached The Age in Melbourne, Australia, which, as was said far too many time when Oprah was here last month, is a very long way away. HiLo48 (talk) 06:55, 5 January 2011 (UTC)

Interestingly, a very similar event has also happened recently in Sweden - here. Ghmyrtle (talk) 10:45, 6 January 2011 (UTC)

Interesting because the question is: is this actually a thing, or just an artifact of media interest in stories about dying birds? 213.122.26.117 (talk) 14:08, 6 January 2011 (UTC)

I've seen stories like this before, and the answer is usually (if not always) Starlicide. Wnt (talk) 17:09, 8 January 2011 (UTC)

LHC

why is it required that collisions in LHC take place at 99.999% speed of light Raky rough (talk) 18:47, 4 January 2011 (UTC)

Because it takes a lot of energy to accelerate the incoming particles to that speed. When they collide, all of that energy is released and becomes various other stuff, and the scientific point of the LHC is to study what the "various other stuff" is. Somewhat simplified, the point is not just to "smash things together", but to concentrate a lot of energy in a small space and see what it does. That's where speed / kinetic energy comes in -- small particles at high speed is the only practical way to deliver a lot of energy to a sufficiently small volume in a somewhat controlled way. –Henning Makholm (talk) 19:30, 4 January 2011 (UTC)

It certainly is all a matter of energy. If the OP is wondering about the apparent diminishing returns, then consider that a particle traveling at .99999 m/s has only 0.018% more kinetic energy than when traveling .9999 m/s, but, due to special relativity, a particle traveling at .99999 c (99.999% the speed of light) has more than 3.19 times the kinetic energy (219% more KE) than when traveling .9999 c. That close to the speed of light, the kinetic energy of a particle will increase by just over a factor of √10 ≃ 3.16 each time you add another "9" to the string of 99.999999...%. -- 119.31.121.88 (talk) 01:06, 5 January 2011 (UTC)

Actually, it's 99.999999% c; the energy is 7 GeV and the relativistic formula for the velocity is ${\frac {v}{c}}={\sqrt {1-{\frac {1}{({\frac {energy}{mc^{2}}}+1)^{2}}}}}$, and you can look up c and the proton mass. 99.999% c has been achieved a long time ago. Icek (talk) 01:28, 5 January 2011 (UTC)

I think you mean 7 TeV... Nimur (talk) 01:43, 5 January 2011 (UTC)

So one second to the accelerated particle would seem like 7071 seconds to the operator of the LHC? See [14]. Edison (talk) 02:00, 5 January 2011 (UTC)

Sounds about right, since the proton (rest) mass is slightly less than 1 GeV/c² and the accelerator pumps each proton up to about 7,000 GeV. –Henning Makholm (talk) 03:29, 5 January 2011 (UTC)

benzene

why does benzene cause cancer but xylene dosent after all it dimethylbenzene — Preceding unsigned comment added by Tommy35750 (talk • contribs) 20:55, 4 January 2011 (UTC)

All aromatic compounds are somewhat carcinogenic, even xylenes. See This paper from 1988 which indicates that Toluene (monomethylated benzene) and xylenes (dimethylated benzenes) are carcinogenic in animal studies, though only at a higher concentration than benzene. It should be noted that methyl groups are not inert, they have a weak electron donating effect and are mildly activating on the aromatic system; I have no idea how this may work mechanisticly in causing cancer, but apparently it decreases (but does not eliminate) carcinogenic effects; perhaps (a bit of a WAG) by making the aromatic ring more susceptible to attack by substances which may eliminate it from the body before it can do harm; benzene, being more inert than the others, may stick around so much longer in the body. --Jayron32 21:02, 4 January 2011 (UTC)

The claim that "all aromatic compounds are somewhat carcinogenic" seems to refer either to a very broad sense of "carcinogenic" or to a rather narrow range of "aromatic compounds". Can, for example, niacin or phenylalanine usefully be said to be carcinogenic? –Henning Makholm (talk) 21:55, 4 January 2011 (UTC)

Fair enough. I should have said that benzene and its simple derivatives are all likely to be somewhat carcinogenic. You got me. --Jayron32 03:08, 5 January 2011 (UTC)

i remember reading that benzene caused red blood cell problems, but xylene and Toluene dont. whats the explanation for this? — Preceding unsigned comment added by Tommy35750 (talk • contribs) 21:14, 4 January 2011 (UTC)

Substituted aromatic compounds get oxidized at the side chain in the body. Thsi oxidation is necessary to get ride of the compounds because only water soluable compounds can leave the body in the urine. The oxidation of benzpyrene or benzene is done on the ringsystem and than you form a three membered ring with one oxygen at the armoatic ring. This epoxide is highly reactive and has the tendency to move to the nucleus. There the ring opens and reacts with the DNA. The toluene is transformed into benzoic acid and with the addition of one aminoacid you get hipuric acid which leaves the body without problem. --Stone (talk) 15:41, 5 January 2011 (UTC)

This is only based on logic rather than sources I'm afraid, but red blood cells themselves are unlikely to be damaged by benzene directly because they contain no DNA, and damaged DNA is what leads to cancer. They are formed in bone marrow however by rapidly dividing cells, which may be more susceptible to DNA damage, resulting in damaged RBCs. I assume you've read the about the health effects of benzene, which says it can cause acute myeloid leukemia which is also related to problems in the bone marrow. Regarding the differences between benzene and xylene, it's worth remembering that small changes in molecules can have big effects - for example sickle cell disease is caused by a single mutation in haemoglobin, a tiny difference. On a more similar note to benzene and xylene, THC and CBD, two compounds found in cannabis are tautomers, but with very different effects on the brain. SmartSE (talk) 12:13, 6 January 2011 (UTC)

Baking soda as deodorizer

Baking soda is commonly claimed to have deodorizing properties, but our article baking soda only mentions briefly (without citation) that it can be used as an ingredient in home-made personal deodorant. Recently, a Ph.D. chemist told me that this claim is misleading. He said that if you put a carton of Arm & hammer in your fridge, the cardboard absorbs as much or more odor than the baking soda, i.e. bicarbonate is NOT an especially effective deodorizer. Can anyone help clarify if bicarbonate is a better absorber of odors than cardboard? SemanticMantis (talk) 21:43, 4 January 2011 (UTC)

The Arm and Hammer company has long advertised since the 1960's that baking soda [removes odors, [15], but they are hardly an independent and reliable source for a claim that probably results in more sales of their product than for cooking uses. Some books which say that baking soda is an effective deodorizer: [16], [17]. Google Book Search shows few claims that baking soda was a good deodorizer before 1900,(see [18] for one from 1898, but that said to boil baking soda in a cooking vessel to remove an odor from the pot. This use of it in solution was commonly recommended long before Arm and Hammer came up with the recommendation to leave a box of it in the refrigerator, which became "common knowledge" after their late 1960's advertising campaign. Other substances like wood ashes were recommended as a deodorizer, as were vinegar, sandalwood, or charcoal. Baking soda was only discussed as a food ingredient or to counteract acid. In the first half of the 20th century, Consumer Reports 1943 advised using baking soda as a personal deodorant: "CU recommends as "Best Buys" among deodorants either powdered boric acid or a solution of baking soda." (1943) "Farm Journal," 1949 said "To clean and deodorize freezers and refrigerators— sprinkle Baking Soda on a damp cloth and wipe inside surfaces. Wipe again with hot water and dry." in what might have been an ad. The ads from 1967 on such as [19] preceded the huge number of household tips books advocating a box of baking soda in the refrigerator. The Arm and Hammer company launched the "box of baking soda in the refrigerator" campaign in 1972 and sales rose 72% in 3 years, per [20]. The claim just seems to have some face validity, and was "common knowledge" by the late 1970's. I did not find a controlled experiment (even an anecdotal test like Mythbusters). Edison (talk) 21:58, 4 January 2011 (UTC)

Note that personal deodorants do not work by absorbing smell from the air; instead they suppress bacterial skin fauna that would turn (ordinarialy odorless) sweat into smelly compounds. Our sodium bicarbonate article does mention (with source) that it has some disinfectant and antiseptic properties. –Henning Makholm (talk) 22:17, 4 January 2011 (UTC)

Looking at the book search results by the various historical periods, baking soda was recommended on a damp sponge or cloth, or in a liquid solution to be wiped over the surface such as a refrigerator interior, and as an alkaline perhaps it could discourage bacterial growth. Only in the 1960's-1970's did the manufacturer promote putting a fresh box in every 3 months for its supposed "odor absorbing" properties. (Admittedly, I always keep an open box in the refrigerator for that purpose). This vastly more product than the average household would use for baking. Edison (talk) 22:32, 4 January 2011 (UTC)

Thanks for the great research. At the moment it seems that, while bicarbonate will absorb odor, it is not particularly more effective than cardboard or ash. SemanticMantis (talk) 23:04, 4 January 2011 (UTC)

Only in the 70s? Don't they currently sell it in special boxes with cloth-covered vents you can open on the side of the box specifically for this purpose? APL (talk) 23:18, 4 January 2011 (UTC)

"Since" 1972, not "in" 1972. If you can get consumers to buy and throw away a container of your product every three months, you are in "manufacturer paradise." Edison (talk) 01:13, 5 January 2011 (UTC)

Ah! I misinterpreted your line "Only in the 1960's-1970's" to mean that it occurred "only" during those years, when I see now that you meant that they "only" came up with this marketing angle sometime during that range, instead of earlier as someone might suppose. APL (talk) 05:33, 5 January 2011 (UTC)

This book says that because it can act as a weak acid and a weak base it can neutralise basic and acidic food odors, turning them into odor free salts. This (from 1992) says that it is just starting to be used in the cosmetic industry as an ingredient in deodorants because it neutralises short chain fatty acids which are malodorus. I don't think it absorbs odors more so than cardboard, but it can neutralise them, which I'm fairly sure that cardboard can't. SmartSE (talk) 00:00, 5 January 2011 (UTC)

I love chemistry, but do not claim to be a skilled chemist. Could those with more chemistry education comment on the unlikelihood of bicarbonate of soda being both a base and an acid? My 1945 29th Edition CRC Handbook of Chemistry and Physics, page 1374, says that a 0.1 N solution of sodium bicarbonate has a pH of 8.8, which would seem to rule out it being an acid. Edison (talk) 01:19, 5 January 2011 (UTC)

Sodium bicarbonate is NaHCO3. The H can be removed by reaction with a strong base, leaving sodium carbonate behind. See Chemistry section in sodium bicarbonate. --Chemicalinterest (talk) 01:26, 5 January 2011 (UTC)

You did not say if sodium carbonate is an acid or a base. It seems to be a base, so no support is provided for sodium bicarbonate being both an acid and a base as Smartse implied. (That would be a stretch even for GoatSe). Would putting a box of sodium bicarbonate in the refrigerator somehow cause a strong base to react with it, leaving the sodium carbonate? Seems rather unlikely. Edison (talk) 01:37, 5 January 2011 (UTC)

Sorry for not being more specific, if you check the first reference I gave, it says the HCO₃^- ion is what can act as both an acid and a base. I'm not a chemist, but you're right in that a solution of it is slightly basic and according to the same reference, this is what makes it better at neutralising acid odours compared to basic ones. As has been touched on below, this property is important in biology, in maintaining the acid-base homeostasis in our bodies. SmartSE (talk) 10:33, 5 January 2011 (UTC)

(ec) The bicarbonate (hydrogen carbonate, HCO₃^-) ion is definitely capable of being both an acid and a base, depending on your definitions; you'll find a good quick introduction in Acid–base reaction. In aqueous solution, it will exist in equilibrium with a protonated form (carbonic acid: H₂CO₃) and a fully deprotonated form (carbonate ion: CO₃^2-. Using the Brønsted–Lowry definitions, When it reacts with something less acidic (more basic) that itself (like ammonia, to form ammonium ion) and loses a proton then it's acting as an acid. When it reacts with something more acidic (like acetic acid, forming acetate ion) and accepts a proton, then it is acting as a base. It's not an either-or situation; bicarbonate ion is both a weak acid and a weak base. TenOfAllTrades(talk) 01:45, 5 January 2011 (UTC)

See also amphoteric, linked from the sodium bicarbonate article. –Henning Makholm (talk) 01:48, 5 January 2011 (UTC)

How likely are these reactions if the sodium bicarbonate is a dry power in a box in a refrigerator, as opposed to being in a reactant vessel in solution with powerful chemicals in a chemical plant or a test tube in a lab? Be real. Edison (talk) 01:50, 5 January 2011 (UTC)

I'm going to go with 'pretty', or even 'very'. A fine powder gives lots of surface area for reaction, and every time you open the refrigerator door you let in several cubic feet of air that's oversaturated with humidity — some of which will condense on those little sodium bicarbonate particles and make their protons and hydroxide available for chemistry, and the limited amount of solvent means everything has a very high effective local concentration. Carbonate-bicarbonate-carbonic acid equilibria aren't particularly unusual or harsh chemistry; bicarb is the major buffer that maintains your blood's pH.

On the question of the box in the fridge, I might speculate that the volatile compounds responsible for fridge odor are going to be primarily uncharged molecules; charged ions have a low vapor pressure and don't fly well. When those compounds are exposed to bicarbonate, any parts of the molecule that are capable of either picking up or losing a proton have an opportunity to do so. If any reaction occurs then our once-volatile compound takes on a net charge and its vapor pressure is likely to go waaaay down. While the acid-base reaction is likely to be reversible to some degree, the compound is now spending some fraction of its time (possibly quite a very large fraction of that time) in a charged state crashed out in the box of baking soda.

Incidentally, Edison, what's happened? First a spurious goatse reference as an off-color gag, and now a 'be real'? Your answers were really thoroughly researched at the beginning of the thread, and now you're snapping at people who are trying to respond helpfully to your concerns. Is everything okay? TenOfAllTrades(talk) 02:21, 5 January 2011 (UTC)

I do not consider a "reality check" to be "snapping" at other posters. A relatively dry atmosphere at low temperature is not equivalent to a test tube filled with chemical solutions. I checked the box of sodium bicarbonate which has been in the fridge for many months and it looks, feels and tastes exactly the same. No indication that it has been chemically modified. I have trouble accepting that powerful chemical influences are somehow wafting around in the fridge as a couple of posts have implied, changing a base somehow to an acid. If a box of dry white powder modifies the odors in a fridge, might not it be by adsorption of the free floating molecules on the large surface area of the granules, rather than the baking powder turning from a base somehow to an acid? Do I have to get out the Litmus paper to confirm it is still a base? One works all day on improving Wikipedia, then someone is dismayed when one questions whether likely bs might in fact be real bs. Edison (talk) 03:52, 5 January 2011 (UTC)

You assume that "acid" and "base" are mutually exclusive categories. They are not. A molecule (such as bicarbonate) can be both at the same time. It does not need to be "somehow changed" from one into another. How it reacts just depends on which reactants presents to it for reacting.

A pH above 7 simply means that the solution (on short timescales) is less acidic (and more alkaline) than pure water; it doesn't mean that there is no capacity to react like an acid left. Water itself is perfectly willing to act either like a base or like an acid. The difference between water and bicarbonate solution shows up at slightly longer timescales: the bicarbonate that reacts will be replenished by protolysis by some of the carbolic acid in the solution. Therefore it can react with more base than pure water can before its pH rises much (and eventually dissuades new added base molecules from reacting).

