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Wooter

Urban Legend
  
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« #1 : 06-21-2005 22:03 »
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btyrie

Bending Unit
  
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« #11 : 06-22-2005 13:54 »
« : 06-22-2005 13:54 »
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Actually krokei Dark Matter and Anti-Mmatter are very different substances.
This explainasion is a bit technical, but bear with me.
Dark Matter is matter that cannot be detected directly, but whose existence can be inferred on the basis of dynamical studies. Within a spiral galaxy, the stars move as if large quantities of dark matter exist around the galaxy's disk; similarly, within clusters of galaxies, the individual galaxies move as if 10 times more matter is present than that visible in the form of stars and interstellar gas and dust. Cosmologists suspect that dark matter may account for most of the so-called missing mass needed to make the average cosmic density fit that predicted by the inflationary model. Although the nature of dark matter remains unknown, it could take two possible forms: baryonic matter or non-baryonic matter. The former is "ordinary" matter, such as makes up the luminous portions of the universe but cast in the guise of objects that are difficult to detect, such as planets, brown dwarfs, and black holes. Non-baryonic matter, on the other hand, would exist as exotic particles, predicted by certain grand unified theories. There are two possible subgroups of exotic dark matter: hot dark matter (HDM) and cold dark matter (CDM). HDM would be composed of particles such as neutrinos, described as hot because they travel at or very close to the speed of light. Neutrinos are a prime candidate, especially in view of recent evidence that has come down in favor of them having mass. CDM would be composed of weakly interacting massive particles (WIMPs). These particles have relatively large masses, travel relatively slowly and interact only weakly with normal baryonic material; hence, they are difficult to detect. Candidates include the axion and the neutralino. The currently favored view is that CDM makes up the bulk of dark matter in the Universe, with perhaps a minor contribution of 10 to 20% from HDM. A key prediction of the CDM model, that large galaxies are accompanied by huge retinues of dwarf galaxies (gravitationally drawn in by the CDM halos), won observational support in 2002. A study of large galaxies that act as gravitational lenses revealed that about 2% of their mass must be in the form of dwarf galaxies—equivalent to thousands of these small systems-to explain the lensing effects.
Anti-Matter is basically matter whoes quantum properties are reversed, ie- matter with a negitve mass or negitive charge, when matter and antimatter particles meet, mutual annihilation takes place, releasing an enormous amount of energy, how much? Well a mere 10 pounds (4.55 kilograms) of the stuff would release alomost twice as much energy as the largest hydrogen bomb ever built (100 megatons).
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Teral

Helpy McHelphelp
DOOP Secretary

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« #17 : 06-23-2005 08:41 »
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Shiny

Professor

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« #20 : 06-25-2005 14:19 »
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Originally posted by btyrie: Dark Matter is matter that cannot be detected directly, but whose existence can be inferred on the basis of dynamical studies....Cosmologists suspect that dark matter may account for most of the so-called missing mass needed to make the average cosmic density fit that predicted by the inflationary model.
And I have been convinced for years that "dark matter" does not exist. I believe "dark matter" is, like "ether/aether" was in the last century, merely a imaginary construction based on our incomplete understanding of the universe. To refresh our collective memories: in former times no one could explain the wave-like behavior of light in a vacuum - a wave is just a motion through particles, it must have a medium of said particles to go through (like water, air, or metal). A wave can't go through a vacuum - no particles means no waves through them, as there is no sound in space. Yet light (and heat, and radio, etc) did. So scientists theorized "ether," the invisible substance of space that lightwaves moved through. Experiments looked for this ether and failed to find it. Yet light went on behaving like a wave. The concept of “ether” died only when we found out more about how light really works - light is thought to be composed of “wavicles,” which sometimes act like particles and sometimes act like waves, and don’t depend on an invisible, undetectable medium to travel through. “Dark matter,” I predict, will not be found; it will vanish when we find out more about how gravity really works. Originally posted by RectalExamBot: I sometimes wish I was a physicist, so I could say things like "We figure the universe is made up of 95% of stuff which cannot be detected by any means, but it has be be there. It just has to!"
You and me both, brother! 
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Descon

