Newtonian dynamics unmodified

August 16, 2006 7:46 PM

Good evidencethat dark matter is for real.
posted by kliuless (57 comments total)

Um, everything that's not glowing is by definition dark matter. Everything you see in your life, except the sun and stars, is dark matter.

Dark matter isn't some mysterious thing, it's just matter that's not glowing. The question is, why is there so much of it, and what makes up the majority of it, or whether it's just an artifact caused by using Newtonian physics rather then relativity to calculate things.
posted by delmoi at 7:56 PM on August 16, 2006

Everything you see in your life, except the sun and stars, is dark matter.

youkeepusingthiswordidonotthinkitmeanswhatyouthinkitmeans
posted by riotgrrl69 at 8:02 PM on August 16, 2006

could be non-baryonic...
posted by kliuless at 8:15 PM on August 16, 2006

There is the question of why it doesn't collide. Galaxies move really fast, so if there's so much of it, why isn't there evidence of dark matter smacking together?
posted by owhydididoit at 8:15 PM on August 16, 2006

I think several candidates for dark matter wouldn't collide that often. MACHOs like brown dwarfs would be too dispersed and non-baryonic matter like neutrinos barely interact with other particles.
posted by justkevin at 8:21 PM on August 16, 2006

Epoxymoronymous post. Mind boggling. Thanks, kliuless.
posted by weapons-grade pandemonium at 8:24 PM on August 16, 2006

Could somebody explain black matter to me in one bullet point? KTHANKSBYE
posted by Citizen Premier at 8:25 PM on August 16, 2006

Brilliantly explained (to the ninth decimal)via BBC
posted by hortense at 8:26 PM on August 16, 2006

p.s. delmoi, you're thinking of black bodies, probably. But most people aren't black bodies, except for black people.
posted by Citizen Premier at 8:27 PM on August 16, 2006

If this holds up and leads to an explanation of dark matter, it would be one of the greatest astronomical discoveries since CMB Radiation in my opinion. I got chills reading this. I have always had the hunch that Newtons laws needed readjusting at large scales, but maybe there really is tons of stuff out there we can't see! So cool.
posted by anomie at 8:28 PM on August 16, 2006

Good evidence that dark matter is for real.

No. Good evidence would be a link to the materials being released on 21 August by NASA. The evidence you linked includes informed speculation on Slashdot, a mathematical physicist's quoting of said speculation and attempt to explain in more detail (or, arguably, preempt) the announcement for which there is still no information and finally an article from 2003.

Here's the press release, to-be-populated overview page and audio/video of the announcement. Of course, those are pretty boring right now -- but they're the only links which are guaranteed to be accurate.

There will be enough confusion when CNN attempts to cover the story -- we don't need to further muddy the situation by throwing the (last I checked, not widely Maurer-Cartan equation-quoting) MetaFilter community into the speculation phase of the story.
posted by VulcanMike at 8:32 PM on August 16, 2006

I think delmoi is correct that just about anything that's not glowing is dark matter. Based on observations of galaxies, astronomers believe there's either more matter out there than we can see or our model of gravity is wrong. If it's the former, than anything that's generating gravitational forces besides the visible stars, gas clouds, etc. falls under the umbrella of dark matter.
posted by justkevin at 8:34 PM on August 16, 2006

Dark matter isn't some mysterious thing, it's just matter that's not glowing. The question is, why is there so much of it, and what makes up the majority of it, or whether it's just an artifact caused by using Newtonian physics rather then [sic] relativity to calculate things.

Read: Is dark matter for real?

If you're going to post inane comments, at least try not to be the first one in the thread.
posted by anomie at 8:38 PM on August 16, 2006

6:35 into that film (thanks hortense), I am reminded of a book by Isaac Asimov, The Gods Themselves, which stipulates that matter has an infinite number of properties, each of which can only be expressed when there's enough matter. This makes me think that perhaps matter has a repulsive quality when present in extremely high, universe-sized quantities.



But I don't know shit.
posted by Citizen Premier at 8:38 PM on August 16, 2006

Multi-link blahfilter.
posted by cillit bang at 8:45 PM on August 16, 2006

"Galaxies move really fast.."

...if you don't stop and look around once in awhile, you could miss it.

"Could somebody explain black matter to me in one bullet point? KTHANKSBYE"

When a daddy black matter and a mommy black matter love each other very much...

"If you're going to post inane comments, at least try not to be the first one in the thread."

