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Path: utzoo!linus!decvax!tektronix!patcl
From: patcl@tektronix.UUCP (Pat Clancy)
Newsgroups: net.physics
Subject: big bang vs. speed of light
Message-ID: <1427@tektronix.UUCP>
Date: Tue, 4-Oct-83 04:03:05 EDT
Article-I.D.: tektroni.1427
Posted: Tue Oct  4 04:03:05 1983
Date-Received: Thu, 6-Oct-83 21:12:15 EDT
Organization: Tektronix, Beaverton OR
Lines: 34

In an article in the Oct. Scientific American ("The
Large-Scale Structure of the Universe"), the authors make
the statement that "In the early stages of expansion
the galaxies recede from each other at an apparent velocity
that exceeds the speed of light" (p. 75).
This brings up a problem which I have wondered about
occasionally, concerning the execution of the big bang:
if we start with a "singular point of infinite density"
(same article), which expands as both matter and radiation,
then the radiation should "outrun" the matter, so that
at any time after time 0, any observer should see radiation
originating at any point within the radius of the expansion.
That is, if particles A and B started at the same spatial
location at time 0, then at time t > 0, A and B will be
separated by a distance d, which must be less than the
distance light can travel in time t. Therefore, the "event
horizon" at any point should include all other matter
originating in the big bang.
Now, I realize there must be an error in this logic, so
where is it? I suspect it has something to do with the
curvature of space, perhaps in making the transition from
a state of "infinite" to finite curvature (ie., the
transition out of time 0).

In the same vein, the SA article states that "a massive
neutrino cannot continue indefinitely moving at the
speed of light" (p. 80). How can a particle with mass move
at the speed of light for any length of time? Is it possible
to move at light speed and have some mass other than zero
or infinite?

Pat Clancy
Tektronix