Re: Expansion of the universe

From: Sam Wormley (swormley1_at_mchsi.com)
Date: 10/05/04 

Date: Tue, 05 Oct 2004 15:00:28 GMT

john wrote:
> Ok, so the universe is expanding because every point in the universe
> seems to be moving away from every other point. This seems a fair
> asumption, however something troubles me here. When we look back into
> space it seems we also look back in time. Now let say the universe is
> 15b years old and we have a really super telescope the can see some
> distant galaxy at a distance of 12b light years from earth, therefore
> we are looking 12b year back in time. This suggests that if we can
> see this distance from every direction then the diameter of this
> 'sphere' of the visible universe is 24b light years across. Surely so
> far back in time when the universe was only 3b years old how could it
> have expanded from the single point of a big bang to such a size.
> When the universe was 3b years old, the greatest distance any matter
> could have travelled is only 3b light years is it not?
> can someone help me out here?
> john.

We only see a small fraction of possibly an infinite universe.

No Center
   http://www.astro.ucla.edu/~wright/nocenter.html

Also see Ned Wright's Cosmology Tutorial
   http://www.astro.ucla.edu/~wright/cosmolog.htm
   http://www.astro.ucla.edu/~wright/cosmology_faq.html

WMAP: Foundations of the Big Bang theory
   http://map.gsfc.nasa.gov/m_uni.html

WMAP: Tests of Big Bang Cosmology
   http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html

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