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Q & A: Universe after inflation

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Q:
how large was the universe after inflation?
- john kester
rochester ny
A:
John -

That's a pretty interesting question. For background, we should let other readers know that you're wondering about how big the universe was shortly after the Big Bang. The universe has been expanding since the Big Bang, but there's now very strong evidence that the initial expansion had an extremely brief period of extremely rapidly increasing expansion, called inflation.

If by 'universe' you mean all the stuff that makes up the visible universe, its radius after initial inflation was (very roughly) 10 cm, the size of your fist if we understand this site correctly. That's to be compared with 14 billion light years now. If by 'universe' you mean 'everything', including the stuff beyond our current horizon, we can't answer, because we don't know if we're part of a finite universe or an infinite universe.

By the way, it seems that the universe is again in a period of inflation, although this time it's not very dramatic.

Here's a nice Website discussing these questions in more depth
http://www.pbs.org/wgbh/nova/universe/howbig.html

-Mike and Tamara

(republished on 07/19/06)

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