Wikipedia:Reference desk/Archives/Science/2011 August 3

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August 3[edit]

Snowing right now[edit]

Where in the world is it snowing right now? Barbaricslav (talk) 01:35, 3 August 2011 (UTC)

It's winter in the southern hemisphere so it may well be snowing in the ski resorts in the mountains of Chile, for example, or perhaps in the Snowy Mountains of Australia. Antarctica is likely to have a storm or two. I have known it to snow in some of the northern hemisphere mountains in August -specifically in the Canadian Rockies. Bielle (talk) 01:58, 3 August 2011 (UTC)
Perhaps also Alert, Nunavut:
"Alert has a polar climate. The weather is very cold, and there is snow cover for 10 months of the year on average. The warmest month, July, has an average temperature of 3.3 °C (37.9 °F). Alert is also very dry, averaging only 153.8 mm (6.06 in) of precipitation per year. Most of the precipitation occurs during the months of July, August and September, mostly in the form of snow. On average there is 16.1 mm (0.63 in) of rain which occurs between June and September. Alert sees very little snowfall during the rest of the year. September is usually the month with the heaviest snowfall. February is the coldest month of the year. Snowfall can occur during any month of the year, although there might be about 20 frost free days in an average summer.[7]" Count Iblis (talk) 02:09, 3 August 2011 (UTC)
New Zealand's South Island received a heavy snow dump a week or two ago. Plasmic Physics (talk) 04:36, 3 August 2011 (UTC)

It seems that there is no current snowfall in southern Chile, Australia or New Zealand. According to BBC News there should be light snowfall in Punta Arenas on Friday. But Weather Underground reports ongoing snowfall in several locations on Antarctica: Amundsen-Scott, Base Orcadas, Dumont d'Urville Station, and Vostok Station. (talk) 09:30, 3 August 2011 (UTC)

As someone who does a bit of skiing, I can report that, sadly, although it is snow season here in SE Australia, it was 10 degrees C in the nearby mountains today (approx 50 degrees F). But apparently snow is forecast for Sunday. HiLo48 (talk) 10:31, 3 August 2011 (UTC)
South Africa. [1] ~AH1 (discuss!) 14:20, 8 August 2011 (UTC)

hammerhead sharks[edit]

can hammerhead bite head on or do they have to turn there heads to one side to stike — Preceding unsigned comment added by Jteuscher (talkcontribs) 01:42, 3 August 2011 (UTC)

Our Hammerhead shark article (which could do with a few more sources I think) suggests that hammerheads are mostly bottom feeders, and states that they may sometimes pin down rays with the 'hammer' to eat them. I'm not entirely convinced by this, but they certainly look better adapted to taking bites out of things underneath than in front. Given that some species have been known to attack humans though, I think it is safe to assume that they are flexible enough to attack in other ways. AndyTheGrump (talk) 02:10, 3 August 2011 (UTC)
For a specific example, see also Great_hammerhead#Feeding mentioning examples where the shark "disables" the prey (stingray) with its first bite, then pins it with its head, and finally "takes the ray in its jaws head-first". This section does cite five references. ---Sluzzelin talk 02:17, 3 August 2011 (UTC)

Torque and power[edit]

why the maximum power and torque of an engine specified at different RPM's ?

Torque is essentially force, power is essentially force multiplied by velocity. They are different things. You can have a large torque when the engine is not moving, but the power in that case is zero. Looie496 (talk) 02:44, 3 August 2011 (UTC)

Effect of star Jupiter on Earth[edit]

In his series of books beginning with "2001 A Space Odyssey", Arthur Clarke has a race of super advanced aliens cause Jupiter to turn into a star. If such were to happen, would we be likely to see the new Jupiter with the naked eye, and would the light be bright enough to disrupt life on Earth? — Preceding unsigned comment added by GuadalupePeak (talkcontribs) 02:39, 3 August 2011 (UTC)

