Date: Apr 29, 2013 2:05 PM
Author: Rich Delaney
Subject: Re: closed universe, flat space?

On Apr 24, Shmuel (Seymour J.) Metz
<> wrote:
> >>Supposedly, our universe is closed and finite,
> >>although the geometry and topology isn't precisely > > >>known.  This means a straight line (geodesic)
> >>traveler must return to his starting
> >> point, yes/no?  Hence, curved space.

> >>At the same time, astronomers claim, that space
> >>is flat, to the precision of their measurements.

> >>So, space is closed, but also flat...  back in
> >>my day, they had something called a logical
> >>contradiction...

> No, the questions are why the OP is making a false
> claim and and why the OP is falsely claiming a
> logical contradiction.
> "Supposedly, our universe is closed and finite"
> is untrue; what is true is that GR allows for the
> possibility and that a sufficiently
> latge density of matter would require it. The observed
> density isn't large enough.

First, it's still unsettled.
Second, for the purposes of this question -
its motivation - we can hypothesize a closed

> What is worse is that there is no logical
> contradiction between a
> closed universe and a flat universe.

1) "The earth is flat."
2) "If you drive/sail in a straight line,
you return to your starting point."


It could hardly be simpler.