Boys have a penis, girls have a vagina.
posted by ZachsMind at 8:46 PM on August 16, 2006

how bleak.
posted by owhydididoit at 8:46 PM on August 16, 2006

Read: Is dark matter for real?

No, that's not the question. The point is, some dark matter must exist. Anyway comments that simply say "you're wrong" without any evidence or explanation are not conducive to anything in particular.
posted by delmoi at 9:06 PM on August 16, 2006

matter has an infinite number of properties...

"Until recently, most scientists thought neutrinos had no mass either, but in the late 1990s researchers found that the particles change flavor as they travel, and this trans-formation can happen only if they have mass." - the neutrino frontier :P
posted by kliuless at 9:10 PM on August 16, 2006

Thanks kliuless!

Read: Is dark matter for real?

No, that's not the question.

Yes it is. I think everyone understands whats meant by the phrase "dark matter" and its not simply the combination of the words "dark" and "matter."
posted by vacapinta at 9:16 PM on August 16, 2006

Sadly, every astronomy professor I've ever interacted with uses the same misguided definition of dark matter that delmoi does. Unnecessary too, when everyone knows what it means.
posted by Humanzee at 9:25 PM on August 16, 2006 [1 favorite has favorites]

Some dark matter is just normal matter (technically, baryonic matter) that's cold and therefore not visible. However, there is now very good evidence that most of the mass in the universe is non-baryonic. The recent estimates that I've seen are that baryonic matter makes up about 4% of the total mass of the universe (of which about 3.6% is dark), non-baryonic dark matter makes up about 23% of the mass of the universe, and the other 73% of the mass of the universe is dark energy. (Figures taken from this Science review). Astonishingly, this means that 96% of the universe is made of stuff which is totally mysterious. Here's a summary from NASA which doesn't require a password.
posted by pombe at 9:32 PM on August 16, 2006

the future of science revealed!

...neutrinos make up about 0.5% of the stuff in the universe, about the same as the visible matter in the universe. What's the remainder?

That's the big open question, but one that I'd wager will be solved by the end of the decade. There are very good reasons -- particle physics ones, rather than cosmological ones -- for believing that the main constituent of dark matter is a proposed particle known as the LSP. If it is, then the LHC accelerator in Geneva will find it. If not, then the LSP almost certainly doesn't exist and the puzzle will be compounded -- but I think that scientists are extremely optimistic.

cheers!
posted by kliuless at 9:41 PM on August 16, 2006

Yes it is. I think everyone understands what's meant by the phrase "dark matter" and its not simply the combination of the words "dark" and "matter."

Well, a majority of Americans believe WMDs were found in Iraq. That hardly makes it true. When scientists talk about dark matter, they are talking about things that don't emit radiation, which is exactly why what the words "dark" and "matter". It's only recently that the "existence" of large amounts of dark matter has even been called into question, and only by a single paper (that I know of). The question is what is it? Very few scientists question that it exists.

You don't reflect enough light to be detected from another galaxy, neither does the earth. that makes us dark matter, according to the wikipedia definition. this essay. Baryonic dark matter normally refers to normal atomic matter, which includes planets and dead stars. For the past 50 years it's been known that dark matter must exist, again it's only recently that it's been called into question.

An announcement that says "dark matter exists" would be as big as an announcement that "earth exists!". If someone could prove that there was not as much dark matter as previously thought, that would be a big announcement. If people were able to figure out what that dark matter was actually made of, that would also be big news. It would also be somewhat interesting if people could prove dark matter exists when using relativity to calculate the distribution of galaxies, as well as using Newtonian physics, but that would just be confirmation of what's already belived.
posted by delmoi at 9:52 PM on August 16, 2006

Of course, I'm real!
posted by darkstar at 10:06 PM on August 16, 2006

that makes us dark matter, according to the wikipedia definition

"In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation (light) to be detected directly"

I'm fairly certain we know what we're made of.
posted by cillit bang at 10:09 PM on August 16, 2006

"In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation (light) to be detected directly"

"Unspecified composition" would be more in keeping of the way the term is typically used by scientists. Even if you want to stick with "unknown composition", then by that definition, Earth is not dark matter; but another planet -identical to Earth in every respect but in another galaxy- would remain undetectable and thus would be dark matter.

