Larry Caldwell wrote:
> I have been reading the popular scientific articles about Dark Matter,
> and am having trouble digesting the concept. My big problem is figuring
> out how it cooled off enough after the Big Bang to settle down and form
> galactic halos. When normal matter was formed in the Big Bang, it was
> very hot. It cooled by emitting huge amounts of EM radiation. Dark
> Matter doesn't emit EM radiation. Where did the energy go? The weak
> force is far too short range to provide a pathway.
It went away through cosmological red****ft, the same way all the other
energy of the Big Bang went away. As the Universe expands, everything
in it cools, including things that don't interact with anything else.
Energy is not globally conserved in general relativity.
> It's fairly easy to postulate some form of radiation that interacts with
> Dark Matter that does not interact with normal matter, but that just
> leads me to another point of confusion. I don't see how this
> hypothetical 'sneaky energy' could behave like the Dark Energy the
> astronomers talk about.
Dark energy has nothing to do with dark matter in terms of a direct
relation****p. Dark matter is the name for matter we can't see; dark
energy is the name for a repulsive energy whose cause isn't yet clear.
But there's no reason to believe that they are directly related
phenomena; they're just gaps in our knowledge. One name is a spinoff of
the other, but that doesn't indicate any kind of actual relation****p
between the two.
> It would have to be an analog of the EM
> momentum exchange that allows normal matter particles to bump into each
> other and shed momentum. If Dark Matter can collapse into a galactic
> halo, can it form dense aggregates.
That doesn't follow, since present-day cool dark matter is cool enough
to collect around galaxies, but not smaller objects.
--
Erik Max Francis && max@[EMAIL PROTECTED]
&& http://www.alcyone.com/max/
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Most men do not mature, they simply grow taller.
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