Re: [Phys-l] cosmology

[Jack Uretsky <jlu@hep.anl.gov>]

Hi Jeffrey-
	I suggest that you get your cosmology from the popular books by 
active cosmologists.  The notion of ``before the big bang'' has no context 
that any cosmologist I am aware of has been able to give meaning to.
There are papers being circulated (I've not tried to read any of them) 
that are apparently advocating an oscillatory universe.
	The observational problem is that we cannot, at present, look back 
before them time of formation of atoms, when the universe became 
transparent to EM radiation.  For all practical purposes that was time 
zero, but the zero comes after an almost instantaneous inflation in size.
	We'll learn more if we ever learn to detect relic neutrinos left 
over from the big bang (if there was one), and relic gravitational waves, 
if any.  Lots of open questions for the future.  Fun, huh!
					Regards,
						Jack



On Sun, 9 Sep 2007, Jeffrey Schnick wrote:

> I just started a book entitled Maps of Time, An Introduction to Big
> History by David Christian.  David Christian is an historian who began
> teaching "Big History" at the university level in 1989.  In the book he
> states that just prior to the big bang, the universe was the size of an
> atom.  I have heard this kind of statement many times--that the universe
> was tiny or infinitesimal in size and I have always taken it as a
> misinterpretation of the idea that the density of the universe was
> infinite or as the result of treating that part of the universe which is
> observable to us today as the entire universe.  My question is, does our
> current understanding of cosmology suggest that the entire universe was
> infinitesimal or very small when it was most recently most dense?  What
> does it even mean to say that the universe was the size of an atom?
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