"Dark matter" is a term coined by astronomers, who realized long ago that there's a lot more out there in the universe than the things that we can directly see.
posted by Humanzee at 10:19 PM on August 16, 2006

pombe has it right. We're talking here about non-baryonic dark matter. The amount of baryonic (normal) matter, such as MACHOs (mass compact halo objects such as white dwarfs), needed to speed up the rotation of galaxies, to hold in lots of hot gas, and to act as a gravitational lens, is so great that this amount of matter would have affected the fusion of elements just after the Big Bang. We wouldn't see as much Deuterium today if all of the dark matter were normal matter.

MOND (Modified Newtonian Dynamics), pioneered by Mordecai Milgrom, has been investigated by quite a few research papers.
posted by Schmucko at 10:29 PM on August 16, 2006

Earth is not dark matter; but another planet -identical to Earth in every respect but in another galaxy- would remain undetectable and thus would be dark matter.

i think you guys are playing with words. If I take many Earths and smoosh them together, it forms a Sun and that thing lights up.

So, one difference between that "dark matter" and this other "dark matter" is that one of them still doesnt light up!

Simple application of the Virial theorem to galactic clusters shows that the computed potential is not strong enough to bind the observed kinetic energy of the visible galaxies. So it appears that either our assumptions about gravity are off base, or that there is a huge chunk of matter out there which has this strong non-interacting property, except when it comes to Gravity. Odd.

Now, if Baez is right, we have another observation of this second "dark matter", namely that even in an explosive collison of galaxies, it still doesnt light up yet seems to keep moving "ghostlike" through the collision. This observation is amazing because it shows another manifestation for "dark matter" - not simply as a mysterious addition to the potential well but also something that can be observed indirectly as "moving" with an actual location.

is that good enough for you guys? Or do you insist on this "i cant see my hand in the dark so its dark matter" stuff?
posted by vacapinta at 10:31 PM on August 16, 2006

i think you guys are playing with words. If I take many Earths and smoosh them together, it forms a Sun and that thing lights up.

No, you're the one playing with words. I'm talking about the way the word is used by people who study this stuff; you're talking about the way the word is used by you (who you call "most people"), in your own imagination. Generally when we speak of what is and isn't "something" we refer to it's standard usage.

If I take many Earths and smoosh them together, it forms a Sun and that thing lights up.

Yes, that's correct. It was dark matter and now it's not. That's exactly correct, and the correct use of the term "dark matter".

Dark matter means matter that's dark. Nothing more, nothing less. That's why it's called dark matter. The fact that "Dark" has a mysterious connotation and that dark matter is currently mysterious is only a coincidence. In fact I've read about scientist complaining about the phrase because it does sound mysterious and is a little misleading for some people.

And like I said, the existence of dark matter is not really in question, (other then that paper about it perhaps being an error caused by using Newtonian physics, which is very new. Dark matter has been known about for decades). So saying that it exists is not a big deal. The "stuff we see every day" was just an example of that.

Anyway it was just annoying to hear people say "you don't know what it means" without any attempt to define what it actually meant, and in fact they were the ones who did not know what the term meant.
posted by delmoi at 10:51 PM on August 16, 2006

The fact that "Dark" has a mysterious connotation and that dark matter is currently mysterious is only a coincidence.

I thought the whole "mystery" regarding it is simply that there is so much of it, gravitational forces should be acting to create a whole lot more directly-observable (ie: luminous, burning) objects, and so we create explanations like black holes to explain how there can be super-massive yet non-luminous objects affecting the movement of objects we can see in such a strong way.

I suppose that could lead to more mystery surrounding the nature of the stuff itself, if only because massive gravity wells tend to go hand in hand with the directly observable... except that they don't. (Just in our limited experience, they have)

So not exactly a coincidence but not wholly mysterious either.
posted by dreamsign at 11:09 PM on August 16, 2006

I thought the whole "mystery" regarding it is simply that there is so much of it, gravitational forces should be acting to create a whole lot more directly-observable (ie: luminous, burning) objects, and so we create explanations like black holes to explain how there can be super-massive yet non-luminous objects affecting the movement of objects we can see in such a strong way.

It's not that gravity should be causing more stuff to be bright, it's that the shape of galaxies isn't correct unless you add dark matter to the equation.
posted by delmoi at 11:18 PM on August 16, 2006

Hey I know Dark Matter exists.