Yes, of course, there are chemical influences wafting around in the fridge -- at least if there's something that smells in there. That's what a smell means: molecules that waft around in the air and can dissolve in liquids they happen to meet. If they meet the mucous membrane in your nose, they may dissolve and react with sensory cells there. If they didn't, they wouldn't be smelly in the first place. –Henning Makholm (talk) 04:29, 5 January 2011 (UTC)

Did you know that sodium hydroxide is the conjugate acid of sodium oxide? --Chemicalinterest (talk) 18:17, 5 January 2011 (UTC)

Two thoughts come to mind. First, sodium bicarbonate is described as hygroscopic - by sucking up water from the air, it might make stray bits of rotten food drier and presumably less ... juicy. Apparently it's not truly deliquescent, however, and I don't really know how much water is actually absorbed by a package after it's already reached the retailer. Actually, I don't even know the measurement units for a hygroscopic chemical! Second, as a pH buffer, it might tend to absorb stray, strongly scented amines floating around in the air, which upon contact could take up an H+ from the HCO2- ions... but short of strong bases like ammonia itself this doesn't sound like an important reaction. Wnt (talk) 05:32, 5 January 2011 (UTC)

The answers from those skilled in chemistry were quite helpful. Plausible mechanisms were provided whereby the chemical might lessen the odor in a refrigerator. The odd thing is that, post 1972, dozens of "household hint" and "green living " books state as a fact that the "box of baking soda in the fridge, replace every 3 months" works, but nowhere did I see experimental verification. Refrigerators with some stinky contents (various odorants could be used: garlic, fish, rotten produce, sour milk) with no baking soda or with a box of baking soda, closed up for some standard period or varying periods, with blind testing by someone who rates the odor. Right up Mythbusters alley, or someone's science fair project. The experiment sounds too simple for publication in a scientific journal or for a masters thesis, but I suppose it would be mainstream Food science. Google scholar shows several publications related to "baking soda" "refrigerator:"[21], most behind the usual paywall. Besides a bunch of patents, which prove nothing, there appear to be some relevant articles. Does anyone have library access to them, to shed light on effectiveness and method of effect from reliable sources? Edison (talk) 20:01, 5 January 2011 (UTC)

There are peer-reviewed journals devoted to Food Science; I'm not sure what the implication is in the juxtaposition of "food science" is against "publication in a scientific journal" seems to imply that there aren't serious, respected journals devoted to the subject. There are. After a 30 second search, I found this one which looks like a good, generalist overview sort of journal. --Jayron32 20:22, 5 January 2011 (UTC)

I was thinking of "chemistry" as more of a hard science, and could not see someone getting his masters thesis or doctoral thesis approved or publishing in a refereed chemistry journal the fridge and baking soda experiment outlined. On further study there are not many relevant studies seen at Google Scholar. One unpublished paper, from 2008 found that wrapping food waste in newspaper was far more effective than baking soda sprinkled on it or placed in a container in dry form, when it was left at 20 C for 14 days in a sealed container. The study was small (2 observers) with one of them knowing the experimental treatments of the containers, and the odors resulted from room temperature decomposition of moist food waste, where the drying effect of the newspaper may have been important. Perhaps someone with good library access could look at [22] , an ACS publication which apparently says, per the snippet "..Hammer baking soda that we trustingly put in our freezers to absorb odors—they don't work.." Edison (talk) 20:44, 5 January 2011 (UTC)

Wow, lots of good points made here. As a parting argument from authority, this blurb from Argonne Nat'l Lab has been reposted all over the place: [23]. It seems that, although bicarb has some chemical neutralizing properties that activated charcoal does not, the latter will likely provide better deodorizing per unit volume. Still, it does seem like cheap fodder for Mythbusters, maybe someone should drop them a note. SemanticMantis (talk) 21:14, 5 January 2011 (UTC)

I'm afraid something that turns on the presence or absence of smell wouldn't make for compelling TV... –Henning Makholm (talk) 23:04, 5 January 2011 (UTC)

In 2003 Mythbusters once put a dead pig in a car and sealed it up for 2 months, to find out if it was possible to get rid of the smell. It wasn't. I don't recall that they tried baking soda. Edison (talk) 23:36, 5 January 2011 (UTC)

January 5

Jet engines

How do jet engines provide thrust? The mass of the hot air leaving the rear must be the same as the mass of the cold air entering the front, so its not throwing away mass apart from the small amount of fuel used. Thanks 92.28.251.68 (talk) 01:03, 5 January 2011 (UTC)

See Jet engine#General physical principles. It doesn't really have much to do with the mass of the air. Dismas|^(talk) 01:05, 5 January 2011 (UTC)

Simply, here is what happens. Large amounts of air are sucked into the engine. It is then compressed. At this point, fuel is injected. It bursts into flames, causing a small explosion. It is pressure, not mass, that drives the engine. --T H F S W (T · C · E) 02:40, 5 January 2011 (UTC)

I disagree with THFSW. The rate at which the mass of air leaves the engine is almost the same as the rate at which it enters the engine. However, the rate at which momentum leaves the engine is many times greater than the rate at which momentum enters the engine. This is because the exhaust gases leave through a propelling nozzle specially sized so the speed of the exhaust is many times greater than the speed at which air enters the engine. Newton's 2nd Law of Motion can be expressed as the resultant force on a body is equal to the rate of change of the body's momentum. In the case of a jet engine, the rate of change of momentum of the air passing through the engine is very great and is equal to the thrust on the engine. See Turbojet#Net thrust.

If the propelling nozzle was inappropriately sized so that the exhaust left the engine at the same speed as air entered the engine there would be no surplus of momentum and no thrust on the engine. The pressure of the exhaust gas as it exits the propelling nozzle is usually about atmospheric, whereas the pressure of the air as it enters the engine is usually a bit higher than atmospheric so the pressure difference across the engine contributes drag, not thrust. That is why I disagree with THFSW. Dolphin (t) 02:57, 5 January 2011 (UTC)

(edit conflict) Our Airbreathing jet engine article says: "An airbreathing jet engine (or ducted jet engine) is a jet engine that has an inlet duct that admits air for the combustion of fuel in the air stream which forms a jet of hot gases used for propulsion. So thrust is provided by what is in effect a directionally controlled explosion (which our article says "is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases"). WikiDao ☯ 03:23, 5 January 2011 (UTC)

Yes, but if we view the entire engine as a black-box system (as the OP clearly does), the net effect that relatively slow air is ingested at the front of the engine and exits it at a much higher speed. The difference in speeds, times the mass of the air that streams through, is the thrust. The nozzle design serves to ensure that the exhaust jet is about at ambient pressure when it leaves the engine, such that as much as possible of the combustion energy contributes to thrust. –Henning Makholm (talk) 03:57, 5 January 2011 (UTC)

I'm sorry, but by "ambient pressure" do you mean to say that there is no jet blast? WikiDao ☯ 04:30, 5 January 2011 (UTC)

Jet blast is caused by the air's velocity. I think Makholm is saying that as much of the pressure is converted into velocity as possible before it leaves the engine. (After all, it doesn't help the airplane if the air expands 'sideways', which it could do if it were at high presure, but not constrained.) APL (talk) 05:27, 5 January 2011 (UTC)

Well, what I asked myself as a kid, and sometimes still do, is the following: A jet engine is basically a pipe with two sets of fans, one forcing air in at the front, one in the back, being driven by the exhaust and used to power the front fan. In between the two is the combustion chamber, where fuel is injected and burned, so that the gas rapidly heats and expands, causing an increase in pressure that escapes to the rear, providing thrust. Why is the pressurized hot gas not escaping both ways, front and back, thereby of course cutting off its own air supply and fizzle? I suspect it has something to do with both the shape of the "pipe", and the relative size and configuration of the fans, but I never found a satisfactory solution. It's even worse with ram jets, of course. Is is simply that the overpressure from the air speed is larger than the pressure in the burning chamber, and hence the hot gas has to escape to the back? --Stephan Schulz (talk) 13:53, 5 January 2011 (UTC)

Why is the pressurized hot gas not escaping both ways, front and back...? Before takeoff the fans have to start rotating in the right direction. This can be ensured by designing the intake and exhaust fans to have different efficiencies in competing as windmills. As long as they keep rotating, the jet engine produces thrust. Thrust is lost in the case of an abnormal Compressor stall. Ramjets are no good for takeoff because they don't work at all at zero air speed. Cuddlyable3 (talk) 16:29, 5 January 2011 (UTC)

I think the answer to Stephan's question is in the turbojet article: "As the mixture burns its temperature increases dramatically, but the pressure actually decreases a few percent. ... Some pressure drop is required, as it is the reason why the expanding gases travel out the rear of the engine rather than out the front." So the front of the turbine sees a slightly lower pressure than the rear of the compressor. But the temperature is higher at the turbine, so the volume of gas per time unit is larger through the turbine than through the compressor. Therefore the turbine does not need to extract all of the energy from the gas in order to drive the compressor; there is some left for thrust. –Henning Makholm (talk) 17:51, 5 January 2011 (UTC)

Chemical formulæ

What are the rules to identify how to properly write the chemical formula? — Preceding unsigned comment added by Sci-math-tech (talk • contribs) 08:46, 5 January 2011 (UTC)

title added by CS Miller (talk) 08:56, 5 January 2011 (UTC)

Revised title so as not to reflect one rule exclusively. Cuddlyable3 (talk) 15:59, 5 January 2011 (UTC)

Basically, there must be the same number of individual atoms on each side of the equation. If need be, you must have several of each molecule. For example

2 ( NH₃ ) + 3 ( O₂ ) → N₂ + 3 ( H₂O )

Here 2 molecules of ammonia, each containing 1 atom of nitrogen and 3 of hydrogen, react with 3 molecules of oxygen (each 2 atoms of oxygen) to form 1 molecule of nitrogen (2 atoms) and 3 molecules of water (each 2 hydrogen and 1 oxygen). CS Miller (talk) 08:56, 5 January 2011 (UTC)

How to write the formula of a given chemical? Or how to write the formula of a chemical reaction? Perhaps chemical formula or stoichiometry will be helpful to you. 206.116.252.164 (talk) 09:54, 5 January 2011 (UTC)

Formulae for chemical reactions should be in terms of element atoms using their standard abbreviations, as shown in the article Periodic table. Cuddlyable3 (talk) 16:01, 5 January 2011 (UTC)

How did the Big Bang escape its Schwartzschild radius?

When all the mass of the universe was once concentrated in a very small space, why didn't it collapse into a black hole? 93.132.167.177 (talk) 12:02, 5 January 2011 (UTC)

The initial outward exapansion of the big bang must have overwhelmed gravitational collapse. -Plasmic Physics (talk) 13:04, 5 January 2011 (UTC)

Not really my field of expertise, but the nature of the Big Bang's singularity is that it's the point where the math -- specifically, the math of general relativity (and therefore gravity) -- breaks down. GR doesn't claim to explain the initial moments of the BB, and speculation is that the forces involved in the Planck epoch simply may not be the ones we recognize today. As such, it may be that gravity didn't exist (or function) then as we understand it now. — Lomn 14:30, 5 January 2011 (UTC)

To avoid singularities or effects near singularities, look at the time 1 second after the BB. The mass cannot have progressed more than 2 light seconds and that should be much smaller than the Schwartzschild radius. 93.132.167.177 (talk) 15:05, 5 January 2011 (UTC)

The term "Schwarzschild [sic!] radius" doesn't mean an awful lot in that context. Matter had a very high density 1 sec after the "Big Bang", but it filled the entire space homogeneously. Hence every particle was attracted equally in all directions, so effectively, it wasn't attracted at all. Expressed differently, there was no centre toward which the matter could have collapsed. Still, the effect of gravitation was there, of course, it slowed down the expansion. With sufficient matter (and no dark energy) it could have slowed down the expansion and the Universe could have recollapsed. As we know it hasn't done so yet, and as far as we know, it will not in the future. As a general rule I suggest never to start reasoning at the Big Bang — that's a singularity, or in any case a condition that we know little to nothing about, you cannot derive anything from that. Always start your reasoning at the present time, then go backwards. --Wrongfilter (talk) 15:42, 5 January 2011 (UTC)

(edit conflict) The point is that, in the time arbitrarily close to the big bang, our physics breaks down. Things like the mathematics used to explain black holes and event horizons and Schwartzchild radius and all that stuff is based on how the universe works today. We don't have effective tools to look at the big bang itself, so attempting to extrapolate a concept like Schwartzchild radius to the big bang doesn't hold up. --Jayron32 15:44, 5 January 2011 (UTC)

Because it was the inside not the outside of a black hole expanding? Cuddlyable3 (talk) 15:50, 5 January 2011 (UTC)

So then are we to assume that the laws of science we have today are invalid at some point arbitrarily close to the big bang? How long after the BB do we have to wait for the laws of science to become valid? Googlemeister (talk) 16:36, 5 January 2011 (UTC)

No bright line cut off, but physics from the end of the inflationary epoch, at about 10^-32 seconds after the Big Bang, and onwards is well understood. The details of cosmic inflation, from about 10^-36 seconds aBB to 10^-32 seconds aBB, are somewhat speculative, and to go back earlier than 10^-36 seconds aBB you need a Grand Unified Theory, for which we don't currently have an agreed model. Gandalf61 (talk) 16:49, 5 January 2011 (UTC)

(edit conflict) See Lomn's post above; we really don't know since General Relativity literally doesn't work under the conditions present during the very short time periods after the Big Bang. See also Timeline_of_the_Big_Bang#Planck_epoch and Planck epoch. There's lots of propositions, many of the conflicting, about what this time might have worked like. But we have nothing firm or reliable to work from. So, your statement, which seems a bit sarcastic, is actually spot on. Particularly relevent is the statement at Big_Bang#Timeline_of_the_Big_Bang, which says "How closely we can extrapolate towards the singularity is debated—certainly not earlier than the Planck epoch." There is some stuff we are pretty sure about; say everything from the inflationary epoch onward. Some stuff, like the Planck epoch, we're confidently clueless, and the stuff in between is progressively fuzzier the further we go back. --Jayron32 16:56, 5 January 2011 (UTC)

I agree with Wrongfilter and Cuddlyable3. There is no mystery here at all. As our Schwarzschild metric article says: "The Schwarzschild metric is a solution of Einstein's field equations in empty space, meaning that it is valid only outside the gravitating body". But at (or soon after) the Big Bang there was no "outside" - the whole universe was very homogenous and at approximately the same density, hence the assumptions behind the Schwarzschild metric and Schwarzschild radius do not hold. Gandalf61 (talk) 16:41, 5 January 2011 (UTC)

So what you are saying is that there could be more of a structure inside a black hole but the commonly believed singularity within which all the mass is concentrated? Is this just an ad hoc assumption or do you have any reference? 93.132.167.177 (talk) 18:22, 5 January 2011 (UTC)

Actually the answer is we don't know. The singularity is the simplest explanation, and works with current theories, but it is literally impossible to do any experiments, tests, or anything else to study it or confirm it. See Cosmic censorship hypothesis. --Jayron32 19:32, 5 January 2011 (UTC)

Another way to look at this is to think about a black hole. Nothing can escape because even light is sucked back in, and nothing can exceed the speed of light. But in the Big Bang nothing escaped - it is all still inside the "hole". And in the sense in which the universe does "expand", it can expand faster than the speed of light. This is an expansion of space, rather than a motion of everything through space. Wnt (talk) 19:37, 5 January 2011 (UTC)

I feel many of you got me wrong. I'm not speculating about singularities or extreme and unknown physics around them. As from the article, one second after BB is pretty a lot of time for physics to adjust to what we see now. The other point is that we (the universe) might be inside of a black hole but from what I have heard about black holes, everything inside is attracted to the central singularity (or the very proximity in case of unknown effects) in a finite (and, as I remember, small) amount of proper time. So either there is something substantially wrong with my understanding of Big Bang, and/or with my understanding of black holes, or I am missing a clue to conciliate what looks like a contradiction. As my original question is a quite simple and obvious one and I never heard that anyone asked that before I can only guess that the answer is so simple that no one who knows it bothers to tell. 93.132.167.177 (talk) 21:45, 5 January 2011 (UTC)

Where do people get the idea from that there might be a connection between the Big Bang and black holes? From what I know there is none. What is that even supposed to mean, "the universe might be inside of a black hole"? Mind, I don't blame you, this comes up in forums (from laypersons) again and again. --Wrongfilter (talk) 22:38, 5 January 2011 (UTC)

Well, that's easy enough: big mass concentrated in a small volume. But, ok, if you people here feel that everything outside your encyclopaedic universe is a crackpots thought ... well thank you all for your contributions so far but don't waste your time on that any more. 93.132.167.177 (talk) 23:24, 5 January 2011 (UTC)

There have been some pretty bad answers above. There is nothing mysterious about Big Bang plus one second. All the normal rules of physics apply. The problem is actually with the understanding of how black holes form. If you have an isolated mass that is more compact than a Schwarzschild radius then it will inevitably collapse into a black hole. However the "isolated" part is important. If you view gravity in terms of the "rubber sheet" analogy, then the isolated mass creates a depression so deep that nothing (not even light) has enough energy to climb out of. But what happens if you sprinkle mass uniformly across the sheet? Every part of the sheet is pressed down but no part forms a localized depression. Nothing has to expend energy climbing out of a hole, because there is nothing to identify a "hole" or an "outside", everything is the same. If you assume that the universe was uniformly filled with mass and has no boundary, then the Schwarzschild solution just doesn't apply. Predicting a collapse from the Schwarzschild radius relies on the ability to distinguish between a very massive region and an approximately massless region around it. In a homogeneous universe that contrast just doesn't exist. (The universe actually could still collapse into a singularity. This is the possible future that we refer to as the Big Crunch, but the mechanics of how this occurs are more nuanced than the simple Schwarzschild considerations.) Dragons flight (talk) 06:08, 6 January 2011 (UTC)

The rubber sheet model isn't a good model of GR, but yes, it's important to understand that the early expansion of the universe (including inflation!) is modeled by general relativity and not by some unknown pre-GR theory of gravity. There are theorems establishing certain conditions under which a black hole singularity must form, and the big bang doesn't satisfy those conditions. The conditions are more complicated than just a lot of mass concentrated in a small volume. A big bang universe that's above the cosmological "critical density" does satisfy the conditions for black hole collapse, and does (re)collapse (the big crunch).

