Roland Thigpen (email@example.com)
21 Sep 2000 02:58:52 -0000
Thank you Prof Z....I'm definately going to have to save this email.
On Wed, 20 Sep 2000 19:43:18 -0700 -Z- <firstname.lastname@example.org> wrote:
>> -----Original Message-----
>> From: email@example.com [mailto:firstname.lastname@example.org]On
>> Behalf Of Roland Thigpen
>> Sent: Wednesday, September 20, 2000 19:04
>> To: email@example.com
>> Subject: Re: [gundam] Gundam and super robot wars....
>> On Thu, 21 Sep 2000 01:56:47 GMT Chris Beilby <firstname.lastname@example.org> wrote:
>> >> What is dark matter?
>> >I'm not sure, but it might be Anti-Matter...
>> NO! Dark matter is a theorized state of matter which supposedly
>> explains why about 90% of the mass of the universe cannot be
>> accounted for (don't ask me to explain, this is how I read it a while
>> back). It is called dark matter because it cannot be seen or detected
>> with our current technology. Therefore, no one has ever seen dark
>> matter. Many scientists and astronomers debunk its existence, but
>> studies are still going on (at least to my knowledge) to try and
>> prove that it is out there. It might have some special energy
>> properties to it, but I don't recall from the articles I read on it.
>There are several possible candidates for the material that makes up dark
>matter. These include neutrinos with mass, undetected brown dwarfs (starlike
>objects that are smaller and much fainter than the sun), white dwarf stars,
>black holes, sun-sized Massive Compact Halo Objects (MACHO) and exotic subatomic
>particles whose properties preclude detection by observing electromagnetic
>radiation. The exotic subatomic particles might be what's intended here, as
>they could include an analog of the Minovsky particle.
>That being said, there's a framework in which we must work. Nucleosynthesis,
>which seeks to explain the origin of elements after the Big Bang, sets a limit
>to the number of baryons—particles of ordinary, run-of-the-mill matter—that can
>exist in the universe. This limit arises out of the Standard Model of the early
>universe, which has one free parameter—the ratio of the number of baryons to the
>number of photons.
>From the temperature of the cosmic microwave background, which has been
>measured, the number of photons is now known. Therefore, to determine the
>number of baryons, we must observe stars and galaxies to learn the cosmic
>abundance of light nuclei, the only elements formed immediately after the Big
>Without exceeding the limits of nucleosynthesis, we can construct an acceptable
>model of a low-density, open universe. In that model, we take approximately
>equal amounts of baryons and exotic matter (nonbaryonic particles), but in
>quantities that add up to only 20% of the matter needed to close the universe.
>This model universe matches all our actual observations. On the other hand, a
>slightly different model of an open universe in which all matter is baryonic
>would also satisfy observations. Unfortunately, this alternative model contains
>too many baryons, violating the limits of nucleosynthesis. Thus, any acceptable
>low-density universe has mysterious properties: most of the universe's baryons
>would remain invisible, their nature unknown, and in most models much of the
>universe's matter is exotic (nonbaryonic).
>The range of particles that could constitute nonbaryonic dark matter is limited
>only slightly by theorists' imaginations. The particles include photinos,
>neutrinos, gravitinos, axions and magnetic monopoles, among many others. Of
>these, researchers have detected only neutrinos—and whether neutrinos have any
>mass remains unknown. Experiments are under way to detect other exotic
>particles. If they exist, and if one has a mass in the correct range, then that
>particle might pervade the universe and constitute dark matter.
>In any case, I think we can preclude black holes and other super-massive objects
>as the "dark matter" in question and assume that massy neutrinos or some other
>exotic particle is being used in place of the ubiquitous Minovsky particle.
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