Delivery Boy
 
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« #23 : 06-25-2005 19:18 »
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From what I have heard and read, the problem of dark matter came when scientists tried to weigh a galaxy based on how much light it reflects, and how their orbits work. when the two numbers didnt match up, they decided there must be some matter that we cannot see, or does not reflect light.
but shiny, you may be right about dark matter, what some physicists suspect is that gravity is made up of strings the same way light is (well close to), but one property of gravitons is their ability to 'jump' dimensional planes (ie, more strings than the one we live on) so my theory on the missing gravitons, is that in the process of jumping dimensions, they have taken the light with them, sort of like a black hole.
now, i know there may be repercussions from talking about interdimensional travel, but trust me, it is something that physicists have considered.
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Teral

Helpy McHelphelp
DOOP Secretary

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« #26 : 06-26-2005 16:11 »
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Originally posted by btyrie: By the way the weight of 1lb of dark matter was stated to be greater then 10,000lbs not a thousand suns. Two different episodes... LLLiS: 1 lb = 10000 lbs (illogical statement) The Why of Fry: 1 sphere weighs as much as a thousand suns (hyperbole) As for the calculations, we don't know if 6000 lbs (why didn't they use metrics!! So much for the scientific excellence of the Futurama writers...) is the breaking point of a hover dolly, it could just as easily be 3000 lbs. All we know is, 6000 lbs is over the limit. Additionally, the back-up dolly might've been a lesser version of the hover dolly, why else is it the back-up dolly?
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Shiny

Professor

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« #29 : 06-29-2005 21:37 »
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Originally posted by cujoe169: shiny it already seems like ur quite qualified to be one of our resident physicists Originally posted by Wooter: More like a physics historian, from what I've read. Wow, thanks - both of you. I wish I was that edumacated, but I'm a member of Fry's class (a certified dropout  ). I just read a lot. But science and how it advances (or doesn't) has always been interesting to me. The parallels between ether and dark matter are just too great not to notice; problem is, most scientists don't seem to study history and most historians don't seem to study science. But Isaac Asimov's science essays always went to the beginning (usually the Greeks) and followed the subject forward, and I love that approach. (I learned the story of ether first from him). I: I didn't say we understand everything about light or other particles; just that we know enough to say there's no ether. As for string theory, well, EVERY theory that breaks an old paradigm starts life as the red-headed stepchild; some chemist, I can't remember who, once complained that the only way for new ideas to be accepted in science is for old scientists to die. People just get attached to their worldviews and don't want to give them up.
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duff77
Poppler

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« #30 : 07-01-2005 15:44 »
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Dark matter is a strange scientific concept the Futurama writers decided to use to take the place of coal and, one time, oil (in the penguin episode). But I'm sure the nerds on the staff knew what they were doing picking dark matter to be a show element that was so flexible in size and shape.
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SpaceCase

Liquid Emperor
 
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« #35 : 08-09-2005 13:09 »
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There may not even be such a thing as "Dark Matter." BenderforPres is right about one thing at least; the pointy-headed cosmology types have figger'd that there just isn't enough matter to exert enough gravitational force to explain why, for example, galaxies rotate the way they do.  One postulated solution to this is that the the matter is out there but, we just can't see it. That is, dark matter. But... Those same pointy-headed cosmology types have invented "String Theory." One feature of String Theory says, that there are additional spatial dimensions 'wound up' in our universe, as well as the three we can see ( length, width, and height). There's plenty of gravitatin' going on out there, but owing to vagueries of the theory that I sure as hell don't understand, the 'missing' gravitation might be 'leaking' away along those other spatial dimensions. (Try wrapping your mind around that!  ) If this is the case, "Dark Matter" will vanish from thought, like the 'aether' of the ninteenth century... but that is a different story... I'll just ooze back under the laboratory door now...
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SpaceCase

Liquid Emperor
 
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« #39 : 08-18-2005 10:57 »
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Originally posted by Al: Hi
Dark matter is the third leg of the tripod-paradox of dark matter, antimatter and doesn't matter. *DING!* *DING!* *DING!* Ah, we have a winner. Um, just one thing... What about Wassa-matter? <Buh- DUMP-bump> Thank you, thank you, I'm here all week. Try the chicken, and don't forget to tip your waitress... <Dodges thrown tomato> Geeze! Tough room...
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