There is a close connection between the big bang and black holes. The big bang resembles a time-reversed version of a (highly symmetric) black hole collapse. You can surround the whole visible universe by a Schwarzschild vacuum, putting everything "inside a black hole", without contradicting observations. -- BenRG (talk) 00:18, 8 January 2011 (UTC)

The above discussion confuses me in one respect: it was my understanding that there was no matter up to and including the inflationary epoch (and a bit beyond) -- i.e., that the universe was "space" and only space. Did I mistakenly believe that I'd repeatedly read that? 63.17.67.25 (talk) 03:59, 8 January 2011 (UTC)

It's not what the what the inflationary hypothesis ordinarily says. During the inflationary period, space was certainly not empty. What you may have read is that the elementary particles of our current universe could not exist during inflation. But there would have been something else there instead -- weird and wonderful high-energy stuff that nobody can explain in detail given today's knowledge. The inflationary epoch ended when the weird stuff eventually "crystallized" into our current set of quarks, leptons and so forth. –Henning Makholm (talk) 04:14, 8 January 2011 (UTC)

I don't have all or even most of what I've read on hand. But here's one example (similar to others) from what I do have: "During this brief but critical period the universe was but a vacuum.... [T]he cosmic vacuum remain[ed] empty even after falling below the temperature at which particle production ordinarily would take place." -- "Coming of Age in the Milky Way" by T. Ferris, pp. 358-59. 63.17.67.25 (talk) 04:35, 8 January 2011 (UTC)

The universe during the inflationary epoch is often modeled as a "Lambda vacuum". This has the word "vacuum" in it, and it's perfectly fine to think of it as a vacuum, and many physicists do think of it as a vacuum; but that doesn't mean quite what you might think. The GR field equation (ignoring some uninteresting constants) looks like G + Λg = T, where G is the "Einstein tensor" describing spacetime curvature, Λ is the "cosmological constant", g is the "metric tensor" describing... well... spacetime curvature again, I suppose, and T is the "stress-energy tensor" describing everything else (the other forces and the fermions). Inflation is described by a model with T zero and Λ nonzero. T=0 makes it a vacuum, by definition. However, you could just as well define T' = T − Λg and write the equation as G = T', with T' nonzero. T' includes the stuff that was in T plus something else represented by −Λg, and the extra thing turns out to behave like a spin-0 particle (=field) with a nonzero value everywhere (like the Higgs field). In point of fact, you need a particle with some kind of time-varying behavior in order for inflation to eventually end (Λ can't really be a constant), so this view is more accurate that the cosmological-constant view. Inflation ends when the background field decays into a mess of weird and wonderful high-energy stuff, which eventually turns into the low-energy particles that we're made of. -- BenRG (talk) 05:57, 8 January 2011 (UTC)

63.17.67.25 - I think you are confusing "matter" and "mass". There was no matter before the inflationary epoch (in the sense that the elementary particles that make up what we currently think of as matter did not exist) but there was certainly plenty of mass (or, if you prefer, plenty of energy). Gandalf61 (talk) 06:49, 8 January 2011 (UTC)

grueblers equation

relation between number of pairs and number of links as given by the L=2P-4.is it also named as the grueblers equation ..? there is one equation for degrees of freedom by gruebler.. is this also ... please help me .. —Preceding unsigned comment added by 59.93.130.246 (talk) 14:23, 5 January 2011 (UTC)

Your question is not at all clear to me, but you might find the information at Linkage_(mechanical)#Theory useful. AndrewWTaylor (talk) 14:45, 5 January 2011 (UTC)

I am asking that besides popularly known(F=3(n-1)-2f) can we name (l=2p-4,applies to kinematic chains) also as gruebler's equation. very simply can we call L=2p-4 as gruebler's equation. —Preceding unsigned comment added by 59.93.130.246 (talk) 14:59, 5 January 2011 (UTC)

Your popularly known equation is Kutzbach-Gruebler's equation. Wikipedia doesn't have an article about Arnulf Grübler but his Curriculum Vitae is online with an e-mail address so you could try asking his opinion. Cuddlyable3 (talk) 15:46, 5 January 2011 (UTC)

Color of food and nutritional value

Is the color of food related to its nutritional value? A certain Gillian_McKeith claims it is, however, she is a mixture of crackpot theories and common sense advice, so I don't know if she's right on this point.Quest09 (talk) 15:23, 5 January 2011 (UTC)

Certainly not in the modern world. Many foods have colors added to them that don't effect the nutritional value. Even some fruits and veggies have been selectively bred so that they don't have the same colors as their wild counterparts! (Carrots weren't originally orange, for example.) APL (talk) 15:34, 5 January 2011 (UTC)

It depends a bit on what you mean by "color". There's a rough rule of thumb that "white foods" tend to have less nutritional value (that is, they have less vitamins and minerals and fiber per calorie) than more colored foods; so one can consider "white bread" to be less nutritional on that metric than whole-grain bread, and "white rice" as less nutritional than brown rice. Also, some nutrients are known for bright colors; lycopene is associated with tomatoes and other red foods, beta carotene with orange carrots, the so-called "green-leafy vegetables" like spinach and collards carry more nutritional value than the less strongly colored ones like iceberg lettuce. However, it only goes so far; white-meat chicken is lower in fat than say, more brightly colored steak. Using color as a metric to help remember which foods are more nutritious and healthier for you may be helpful, but it probably isn't the color itself which is the key factor. After all, if it were, wouldn't artificially colored foods be just as healthy as brightly colored vegetables? --Jayron32 15:39, 5 January 2011 (UTC)

I suppose that she meant raw food. Processed food can certainly have (almost?) any color you want.Quest09 (talk) 15:44, 5 January 2011 (UTC)

Well in the same vein as APL above, with modern biotechnology raw food probably can almost as well if you really want to. Nil Einne (talk) 16:10, 5 January 2011 (UTC)

Yes, you both are right on this. Food color can be manipulated. Salmon from fish-factories, for example, has its color due to what it was feed to. It's appealing salmon color is not that prevalent in nature. Quest09 (talk) 17:21, 5 January 2011 (UTC)

I'd never heard of the food-colour strategy in such a broad sense as that. I've only heard that rule of thumb applied to fruits, particularly berries. Our article on berries touches on this, but notes that the effect may not be that great. That being said, it's hard to argue with any rule of thumb that encourages eating a diversity of foods; that will almost always turn out to be more nutritious than eating a more limited diet. Matt Deres (talk) 16:06, 6 January 2011 (UTC)

Keep in mind that Gillian McKeith has a really poor understanding of science. She claims ... (quote) Chlorophyll is "high in oxygen". And the darker leaves on plants are good for you, she explains, because they contain "chlorophyll - the 'blood' of the plant - which will really oxygenate your blood." [[24]] -- JSBillings 20:12, 6 January 2011 (UTC)

A six month old orange.

This is a bit of an odd question, but here goes. I keep dried fruit on my desk. Well, sometimes I don't eat an orange, and instead of rotting, it goes hard and shrivels. I have a three year old satsuma that is like a ping-pong ball now.

I had an orange. I let it dry for six months (the secret is to keep turning it, otherwise it rots). I colleague wanted to see what it was like, cut in half. So, I cut it in half, and to my surprise it was still juicy inside.

Here's the question. I was dared to drink the juice, and I did. It tasted a bit funky, but it didn't kill me. What has happened to the juice in the six months? Is it toxic? Is it safe to drink?

Thanks in advance,

Zzubnik (talk) 15:46, 5 January 2011 (UTC)

Just hazarding a guess based on the funky taste, but it might be possible that the juice inside the orange fermented. Note, though, that this is sheer speculation, and I'm not claiming that this is necessarily the correct answer to what happened. Ks0stm ^(T•C•G) 16:01, 5 January 2011 (UTC)

(edit conflict)If the juice inside was protected by the peel (which I suspect it would have been) so that nothing could get inside to ferment it, I suspect it wouldn't be all that bad for you. Without yeasts or bacteria to turn the juice into alcohol or vinegar, I don't see that much could happen. There may be internal reactions within the juice that slowly change it, but keeping out air completely is a common method of preservation. Well-sealed and properly handled bottles of wine can last decades and still be drinkable. They do change over time, but they remain perfectly fine. Wine that is exposed to air goes rotten to the point of inedibility in much shorter time periods. The trick is, keeping it so the peel remains intact; even microscopic holes in the peel could let in cultures which could spoil the orange. So, I would probably count yourself "lucky" it wasn't bad; you could run the exact same experiment again and get a very different result. --Jayron32 16:03, 5 January 2011 (UTC)

We seem to be thinking the same means with opposite ends...I was thinking the sealing of the peel would block oxygen from getting in, creating the anaerobic environment needed for fermentation...but given my lack of knowledge in the area, I'll defer to your answer. Ks0stm ^(T•C•G) 16:06, 5 January 2011 (UTC)

Well, if it is so sealed that oxygen cannot get in, then bacteria and yeast, many orders of larger than oxygen molecules, would ALSO not be able to get in. Furthermore, if there were bacteria present in an oxygen-poor environment, it would be REALLY bad, anaerobic bacteria are particularly nasty, bacteria that cause botulism are anaerobic. Fermentation is also an anaerobic process, see Fermentation (biochemistry), but it too usually requires cultures to be carefully controlled; you want the right yeasts and bacteria to be present, random stuff from the environment can be a hit-or-miss prospect when it comes to getting "good" fermentation versus a nasty mess. But in general, fermentation cannot go on without some little bacteria or yeast to do it. --Jayron32 16:12, 5 January 2011 (UTC)

But plants have an innate immune system. This (probably) stops the Clostridium botulinum from entering the orange whilst it is developing; after that, as long as the skin is intact, the bacterium can't enter it. CS Miller (talk) 18:46, 5 January 2011 (UTC)

That's kinda, exactly, my point. --Jayron32 19:25, 5 January 2011 (UTC)

Indeed it was. I should have read your earlier reply better before posting. CS Miller (talk) 23:51, 5 January 2011 (UTC)

An important factor here is that the oranges you buy in the store are invariably coated with wax. Unwaxed citrus fruit will dry out within a few days. The peel itself has strong antibiotic properties, unless it is punctured, and the wax helps even more. Looie496 (talk) 18:48, 5 January 2011 (UTC)

I don't think they are coated with wax, at least not here, in Detroit. I know the feel of wax on my hands, which I get when touching waxed fruit, and I don't get that feeling when peeling an orange. StuRat (talk) 19:27, 5 January 2011 (UTC)

Also, I'd expect the orange to be dessicated, so that the juice is rather concentrated. Did it taste like that ? StuRat (talk) 19:28, 5 January 2011 (UTC)

Hi guys, and thanks for all the replies! To answer the question, it did taste concentrated, but it also had a different taste that I didn't recognize. I presume this is just what happens to orange juice over time if it doesn't spill. Like with wine, the flavour changes over time. Zzubnik (talk) 08:43, 6 January 2011 (UTC)

Interesting. And I suddenly feel much better after having just eaten a two week old Clementine! 10draftsdeep (talk) 14:41, 6 January 2011 (UTC)

Dog Knot

What is the puprose of the knot at the base of a dogs erect penis?

See here. --Sean 17:47, 5 January 2011 (UTC)

I think you mean see here. Cuddlyable3 (talk) 22:01, 5 January 2011 (UTC)

Nope. --Sean 22:34, 5 January 2011 (UTC)

Dark side

Does Uranus ahave a dark side? — Preceding unsigned comment added by BenYorkie (talk • contribs) 17:17, 5 January 2011 (UTC)

Yes, the one where the sun don't shine. See night. --Sean 17:44, 5 January 2011 (UTC)

No. All parts of Uranus receive direct sunlight at some point, so there is no permanent "dark side". However, due to Uranus's unusual axial tilt and 84-year orbit, some parts of the planet can spend extended periods in the dark. See Uranus#Orbit and rotation, where it states: "Each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness". Karenjc 18:03, 5 January 2011 (UTC)

It's exactly analogous to the Midnight sun in the polar regions on Earth. The only difference is that Uranus has much larger polar regions (due to the extreme tilt), comprising nearly the entire planet, and that the Uranian year is much longer than a terrestrial year. Buddy431 (talk) 01:45, 6 January 2011 (UTC)

Okay, we've had "yes" and "no"; I'll add that the sunlight at that distance is so weak — under 1/300 of the amount we get here — that you could say it's all dark. --Anonymous, 19:01 UTC, January 5, 2010.

Eh, that'd be plenty of light for reading (it's substantially more than a full moon on Earth), so I don't think "all dark" holds up. — Lomn 19:34, 5 January 2011 (UTC)

Depends on how many clouds you have above you, since as a gas giant there really isn't a surface you can stand on, thus the point chosen is pretty arbitrary. Googlemeister (talk) 19:36, 5 January 2011 (UTC)

Wine Grape variety abreviations

Is there a universal Vitis vinifera grape variety abreviation list? —Preceding unsigned comment added by 200.6.100.224 (talk) 19:13, 5 January 2011 (UTC)

See List of grape varieties. --Jayron32 19:23, 5 January 2011 (UTC)

The OP is asking for a list of abbreviations - which are not in our article. Some of them are in this list, but it is not exhaustive. SpinningSpark 02:50, 6 January 2011 (UTC)

Soap making

I have been making my own bar soap .what chemicals can i add to the soap to improve the quality ? —Preceding unsigned comment added by 41.221.209.6 (talk) 19:57, 5 January 2011 (UTC)

Soap#Traditional_soap_making has an overview of homebrew soap making, as well as some ingredients and methods to alter the finished product. --Jayron32 20:00, 5 January 2011 (UTC)

Miracle Mineral Supplement

Where can I get this? --98.221.179.18 (talk) 21:13, 5 January 2011 (UTC)

You don't want to. Seriously. Read the article. You have no use for it. --Jayron32 21:17, 5 January 2011 (UTC)

The claims made on the "official website" clearly fall within the realm of jurisdiction of the FDA - and in fact, has drawn legal and regulatory attention. The product is being illegally marketed as a drug without passing regulatory and safety requirements, according to the F.D.A. - so not only this substance highly toxic and hazardous, it is also against the law to sell or purchase it for medical use in the United States. Nimur (talk) 21:30, 5 January 2011 (UTC)

It's a total fraud, i did a lot of investigating into this because a close relative of mine got their hands on some about a year ago. This is a site which has some good information about this fraud.Vespine (talk) 21:48, 5 January 2011 (UTC)

(edit conflict)I was looking forward to getting some chlorine dioxide and/or sodium chlorite (for chemistry experiments). At least to get some pictures for Wikipedia. Of course I wouldn't drink it any more than I would drink bleach! --98.221.179.18 (talk) 21:49, 5 January 2011 (UTC)

(ec)(ec) The book by Miracle Mineral Solution's promoter Jim Humble states "I have provided complete details on how to make the solution in your kitchen, and to buy most of the ingredients off the shelf". Sale of the MMS concoction for any medical purpose whatever is judged illegal and dangerous. Its ingredient Sodium chlorite is a toxic oxidant of which 1 gram causes sickness and 10-15 grams death. The only positive medical advice we can give is that it is healthy to take reasonable doses of the compound dihydrogen monoxide in pure form. Cuddlyable3 (talk) 21:51, 5 January 2011 (UTC)

The book's author also links to this excellent example of a Medicare scam - a phony "cancer screening test kit." "While we do not work directly with private insurers, HMOs, or PPO plans, we can provide you with a receipt which you may be able to use to get reimbursement from your provider." Sadly, they probably have been successfully billing the Government for numerous sham tests. Let's hope the Feds swoop in on the whole operation quickly. Nimur (talk) 21:53, 5 January 2011 (UTC)

If you are after sodium chlorite fir experiments, just get some water purification tablets from a camping store. Vespine (talk) 22:08, 5 January 2011 (UTC)

Searching "Miracle Mineral Solution" in Google [25] will net many places willing to ship the solution to you for a hefty price. Some of the places even appear to have brick and mortar stores as well. As a random example, "Moon's Light Magic" appears willing to ship you the stuff, and also appears to have a physical store in Roselle, Illinois. If you could be more specific in where you are, we could help you find a store that's closer. Buddy431 (talk) 23:40, 5 January 2011 (UTC)

Under 3 dollars, of course, or I wouldn't want it. That would probably rule out everything. --Chemicalinterest (talk) 23:44, 5 January 2011 (UTC)

I think Buddy431's reply is inappropriate for the science ref desk! Regardless of what the op claims he wants it for, this IS a question of medical claims and dangerously false ones at that. I strongly disagree with promoting or even linking to sites which sell this snake oil. Vespine (talk) 00:27, 6 January 2011 (UTC)

Why do you have a prejudice against a sodium chlorite solution? --Chemicalinterest (talk) 11:42, 6 January 2011 (UTC)

It's in deciding what is and isn't appropriate treatment that we are dispensing medical advice. Providing a link to a specific treatment that is asked for, whatever we think about the appropriateness of it, is not medical advice. Buddy431 (talk) 01:42, 6 January 2011 (UTC)

I've looked too deeply into this fraud to agree, spend a few minutes googling Jim Humble and if you are not flabbergasted by the blatant fraud and disinformation this guy spreads I'll be very surprised. Have a look at the google site i linked above. If you had said: "you can get homeopathy from here" you could argue that you're just giving information and leaving the choice to the individual, we could have an argument about scientific proof and what harm it can do and whatever, but MMS is a FRAUD, full stop, and it has been proven to be dangerous and is now illegal in several countries. It's definitely not just harmless woo woo. What you are doing is not just "giving information"; by linking sites involved in this scam you are in effect promoting for them, whether you do it inadvertently or not is beside the point IMHO. I still believe it's still inappropriate for the science ref desk. Vespine (talk) 02:05, 6 January 2011 (UTC)

The OP clearly says he wants it for chemical experiments, not as medicine. If he's lying, and takes the "supplement" as medicine despite all the warnings here, then he's an idiot and deserves whatever consequences result. --140.180.26.37 (talk) 07:48, 6 January 2011 (UTC)

Please note that User:Chemicalinterest is the same as User:98.221.179.18 (I memorized my IP). The only reason I am interested in this product is because it contains sodium chlorite; if I can find out how to make sodium chlorite from sodium chlorate without the explosive chlorine dioxide intermediate, then I will not ask for this product. --Chemicalinterest (talk) 11:43, 6 January 2011 (UTC)

Formula pronunciation

This formula appears in our proton-proton chain reaction article:

+

→

+

e+

+

ν e

+

0.42 MeV

Can someone tell me how that would be pronounced in English? Thanks. --Sean 22:33, 5 January 2011 (UTC)

