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Old 09-08-2009, 12:23 PM
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sjastro
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Quote:
Originally Posted by xelasnave View Post
Sorry to be late in thanking everyone for their input...but thank you all.
May I ask this...
If we have the Big Bang theory and observations consistent with it can they not extrapolate how big it must be by now with reasonable accuracy.
alex
It depends on whether the accelerated expansion of the Universe has remained constant since the end of the Inflation era. (And that is assuming of course the acceleration started from that point of time.)

Since the Universe has expanded by a certain amount in the period of time it takes the light for distant objects to reach us a scale factor is introduced. The scale factor can only be reasonably accurate if the acceleration has stayed constant.

If the acceleration has varied with time then we have no way of accurately determining how large the observable Universe is.

Steven
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