I read Dan Brown, afterall.
posted by oxford blue at 11:21 PM on August 16, 2006

So not exactly a coincidence but not wholly mysterious either. posted by dreamsign

Yes, it is wholly mysterious. Look, they've added up all the stuff in the universe that is made of atoms, whether glowing (stars) or not (dust, planets) and it totals less than ten percent of what's necessary to explain the extremely fast rotations of not only galaxies, but the hydrogen cloud at the edges of the universe. These structures would tear themselves apart if they just had all known atomic matter holding them together. Ninety-six percent of the universe is made of something that has mass (gravitational attraction), yet it is NOT MADE OF ATOMS. So delmoi and others, please have a look at hortense's link (you can cut to the chase a third of the way in) before posting any more nonsense. The distinction between illumination and non-illumination applies to comments in this thread, not to dark matter.
posted by weapons-grade pandemonium at 11:39 PM on August 16, 2006 [1 favorite has favorites]

it's that the shape of galaxies isn't correct unless you add dark matter to the equation.

Of course, but that's hardly mysterious, since until recently we relied on direct observation almost entirely. What's mysterious, I thought, isn't that there's a lot we can't see, but there's a lot that we can't see that we should be able to see.

Ninety-six percent of the universe is made of something that has mass (gravitational attraction), yet it is NOT MADE OF ATOMS.

Whoah, if this is the kind of thing we're talking about, then ok, yes, fascinating, amazing, mysterious. But where do you get "not made of atoms" from incredibly massive non-luminous matter?

This is beginning to sound more and more like the pop-culture description of black holes, as something other than a reeeeeaaaally dense chunk of matter. (ie: capital M Mysterious)

Sorry, wpg -- not everyone can watch video from where they access the internet. I checked hortense's link as soon as it was posted. I would settle for some agreement from other knowledgable folks that we are indeed talking about a somehow-atomless source of mass, and then I will be head-noddingly agreeable about the ineffable mystery of dark matter.
posted by dreamsign at 11:58 PM on August 16, 2006

, (other then that paper about it perhaps being an error caused by using Newtonian physics, which is very new.

No. And that's just Modified Newtonian Dynamics (MOND). I remember sitting through some alternative gravity theory talk involving particle physics three years ago. And I gave a MOND journal club talk back in my first year of grad school in 1998. The thing about MOND is that it simply doesn't work with GR (or at least, not the last time I looked into it).

I second hortense's link. It's about 90 times better than what's gone on in this thread so far. Damn.

Another decent link about DM, if you don't want to sit through a 50 minute video.

Here's a news release from Chandra regarding cold dark matter.

As far as "not made of atoms", neutrinos are non-baryonic (a.k.a. not protons, neutrons, or electrons), thus are non-atomic matter. The consensus at this point is that DM does seem to be non-baryonic (it doesn't interact with the rest of us like it should if it were baryonic). Though neutrinos have mass, they don't have enough to account for DM.

The problem is, of course, that no one has detected the particles that would fit the cold dark matter theory. Of course, the interesting thing about neutrinos is that they were theorized three full decades before they were discovered. The dude that finally discovered them won a Nobel prize for it.

Actually, the Wikipedia link isn't bad, either.
posted by dirigibleman at 12:25 AM on August 17, 2006

Ninety-six percent of the universe is made of something that has mass (gravitational attraction), yet it is NOT MADE OF ATOMS.

You're talking about non-baryonic dark matter. There is still baryonic dark matter, and we can't measure baryonic dark matter any more then we can measure non-baryonic dark matter (the stuff that's NOT MADE OF ATOMS!!!!111@). Also, not all baryons are atoms anyway. It's not like I somehow don't understand how totally awesome non-atomic matter mystery is. The fact that some matter is not made of atoms is not exactly new. We know of lots of different non-atomic particles that have mass. here is a list of all the particles we know about or have theorized in the standard model. Enjoy.

The point I was originally trying to make was that there was never a question about whether or not dark matter existed; it was only a question of what it was.

Saying that dark matter exists is like saying the earth's core exists. No one's ever seen it, but we've always known it was there.

And very recently, like this year, someone put out a paper that says dark matter doesn't exist because people are using the wrong version of physics, Newtonian rather then Relativistic to predict it. That's an interesting idea, but I don't know if it's gotten much scrutiny/analysis yet.
posted by delmoi at 12:25 AM on August 17, 2006

Metafilter: Why is there so much of it?

