Re: More Open Universe(?)
Dan Clemmensen (Dan@Clemmensen.ShireNet.com)
Sun, 18 Jan 1998 22:17:15 -0500
EvMick wrote:
>
>
> If EVERYTHING is expanding...(The girl, the gold watch...and
> everything)...then why should a red shift be noticeable? Is this Eienstein's
> non-intuitive relativity theory again...? To me it would appear that for a
> red shift to be noticable there would have to be SOME type of constant...by
> which velocity, expansion...or whatever is measured against...if "Space-Time"
> is expanding...(which includes light)...then how would we know? And what
> difference would it make?
>
The current "standard" expansion theory holds that the universe expands,
but
that local effects (mostly gravity) keep certain small bodies (up to
about the
size of galactic clusters) together. Galaxies therefore don't expand,
and
neither do gold watches. because the expansion isn't strong enough
to overcome chemical bonds, or even gravity when matter is dense enough.
In fact, the "open or closed?" question is actually a question of
whether
the universe's average density is great enough to eventually
gravitationally
overcome the expansion.