From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Aug 16 2002 - 01:45:09 MDT
On Thu, Aug 15, 2002 at 07:01:03PM -0700, Lee Corbin wrote:
> If the universe is closed, then there are finitely many galaxies,
> and the universe can even be said to have a radius. But if the
> universe is open, then like I say, there probably exist aleph
> zero (i.e. countably many) galaxies.
Actually, it turns out that you can have infinite volume closed universes
and finite volume open universes if the topology is non-trivial.
We can only observe the visible universe, out to 15 billion light years.
What lies beyond depends on the topology.
Here are some numbers:
http://www.anzwers.org/free/universe/universe.html
Number of superclusters within 15 billion light years = 270 000
Number of galaxy groups within 15 billion light years = 500 million
Number of large galaxies within 15 billion light years = 10 billion
Number of dwarf galaxies within 15 billion light years = 100 billion
Number of stars within 15 billion light years = 2000 billion billion
(he also has a good expansion page:
http://www.anzwers.org/free/universe/bigbang.html)
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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