Sorry.
posted by uncle harold at 12:30 AM on August 17, 2006

Oops. Electrons are leptons. Like neutrinos, actually.
posted by dirigibleman at 12:31 AM on August 17, 2006

No. And that's just Modified Newtonian Dynamics (MOND). I remember sitting through some alternative gravity theory talk involving particle physics three years ago. And I gave a MOND journal club talk back in my first year of grad school in 1998. The thing about MOND is that it simply doesn't work with GR

Regular Newtonian dynamics does not work with GR either. Newtonian physics is an approximation that works very well at non-relativistic speeds and (I guess) distances. here synopsis of the paper on CERN. They claim that by using GR alone the need to have exotic dark matter disappears. here is the paper. It's on xxx.lanl.gov so I'm not even sure if it's been peer reviewed. If the authors are right, then that means the need for all the non-atomic dark matter to explain the shape of galaxies goes away.

We know for sure that General Relativity is more accurate then Newtonian physics.

Anyway, that's just a footnote. My original point was that the existence of dark matter is uncontroversial (except for that paper). So saying "new evidence that dark matter is real" is like saying "new evidence earth has a molten core" or "new evidence earth is round".
posted by delmoi at 12:36 AM on August 17, 2006

For those who watched the video,that model of the universe that was shown is remarkably similar to the distribution of neurons in ....mice. now how weird is that?
posted by hortense at 12:58 AM on August 17, 2006

For those who watched the video,that model of the universe that was shown is remarkably similar to the distribution of neurons in ....mice. now how weird is that?

Sigh...
posted by delmoi at 1:02 AM on August 17, 2006

Seriously weird, I found olanzapine helped a lot with all the freaky stuff.
posted by econous at 2:19 AM on August 17, 2006

Since there's a lot of confusion here I will weigh in (excuse the pun).

When we first started coming up with the idea of dark matter (to explain how galaxies stay together given their rotation speeds and such that has been mentioned above) we probably didn't have much clue what it was. It was maybe not totally implausible that it was baryonic - made of everyday matter.

However, models of big bang nucleosynthesis (which is a major piece of evidence for the big bang, and correctly predicts proportions of hydrogen and helium in the universe etc.) requires that the total amount of baryonic matter comes to about 5% of the critical density (that's the density required to make the universe flat, which as far as we can tell it is).

We can figure out from galaxy motions and so on - the sort of thing that originally led us to dark matter - that the total amount of matter in galaxies must be such that we have about 30% of the critical density. So the other 25% must be dark and not everyday stuff.

So we start wondering what it is, and what we now generally mean when we talk about dark matter is this stuff. Even though originally things like brown dwarfs and other cold non-luminous things made of atoms were previously included.

So, dark matter nowadays is thought not to interact with light (or at least only extremely weakly). It's some weird sort of particle. If we define dark matter now as such a particle then neutrinos come into that category - but we think that both a) they're not heavy enough to add up to it all, but most importantly b) they move just too quickly to stay in one place and help hold your galaxies together. They zip off at the speed of light and tend not to come back. It totally kills any attempt to use them to explain the galaxy stuff.

The reason you're all arguing then is because you're all choosing to pick a different definition of dark matter. Those of you calling cold failed stars dark matter are in one sense right, but for those thinking of non-baryonic stuff you seem wrong. Those of you mentioning neutrinos might be right to some of those talking about non-baryonic dark matter, but are wrong to those talking about cold non-baryonic dark matter.

If I were to talk about dark matter to a colleague they'd assume I meant the cold non-baryonic stuff, just because that's what there's most of, it's what we probably know least about, and in this context it's obviously what they're talking about. But if I spoke about some other stuff and described them as dark matter they might not think I was wrong (but they'd probably think I was using the term in a peculiarly outdated way).

We're definitely talking about the non-baryonic cold dark matter here - nothing else exists in enough quantity to be explained by this, and it's the only stuff that would do the whole zip-right-through thing that this stuff is.

As for that other 70% - the dark energy - that's not relevant here. We've no evidence that that is anything other than totally uniform throughout the universe. It's fascinating in its own right, but isn't at play in this story.

Lastly - while electrons aren't baryons as far as a particle physicist is concerned, as far as astronomers are concerned they get bundled in too. It's the electrons at the end of the day that do the whole light-emitting thing, and since they have a habit of living with the protons they just get bundled in together. Plus at 1/2000th the mass of a proton they don't really add up to much.