One hydrogen atom fuses with another hydrogen atom, resulting in an atom of deuterium, a positron, an electron neutrino, and some extra energy. I mean, that's one way to do it. You could get more or less technical about it if you wanted to, e.g. describing the hydrogen as "hydrogen-one" and making clear how much energy there is (.42 million electron volts). You don't have to call deuterium anything other than deuterium (there is only one kind, by definition—I don't know why the formula links to "Deuterium-2", because deuterium has, by definition, a mass of 2). --Mr.98 (talk) 22:49, 5 January 2011 (UTC)

I think it is a priori ambiguous whether the notation ¹
₁H
stands for neutral atoms or just the nuclei. Your suggestion picks the wrong interpretation (because then charge is not conserved across the reaction). –Henning Makholm (talk) 22:56, 5 January 2011 (UTC)

OK, that makes sense. I think specifying it as a bare proton probably is indeed most straightforward. --Mr.98 (talk) 23:24, 5 January 2011 (UTC)

(ec) "A proton and a proton become a deuterium nucleus, plus a positron, plus an electron neutrino, plus zero point four two megaelectronvolts"? –Henning Makholm (talk) 22:51, 5 January 2011 (UTC)

Going fully wordy: Hydrogen having 1 proton and one nucleon combines with hydrogen having 1 proton and one nucleon resulting in hydrogen having 1 proton and 2 nucleons (aka deuterium) plus a positively charged electron (aka positron) plus a neutrino of the electron type (aka electron neutrino) plus point four two Mega electron volts of energy. A lot of the more common particles have shorthand names, and and are the same thing - so you can write and say it either way. Ariel. (talk) 23:22, 5 January 2011 (UTC)

But that's not how you would actually pronounce the notation, is it? –Henning Makholm (talk) 00:20, 6 January 2011 (UTC)

Not for this, but by listing all the parameters it can help the OP generalize to other chains. Ariel. (talk) 00:53, 6 January 2011 (UTC)

I would be cautious about a potential ambiguity in that phrasing — the statement "hydrogen having 1 proton and one nucleon" can be readily and incorrectly misread as meaning that hydrogen nuclei contain one proton and one (other) nucleon. It might be clearer to go with something like "hydrogen, having 1 nucleon (a proton)..." or something in that vein. TenOfAllTrades(talk) 16:41, 6 January 2011 (UTC)

I'm not a physicist, so this is not an answer, but I think what the OP wants is a literal reading, as you would say when reading off the equation. Something like "one-hydrogen-one plus one-hydrogen-one yields one-deuterium-two plus electron-positive plus electron-neutrino plus zero-point-four-two em ee vee". But that's almost surely wrong - for example, I'm not sure exactly what order a physicist should read off the numbers or whether anyone would really say "electron-positive" rather than "positron" even when writing it on a blackboard. Wnt (talk) 18:51, 6 January 2011 (UTC)

Thanks to all. I was interested in both the minimal-ambiguity and colloquial readings, and they've been covered well, I think. --Sean 21:54, 6 January 2011 (UTC)

Plant food

I boil water on the stove as a method of humidifying my home. After a while of adding water and having it boil down, I end up with mineral-rich water that I need to dump to prevent it from depositing minerals on the pot. I was wondering, if, after I let it cool, of course, this would make good plant food. That is, would the mix of minerals in tap water be appropriate for your typical house plant ? StuRat (talk) 23:31, 5 January 2011 (UTC)

It's mostly calcium and magnesium (hard water), and they are listed as secondary macronutrients for plants. This and this don't mention any upper limit for them, but I didn't check any other sources. Ariel. (talk) 23:41, 5 January 2011 (UTC)

Edit: If you have a water softener then it's actually sodium and would be pretty bad for plants. Ariel. (talk) 00:04, 6 January 2011 (UTC)

Tap water composition depends a great deal on where you live. If your water company or municipality provides information about the tap water quality and composition, then you have a pretty good idea about what's left in your pot after boiling the water down. It is unlikely there will be a lot of potassium, phosphorus, and nitrogen, which is what plants need most; more likely you'll find a lot of calcium, magnesium, sodium, iron, chloride, and (bi)carbonate. Calcium carbonate is used to make soil more alkaline, but many houseplants actually prefer acidic soil. Sodium chloride is table salt, you definitely don't want that in your plants (see Soil salinity and salting the earth). --Dr Dima (talk) 00:11, 6 January 2011 (UTC)

You know, I don't think I've ever really thought about this before, but wouldn't it take kind of a lot of salt to make a large plot of land infertile? And salt used to be fairly expensive. The salting the earth article doesn't seem to provide any account of whether the method was actually effective, as opposed to symbolic. --Trovatore (talk) 06:06, 6 January 2011 (UTC)

I've long wondered if there was a chance that such stories didn't refer to NaCl but something else like copper sulfate that might have been available to the ancients from mining, or borax from desert evaporite deposits. But I've never seen the possibility mentioned let alone evaluated skeptically. Wnt (talk) 10:53, 6 January 2011 (UTC)

Salinity tolerance varies greatly among plants. For some orchids, a regular (not boiled-down) tap-water is often too salty. At the other extreme, there are quite a few plants that can tolerate ocean-water salinity level. Also, it matters a lot how you water the plants. If you remove the excess water from the saucer under the flowerpot every time, some of the salt is washed out. If, on the other hand, you let the plant "drink" all of its water every time, and never empty the saucer under the flowerpot, then the salt accumulates in the soil, and may kill the plant eventually. There are tables on the internet (e.g. here and here that quantify the salt tolerance of various plants. The tables use either units of concentration (ppm) or units of specific conductance (dS/m). A rule of thumb -- not exact! -- is 1 dS/m = 600 ppm. This roughly equals 0.6 gram of table salt per one liter water. In other words, if a quarter-gallon flowerpot has 6 grams of salt in it, you will have soil salinity of about 10 dS/m, which would kill some plants and stunt the growth of most others. --Dr Dima (talk) 21:01, 6 January 2011 (UTC)

January 6

Dragonfruit question

What are those things that look like artichoke leaves on the outside of the fruit of a dragonfruit, or pitaya? Wiwaxia (talk) 00:06, 6 January 2011 (UTC)

Bracts. Vespine (talk) 00:54, 6 January 2011 (UTC)

Oscar (fish) question

I've had a single Oscar for about 2 months and now I've just added 2 more. When I approach the tank, all 3 now come right to the top, and when I drop the food in, they all but attack the pellets, etc. But the single Oscar didn't do that when he was alone -- is this how they usually act when in groups? DRosenbach ^{(Talk | Contribs)} 04:20, 6 January 2011 (UTC)

I know really know, but I can only assume that they are running to the food to make sure to get it before it's all eaten. With just one there is no urgency. I assume that in the wild there usually isn't a concentrated source of food, and they just each search on their own for what they can find. (Again, this is just conjecture on my part.) It does remind me of something I read a while ago where someone was trying to breed an animal (some type of deer or gazelle) with no success - the male showed no interest in any of the females. Then one day males from other pens broke loose and the all ended up together - the competition from the other males stirred all of them, and all the females ended up pregnant. (The original author was rather more dramatic in how he described it, it's too bad I don't remember where it's from.) It seems that competition is not just for capitalism. Ariel. (talk) 06:32, 6 January 2011 (UTC)

Absolutely. The impulse towards competition can be absent when potential competitors are absent. 71.198.176.22 (talk) 14:07, 7 January 2011 (UTC)

evolution propaganda

Does anyone know of any evolution propaganda in the same format as the creationist pamphlets that you get from Jehovah's witnesses et al? I'm thinking of making my own but wondering if someone has done it already, I haven't really been able to find anything my self. Searching for "evolution pamphlet" predominantly gives results for the creationist ones. Vespine (talk) 05:38, 6 January 2011 (UTC)

What would be the need for such propaganda? Evolution has the weight of evidence on its side, it doesn't really need loud, garishly colored pamplets with words in all caps announcing that EVOLUTION IS THE DEVIL'S HANDIWORK or something like that. Science is generally publicized via peer reviewed journals and the popular scientific press; something the creationists lack access to, being that what they do isn't really "science". Hence the garish, badly made pamphlets. --Jayron32 05:54, 6 January 2011 (UTC)

Anyways, giving out pamphlets would only further expose the fact that evolution is desperately looking for support and evidence. --T H F S W (T · C · E) 07:04, 6 January 2011 (UTC)

Evolution can not look for support and evidence, it does not have a mind. Scientists have found a lot of evidence for evolution. I think THFSW is correct in the fact that evolution could loose credibility in the public if pro evolution propaganda pamphlets are distributed widely.--Gr8xoz (talk) 10:10, 6 January 2011 (UTC)

I would find such mock-tracts amusing. WikiDao ☯ 10:28, 6 January 2011 (UTC)

Does something that can be observed and there is no doubt about need propaganda?Zzubnik (talk) 10:34, 6 January 2011 (UTC)

In the USA, "no doubt" is the minority view, presumably because more people read Chick Tracts than Nature. --Sean 14:28, 6 January 2011 (UTC)

While those who reject evolution may be stronger in their beliefs [26] for example show it about even with about 20% not sure. Level of support for evolution#Support for evolution in medicine and industry mentions something from 2007 where 49% believe in evolution although only 14% of the total don't believe god had a part. (This may seem to be a minority but I presume there are some 'not sure' there in particular while the citation seems dead the title suggestions it's 45% who believe in creationism.)Nil Einne (talk) 16:19, 6 January 2011 (UTC)

Your first link says, "In the U.S., only 14 percent of adults thought that evolution was "definitely true,"...". "Definitely true" is not a bad synonym for "no doubt", and 14 percent is certainly a minority, so I stand by my statement. --Sean 16:47, 6 January 2011 (UTC)

Apologies, I missed the 'no doubt' part. However I still have strong doubts about your statement. It seems unlikely the reason for the entirety of the 86% of the population who don't have 'no doubts' read or have had much influence from Chick tracts. Perhaps the 45% or whatever who believe in creationism at most. It's also questionable if reading Nature is needed. For starters, understanding journal articles can be difficult for those without much experience in the field. Also the evidence for overwhelming evidence for evolution has existed for so long it's well covered in far more accessible publications and in fact what is in Nature nowadays is often going to be limited and written without any consideration of the possibility of dispute of evolution. Nil Einne (talk) 21:57, 6 January 2011 (UTC)

There's also the question of where exactly 'no doubt' isn't in a minority. Not the UK for example [27]. The survey referred in the earlier link appears to be [28] from the supplementary material [29] it appears in 2002-2003 only Denmark of the 10 countries surveyed had a majority with 'no doubt'. (United States), Poland, Netherlands, Italy, Spain, (Britain), Austria, Germany, France, had a minority having 'no doubt'. In fact France the highest after Denmark didn't even have 40%. So while it may be true the US lags behind most of the developed world in acceptance of evolution and from the ref, also differ in a number of ways, having only a minority with 'no doubt' isn't one aspect that differentiates them. BTW if you look at the main article, it has more countries but without the 'definitely true' part, interesting France is the 4th highest in this list of acceptance, and the UK is 6. Denmark is 2. Of course that doesn't mean at most 3 of the surveyed countries would have no doubt, it's 2-3 years in the future so attitudes would have changed and the different positions of countries tells us not surprisingly that potentially there's greater acceptance in some countries among the population even if fewer who think it's 'definitely true'. Nil Einne (talk) 22:07, 6 January 2011 (UTC)

You could always set up a new religion like L Ron Hubbard did. How about 'The Church of the Evolved Christ' where we have to evolve to get better, give Christ a blue skin too - that looks good. With a few million followers donating a tithe you could easily get them to produce pamphlets just like the creationists' ones and distribute them all around the world translated into a hundred and fifty different languages. How else would you distribute such pamphlets? How else would you get people to do anything with them except put them with the other paper for recycling? Dmcq (talk) 13:50, 6 January 2011 (UTC)

It could be fun to just change the words on Chick Tracts, like this one where Chick demonstrates to his own satisfaction that Jesus -- not gluons -- mediates the strong interaction. --Sean 14:28, 6 January 2011 (UTC)

I'm not sure how possible it is to mock something which is so inherently risible already. (It's not just physics, Chick even fails theology. Here he claims that Jesus's blood was not human blood, which is not exactly mainstream Christian thinking.) Marnanel (talk) 15:54, 6 January 2011 (UTC)

You make it sound like Chick Tracks are the supreme authority for anyone who doesn't believe evolution. The're not. --T H F S W (T · C · E) 17:17, 6 January 2011 (UTC)

Well, that first tract (the one with the irritable douchebag teacher and the tranquil babyfaced student) is a pretty good showcase of most arguments used against evolution. Ok, the gluon thing isn't exactly omnipresent, but open up any anti-evolution site and you'll find things like the ridiculous "six stages of evolution", the "carbon dating is inaccurate" silliness or the endless masturbation over the Piltdown man. TomorrowTime (talk) 18:47, 6 January 2011 (UTC)

Not terribly sure how you got that out of my words, or Sean's. I am sure even such people can see the foolishness of Chick tracts. Marnanel (talk) 18:32, 6 January 2011 (UTC)

I think you're looking to use your creativity to compose a novel joke, and that's not something that a science refdesk can really help you with much. You already have evolutionary theory - what you need is a mock religion to make it funny. Existing groups like the Church of the Subgenius might give you some ideas.

There is not actually any need for a conflict between religious creationism, which occurs in the dimension of time in which God authors and edits the universe, and scientific evolution, which occurs in the dimension of time in the universe as created. Just because the Foundation Trilogy covers many centuries doesn't mean that Asimov took that long to write it, or wrote it all in the order you read it. Wnt (talk) 18:44, 6 January 2011 (UTC)

I'm not trying to compose a joke. The fact that most of North America thinks people magically changed from lower animals is funny enough to me. --T H F S W (T · C · E) 19:10, 6 January 2011 (UTC)

As opposed to being magically created from dust (or ribs)? AndrewWTaylor (talk) 20:59, 6 January 2011 (UTC)

That happened due to an external influence. Different animals changing into one another is supposed to happen by itself. Would you say its weird for the keys on my keyboard to type out this message? No, because there's someone doing it. --T H F S W (T · C · E) 21:09, 6 January 2011 (UTC)

For THFSW: Introduction to evolution. You look markedly un- or mis-informed if you think the modern synthesis of evolution is "desperately looking for support and evidence" or that "people magically changed from lower animals". We have good articles on the subject; read them. — Scientizzle 22:02, 6 January 2011 (UTC)

...and keep reading. Unlike creationism, which is based on one unchanging, not allowed to be questioned, source, evolution is based on an ever growing body of knowledge being observed and interpreted by open minded scientists happy to change their minds when new evidence appears. HiLo48 (talk) 23:28, 6 January 2011 (UTC)

OP here, I was about to write, STICK TO THE QUESTION! I'm not starting a debate.. but i had to run and i thought it might be a little presumptuous, i was obviously wrong! lol.. I don't care if you think such propaganda is needed, i'm asking if it is around. I have some people close to me which have been given the creationist propaganda and it is making an impression on them. I understand "the weight of scientific evidence" is behind evolution, but there are obviously a lot of people not so scientifically literate who find a concise "to the point" pamphlet more convincing then "the weight of scientific knowledge". Thanks.Vespine (talk) 00:51, 7 January 2011 (UTC)

For the record, I agree with you that 1. the off-topic responses here have really gotten out of hand (which is entirely the answerers fault in my opinion), and 2. there's a lot of good reason to believe that good would be served if the basic arguments in favor of evolution could be condensed down into something that a "man off the street" could read, understand, and be convinced by.

There's plenty of evidence that the Chick tracts have been compelling; heck, even when I read some of them, I think, "gosh, this guy is a clever manipulator of emotions, even if he is a nut." Throwing scientific papers at laymen (even intelligent ones) doesn't do anything; appealing to scientific authority only gets you so far; and dismissing the "lay" opinion as unchangeable or, worse, irrelevant is dangerous and wrong as well. As for having examples of said good "propaganda" (which is really an unfortunate word to use because of its negative connotations), the National Center for Science Education produces a good number of pamphlets and short books that are aimed for this purpose. I'm not sure they have them posted online, and when I saw them (in the late 1990s, in their Oakland location), a lot of them were moldy golden oldies of an earlier time (arguing against Henry M. Morris and other, uh, transitionary fossils). But I'm betting if you wrote them or sent them an e-mail they'd send you some samples; they're a pretty generous bunch and I seem to recall the pamphlets being free anyway. --Mr.98 (talk) 02:38, 7 January 2011 (UTC)

Try "An Introduction to Evolution" from UC Berkeley's "Understanding Evolution" project. There are printable links on each page. I'm pretty sure it's as close as you're going to get to a religious tract about evolution, without the appeals to emotion, authority, or circularity. 71.198.176.22 (talk) 13:04, 7 January 2011 (UTC)

Rotating momentum exchange tethers in LEO, drag and space debris

Does there exist a altitude range in low earth orbit were a rotating tether (Tether_propulsion#Bolo) for launch assist cold be placed?

I am thinking of a tether with the tip 50 km from the centre of mass and a tip speed of about 2 km/s relative to the centre of mass and an allowed load of at least 80 kN (1000 kg). It should be used by gaining orbital momentum by moving incoming objects from a high orbit to a lower unstable orbit and then give that orbital momentum to payloads launched by suborbital launch vehicles. The tether need of curse to be constructed with multiple strands for redundancy like the Hoytether. This would be part of a larger transportation system.