I guess you didn't read the book. (2010: Odyssey Two, that is.) In the book, he has the aliens turn it into a very dim star, just bright enough to warm up Uupiter's moon Europa. Looie496 (talk) 02:50, 3 August 2011 (UTC)
As far as the visibility is concerned, you can already spot Jupiter with the naked eye during daytime, see here. If Jupiter were to turn into a star, it would be much easier to spot, of course. Count Iblis (talk) 02:56, 3 August 2011 (UTC)
Jupiter's Moons Ganymede and Callisto can also be seen using the naked eye, see here. Count Iblis (talk) 03:13, 3 August 2011 (UTC)
I think we used to have a page on the Lucifer Project which is a conspiracy theory that NASA (or the illuminati or NWO or whatever malevolent power you want to believe in) were going to try to ignite Jupiter.. Looks like the page is gone, but you can still find info about it if you google the term. Vespine (talk) 03:51, 3 August 2011 (UTC)
I think the main concern with this would be whether the new star would be bright enough to damage the retina, like an arc welder. Jupiter is about 1/10 the radius of the Sun, thus 1/100 the area - but it's also 4-6 times further away, making it 1/16 to 1/36 smaller in apparent size than that. But if it had the same color temperature as the sun, that 1/1600 bit of area would be just as bright as the sun itself. In total eclipses even fairly small areas of exposed sun are dangerous - actually much more dangerous than looking at the sun because the iris opens up, not being designed for extreme brightness in an overall dark scene. Especially at night this would be dangerous. Humans might learn to avoid looking at it before going blind (though I think something like that would be harder to learn than you'd think) but certainly nothing else would. These risks would be much reduced if it turned out to be a brown dwarf or something, much cooler on its exposed surface. Wnt (talk) 04:46, 3 August 2011 (UTC)
It's a pretty pointless question, it's like asking: if Jupiter gives off light, how much light would it give. The answer is pretty much up to you. Alternatively, if this lead sinker floats in water, how dense is it. Lead doesn't float in water, so the answer is: it is as dense as you want it to be, although less than water. So, if Jupiter was a star, it is as bright as you want it to b, as long as it is brighter than it's natural reflection. Plasmic Physics (talk) 05:26, 3 August 2011 (UTC)
Not to get too picky, but Jupiter is technically "brighter" than its natural reflection, it emits more energy than it gets from the sun, per the Kelvin–Helmholtz mechanism. What makes Jupiter not a star is that it doesn't undergo nuclear fusion; according to our article on Jupiter, it would need to be 75 times more massive in order to support nuclear fusion. In order to make it a star, Arthur C. Clarke had to invoke his own third law by introducing a little bit of "magic" in the form of the monolith. As Plasmic Physics notes, there is no conceivable way Jupiter could actually be a star, so discussing how it would become one is a purely fictional venture. --Jayron32 05:44, 3 August 2011 (UTC)
Well, in the 2010 film it was shown about the same color temperature as the Sun, and I think then my comments would hold. People would look up in awe and wonder, and end up tapping around with the white cane. Wnt (talk) 16:54, 3 August 2011 (UTC)
Meh. There's no evidence the filmmakers were terribly interested in making a scientifically accurate depiction of such a star anyways. Like anything else in the film, the effect is for dramatic purposes and isn't supposed to be scientifically accurate. I mean, you've completely accepted that a giant magic rectangle is capable of turning Jupiter into a star and yet have a problem with the spectral class of the star so created as represented in the film? If physics already doesn't work as it is supposed to in said film, what's the point of picking and choosing which wrong physics to complain about? The new star doesn't blind the people in the film because film physics works different than real physics. There's almost no point in playing the "how many ways is this film wrong" game unless you want to go all the way, and really what's the point. Films, like nearly all fiction, depend on suspension of disbelief to work; if you're so unwilling to accept such a suspension of disbelief to enjoy the film on its own terms, I don't see where this is a productive line of thought anyways. --Jayron32 18:00, 3 August 2011 (UTC)
Well, you don't neccesarily have to go all the way, as long as you are willing to make exceptions, and not to base an argument on those exceptions, to avoid circular reasoning. Plasmic Physics (talk) 19:31, 3 August 2011 (UTC)
The article was Lucifer Project I change the link supplied by User:Vespine and restored the page for those that want to read it. Graeme Bartlett (talk) 13:15, 4 August 2011 (UTC)