Wow. Long comment.
posted by edd at 5:17 AM on August 17, 2006 [3 favorites has favorites]

Look, Delmoi, we have an UPPER LIMIT on the number of normal, baryonic atoms in the universe, from big bang theory and CMB. It's very well tested and understood. And that upper limit is about 10 percent of all the mass! So it's KNOWN that about 90 percent of all mass is non-baryonic.

Dark matter as referred to by actual astronomers usually means the mysterious non-baryonic stuff, which could be axions, mini-black holes, cosmic strings, blah blah, but it's DEFINITELY not normal atoms since there weren't enough made in the big-bang!

Most mainstream astronomers accept that the bulk of the mass in this "bullet" cluster example is in fact the mysterious non-baryonic stuff. Here in the milky way, we're also swimming in a giant dark matter halo which is 90 percent (roughly) of the milky way's mass. (MOND is basically some crap that allows people to publish papers disproving it).

(That said, people also speculate about MACHOS and baryonic dark matter, but unless you believe that the constraints from nucleosynthesis and CMB are flat wrong, such matter cannot account for more than 10 percent of the total mass).
posted by snoktruix at 5:24 AM on August 17, 2006

My original point was that the existence of dark matter is uncontroversial (except for that paper). So saying "new evidence that dark matter is real" is like saying "new evidence earth has a molten core" or "new evidence earth is round".

Some of the most exciting science is getting confirmation of ideas that were already widely accepted. For example, the Sudbury Neutrino Observatory's confirmation of neutrino flavor mixing was big news, even though everyone believed that they changed flavors (and that this was responsible for the solar neutrino paradox.) Nobody doubted the existence of gravitational waves, but the first indirect evidence for them won the Nobel Prize, and there's a big project still looking for direct evidence. Inflationary theory is uncontroversial, but scientists are only now getting to test its predictions -- and there will be Nobels aplenty for those who do.

I'll have to read the paper when it comes out to determine whether this observation rises to that level -- my instinct is that it's not quite as dramatically different from previous observations as NASA will say -- but it's still potentially very, very interesting. If it blows MOND (and Beckenstein's new version) out of the water, that, alone, will be a big deal.
posted by cgs06 at 5:54 AM on August 17, 2006

There is no dark side of the Moon, really. As a matter of fact it's all dark.
posted by kirkaracha at 6:13 AM on August 17, 2006

I think a lot of the arguments here could be solved by tweaking the headline:

Exotic Properties of Apparently Non-Baryonic Dark Matter Suggested by Comparison of X-ray Emission and Gravitational Lensing Effects

Kinda punchy, eh?
posted by Mister_A at 8:02 AM on August 17, 2006

Thank you edd for clearing this mess up. I am not a science guy at all, but even I intuitively knew what kind of dark matter was being referred to in the post. It was frustrating to see this thread become an argument about the definition of dark matter.

It could have been a better thread. Instead it became about a guy pulling his putz with his right hand and claiming that when the sun and stars didn't shine on his left hand he could move celestial objects with it. I jest.
posted by TrolleyOffTheTracks at 1:56 PM on August 17, 2006

Well then, let me be the first to say I for one welcome our Exotic Properties of Apparently Non-Baryonic Dark Matter Suggested by Comparison of X-ray Emission and Gravitational Lensing Overlords!
posted by ZachsMind at 2:05 PM on August 17, 2006

yeah, i saw this more as closing the door on MOND :P more generally, tho, it feels like observation is beginning to overtake theory!
posted by kliuless at 6:54 PM on August 17, 2006

So, if I am in the dark and made of non-radiating matter and no one sees me, do I still exist? I can't believe the amount of dark matter that mefi has been blowing out of its ass on this particular thread. All of a sudden, everyone is a physicist. This has got to be one of the most hilarioulsy inarticulate threads in a while. Interesting topic, though.
posted by blue shadows at 12:14 AM on August 18, 2006

blue shadows, You didn't know physicists were the people with the most time to screw around on MeFi?
posted by jeffburdges at 4:29 AM on August 18, 2006

Excellent comment edd, thanks for the explanation.
posted by Djinh at 1:52 PM on August 19, 2006

Likewise,　edd, thanks for clearing that up.
posted by dreamsign at 2:21 AM on August 20, 2006

Now some words from NASA
posted by hortense at 11:55 AM on August 21, 2006

here're summore...

UA
eurekalert
cosmic variance
ars
/.

!P
posted by kliuless at 7:21 PM on August 21, 2006