It must be operated at an altitude below most of the space debris in order to get a useful expected survival time. At the same time it will have high surface area and need to operate at an altitude where the atmosphere are thin enough to not generate a prohibitive high drag. Does such a altitude exist?

Would (micro) collisions with the tether generate a significant amount of new space debris? --Gr8xoz (talk) 11:07, 6 January 2011 (UTC)

I don't think we should assume that a tether needs to passively accept collisions with debris or other micrometeorites, given sufficiently effective sensors. To take a simple example, suppose that a tether has two cables separated by a few meters. If a piece of debris heads for one of the two cables, it temporarily relaxes its hold (perhaps at the expense of tightening in several other segments upward and downward). As a result, the loosened cable can be pulled out of the way toward that which is still taut, and the space debris flies through the hole. True, this requires a 2x redundancy factor, but only temporarily, and in case of catastrophic failure of the taut cable the lax one may still be able to hold the elevator while a repair module is dispatched to the site. And in practice I suspect that there would be quite a few more cables than just two, lowering the required strength-to-weight ratio needed for redundancy in all cases. Wnt (talk) 18:35, 6 January 2011 (UTC)

The ability to avoid collisions is very useful but I think there exist a gap between the debris that reasonable can be detected and the size of debris that can cut the tether. [30] on page 180 or according to the pdf-reader 187 estimates that debris as small as 0.2 mm can cut a 1 mm strand. I think it is hard to detect so small debris if it is approaching at 15 km/s (page 164 or 171) --Gr8xoz (talk) 20:22, 6 January 2011 (UTC)

How do you plan to detect debris or micrometeoroids on the order of millimeters in dimension moving thousands of meters per second, especially far enough in advance to calculate the probability of impact and take action to move the tether? The tether WILL be hit with MMOD. I doubt that these small pieces would pose a new debris risk, though damage would accumulate over time and threaten the tether. A large, undetected object would also threaten the tether. So for any space elevator, this is a real problem with no easy solution. anonymous6494 19:56, 6 January 2011 (UTC)

To me, it seems absolutely unbelievable that people can track a satellite in Earth orbit, or even smaller bits of lost materials. Getting down to 0.2 mm is not that many orders of magnitude of difference. Also, pieces that are isolated specks and cut only a single cable should not really be so dangerous, because there should be periodic cross-struts between several cables, and repair modules that fix one broken cable while the others hold the structure together. After all, there will be spontaneous ruptures in the cables due to defects in manufacturing or deployment or during use, and the system will have to be ready for those. Wnt (talk) 06:32, 8 January 2011 (UTC)

Cause of vibration of a string

Project of “ ANKITIUM ” , The Unit Of Life :---------- When we make an approach to the string, we assume the mass, charge and energy as the fundamental properties of a particle. In this way of approach all of our thinking ends up to the Big Bang. We could not be able to know that how does it occurs or what was the situation before it occurs. But if we change our approach by considering the cause of producing mass, charge in an electron (or proton) from a string vibration, we might be able to find out the reason lying behind the Big Bang or the situation before the Big Bang.

Every mass contains some atoms. An atom contains a nucleus and some electrons. Nucleus contains protons and neutrons. Protons are positively charged, neutrons are neutral and electrons are negatively charged (It is our convention to assume that the charge in protons is positive and the charge in electron is negative.).

As all we know that vibration is the only way to transfer energy (such as thermal energy, sound energy etc.) from one place to another, we can conclude all of the energies can be created from vibration. As vibration takes place in different mode, different kind of energy can be produced at different mode of vibration.

Now, consider one electron. The electron is negatively charged. But from where does the charge come from or rather I would say where does it produce from? We can assume an electron as a negatively charged spherical cloud (as per electron’s wave nature). The radius of the spherical cloud is equal to the radius of an electron when it is considered as a particle. The spherical cloud implies the area of the electric field, produced due to the negative charge, in which it acts. In between this spherical cloud, there exists a vibrating string according to the String Theory proposed by Sir Stephen Hawking. The vibration is at one direction (say in anti-clockwise direction). This vibration produces some amount of energy. A part of which converts into a mass which is equal to the mass of an electron, obeying the famous equation E=mc2, of Sir Albert Einstein. Another part of this energy gets converted into some amount of charge, equal to the charge of an electron. This amount of charge produces a spherical shaped electric field which is called an electron in particle theory and electron cloud in wave theory, owing to the dual nature of the electron. Now, from where does the vibration of the string produce? In account to solve this problem, we can assume a string consists of many infinitesimally small units which are continuously getting compressed and elongated in success. These units can be called as the unit of life or rather I could name it after my girl friend, “Ankitium” (“Ankitia” in plural). But why does an Ankitium get compressed and elongated in success?

As we all know that the photons (unit of energy) are absorbed in multiple integrals of a quantum, energy of which is equal to ‘hv’ (h= Plank’s constant and v= frequency of the incident light). Our universe consists of different types of rays with different frequencies. Let, the different rays in this universe are of frequencies v1, v2, v3, v4....... and so on. Let us assume that v1=v. Hence, from Plank’s theory E=hv=hv1. An Ankitium absorbs the amount of energy in multiple integrals of ‘E’ or v1. When an Ankitium absorbs energy from the rays having frequencies which are of multiple integral of v1, the total energy of an Ankitium increases and the Ankitium reaches to a higher energy state. As a result, the Ankitium tries to elongate and a tensile force is built up. But all the frequencies must not be a multiple integral of v1. So, energy will not be absorbed by the Ankitium when the frequency of the incident photon are not of a multiple integral of v1. As a result, then the energy state of the Ankitium gets lowered and it comes across with a compressive force. Thus an Ankitium gets elongated and compressed in success. In case of protons, the vibration of the string must be at opposite direction that of in an electron. As a result, an amount of positive charge is produced. In the neutrons, the vibration must take place in such a way that it only produces an amount of energy which totally converts into a mass equal to the mass of the neutron. As a result, no kind of charge is produced in neutrons.- 61.11.120.66 (talk) 11:23, 6 January 2011 (UTC)

Is there a question in there? I didn't see it. SpinningSpark 11:42, 6 January 2011 (UTC)

I think the questions are 1) Where does an electron get it's charge from, and 2) Where does a string get it's energy from Zzubnik (talk) 11:56, 6 January 2011 (UTC)

I can't answer the questions because not even Stephen Hawking knows the answers. The charge of the proton is known to come from the arrangement of quarks, but that only moves the question one stage back and doesn't explain the charge of leptons. I don't think the "ankitium" will ever be discovered because strings are not believed to consist of matter, or to be in any way "divisible" (or even "real"), they are just mathematical constructs. The vibration modes of the strings are the mass, energy and charge. Alternative theories are M-theory and loop quantum gravity. Dbfirs 12:43, 6 January 2011 (UTC)

I agree, Dbfirs. This is somewhat like asking for a grand unification theory, or the answer to the question of life, the universe, and everything. Although, the answer to that last one is known to be 42. — Preceding unsigned comment added by Zzubnik (talk • contribs) 18:38, 6 January 2011 (UTC)

I asked a similar question just last month: Wikipedia:Reference desk/Archives/Science/2010 December 24#Why do superstrings "vibrate"? -- œ^™ 19:13, 6 January 2011 (UTC)

What's the single best case for evolution?

The conversation about evolution above makes me think that we should pick out a single best case for evolution, a situation so well studied with so many different techniques that it provides a more than compelling argument. Of course, no evidence from the natural sciences can disprove that the world could have been affected by supernatural means, but the point to prove is that if someone made the world, it was deliberately made to look like it has a single consistent history going back millions of years which includes evolutionary change.

The case I want involves:

• Two points on opposite sides of the Atlantic Ocean, in places which visibly look like the continents once fit together there.
• The currently measured rate at which these two points are drifting apart closely matches the established breakup of Pangaea.
• Magnetic field reversals in the crust have been observed close to the line separating these two points, confirming a large number of reversals which match the time frame (though this is a weak argument, as a skeptic will argue the presumed reversal rate is only inferred from the data)
• A land species has been found fossilized near each of the two points.
• The radioactive dating of these fossils matches one another and the time at which Pangaea was breaking up.
• According to radioactive dating, fossils of this land species are found only during a narrow interval of time. However, transitional fossils closely link it to later species which continued to thrive on either side of the ocean, which are different on either side of the ocean. There should be as little confusion about this ancestry as possible.
• DNA analysis of modern living descendants of this species from either side of the ocean reveals differences between them. Modern phylogenetic analysis concludes that they diverged at about the period of time shown by the fossils, assuming mutation rates that are typical judging by those observed today.

I know that there are many situations where a few of these points are met. But I'd like to see an argument with sledgehammer strokes in which we show that geology, paleontology, radioactive dating, and conventional and molecular taxonomy all come together and show the same time frame over and over. That way the skeptic has to try to prove that most if not all of these disciplines are simultaneously wrong or conspiring to conceal the truth, an argument which becomes exponentially harder with each type of data that needs to be ignored. I know that finding such a case is very difficult, even for the expert - I'm just curious if people have in the course of disputations on the subject managed to hit across a good case that is suitably convenient and well-studied. Wnt (talk) 20:00, 6 January 2011 (UTC)

Peppered moth evolution is a common example, perhaps not as spectacular as you hoped for but it did take place in the blink of an eye rather than aeons. 92.24.188.182 (talk) 20:27, 6 January 2011 (UTC)

(ec): How about this paper on E. coli long-term evolution experiment? --Dr Dima (talk) 20:29, 6 January 2011 (UTC)

Guys! Neither of those examples have anything to do with the above post other than the heading. Did you read the post? Please don't bother posting an answer if you haven't read the question! --Mr.98 (talk) 20:56, 6 January 2011 (UTC)

The OP lists so many criteria that its unlikely that anything can fulfill all of them. So in the abscence of that, other examples of evolution were given. 92.24.188.63 (talk) 00:22, 7 January 2011 (UTC)

No, I did read the question. The OP asks for "single best case for evolution", and both my reply and that of 188.182 give examples of some of the best cases for the evolution. I simply do not think that "combining many different techniques that it provides a more than compelling argument" is a good educational strategy in this case. The reason is, whatever scientific evidence of evolutionary history -- no matter how compelling -- you present to a person who thinks the world was created as-is 5800 years ago, fossils and all, it will not alleviate that person's doubts. But if you show this person a colony of bacteria that has actually evolved to metabolize citrate literally in front of researchers' eyes, you may actually have a compelling argument that evolution does happen. --Dr Dima (talk) 21:27, 6 January 2011 (UTC)

The question qualifies very heavily what it means by the "single best case", and your answer ignored that completely. That's what I meant by it appearing not to have read the question. --Mr.98 (talk) 21:29, 6 January 2011 (UTC)

Regardless of the example, this attempt will fail miserably. People who do not want to believe in evolution will not believe in evolution. Another way to put it is: You cannot reason a person out of a belief that they formed without reason. No matter what you attempt to prove, the response is simply, "God made it look like that" - the religious equivalent of "a wizard did it." -- kainaw™ 20:31, 6 January 2011 (UTC)

Your arguments seem more in favor of Plate Tectonics Theory than the Theory of Evolution. As for the strongest support for evolution, I'd have to go with dinosaur bones. There are many skeletons of nearly intact dinosaurs, which are completely inconsistent with the Biblical record. The number and variety of those skeletons shows that there were many eras of dinosaurs. So, which day of Biblical creation were these created ? It just doesn't fit. And, unlike radiocarbon dating, the Big Bang Theory, etc., it really doesn't require any great scientific understanding to look at a T-Rex skeleton and see that it is very different than anything in human experience (or Biblical accounts). StuRat (talk) 21:10, 6 January 2011 (UTC)

Creationists have long made their peace with dinosaurs. (They would have been created on the same day as the other animals, incidentally.) See e.g. this particular discussion. What the OP is asking for is something that is totally scientifically air-tight, not something that appeals to the common man. --Mr.98 (talk) 21:29, 6 January 2011 (UTC)

But that doesn't explain why the Bible didn't mention them (how about a full inventory, just like the "begets" ?). Also, are they supposed to have all died on that same day, too ? If so, why ? And are we taking the Bible literally, so that they only existed for 24 hours ? StuRat (talk) 22:42, 6 January 2011 (UTC)

It doesn't mention a lot of animals, either, and in fact, as the page points out, big, dinosaur-like creatures (and dragons) are mentioned far more than a lot of other common world critters. It's not meant to be an atlas of all animals. I'm not a Creationist at all, but purposefully misreading the Bible (like the idea that they existed for 24 hours, which nobody contends) just sets up a rather foolish straw man, which is convincing to none. If you want to be truly convincing, you argue against the best oppositional case, and show why it is wrong. Not the worst. --Mr.98 (talk) 00:35, 7 January 2011 (UTC)

OK, then, just what is the strongest Biblical case ? The other one I've heard is that dinos were around until The Flood and didn't make it onto The Ark. That seems even more absurd though, if they were supposedly running around with people, as in The Flintstones. Is there also an idea that they were around with Adam and Eve, but died out soon after ? StuRat (talk) 04:09, 7 January 2011 (UTC)

It's creationism that's based on a single, unchanging, unquestioned source. Evolution, like all science, is based on an ever accumulating set of knowledge, combined with an ever questioning community of scientists. The knowledge is massive. Heck, Darwin's voyage in the Beagle took five years! Those who want to believe in creationism are missing most of that knowledge, or choose to ignore it. They oppose letting children have the former and will continue to ignore. HiLo48 (talk) 21:24, 6 January 2011 (UTC)

As the form of the question makes clear, the dispute about evolution is really a surrogate for a dispute about a far more important question, the age of the Earth (and the Universe). The two contending hypotheses for the age of the Earth are (1) about 4.5 billion years (modern science); (2) about 6000 years (biblical literalism). As an argument in favor of the scientific age, the one given above is pretty strong, although not necessarily the strongest possible. It is basically impossible to support an age of 6000 years without assuming that the visible universe is at most 6000 light years in size, which pretty much trashes modern physics. Looie496 (talk) 21:26, 6 January 2011 (UTC)

There is a fundemental flaw in the question itself, in that it assumes that theories like evolution are built on isolated pieces of evidence, and that some of those pieces of evidence are better than others. This isn't how science works. The theory of evolution is a working theory, and has been for the better part of a century. No one works at building evidence for it, they just use it as background understanding for their research, and the research works. In a sense, all of biology and its subdisciplines has evolution as one of its cornerstones, and insofar as every experiment in biology and subdisciplines works, that's the evidence. All of life is itself the evidence for evolution. The flaw in the question asked in the title of this thread is why the creationist/intelligent design crowd always ends up fighting the wrong battle. There is a belief that evolution (and indeed science) works only if every single piece of evidence that exists is correctly interpreted, and completely true. If you can find one error, or find one single thing that does not yet have adequate explanation, then the entire system is completely and utterly wrong. This sort of reasoning showed up in the defendant's testimony at Kitzmiller v. Dover Area School District, the most important trial case since the Scopes trial in this area, and forms a major part of what is known as the Wedge strategy known as Irreducible complexity. The idea being that certain key elements of living systems, as yet unexplained by science (classic examples are the eye and the flagellum) can be used as the point of the "wedge" to drive into evolution, and prove it wrong. The OP's question presumes the same sort of misguided reasoning, that there are "best examples" and "wrong examples" and that we merely need to put forth the "best examples" to prove evolution or the "wrong examples" to disprove it. --Jayron32 21:33, 6 January 2011 (UTC)

Furthermore, all observational evidence is moot, because it is fundamentally impossible to verify the existence of "reality." This isn't new; Allegory of the Cave predates Christian thought; and the philosophical concept has been re-hashed out by every major school of thought, from rationalism to post-modernism. If somebody doesn't want to accept observational evidence as proof of reality, it doesn't matter how solid your observational evidence is. At best, we can prove that "I perceive something." The next step, "I assume that my perceptions represent a real, natural, material world" is completely unfounded. Religious belief attacks scientific thought at this level by presuming that a supernatural reality exists beyond anything which we can perceive. So, purple unicorns, space teapots, and all that. Nimur (talk) 21:45, 6 January 2011 (UTC)

(Pedant) I think you mean pink unicorns and purple oysters [31]. CS Miller (talk) 00:19, 7 January 2011 (UTC)

Burn the heretic! --Stephan Schulz (talk) 09:52, 8 January 2011 (UTC)

The case for evolution is the same as the case for any other well established scientific theory: It is a simple explanation for our observations. There is no other explanation that even comes close. --Tango (talk) 00:10, 7 January 2011 (UTC)

The best argument I can find against young-Earth creationism is varves. Unlike dating based on radioactive decay, varves provide a very direct, very simple to understand measure of the geological passage of time, even to people with a very weak understanding of any branch of science. And the six million varve depth of the Green River Formation shows that the Earth is at least six million years old, which although that's only a small fraction of the total age of the Earth, is still vastly older than is thought by anyone who measures the time since creation in the thousands of years. However, I still had no luck convincing some Jehovah's Witnesses I talked to that the Earth is at least millions of years old. They didn't have any explanation for the six-million varve depth of the Green River Formation, but they really didn't care. Some people are just going to believe what feels good to believe, regardless of what the evidence says.