Beyond the standard model and low temperature physics experiments[edit]

Hi, is it possible that one could find standard model discrepancies at very low temperatures (like someday 10^{-50} kelvin?) as well as at the very high energies in particle accelarators? Thanks, Rich Peterson24.7.28.186 (talk) 03:54, 3 August 2011 (UTC)

  • Like maybe dark energy doesn't "work" except at low temps? (talk) 03:56, 3 August 2011 (UTC)
    • The reason why high temperature testing of the Standard Model is done in the first place is generally to try to understand what the universe was like arbitrarily close to the Big Bang. The deal with low-temperature physics is, we have lots of examples around us (i.e. most of the universe is pretty cold) and most of the really exotic stuff happens when particles are energized enough to start to break down. You can get essentially infinitely hot (pre-empting the objections: yeah, I know there are limits here too, but not the same way as at the other end), but you've got a limit to how cold you can get. We've gotten very close to that cold limit, so we've got a pretty good handle on what happens there, but we've come nowhere near recreating the conditions at Big Bang time, which is why that is where the bulk of research is driven. --Jayron32 04:22, 3 August 2011 (UTC)
I feel like the "limit to how cold you can get" is illusion. The universe goes through different regimes of physics according to the log of its age, and the log of its temperature. There may be no limit to how old or how low temperature it can get, and I'm also suspicious that over very long time scales at very low temperatures and very low masses, some new physics could emerge when ours is too hot to be of much importance, just as has happened so many times before in history. Wnt (talk) 04:56, 3 August 2011 (UTC)
Could you please explain to me how one can go a slower speed than "stopped". Because I am not smart enough to understand how one may get colder than absolute zero. --Jayron32 05:35, 3 August 2011 (UTC)
Seconded. --Stephan Schulz (talk) 07:07, 3 August 2011 (UTC)
As I said, a logarithmic scale. People have proposed all sorts of bizarre physics for the first second after the Big Bang. What happens when you look at the interactions of matter at 10^-30 Kelvin over a period of 10^50 years? Maybe we're living now in another one of those periods of strange high-energy physics in the "moment" after the Big Bang, from that perspective? In other words - suppose there's proton decay. Suppose there's electron decay.[2] Suppose you have a sea of neutrinos and nothing else, whizzing around over unimaginable time spans until they somehow come to rest with respect to one another. Do they start forming chemical-ish interactions? (No, I don't know, but I think it's a fair question) Wnt (talk) 08:09, 3 August 2011 (UTC)
I suppose it's possible, but it may also be outside of the range of human observability. Imagine a world where stuff happens on a timescale where one second of our time is expanded into 1 million years of real time (that's basically the logarithmic scale you are talking about here). Effects on THAT scale may well be unobservable within the limits of our methods to detect them. If humans lived one billion years rather than 70 years, and were able to observe the universe at such a time scale who knows what we may see. But, Wnt, you're delving into the realm of pure speculation; and while we may hold that technology may allow us, in the future, to delve into such realms scientifically, there is no indication that we may now or even within our lifetimes, so there's really no point in making it a big deal, right now. We can only say that, based on our current observations we have no reason to suppose anything terribly interesting happens at such low temperatures. It might, but there is nothing to say that it will. --Jayron32 11:37, 3 August 2011 (UTC)
I recognize this - though I wouldn't rule out that physicists might do a fair job of describing what a particle mediating a neutrino-neutrino bond would look like if there were one. The main reason why I think about this is that so often I have seen "the end of the universe" (and the "beginning of the universe" for that matter) described in such definite terms, when I feel like there is no real evidence that any era of time and temperature is truly the first or the last. Wnt (talk) 13:29, 3 August 2011 (UTC)
Except that the end of the universe may not even be at absolute zero, it could be considerably warmer than that. See Ultimate fate of the universe. While the physics of what might happen at some (currently impossible to achieve) arbitrarily tiny temperature close to absolute zero may be interesting, there is no wide spread agreement that the universe is asymptotically approaching that temperature. It is but one model of the end of the universe, and there's not yet a whole lot of evidence that it is far-and-away the best model. --Jayron32 13:52, 3 August 2011 (UTC)
Also agreed. But an open universe is still the leading contender. I think that any glimmer of evidence in this direction would do much to dispel the pall of fatalism that pervades modern pop physics. If people realize there's even a chance that the universe goes on and on and on, with new kinds of physics at each new time scale, it would fire up their imaginations. Wnt (talk) 16:52, 3 August 2011 (UTC)

