From: NFetter <NFetter@aol.com>
Date: Sun, 5 Apr 1998 19:38:11 EDT
To: pinhole@exploratorium.edu
Subject: Re: Re: Pinhole Daily Digest
Hi emile,
If there were only two objects in the universe, they would still obey Newton's
rule, namely: F = G m1 x m2/r xr. The attractive force is inversely
proportional the to the square of the distance between the centers of mass of
the two objects. The attractive force extends to infinite distance. If you
waited long enough the two objects would come back together from a very great
distance. That brings up the expanding universe. Assuming you will agree that
the universe started as a Big Bang from a singularity (whatever that is), the
fate of the universe depends on it total mass. If the total mass is not
enough, the universe will expand forever. If the mass is just right, a steady
state will be achieved someday, and if the mass is too great, gravitational
attraction will result in an implosion--the Big Crunch. What makes up most of
the mass of the universe? Neutrinos? Dark matter? The jury is still out on
this, but I get the feeling that right now, most astronomers go for indefinite
expansion. Paul probably knows more about this stuff than I do, so maybe he
will offer some information.
Neil Fetter