What I think is one of the best arguments for evolution are the Australian marsupials (Australidelphia). There are scads of different species of them, but there are biological similarities among them that aren't found elsewhere in the world. Why all those different species of biologically similar animals happen to only be found in Australia is easy to explain with evolution, but hard to explain if all of those different species independently made their way to Australia somehow from Noah's ark. But like with the varves, although the Jehovah's Witnesses I talked to had no explanation for the geographical isolation of the Australidelphia, that didn't actually affect their beliefs. They just didn't care. Red Act (talk) 01:47, 7 January 2011 (UTC)

All observational evidence, even varves, is counteracted by "God made it that way". It's a pointless arguement. Either people are prepared to accept that God created the world as it really exists, with evolution and the Big Bang, and all of it, or they believe that God created the world as they wish it to exist, on a Tuesday morning about 6000 years ago. If they believe the latter, the believe it without any need to look for evidence for how God really made the world. So any evidence you provide is pointless. --Jayron32 02:56, 7 January 2011 (UTC)

Your third sentence is a false dichotomy, in that it assumes that all possible belief possibilities include the belief in the existence of a God that created the world one way or another, which is not a valid assumption. Red Act (talk) 05:28, 7 January 2011 (UTC)

True, you could take God out of the picture and have the same arguement though; he's optional for the point of argueing the validity of evolution in this case as an aside, I do not find God personally optional; as an evangelical Christian myself, I find God pretty mandatory to any of my own belief systems. I also recognize, however, that it isn't necessary for this particular arguement, and so I won't belabor the issue. However, if your point is to help those who believe in God also accept the validity of evolution, its probably more helpful to show how evolution is not fundementally contradictory of anyone's religious belief. If you imply that God and evolution cannot coexist in the same belief system; then you fall into the same exact faulty thought processes that make it so that the strongly religious refuse to accept evolution. Argue the important point; which is the reality of evolution, not the unimportant point, which is the existance of God. unimportant, I might add, to the validity of the case for evolution, not in general. See my aside above. --Jayron32 06:21, 7 January 2011 (UTC)

If God's so smart, why does He simply not tell us what we should believe about evolution? Why leave us guessing? He dosnt reply to prayers etc, has no address, no telephone number, no webpage, no nothing. Do you think He has passed on? On the other hand, when I pray to Santa Claus at the right time of year, He (Santa I mean) brings me presents. Next time I see Santa, I will ask him what the trutrh regarding evolution is. 92.24.183.6 (talk) 16:58, 7 January 2011 (UTC)

Well, he doesn't reply to YOUR prayers. Or maybe he does, and sometimes his reply is "No". --Jayron32 20:06, 7 January 2011 (UTC)

Is the pronoun "He" for Santa and "he" for God ? Cuddlyable3 (talk) 01:56, 8 January 2011 (UTC)

For the OP, a good start would probably be a book like The Greatest Show on Earth: The Evidence for Evolution by Richard Dawkins. If anyone is going to summarize the best arguments in support of evolution it is Dawkins. You might also want to look at our article on biogeography which briefly discusses some evidence based on paleogeography, plate tectonics, and molecular analysis of fossils. --- Medical geneticist (talk) 03:08, 7 January 2011 (UTC)

I had a feeling it would end up in Dawkins... I'll have to actually read him the next time I happen across a copy. I should clarify though that I understand that such a perfect example is not necessary to justify the idea scientifically, and it is also not sufficient to disprove the religious idea of creation. The point is to justify to creationists the idea that the universe is truly a four-dimensional work of art - a story for which a very long past has been written. The creationist does himself an injustice when he fails to consider that if God wanted our planet to have a consistent, logical, richly detailed history stretching back hundreds of millions of years, it means that there is something to be learned from it. Wnt (talk) 10:13, 7 January 2011 (UTC)

You won't find such an arguement in Dawkins. His stance on Evolution is a pretty good read, however he's rather intolerant towards any religious worldview. His writing on religious issues is quite bitter and angry, and not at all "rational" if you ask me. The God Delusion, for me at least, comes of as no less dogmatic than any religious apologetic text. --Jayron32 14:09, 7 January 2011 (UTC)

As an aside, if you want to read someone who DOES do a good job of balancing the religious worldview with the scientific one, might I recommend Stephen Jay Gould, especially Rocks of Ages. --Jayron32 14:14, 7 January 2011 (UTC)

The Speciation article has some concrete examples of natural and artificial speciation which make the case pretty well. 71.198.176.22 (talk) 13:12, 7 January 2011 (UTC)

Wnt - that's a significant comment about time being a critical factor. Evolution has created the complexity we now see through having 3 billion years in which to do it. And there's one of the big stumbling blocks. A creationist argument is that evolution couldn't have created what we now see in the pathetic 6,000 years which they think their god tells them it's had. And they're right. It couldn't have happened in 6,000 years. Dunno what "single best case" we could use to get over that hurdle. HiLo48 (talk) 04:01, 8 January 2011 (UTC)

Even a much less than omnipotent god could get past the physics difficulties if it were required - you could say, he just blew on the continents early on to separate them much more quickly than in the current day. But the difference is that such a minor deity would leave no field reversals in the part of the ocean that was separated in some rapid semi-cataclysmic fashion. Now a suitably powerful deity can get all the tricky little details right, but doing that displays a deliberate intent to make the result match what would occur from the physical processes observed by natural scientists. The point is not to show that the natural science model is absolutely true, notwithstanding supernatural intervention. It is to show that it is meaningful - that even God thought it was important to keep the theory consistent! I should point out that even a run-of-the-mill atheist can read Hitchhiker's Guide to the Galaxy and at least suspend disbelief on a model in which an alien species perfectly recreates the Earth after it has been destroyed - for people on such an Earth a nonreligious creationism is actually the truth, and yet one supposes that it is still useful for them to study evolution. Of course, with anything less than an omnipotent, omniscient deity, the errors will eventually show. Actually, it has sometimes been my speculation that this really isn't the original Earth, but a historical recreation of the first period of history that was recorded well enough to make a decently accurate simulation, and occasionally I am prone to wonder whether certain details are errors in it. (For example, I've wondered whether a primate species capable of such amazing feats of acrobatics truly could not manage to put one of a few keys into a lock without fumbling around for half a minute; perhaps the original humans did this only as a matter of politeness? But I digress!) Wnt (talk) 04:57, 8 January 2011 (UTC)

I am prepared to believe in a God that has created the world, by Intentional Design, so that it very cleverly in all its details is entirely consistent with modern Evolutionary biology (and Evolutionary psychology, too, and so on).

But the overwhelming weight of all the available evidence, and the learned consideration of it, supports -- is consistent with -- the possibility that it has all occurred the way it has over the course of aeons without any need for any "Divine Guidance" of it according to some divinely "Intelligent Design" of it.

But, still, God, for reasons of God's own, could have made it just look that way – exactly as if there is no need for a God even though there really is a God! Right? But... what difference would the existence of such a God make? And why would God want to do that? If it is the God of the JudeoChristian bible that you believe to be behind such diabolical trickery, could it be because that God is a very "jealous" God, and just wants to test to see if we will still "believe" even though there is absolutely no good reason to do so on the basis of the evidence that God has seen fit to make available to us...? Do you think a God capable of "creating" this whole world in all its unimaginable vastness and complexity would really be inclined to such childish games?

I am prepared to believe in any God in Whom there is any good reason or cause or use to believe in. That God is welcome to make Its existence known to me at any time. If you have some reason to believe in the God you believe in -- well, God bless you and more power to you. But don't assume that reason or that God must necessarily exist for anyone else - and I recommend just leaving it at that, especially here at the Science desk. WikiDao ☯ 05:26, 8 January 2011 (UTC)

The "no need for God" part is tricky. Very tricky. The universe could have operated "spontaneously" with a set of physical laws that didn't allow for life. The strong anthropic principle suggests that we just happen to see the universe which allows us to exist. But what does it mean for us to exist? To perceive things? Why doesn't a fire, say, count as having a perspective that it devours fuel and responds? Why aren't its ever-changing currents as capable of feeling and experiencing as our brains' electric currents? (Then again, I suppose I don't know for sure that they're not...) The point is, this idea that things can be experienced comes from somewhere. The ideas that there's such a thing as space, such a thing as time, such a thing as perception, such a thing as thought, where do these come from? The materialistic idea that matter just exists and knows what to do by some laws of physics, all without any designing intellect ... it seems like a shell game. God has just been swept into tidy little corners, The Mind's I kind of stuff, where we find the philosophy so hard to think about that we ignore it. But it's not a meaningful settlement.

The simplest way to describe the difference between the purpose of religion and that of science is to picture the universe being intelligently designed in stages, like a draft that is gradually written and revised by an author. If you picture space as a movie, and take one "frame" of three-dimensional space frozen in time, then the relationship of that frame to the ones before and after it as defined by physical laws and perceived by mundane consciousness is one temporal dimension. God's involvement in that dimension is deliberately very small, and may not be distinguishable from the indeterminate laws of physics. But another dimension of time links a frame to a different frame in which a process of divine authorship and revision is going on, according to its own supernatural laws. Thus there is a linear succession of parallel universes in a fifth dimension, which is defined as "God's sense of time". This is particularly consistent with Christian theology in particular, which postulates that the universe was created on a succession of days (in God's time only, as there are no humans described to see the first few days) leading to a small, simple, easy universe, which is then replaced by a series of more complex universes, and where even the current universe is not the final form, but is to be replaced by a perfected version. Wnt (talk) 06:25, 8 January 2011 (UTC)

Lost in taxonomy

A Pliosaur discovered in Stretham in 1952 and discussed briefly in that article is causing me some nomenclature concern. In his 1959 paper, Tarlo argues that "... the characters of the anterior cervical vertebrae show that the Stretham specimen belongs to the species P. macromerus Phillips ..." then goes on to suggest "... a new generic name [is] necessary for P. macromerus. The name Stretosaurus gen. nov. is chosen as it seems fitting that the village of Stretham where this giant skeleton was discovered should be commemorated".

What does Tarlo mean? Is he suggesting Stretosaurus gen. nov. is a synonym for P. macromerus or even P.? Confirm P. is the genus and in this case is Pliosaurus. How should I refer to this extinct animal? Is it a Stretosaurus, a Stretosaurus gen. nov., a Pliosaur, a P. macromerus, a Pliosaurus, all of the above or a what?

yours sincerely, very confused --Senra (Talk) 21:19, 6 January 2011 (UTC)

You will find further reference to this question, which may or may not clarify, in the article Liopleurodon. 87.81.230.195 (talk) 15:52, 7 January 2011 (UTC)

Thank you 87.81,230,195. Just to be very clear here, I am refering to the specimen with the Sedgwick Museum catalogue number: J. 35990 a–z, aa–zz, A–Q. I have looked at Liopleurodon which seems to suggest

Stretosaurus macromerus Tarlo 1959 -->

Liopleurodon macromerus relegating Stretosaurus to a junior synonym of Liopleurodon Halstead 1989 -->

Pliosaurus macromerus Noè 2004

implying (to me) I should refer to this animal as a Pliosaur, P. macromerus? Am I correct? --Senra (Talk) 00:08, 8 January 2011 (UTC)

The Pliosaurus article mentions the species with no content on a dubious classification, so yes, I think you're right. Crimsonraptor | (Contact me) Dumpster dive if you must 00:21, 8 January 2011 (UTC)

Followup on element symbols

In chemical symbols like what is the purpose of the left-hand subscript (6 in this case)? Chemical symbol says it's the atomic number, but that's already known from the element name. Why the redundancy? --Sean 22:17, 6 January 2011 (UTC)

Chemical formula#Isotopes notes, "This is convenient when writing equations for nuclear reactions, in order to show the balance of charge more clearly." DMacks (talk) 22:30, 6 January 2011 (UTC)

(ec) Nobody needs that for Carbon, because "everybody" remembers the atomic numbers of the first twenty or thirty elements. But Yttrium and Ytterbium, now that's a whole other story! Heck if anyone can remember the atomic numbers of all hundred or so elements. Particularly in nuclear chemistry when we have a lot of nuclei on the paper, and a lot of changes and intermediate products, it's convenient, albeit redundant, to annotate the atomic number. Nimur (talk) 22:31, 6 January 2011 (UTC)

(ec, continuing my thoughts) In general, if the whole focus of some discussion is centered on the nuclear charge (for whatever reason), may as well just state it instead of having to look it up, and especially for cases where the atomic symbol is not universal (systematic vs eventually blessing by IUPAC, or international language differences). DMacks (talk) 22:37, 6 January 2011 (UTC)

As an addendum, nuclear physicists also draw the periodic table a little differently than regular chemists: Table of nuclides (complete); it visualizes the information differently and makes it easy to draw decays and reactions on the chart. Nimur (talk) 22:38, 6 January 2011 (UTC)

It's not strictly necessary, and you'll find lots of instances where it is dropped. But it's convenient. --Mr.98 (talk) 23:14, 6 January 2011 (UTC)

Why does a grape soda stain on a white paper towel look like a bird map?

A small paperback book I've had since I was a child has pictures of familiar American birds and shows a map of where they live. The summer range is pink, and the winter range is blue. Some birds can live in certain areas year-round, so the area where the ranges overlap is purple.

One would think a grape soda stain would be purple.Vchimpanzee · talk · contributions · 22:41, 6 January 2011 (UTC)

The pink/blue map overlay sounds characteristic of the Peterson Field Guides A Field Guide to the Birds; I have found those to be better than the official National Audubon Society bird guides. Do you have a question? Nimur (talk) 22:59, 6 January 2011 (UTC)

The question is hidden in the section title (annoying but common) and would appear to ask about the separation via paper chromatography of the various pigments in grape juice. -- 119.31.126.67 (talk) 00:33, 7 January 2011 (UTC)

It is really a shame that that article has no illustration in it. I seem to recall endlessly doing this experiment as a child, where you separate out black ink into its component colors. It's a very vivid illustration of a basic concept, and easy to do if you have the right materials (e.g. a bottle of blank ink). Anyone game? --Mr.98 (talk) 21:07, 7 January 2011 (UTC)

India ink ? Cuddlyable3 (talk) 01:51, 8 January 2011 (UTC)

ER

can anyone tell me the names of tv show's where they take you into the emergency room and show whats going on ? example

http://www.youtube.com/watch?v=j0p74MgfV-8 — Preceding unsigned comment added by Tommy35750 (talk • contribs) 22:54, 6 January 2011 (UTC)

Sorry to be blunt, but what has this got to do with science? You'd be better off asking the uploader of the video on youtube. SmartSE (talk) 23:11, 6 January 2011 (UTC)

Why the need to bite the questioner? The link to science seems pretty obvious: a desire to see examples of the science (admittedly sometimes considered an art) of emergency medicine in practice. Edison (talk) 00:41, 7 January 2011 (UTC)

We have many entries in Category:Medical television series. ER sounds a lot like what you describe? DMacks (talk) 00:24, 7 January 2011 (UTC)

I think the OP is looking for documentary material, not drama. SpinningSpark 01:23, 7 January 2011 (UTC)

I think it's Trauma: Life in the E.R. APL (talk) 00:45, 7 January 2011 (UTC)

The OP does not make it clear whether he wishes to know about actual medical emergency departments or fantasy fiction. Richard Avery (talk) 07:43, 7 January 2011 (UTC)

I don't think they are asking about this show, but any show that covers the subject. 72.2.54.34 (talk) 01:01, 8 January 2011 (UTC)

It is a fact that the OP chose not to post the question at the Entertainment desk. Cuddlyable3 (talk) 01:47, 8 January 2011 (UTC)

January 7

Yellow zinc passivated screws and chrome-6 carcinogen

I've bought some "yellow zinc passivated" woodwork screws, and after looking up on the internet what "passivated" means, I've found information like this page http://www.ewes.se/doc.asp?M=100000096&D=600000326&L=EN which says that some kinds of passivation use a "grade 1" carcinogen, described as chrome six, and are in the process of being banned by the EU.