Yes, it is possible that one will find that the Standard Model is false by studying physics at very low temperatures. That could happen if quantum mechanics (on which the Stanard Model is based) is not fundamental. If quantum mechanics is only approxmately true, then that would give rise to an effective theory in which decoherence would happen eve if there are no nteractions with the environment. This would then become visible only at extremely low temperatures at which the decoherence rate due to the environment becomes very small. Count Iblis (talk) 14:52, 3 August 2011 (UTC)

Thanks199.33.32.40 (talk) 18:46, 3 August 2011 (UTC)
That of course implies that any human created model of the universe could even be fundemental. I'm not entirely convinced that any model could exist at infinite precision; The Standard Model exists because it works, not because it is (or even should be expected to be) infinitely true under an arbitrarily high level of precision. If the Standard Model is shown to not apply at certain conditions (be it very high or very low temperarures, or any other set of extremes) then science would supplant it with a more precise model which includes the new data and the new paradigm. It wouldn't make the Standard Model substantially more wrong however; the existance of quantum mechanics doesn't make the Newtonian models invalid, for say, calculating ballistic trajectories or figuring out the stresses on bridge supports. Models are always going to be an approximation on reality, and we choose which models we use by the specific application where they work not because they are expected to be right for all applications. It isn't a question of being "fundementally" correct, just in finding the correct paradigm to give you the best solutions for your particular problem... --Jayron32 15:06, 3 August 2011 (UTC)

Getting sulfur from Gypsum.[edit]

Gypsum is Calcium Sulfate and has the formula CaSO4·2H2O, which seems to indicate it has a lot of sulfur in it. Let's say I wanted to get pure sulfur out of gypsum, what would I need to do? — Preceding unsigned comment added by (talk) 06:41, 3 August 2011 (UTC)

You could use a strong reducing agent to obtain the sulfur - though the reducing agent would be worth more than the sulfur. Or you could use microorganisms that extract oxygen from the gypsum under anaerobic conditions - I'm not sure if this has been done on a large scale for synthetic purposes, but it happens accidentally with drywall, which can thus emit hydrogen sulfide which can more readily be used to make elemental sulfur.[3] Google knows no hits for "fermenting gypsum" - somebody ought to fix that. ;) Wnt (talk) 08:04, 3 August 2011 (UTC)
To what temperature in Kelvin or degrees Celsius does Gypsium have to be heated to decompose it into vitriolic aire and calx? Is it easier to reduce vitriolic aire to sulfur? Plasmic Physics (talk) 08:44, 3 August 2011 (UTC)
"Vitriolic aire" is not a common term for me, but as sulfuric acid is called "oil of vitriol" I'll assume that it is SO3. Usually people are interested in doing this reaction the other way, in Flue-gas desulfurization. From a few scraps I just read it sounds like the decomposition of gypsum isn't very pretty, with decomposition starting around 900 C but peaking at 1200-1300 C.[4][5] Decomposition is into lime (CaO, calx?) and SO3, but at that temperature SO3 is more or less in equilibrium with SO2. At much cooler temperatures, 500-800 C, SO2 (and I assume SO3) can react with carbon to produce elemental sulfur.[6] Wnt (talk) 13:50, 3 August 2011 (UTC)


Apart from Index to Creationist Claims, what other major, long, detailed or comprehensive list of arguments defending evolution or responses to arguments against evolution are there on Internet websites? Is that list the only such list in

