From: Ramez Naam (mez@apexnano.com)
Date: Sun Feb 09 2003 - 23:39:50 MST
From: Anders Sandberg [mailto:asa@nada.kth.se]
> I think most cosmologists think of spatially
> unbounded universes when they consider the open
> universe scenario (although it is not topologically
> required). These would have an infinite number of
> galaxies, although I don't think this is widely
> remarked on.
Really? I'm no cosmologist, but this doesn't jive with my
understanding. An open universe is one that will expand infinitely
and is therefore *eventually* infinite in volume.
However, an open universe has finite mass, which clearly limits the
number of galaxies. Indeed, if an open universe had an infinite
number of galaxies it would have infinite mass, which would result in
a mass density that would guarantee collapse, thus implying a closed
universe.
Or at least, that's how this non-specialist sees things.
mez
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