The screws I've got look reddish with a little pale green rather that the "yellow" of the label. Have I bought the bad kind that are beginning to be banned? Thanks 92.24.188.63 (talk) 00:15, 7 January 2011 (UTC)

See zinc chromate. --98.221.179.18 (talk) 01:19, 7 January 2011 (UTC)

I understand that what is to be regulated are the exposure of industrial workers to the carcinogenous chemicals, and use of the plated surfaces in medical or food preparation applications. The woodwork screws may one day be marked Unsuitable for these but I doubt that sale of them will be banned.Cuddlyable3 (talk) 02:11, 7 January 2011 (UTC)

The answer appears to be "probably". Hexavalent chromium and passivation are relevant. 92.24.178.121 (talk) 11:11, 7 January 2011 (UTC)

I agree; avoid exposure to hexavalent chromium. If you're just using a handful of screws, wear gloves and/or wash your hands. If you're a carpenter, buy galvanized screws or screws passivated with a different oxide instead. 71.198.176.22 (talk) 14:00, 7 January 2011 (UTC)

It is better to get other types of screws like galvanized ones. --98.221.179.18 (talk) 21:48, 7 January 2011 (UTC)

New Jersey Department of Fish and Wildlife field guides

I would like to know if these are copyrighted. --98.221.179.18 (talk) 01:19, 7 January 2011 (UTC)

Probably. In the U.S., the only things which are safe to assume are in the public domain are those a) expressly released into the public domain by the rightful copyright holder b) published before 1923 or c) published before 1978 whose copyright was not registered or renewed properly before 1978. Anything created and published since 1978 is presumed to be under copyright to someone unless expressly released into the public domain. --Jayron32 02:45, 7 January 2011 (UTC)

Things created by an employ of the federal government, as part of their capacity as a federal government employee, are also considered non-copyrightable: Copyright status of work by the U.S. government. However, this does not apply to state governments or employs. The State of New Jersey specifically claims copyright to the NJDEP Division of Fish & Wildlife webpage (at the bottom), so I think it's likely that they'd claim copyright to the guides as well. I don't see a specific copyright claim on the guides, but as Jayron pointed out, there doesn't need to be a claim to copyright to be copyrighted. It also remains unclear whether the state of New Jersey holds the copyright to the work, or the authors ("Schwartz, V. & D. Golden", as attributed). I am not a lawyer, but in general, I believe it's only the owners of the copyrighted material that are allowed to sue (or issue Takedown notices)

Of course, depending on what you're using the material for, copyright may or may not matter. Something like Wikimedia Commons will only accept work that is truly under a free licence, but in many cases, if you're confident that the copyright holder won't sue, you can do whatever you like with the material, irrespective of the law. I'm not sure if the state of New Jersey (if they are indeed the copyright holders) is likely to sue anyone over some obscure field guide, even if they don't do find out. If you intend to use the material in any serious way, it would be a good idea to seek the advice of a lawyer. You could also send a polite e-mail to the New Jersey Department of Fish and Wildlife inquiring about the work. Even if they aren't willing to release the material under a free licence, they may be willing to grant you permission to use it in specific ways. Buddy431 (talk) 03:38, 7 January 2011 (UTC)

Edit: NJ Division of Fish and Wildlife Contact Info. Buddy431 (talk) 03:46, 7 January 2011 (UTC)

Edit: I did find one example of a New Jersey government agency suing Youtube for a copyright infringement, [32], so I guess they're willing to protect their copyright if they want to. I'll let you interpret the article as you will, but I think it's likely that the copyright concerns were not the NJTA's chief concern in trying to get the material removed from Youtube. Buddy431 (talk) 03:44, 7 January 2011 (UTC)

Speed of gravity

If nothing escapes from a black hole,how does gravity which also travels at the speed of light?02:09, 7 January 2011 (UTC)118.208.93.193 (talk)

John Cowell

Although perturbations to the curvature of spacetime, i.e., gravitational waves, are thought to travel at the speed of light, the curvature of spacetime in the vicinity of a black hole is in a steady state. As physicists say, "black holes have no hair". There's no gravitational information to escape. Red Act (talk) 02:18, 7 January 2011 (UTC)

And the gravity field starts before the black hole is formed, and perhaps the black hold never forms in the reference frame of those outside it. Graeme Bartlett (talk) 07:58, 7 January 2011 (UTC)

Alan Guth's inflation period.

If matter,time and space were created in the big bang and Alan Guth claimed everthing accelerated beyond the speed of light then; What force accelerated it? What did it expand into? If it exceeded the speed of light then it would be travelling into a past that never existed, What FTL force decelerated it.

   John Cowell118.208.93.193 (talk) 02:30, 7 January 2011 (UTC)

The expansion of the universe is not the result of a force moving matter around. It's not the objects themselves moving. It is the actual space itself being created. See Metric expansion of space. There's nothing pushing because matter itself isn't being moved. It's the space between the bits of matter that is getting bigger. And space, lacking a mass, requires no force to make it accelerate. --Jayron32 02:40, 7 January 2011 (UTC)

Nothing has really accelerated to a speed greater than the speed of light (c). The rate at which the distance between very distant objects increases can be a faster rate than c, but that's because the space itself is growing, not because any objects are moving faster than c within space. All objects are locally traveling at a speed less than c, as measured in any (local) inertial frame of reference. Red Act (talk) 04:04, 7 January 2011 (UTC)

The balloon example is often used to explain this (and to make physics students cringe at the absurd oversimplification of the example). Blow up a balloon. Place two dots on the outside of the balloon. Those are two points in space. By law, nothing can travel across the outside the balloon faster than a certain speed (c). All is well. Now, blow up the balloon some more. The dots move apart, from your perspective of looking at the whole balloon, but from the view of the points, they haven't moved at all. So, the speed limit wasn't affected by blowing up the balloon. Continuing, you can blow up the balloon faster than the speed limit, making the two points move away from each other faster than c. From your point of view of looking at the whole balloon, they are breaking the speed limit, but they aren't really. The speed limit states that nothing can travel across the surface of the balloon faster than c. The two points aren't moving at all from their perspective. All in all, it is has to do with what the speed is relative to - hence relativity. With that understanding, you can see how a person can say that the dots on the balloon are expanding faster than c, but they aren't actually moving at all. So, there is no concept of force involved. Therefore, asking what force moved them is missing the point of the expansion theory. -- kainaw™ 14:40, 7 January 2011 (UTC)

At what temperature does the volume of water decrease, regardless of whether your increase or decrease the temperature?

Assuming 1 atmosphere of pressure.--70.122.125.20 (talk) 03:23, 7 January 2011 (UTC)

See Properties_of_water#Density_of_water_and_ice. Its right in the first paragraph, and in the chart at the right. --Jayron32 03:40, 7 January 2011 (UTC)

You are really just asking the temperature at which water has the minimum density (at 1 atmosphere), right ? StuRat (talk) 04:00, 7 January 2011 (UTC)

Maybe I'm misreading - but there is no temperature where the volume decreases when the water is either warmed or cooled. At 4 celcius, the density will decrease in either direction on the temperature scale; volume will increase. Nimur (talk) 04:02, 7 January 2011 (UTC)

Ah. That is what he said. In that case liquid water has a minimum density at the boiling point. Gaseous water has no minimum density, due to the fundemental nature of gases. Solid water (ice) has numerous allotropic forms, each with their own behavior in regards to temperature, so its difficult to answer. --Jayron32 04:08, 7 January 2011 (UTC)

Liquid water at 100°C isn't a right answer, though, because if you increase the water's temperature a bit, it will turn to gas, and the water's volume will increase.

The question specifies a pressure of 1 ATM. If you freeze liquid water at 1 ATM, it will form ice I_h (normal ice). Normal ice at 0°C has a density that's at a local minimum (volume at a local maximum), because if you increase its temperature a little, it will turn into liquid water and shrink, but if you cool the ice, it will also shrink (see Ice#Characteristics). Red Act (talk) 05:02, 7 January 2011 (UTC)

ball bearing

what kind of link a ball bearing forms(a turning pair,a spherical pair etc..,what?). i know its higher pair. —Preceding unsigned comment added by 115.248.161.154 (talk) 04:27, 7 January 2011 (UTC)

It's called a rolling pair[33][34]. Red Act (talk) 06:36, 7 January 2011 (UTC)

gravitational acceleration

what is the relation between gravitational acceleration and gravitational constant? — Preceding unsigned comment added by Dev follower of maths (talk • contribs) 08:27, 7 January 2011 (UTC)

We have articles on Gravitational constant (denoted G) and Gravitational acceleration (usually denoted g), and the approximate relationship (ignoring rotational effects) is

g = GM/R² (where M is the mass of the earth, and R is its radius). The second article explains the subtleties. Dbfirs 09:54, 7 January 2011 (UTC)

electronics

describe of ac and dc? — Preceding unsigned comment added by Dev follower of maths (talk • contribs) 08:28, 7 January 2011 (UTC)

The articles on Alternating current and Direct current should answer your question (basically DC is electricity that flows one way, whereas AC changes direction), but please come back to ask again if you don't understand them. Dbfirs 09:59, 7 January 2011 (UTC)

Ceramic flat iron

Can someone explain to me how,infrared ceramic flat irons work? I bought one in Europe and it makes a humming noise but no detectable "heat" the brand is ASCET...the iron came with no instructions............. —Preceding unsigned comment added by 24.127.222.196 (talk) 10:15, 7 January 2011 (UTC)

Are you using it on the recommended supply voltage (i.e presumably the same as the country in which you bought it)? If not, it will never work.--Shantavira|^{feed me} 12:09, 7 January 2011 (UTC)

...or at least not work well. Europe has (nearly?) universal 230V/50Hz. The US has 120 V. As a consequence, unless there is a universal power supply, a simple heating element will dissipate about 1/4 of the expected power on a US mains outlet as opposed to a European one - it might become warm, but very probably not hot. And if it has more complex electronic components, it will probably not work at all. --Stephan Schulz (talk) 12:46, 7 January 2011 (UTC)

Removing a mole

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

Please speak to your family physician or another qualified medical professional if you have any questions about how to perform a medical procedure on yourself or others. TenOfAllTrades(talk) 15:03, 7 January 2011 (UTC)

To remove a mole, put a hose down it's hole and fill with water. :-) StuRat (talk) 19:10, 7 January 2011 (UTC)

Those who do not write well do not read well. Cuddlyable3 (talk) 01:42, 8 January 2011 (UTC)

The loneliest thing in the universe

Hello,

Imagine a lone elementary particle which is so far away from everything else that it interacts with nothing and is beyond the reach of any force. What effects would this total release from outside influence have on properties such as charge, spin, etc.? To what extent does interaction with the elementary forces shape the properties of elementary particles?

I know we couldn't observe such a particle if it existed, I just want to know what the theory tells us. Thank you. Leptictidium (mt) 12:33, 7 January 2011 (UTC)

There are no particles within the observable universe which aren't effectively gravitationally and electromagnetically bound to other particles to some extent. The ratio of leptons such as photons to baryons is just too large for a person to meaningfully comprehend. Light from other galaxies is visible to the naked eye. 71.198.176.22 (talk) 13:51, 7 January 2011 (UTC)

This is a "What sound does a falling tree make when nobody is listening?" type of question, isn't it? Any physical measurement requires interaction. As soon as we try to measure the charge, spin, etc. we have to interact with the particle, and therefore we cannot answer your question by measurement. I don't think any theory would predict anything other than that the particle has the charge, spin, etc. appropriate for its type. Anyhow, whatever a theory says, it would be an untestable, therefore from a scientific viewpoint useless, statement. --Wrongfilter (talk) 14:02, 7 January 2011 (UTC)

If such things amuse you, you may look up Mach's take on the bucket argument. Beware, however, that Mach's position on this is nowadays considered to be wrong. Einstein, among others, tried hard to find a way in which it could be right, but with no success. –Henning Makholm (talk) 15:48, 7 January 2011 (UTC)

Holy shit! That bucket argument was what I tried to ask my physics teacher 10 years ago, and they stared at me blankly! Just so I'm clear, is Einstein's position that, if the bucket of water were the only thing in the universe, the water would still have a concave surface because it is rotating relative to the geodesic formed by the mass of the water and bucket? Or is his position that it couldn't be said to be spinning at all, and thus the water would be flat (although I suppose the water might be convex if the only gravity is the water and the bucket, but the question remains of whether it would experience centrifugal 'force')? Perhaps rephrased as 'if a gaseous planet were the only thing in the universe, can it be said to spin, and would it therefore bulge?' And is the situation of a real gas giant bulging said to be because it is spinning relative to the gravity fields of everything else in the observable Universe? Would it bulge less if the Universe were smaller in terms of mass? <sorry if this is threadjacking: I got overexcited. Should I start a subsection? 82.24.248.137 (talk) 22:56, 7 January 2011 (UTC)

Einstein and modern science in general (and the General Theory of Relativity in particular) say, unambiguously, that a rotating gas giant in an otherwise empty universe would bulge. Space itself knows what "non-rotating" means; it is an absolute -- in stark contrast to "non-moving", which has no inherent meaning except relative to a particular frame of reference.

What Einstein felt, on philosophical grounds that he attributed to Mach, is that it ought not be so -- that the universe would be a beautifuller place if it were governed by a theory where "non-rotating" doesn't need to be a built-in primitive property of space. But he never succeeded in constructing such a theory, and neither has anyone else. –Henning Makholm (talk) 02:39, 8 January 2011 (UTC)

For an actual answer, we can look at the Schrodinger Equation. One of the first exercises in a quantum mechanics course is to take a lone particle in empty space, as you describe, and watch it evolve in time. Basically the particle, without anything to constrain it, expands out into the void. It becomes everywhere and nowhere until it has some constraint, something with which it can interact. If you know some mathematics, picture a Normal Distribution that just gets infinitely wider. The particle is there, but found anywhere with equal probability - it will "stick" to whatever it can find, but if alone it will be without definition forever.

When you expand the situation to include Quantum Field Theory, you get vacuum fluctuations which spontaneously appear and are able to localize the particle. To me, this is the most intuitive aspect from which to "trust" quantum mechanics: the void is equally nothing and anything, for if it were entirely nothing, then the universe is a contradiction. SamuelRiv (talk) 20:39, 7 January 2011 (UTC)

Primordial black hole evaporation as gamma ray bursts

The Primordial black hole article says, "The evaporation of primordial black holes has been suggested as one possible explanation for gamma ray bursts. This explanation is, however, considered unlikely.^{[by whom?]}"

That's what I want to know: By whom? And why is it considered unlikely? Gamma-ray burst#Progenitors cites Cline, D.B. (1996). "Primordial black-hole evaporation and the quark-gluon phase transition". Nuclear Physics A 610: 500.... as supporting the possibility, but doesn't say what the evidence against it might be. The "Related Articles" on that cite include [35], [36], [37], and [38], which don't seem to discount the possibility either. Why is it unlikely? 71.198.176.22 (talk) 13:42, 7 January 2011 (UTC)

A disappearing black hole should give a burst that rapidly rises in strenght and then suddenly stops, where as the burst actually appear to be steady. Also the optical counterparts look like supernovas, you would not expect to see much from a black hole evaporation from a long distance. And finally you have the energy levels involved, the black hole releases far less energy than a supernova and would not be observable half way across the universe. Graeme Bartlett (talk) 22:58, 7 January 2011 (UTC)

Relativity

If time is relative, and speed is relative, then what about size, shape, and distance? —Preceding unsigned comment added by 165.212.189.187 (talk) 14:37, 7 January 2011 (UTC)

In a nutshell: yes, because if time and speed are relative, it affects how you measure length in profound ways. See Length contraction for the full discussion. ("Shape" is only a "yes" if you mean the general dimensions of something, not "it's a square no wait it's a circle." Ditto "size.") So two observers traveling in different reference frames will disagree on the length of space and length of objects in rather striking ways. The Ladder paradox illustrates this rather vividly. --Mr.98 (talk) 14:58, 7 January 2011 (UTC)

Please explain what you typed in parentheses. shape is either yes or no. I mean square vs. circle, duh. —Preceding unsigned comment added by 165.212.189.187 (talk) 15:43, 7 January 2011 (UTC)

An intrinsically circular object will be seen measured as being elliptical in a coordinate system that moves with respect to it. Incidentally, the theory of relativity is more concerned with absolutes or invariants rather than relative (coordinate-dependent) things, and Einstein himself later regretted the name he had given to his theory (I don't have a quotation right now). I struck out "seen" because miraculously an individual observer always perceives a sphere as a sphere albeit rotated. --Wrongfilter (talk) 16:09, 7 January 2011 (UTC)

I've forgotten most of the relativity that I ever knew (and that wasn't much) but I thought that the relative view was effectively a rotation (as mentioned by Wrongfilter), so that a rod viewed from the side would appear shorter, but a sphere would maintain its "apparent shape" , and a cube would appear rotated with the trailing side being visible when it "shouldn't be". What would one "measure" to record an ellipse? Dbfirs 17:57, 7 January 2011 (UTC)

... (later) Oh, yes, I "see", one would measure the distance between two marks on the original sphere at opposite ends of the diameter along the direction of motion in its rest-frame. If the moving sphere had its "pole" pointing towards the observer, and had a circle painted round the equator, the observer would see this circle as an ellipse only if the sphere was transparent, otherwise part of it would be hidden. Is this correct? Dbfirs 17:59, 7 January 2011 (UTC)

Well, measuring means taking the coordinates of various points simultaneously (in your rest frame). Imagine placing two rulers in the path of the moving sphere, one aligned with its direction of motion, the other perpendicular. Then mark simultaneously (in your restframe) the points where opposite sides of the sphere are on those rulers. The marked length in the direction of motion will be shorter than that perpendicular to it. If you trace out a cross-section of the sphere, it will be an ellipse. "Seeing" means perception by an individual observer. Consider two photons that hit your retina at the same time, one from the near side, one from the far side of the sphere. The latter photon will have travelled a longer distance, hence it was emitted earlier than the former one. In fact, it will have been emitted when the sphere was actually farther away. Taking the light travel time into account returns the ellpsoid to a sphere. --Wrongfilter (talk) 18:29, 7 January 2011 (UTC)

What I'm worried about is what you mean by "opposite sides of the sphere". Is that "opposite ends of a diameter in its own rest-frame", or opposite ends as you "see" it. I think these would be different. Dbfirs 08:18, 8 January 2011 (UTC)

What about SIZE??? —Preceding unsigned comment added by 165.212.189.187 (talk) 21:21, 7 January 2011 (UTC)

Microwave oven flavor transfer

If someone heats up a spicy dish of food in a Microwave oven, and seconds after it is removed a cup of water is placed inside, (let's assume for the purposes of making tea or other hot beverage), could the water in the cup possibly obtain any of the characteristics of the flavors of the food previously heated? Could the water take on the smell or taste of the food? 10draftsdeep (talk) 16:42, 7 January 2011 (UTC)

Absolutely. Heating increases the rate of evaporation of any substance; so the microwave, after heating food, will likely have a non-trivial amount of smellable and/or tastable compounds in the air. The water that follows your burrito into the microwave can certainly collect some of these compounds. --Jayron32 16:50, 7 January 2011 (UTC)

(Edit Conflict) This seems to me, as a frequent microwave user, entirely possible and indeed likely, though not due to any mysterious properties of microwave ovens as such.