I am asking this because there is a list of responses to Index to Creationists claims in Creationwiki. — Preceding unsigned comment added by (talk) 08:34, 3 August 2011 (UTC)

There is no need for a list since the validity of scientific theories is not decided by a list contest. Dauto (talk) 14:29, 3 August 2011 (UTC)
That really doesn't answer the poster's question at all. I can think of plenty of reasons why a list would be useful, besides a "list contest". —Akrabbimtalk 14:50, 3 August 2011 (UTC)
Don't know if you'll think it counts but there are several YouTube channels with lots of evolution videos that give evidence for evolution and also rebut creationist claims. I can't search YouTube at work but the main one I can think of off the top of my head is thunderf00t, if you find his channel you should be able to go through related videos from there. His most recent videos have him debating banana man, I recommend you don't start with those videos since his debating is not nearly as polished as his self produced videos. Vespine (talk) 22:27, 3 August 2011 (UTC)

EM waves traveling through a vacuum[edit]

What's the physical difference between a volume of space in a vacuum with no EM wave propagating through it and another volume of space in a vacuum with an EM wave propagating through it? (talk) 18:18, 3 August 2011 (UTC)

The physical difference is that one has an EM wave propagating through it and the other does not. Sorry, but that is a physical difference, and there's no simpler way of stating it. I could say that one of them contains photons and the other doesn't, but that really isn't any simpler. Looie496 (talk) 18:24, 3 August 2011 (UTC)
"I could say that one of them contains photons and the other doesn't, but that really isn't any simpler." If that's true, then the presence or absence of wave/particles is something I can begin to get my head around. (talk) 18:27, 3 August 2011 (UTC)
It may be easier to take your thinking back one step, classification wise, to understand how EM radiation works. Think of EM radiation as a physical thing itself. That thing can be modeled as or observed as a wave, or it can be modeled as, or observed as, a particle, depending on which context you want to work with it. It's kinda like asking "am I a father or am I a son". I am actually both, but it depends on what context (in relation to my own father, or in relation to my own child) you are asking the question. Likewise, "electromagnetic radiation" is a thing like me. Asking whether or not EM is a wave or a particle depends purely on the context of the question. Just as I am both a father and a son at the same time, and I can say that without contradiction, you should also be able to accept that EM is both a wave and a particle at the same time. When you ask "what is the difference between the a vacuum with EM radiation and one without", the simple answer, as Looie496 stated, is the radiation itself. --Jayron32 18:37, 3 August 2011 (UTC)
And from the experimental point of view, the presence of a EM wave can be detected with, for instance, an antenna. Associated with the wave there are oscillating electric and magnetic fields (That's what's waving) which influence the behavior of the electrons in the antenna creating a measurable signal. Dauto (talk) 18:43, 3 August 2011 (UTC)
However you want to slice it: electric fields, and magnetic fields, are fundamental properties of the universe. They exist. We can measure their values. We can write equations that precisely model their observed behaviors. You can choose a variety of different approaches to write accurate equations that work well for particular scenarios.
(Classical electrodynamics): If you want to model the universe as a coordinate-space, you must define a vector-field for the electric (E) and magnetic (B) fields. An electromagnetic wave exists when this vector-field takes on certain specific values, and can propagate. We explicitly define those values by solving the wave equation for Maxwell's equations, which define the relationship between the position and value of E- and B- fields.
(Relativistic electrodynamics): Special relativity explains the coordinate-transform that relates electric field and magnetic field. Using the mathematical framework provided by relativity, it becomes trivial to translate your coordinates into a different frame; physically, this means that magnetic field and electric field represent the same phenomenon. For example, one observer at one position at some instant may see a static magnetic field; while relatively-moving observer (moving at a specific velocity) may see no magnetic field, and a time-varying electric-field. These observations are equivalent and consistent with a coordinate transform. Maxwell's equations, which work in classical situations, work equally well for relativistic treatments.
(Quantum electrodynamics): If you want to model the universe using particles, you must specify the position and value of the photons, which is equivalent to defining the wavefields as above. If you consider incredibly small time- and length- scales, or very high energies, you must consider other fundamental interactions, in addition to electric and magnetic interactions.
(Electroweak unification): Furthermore, electric field and magnetic field are special cases of electroweak interaction, observed at low energy scales. Electroweak unification is the rigorous mathematical formulation that explains how electric field, magnetic field, and the weak interaction can all be represented in a single equation.
Whether you want to model this universe by representing it with quantized state (including inherent uncertainties in those quantized states); or if you prefer to model it as a set of continuous fields for all coordinate-points; or as a lorentz-contracted, general-relativity-compensated space-time coordinate system; it is just this simple: electric field, and magnetic field, are fundamental properties of the universe, along with the value of mass and charge, and a few other physical quantities. We take their existence in the equations as axioms, because that matches our observations of the universe. Despite their apparent mathematical simplicity, the equations we use to define field or particle interactions are based entirely on experiment. Nimur (talk) 19:05, 3 August 2011 (UTC)

