How Big Was the Universe When It Was First Born?

Posted by timothy on Saturday December 26, 2015 @08:30PM from the that's-gotta-be-some-afterbirth dept.

StartsWithABang writes: Looking out at the distant stars, galaxies and radiation in the Universe today, we've been able to determine not only what it's made out of, but how long it's been since the Big Bang: 13.8 billion years. Put all that information together, and you can also figure out how large the observable part of that Universe is today. From our point of view, it appears to extend for 46.1 billion light years in all directions. So what if you extrapolate backwards, to the very end of inflation and the start of the hot, dense state we identify with the Big Bang, and ask how large that 46.1 billion light year "size" was back then? How big would it be? Depending on the particulars of when inflation came to an end, the answer is somewhere between the size of a soccer ball and the size of a city block, no smaller and no larger.

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Refers to Observable Universe Only by Anonymous Coward · 2015-12-26 20:55 · Score: 4, Insightful

Note that this is only talking about the portion of the original the universe that became today's observable universe. There's absolutely no reason to believe that the size of the observable universe is the size of the total universe (and we happen to be at the very dead center of it.)
There is good reason to believe that the universe is far far larger than the observable universe, and it may even extend infinitely in all directions, for all we know. Measurements on the curvature of the universe make that a plausibility.