When one heats food in a microwave oven it becomes filled with water vapour laden with the odours of the food, some of which (depending on the efficiency of its ventilation system) both remains in the oven's air and is deposited as condensation on its inside walls. If one immediately afterwards places and heats a cup of water in that oven, it is quite likely that enough of that 'flavoured' vapour, both from the air and revaporised from the walls, will mix into the water so as to leave a detectable taint. I must confess I haven't experienced this, but only because I usually boil a kettle for my (often concurrent) tea or coffee (though I sometimes reheat an undrunk, cold cup in the microwave). On the rare occasions when I heat a meal's second course (a steamed pudding, say) in the same microwave, I usually try first to disperse/remove (by mopping condensation) as much as possible of the previous course's 'residue' precisely so as to prevent such taste taints. 87.81.230.195 (talk) 17:07, 7 January 2011 (UTC)

It's critical to dispel the myth that evaporation produces 100.0% pure steam. Even in professional grade distillation apparatuses, the evaporation process can create a vapor that may contain evaporated residues, or even solid particulate matter, from any compound that was dissolved in the water. I'm surprised we don't have a vapor transport article; it's a redirect to a related article. Nimur (talk) 19:57, 7 January 2011 (UTC)

It also bears reminding people that if you can smell it, it is in the air. If it is in the air, it can come back out again. --Jayron32 20:25, 7 January 2011 (UTC)

Definition of life

I was reading the "life" page on wikipedia. and the first definition of life seemed a little confusing:"systems that tend to respond to changes in their environment, and inside themselves, in such a way as to promote their own continuation." because every closed system containing chemical substances that are in a chemical equilibrium respond to the changes the same way (acording to Le chatelier principle) I know that life is not a closed system. but is this definition correct? can we say that such behaviors in living organisms is because of the chemical equilibriums in them? — Preceding unsigned comment added by Sina-chemo (talk • contribs) 20:06, 7 January 2011 (UTC)

You aren't alone in being confused. Defining life is a very fuzzy thing. It actually isn't that easy to do. For every actual written definition of life I have ever seen, there exists some obviously non-living thing which can be shown to meet it. It becomes especially tricky to define life when it comes to looking at the border cases, such as viruses and prions. --Jayron32 20:23, 7 January 2011 (UTC)

Keep in mind that in the Life article, it says: "Since there is no unequivocal definition of life, the current understanding is descriptive, where life is a characteristic of organisms that exhibit all or most of the following phenomena:..." Each of the phenomena can describe something non-living, it's the collection of phenomena that is used to define life. -- JSBillings 20:42, 7 January 2011 (UTC)

Also, the spectrum of definition ranges from mainstream biology, where the definition is a lot easier ("koala = alive, rock = not alive"); to extremophile biology (where the definition is much more complicated and requires detailed analysis of biochemistry); to the borderlines of current scientific knowledge (SETI and artificial intelligence both make efforts to scientifically define "life", sometimes coming up with something that could include astrophysical phenomena, sophisticated machinery, computer software, and so on); and at some point, we go off the deep end into fringe science and eventually "religion." (If they exist, is a "God" alive? And ghosts? Pseudoscientists actually suffer seriously from a lack of definition - which lends to the enormous gaping holes in their thought-process). Within any particular realm, the community will develop an operational definition. Most mainstream biologists use a few chemical indicators and particularly rely on the concept of tropic response, which can be more concretely defined (see the list at the bottom of our article). Nimur (talk) 21:17, 7 January 2011 (UTC)

Stuart Kauffman has written about abiogenesis via auto catalytic sets of chemical species. In short, properties similar to homeostasis can be exhibited by non-living things, and he argues that non-life can transition to life in this manner (See his book "At home in the universe" for an accessible pop-sci account). However, contrary to your example, chemical systems that look similar to life are generally not equilibrium systems, but far from equilibrium Dissipative systems. Essentially, pumping energy into the system allows the formation of stable, persistent structure. In this light, my personal favorite edge case for life is the Great Red Spot. Lastly, "obviously living" organisms, such as amoebae, lizards or humans, considered chemically/thermodynamically are far-from-equilibrium, not close to equilibrium as you suggest. SemanticMantis (talk) 21:26, 7 January 2011 (UTC)

More directly to your question, Le_Chatelier_principle explains that a new equilibrium can be reached after conditions are altered. But there is a change from the old equilibrium to the new one. The only thing that persists is the notion of equilibrium, and notions can't be alive (when ideas some similar properties in common with life , we call them memes). Because the original equilibrium A disappears and a new one B is formed with different properties, no state or aspect of the system has responded to the changed conditions in a manner that preserves itself. Whatever the (modern) definition of you choose, including the one quoted in our article on life, a closed system at equilibrium will not satisfy it. SemanticMantis (talk) 23:01, 7 January 2011 (UTC)

Gould on transitional fossils

Hi guys. I have a question about evolution. Creationists seem to think that, due to political pressure, in the early 80s the late Stephen Jay Gould reversed himself on whether good examples of transitional fossils exist. Examples:

http://creation.com/punctuated-equilibrium-come-of-age

http://www.discovery.org/a/7271

I should be candid: I suspect that they have a point. I cannot see how Gould’s earlier statements to the effect that “transitions between major groups are characteristically abrupt” [39] can be reconciled with later claims that “transitional forms are generally lacking at the species level, but they are abundant between larger groups.”[40] If Gould reversed himself on the status of transitional forms, the perennial charge that creationists “quote mined” his views seems a little silly.

What I’m asking is if anyone knows some scientific context that I’m missing here. Does “major groups” mean the same thing in both quotes? Before c~1980, did Gould ever clearly say that transitional forms or fossils exist, or cite some specific examples? I glanced through Gould’s papers from 1972 and 1977 but I’m afraid that they’re a bit too far over my head for me to be certain of their meaning.

I’m not a creationist and I’m not asking anyone to “argue me out” of creationism.

However, for my education, I would appreciate if anyone can point out something that I’ve missed.173.13.48.54 (talk) 20:07, 7 January 2011 (UTC)

I think that the above statements are, like most arguements out of the creationist camps, based on overanalyzing a tiny amount of data while ignoring the abundance of the rest of the data. I don't see the statements as contradictory at all. He says "transitions are abrupt" in the first one, but "transitional forms" in the second one, without defining how long is "abrupt". Transitions can be abrupt, but not so abrupt as to leave zero evidence. Also, science and scientists DO change their opinions about things over time. This is how science works. Perhaps Gould's earlier theories on punctuated equilibrium became more refined over time as new evidence became availible. That isn't a contradiction; its a refinement of the existing theory. I'm not sure which interpretation of Gould's statements is correct, but there are two alternate interpretations to the creationist one. Furthermore, you could just say "Come on, its two sentances made from a man who published enough works to fill a small library. Taking two statements, out of context, and attempting to "prove" that Gould somehow based his scientific pronouncements on "political pressure" rather than sound science is complete and utter bullshit. --Jayron32 20:16, 7 January 2011 (UTC)

Furthermore, it also represents a fundemental flaw in the creationist strategy. Rather than reading Gould with an open mind, and lacking any preconceived notions, and then try to work out what he means and if it makes sense, the "contradiction" claim starts from the premise that Gould MUST be wrong, and if we dig hard enough we can find evidence to support that. And THIS evidence was the best they could come up with to verify their preconceived conclusions. That should tell you something. That doesn't mean that everything Gould ever published or ever had to say about evolution should turn out to be 100% correct. That isn't how science works either. Gould may have been wrong on some of his stuff. That doesn't mean that everything about evolution is just "made up" or "completely wrong". --Jayron32 20:20, 7 January 2011 (UTC)

I think Jayron's point about punctuated equilibrium is probably the germane one. Gould was the primary promoter of PE as an explanation for the gaps within the fossil record; my understanding of the situation is that most other evolutionary theorists didn't so much disagree with it as think he and Eldredge were putting more emphasis on it than they should (and, of course, many people simply thought it was a rewording of various other hypotheses - as our article goes into in some detail). As he became more and more the public figure in the case against creationism, I imagine Gould found himself in an uncomfortable position: any weakening of his support for PE would be used as fodder by the creationists to say that he was admitting that his understanding of evolution was wrong. It's tough enough to admit that you've mis-stated something or changed your opinion on something you used to promote, but it becomes extremely sticky when you know beforehand that your relatively minor change in evaluation will get turned into something completely other by professional liars. I've read a good bit of Gould's stuff (though it's been a while) and it's my impression (WP:OR alert) that, as evidence and support began to shift away from PE into a more gradualist view, Gould's popular writing at least began focusing on slightly different topics (the relationship of science to religion, his Full House book, etc.), perhaps as a way of avoiding (or at least downplaying) the issue. Matt Deres (talk) 20:35, 7 January 2011 (UTC)

I will note that the first quote doesn't include anything like its full context; even ignoring the rest of the document, it is illuminating to read the entire sentence from which the fragment was extracted. "All paleontologists know that the fossil record contains precious little in the way of intermediate forms; transitions between major groups are characteristically abrupt."

Note that he does not state that transitional forms are unheard of or nonexistent in the fossil record, only that they are rare. This would be exactly what is predicted under punctuated equilibrium. Pulling some plausible-sounding numbers out of thin air, let's suppose that 0.1% of fossils are the remains of transitional forms; that's just one out of every thousand fossils, certainly qualifying as "precious little". On the other hand, if paleontologists have collected and fully characterized a million different sets of fossilized remains, you'd still expect to find a full thousand transitional forms in the collection: "abundant" in terms of absolute number.

One could make a similar set of statements about diamonds. They're certainly quite rare; odds are that if you pick up a random rock, it won't turn out to be a diamond. Nevertheless, they're abundant — thousands are traded every day in New York and Amsterdam, and you can see dozens of examples in most jewellery stores. TenOfAllTrades(talk) 21:21, 7 January 2011 (UTC)

Yeah, but diamonds exist because God put them there. Checkmate, atheists!. TomorrowTime (talk) 23:35, 7 January 2011 (UTC)

It would be an interesting undergraduate research paper to try and ferret out the change in Gould's thinking. I think calling it "reversing" and impugning it as somehow meaning he is unreliable is clearly wrong. We stress different aspects of our arguments to different audiences, because we assume different things about what they know and how they will interpret our work. To other specialists, we emphasize the novelty of our own small tweaks (e.g. Gould arguing for PE as a preferred model over gradualism, all within the framework of Darwinian evolution); to a broader public, we try to make sure that our in-discipline arguments don't detract from larger understandings (e.g. Gould emphasizing that PE does not mean that there aren't transitional forms, or that Darwinism is wrong). These two statements of Gould's are not incompatible if you take the purpose of their broader context into account, but I think it's clear that in the later articles, Gould is really trying to debunk any notion that PE opposes Darwinism. I wouldn't call that a reversal, so much as, er, an evolution in his expression. I doubt his underlying opinions changed too much. But it would be interesting to actually track this down historically. --Mr.98 (talk) 01:10, 8 January 2011 (UTC)

One thing to bear in mind is that the form of a species may not be free to vary as much as the underlying genetics - two recognizable forms may exist that are functional, but the intermediates between them fail badly. This is best seen in a spatial distribution - hybrid zones - you can have a butterfly which mimics one group of species, or another very different group of species, but those intermediates get eaten, so they take up only a rather small band of territory - and outside the bands, the two forms don't get more and more extreme as you move away. This is maintained actively by selection, and presumably also by genetic mechanisms that tend to stabilize certain phenotypes (heat shock proteins are known for that). The same could happen over the course of time, with selection forcing a species first to resemble one standard appearance and then a different one. Wnt (talk) 06:46, 8 January 2011 (UTC)

January 8

Gravity/Conciousness

It has been suggested that the incredible weakness of gravity compared with the other forces is because gravity is the only force which mainly resides in the other dimensions postulated by string theory.Is it conceivable that thought/afterlife/conciousness act similarly as gravity waves, like thought waves, have yet to be detected.

 John Cowell.00:28, 8 January 2011 (UTC)=  —Preceding unsigned comment added by 118.208.93.193 (talk)  

Certainly it's conceivable: you've just conceived it. Whether it has any merit as a scientific theory is another matter. I am not aware of any evidence that thought, whatever it might be, has any properties in common with any of the fundamental forces of nature or the waves that mediate them. --ColinFine (talk) 00:54, 8 January 2011 (UTC)

Roger Penrose believes that there is an important relationship between consciousness and quantum gravity. The idea strikes me as kind of silly, but it has received a certain amount of attention, or perhaps notoriety is a better word. Looie496 (talk) 01:04, 8 January 2011 (UTC)

Yes, but Penrose does not claim that he has actual evidence for that hunch. (His metaphysical ideas are controversial, whereas his actual science is acknowledged by everyone to be solid -- and he seems to be perfectly aware of and candid about which is which). –Henning Makholm (talk) 03:00, 8 January 2011 (UTC)

It strikes me that the burden of proof is that on those who would claim that consciousness is anything more than something materialistic. The brain seems to be a fairly modular thing — there's a strict movement "upwards towards consciousness" (metaphorically, of course) moving from less-to-more complicated brains (lizards, dogs, dolphins, chimps, humans, etc.). This strongly seems to suggest that consciousness is "simply" a very complicated function of a very complicated set of neural wirings. Why one would want to introduce extra dimensions into the equation (other than the desire to not simply be a blot of matter, doomed for a finite amount of time) seems, from a scientific standpoint, fairly unclear. It doesn't mean it isn't possible. But does a lizard have the same physical hardware that you are postulating? Does a dog? Does a housefly? Does an amoeba? Does a virus? And if not, why would humans have it, and no others? Where does it start, and where would it stop? It just doesn't really seem, a priori, to be a very compelling theory, at least to me. It seems far more likely that what we call consciousness is just a measure of specialized computational organs/circuits/what-have-you within the forebrain brain. Circuits we do not at all fully understand, to be sure, but I think we're starting to get close to a general model of things, and it doesn't include anything like you're suggesting. --Mr.98 (talk) 03:43, 8 January 2011 (UTC)

I'm reading the question as discussing gravity just as an initial example of something the OP has heard may also exist "in other dimensions" according to "string theory".

The actual question is then: could consciousness exist in other spatial dimensions, and if so could our sense of consciousness in this 3-space be in some meaningful way "connected" to corresponding consciousnesses in other sets of spatial dimensions?

If I'm interpreting that correctly, then I'd have to say "maybe". I don't know enough about strings and Mbranes and whatever else to know whether in the various theories about them, it is possible for an elementary particle in our 3-space to be a manifestation of a multidimensional vibration that also manifests as "corresponding" elementary particles in other N-spaces. If so, then perhaps the particles making up our brains are mapped onto various other "brains" (including whatever higher-than-3-dimensional corresponding structures might be called). Maybe the complexity of how those vibrations/string/particles are organized in each of those other spaces also produces a consciousness that corresponds to our consciousness in this world.

That would be kind of spooky, wouldn't it be? :) I don't have an answer as to how likely anything like that might be, though – and, remember, "string theory" is still all just a mathematical framework with no empirical support whatsoever or any likelihood of there being any anytime soon, either, afaik. So even if this kind of thing were supported by theory, there would still be little reason to believe it is anything like that in Reality. WikiDao ☯ 04:38, 8 January 2011 (UTC)

The OP may be interested in Leibniz's Monad theory. Like Penrose, Leibniz had some interesting thoughts regarding consciousness and physics. Also like Penrose, Leibniz's scientific contributions are well respected. In the Monadology he hints that perception and consciousness may be tied to the fundamental units of matter. Or something. I don't think many people subscribe to theory of Monads these days. SemanticMantis (talk) 05:50, 8 January 2011 (UTC)

It seems to me that the fact that consciousness evolved is a pretty strong argument against the idea that it harnesses any sort of subtle as-of-yet unknown physics. Much of modern physics could have been very useful to biological entities (e.g. lasers, radio waves, ...) but organisms "naturally" using such physics completely failed to evolve anywhere in the biosphere. Why should consciousness be an exception? 83.134.178.145 (talk) 10:13, 8 January 2011 (UTC)

Brain

Will putting things in your brain kil lyou? And what do FFI prions taste like? —Preceding unsigned comment added by 203.96.12.131 (talk) 04:13, 8 January 2011 (UTC)

(1) Not necessarily, but it will void your warranty. (2) Chicken. –Henning Makholm (talk) 04:38, 8 January 2011 (UTC)

Depends. A brain surgeon could probably put something in there without doing too much damage. This is occasionally done. Microchips and such. See Neural implant.

If you're just talking about shoving something in there, then sure, there's a serious danger. But even so, some people survive it. See Phineas Gage!

Finally, I doubt you'd ever get enough prions together in one place to actually be able to taste them. APL (talk) 05:01, 8 January 2011 (UTC)

Putting in a couple of working neurons might help some people. Prions taste of nothing but they smell of troll. Caesar's Daddy (talk) 07:42, 8 January 2011 (UTC)

Reading Wikipedia puts thoughts in my brain. It hasn't killed me yet. Gandalf61 (talk) 07:56, 8 January 2011 (UTC)

Motor

First motor invented or generator invented becoz I heared the motor was the first am I right?