Gravitational waves and frame of reference[edit]

I was just reading the article on gravitational waves, and from what I gathered, any moving object produces gravitational waves, like a boat on a lake. Would this mean that there is an absolute frame of reference? --Melab±1 19:38, 3 August 2011 (UTC)

Never mind, I saw the part talking about acceleration. But, does anyone still care to comment? --Melab±1 19:38, 3 August 2011 (UTC)
You said "any object", but I suspect that all massless particles should be excluded from this list, so make that "any object with mass". StuRat (talk) 20:15, 3 August 2011 (UTC)
Your suspicions are unfounded. Massless particles also contribute to gravity, since they do carry energy. Beware that only the rest mass of a massless particle is zero. Dauto (talk) 20:47, 3 August 2011 (UTC)
Well, I'll comment on the original question. My understanding is that gravitational waves are thought to transform in the same way as light waves -- a way that does not yield an absolute frame of reference. Looie496 (talk) 15:42, 4 August 2011 (UTC)

Destroying the Popemobile[edit]

Could the Popemobile be destroyed by an anti-tank weapon? Whoop whoop pull up Bitching Betty | Averted crashes 19:54, 3 August 2011 (UTC)

Simply glancing at both articles that you linked make it clear that the Popemobile has bullet-proof glass around the Pope's seat and anti-tank weapons easily cut through bullet-proof glass. -- kainaw 19:58, 3 August 2011 (UTC)
If the Popemobile was impervious to anti-tank weapons, wouldn't they make tanks out of the same material? AndyTheGrump (talk) 20:52, 3 August 2011 (UTC)
I thought maybe the Popemobile had something besides bulletproof glass protecting the Pope. Whoop whoop pull up Bitching Betty | Averted crashes 21:50, 3 August 2011 (UTC)
"Sir, It's impervious to our anti-tank weapons!" "Then it's time to break out the big guns. Prepare the anti-popemobile weapons." APL (talk) 22:03, 3 August 2011 (UTC)
Many of the Popemobiles don't even have glass. They are completely open. Did you even attempt to scan the article? -- kainaw 15:04, 4 August 2011 (UTC)
Yes hes also protected by God . No weapon forged against his Holy Father shall prosper! (Isaiah 54:17) FeydHuxtable (talk) 15:58, 4 August 2011 (UTC)
[[Except for all of those Popes who were, in the end, assassinated. --Mr.98 (talk) 16:17, 4 August 2011 (UTC)

No. There are several Popemobiles so one anti-tank weapon would be insufficient. Also permission to do the experiment might be refused. Cuddlyable3 (talk) 22:20, 3 August 2011 (UTC)

Answering Kainaw: It says that Popemobiles have been required to have bulletproof glass ever since the Pope John Paul II assassination attempt. Answering FeydHuxtable: Listen to Mr.98. Answring Cuddlyable3: There may be several Popemobiles, but there is only one Pope. All an assassin would have to do is figure out which one is carrying the Pope and then fire off his anti-tank round. Whoop whoop pull up Bitching Betty | Averted crashes 19:37, 4 August 2011 (UTC)
You didn't mention popeicide. Sometimes there has been more than one pope and if that should happen again, your idea could serve as a drastic method of pope-culling. Cuddlyable3 (talk) 13:00, 6 August 2011 (UTC)

the moon should have an atmosphere[edit]

because take ONE lonely molecule of whatever "air" you it wonders around the moon, it would rather go inside (due to the moons gravity however small) than wander off, and once it is around the surface, that small gravity will always be enough to make it go 'Id rather stick around here" than just wander off again, as though the moons gravity was literally 0. so by this reasoning, either there is no moon, its mass is really 0, mass does not correlate with gravity, or the moon actually does have an atmosphere contrary to popular opinion. is this? p.s. excuse lithuanian. — Preceding unsigned comment added by (talk) 22:07, 3 August 2011 (UTC)

Does the article Atmosphere of the Moon answer your questions? --Jayron32 22:13, 3 August 2011 (UTC)
I'm sorry, but that article seems to be gobbledegook to me, and more a coverup than anything else. It's very short, for one thing, and introduces a word word "sputtering' for how sunlight supposedly pushes off the atmosphere from the moon, and also 'outgassing' and 'meteorites' all to push the atmosphere off of the moon. Sunlight obviously has a negligible ability to move anything, as opposed to enough gravity for the astro-men to make just tall bounds, but fall back to the moon. Think about it: the astro-men jumped and fell back down, but we are to assume that sun somehow with light alone makes the atmosphere careen off? Also outgassing is likewise ridiculous suppogestion - it might explain why some things from INSIDE the moon go volcanoing off outside the moon, but that does not explain why atmosphere already hanging around would not fall in, just like astro-men. The only reasonable explanation from reading that article (which does not address any of my specific questions posed above) is that it is a cover-up, invented after a fact, perhaps to match imagery or prevously published astro conjecture. There is nothing in the article which makes sense to me, and the whole thing is fishing. Can you address my points in this paragraph, if I am after all mistaken (which is not without unprecdent). Also with micrometeorites, what is the article suggestion: that for every molecule of gas, a micro-meteorite comes at just the right trajectory to careen off with it like two billiard balls? Or, what is the mechanism supposabled?-- (talk) 22:23, 3 August 2011 (UTC)
You have misunderstood the article that Jayron32 referred you to; it actually explains how the Moon does have a thin but lingering atmosphere. The article Sputtering explains what that word means. Congratulations on your mastery of English as a Lithuanian apparently located near Budapest, and on exposing yet another of Wikipedia's cunning coverups. Cuddlyable3 (talk) 22:46, 3 August 2011 (UTC)
Despite your disbelief solar radiation and solar wind do exert enough pressure to remove most of the moon's atmosphere. Why on earth would anybody want to cover up the existence of a lunar atmosphere?
(WP:EC)As I understand it, you're technically correct; there are a few gas molecules hanging around. See Atmosphere_of_the_Moon, which describes how this 'atmosphere' is so low-density as to be negligible, for all but the most pedantic or specifically detailed purposes. SemanticMantis (talk) 22:16, 3 August 2011 (UTC)
Atmospheric escape has better detail than Atmosphere of the moon, for some reason. Comet Tuttle (talk) 22:34, 3 August 2011 (UTC)
The language desk will be green with envy of "suppogestion". Wanderer57 (talk) 00:59, 4 August 2011 (UTC)
Acutally the reason why earth enjoys such a healthy and thick atmosphere is due to the Magnetosphere, without it the sun would blow most of our atmosphere away too, which is precisely what happened on Mars and is the reason why Mars only has a thin atmosphere. Secondly, comparing astraunaughts to gas molecules is pretty silly. Astraunaughts are huge and slow and gas molecules are tiny and fast, they only need a tiny push in just the right direction to send them flying. Vespine (talk) 01:21, 4 August 2011 (UTC)
I think OP asks a valid, interesting and intelligent question, and the ones who "answered" him perform the usual wp bizzo of setting up a straw man, and bashing that, or just ignoring the question. There are gas molecules that come in from outer space, and ones that are radiated from within the moon. Is it not the case, OP wants to know, that ALL of these molecules will be bound permanently to the moon, and so the atomosphere can only grow, and never be diminished?
I think the answer is that as the sun warms the gas, some of the gas molecules will be bounced up high and come near to the escape gravity zone. There, if they hit again in the right direction, they will leave orbit and escape the moon. The more molecules there are, the more likely it is that such collisions will occur, and the more gas molecules will leave the moon. That means that as the atmosphere is depleted, the gas becomes colder and less active. That it turn means that there will always be a thin gas around such bodies, but the less massive they are, the more likely it is that gas will escape the planet. There is probably some mathematical correlation whereby we could predict how thin the atmosphere of a planet would be, if we know how massive it is. Myles325a (talk) 07:31, 4 August 2011 (UTC)
Nobody is bashing strawmen here. we gave him a straight answer and he disdained it as being ridiculous. There's nothing we can do if someone refuses to read an article with an open mind. By your answer it seems to me that you should read Atmospheric escape as well to get a more thorough understanding of that subject. Dauto (talk) 14:18, 4 August 2011 (UTC)
This is a fair question, not answered in the article, and the language gibes are uncalled for. Now let's get started. From a quick Web search:
Lunar escape velocity = 2.4 km/s
Mars escape velocity = 5 km/s
Venus escape velocity = 10 km/s
Earth escape velocity = 11 km/s
Jupiter escape velocity = 60 km/s
As we see, that's a difference, but not nearly so qualitative a difference as there is between the atmospheres of these planets. Atmospheric escape explains that Mars and Venus have both lost a fair amount of atmosphere due to their lower mass. Specifically it explains (Atmospheric_escape#Thermal_escape_mechanisms that escape happens because some individual molecules of air reach escape velocity, at the level in the atmosphere where the mean free path is comparable to the scale height. That last bit means the bigger a planet's atmosphere, the higher a platform the air has to jump from in order to reach orbit; but even on Earth that isn't really much of a difference. For Jupiter and Saturn it probably matters! But the key here is that there's someplace where you're looking at the Maxwell distribution and asking how many individual air molecules, just because of their temperature, can make the jump all the way out beyond the planet's gravitational pull, never to return.
Now if you think the article about the lunar atmosphere is gobbledygook, you're not going to like that article on the Maxwell distribution, but reading through it carefully it looks like the drop-off for high velocities is proportional to e^(-v^2), which provides a pretty sharp cutoff. (I've tried before to make mathematical articles clearer to the reader, but their incomprehensibility is pretty strongly defended, and I'm not good enough with the topic to accomplish much) Note that the difference between Earth and the Moon is comparable to the difference between Jupiter and Earth - as a result Jupiter swims in a vast sea of hydrogen, whereas the Earth is stripped of hydrogen and helium, and the Moon is stripped of everything. (Temperature also has to do with this, but I think it would only affect velocity according to its square root, which isn't that huge of a difference) Though I suspect that if there were enough xenon it could hold onto that - I see some forum postings and such agreeing but didn't pursue a good source. Wnt (talk) 17:17, 5 August 2011 (UTC)
The Moon has no significant atmosphere because it is blown away by the solar wind the wind is strong enough to take away gas, but not dense objects like rocks or people. The atmosphere of the moon is thinner, and might be said to 'come and go'. High solar flare activity blows it away, ice from comets, asteroids and stones that impact replenish it. The earth has an atmosphere because of the magnetosphere as per Vespine's description. The magnetosphere is generated by the heat in the iron center of the earth, which has been molten since earths creation. Once the core of earth goes cold, the magnetosphere will disappear and the atmosphere will follow. Mars is like an older version of earth, it's core has gone cold, the atmosphere is thinning out. All of these bodies have their atmospheres topped up slightly by ice (comets and so forth) from time to time. Deep space planets can hold their atmospheres without a magnetic force field because the solar wind is not as strong, eventually, the solar wind comes to a halt along with it's booty at the heliopause far far away. Penyulap talk 12:59, 6 August 2011 (UTC)
See lunar water. ~AH1 (discuss!) 14:14, 8 August 2011 (UTC)