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View Full Version : Restrictions of a non-homogenous universe?



SlowCheetah
2016-Jan-12, 06:00 AM
Predictions about the future of the universe are made based on the Mediocrity Principle, such as the assumption that the observable universe is homogenous, so therefore the whole universe is homogenous. My question is, since we only see a very small percentage of the whole universe, isn't it possible that the Mediocrity Principle doesn't apply, and perhaps things such as the geometry or fate of the universe aren't what we think them to be? My specific thought is: what if there wasn't an inflationary epoch, but instead inflation is just always present on the "edge" of the universe and we interpret that as dark energy...

Cougar
2016-Jan-12, 02:30 PM
Welcome to the board, Cheetah!


Predictions about the future of the universe are made based on the Mediocrity Principle....

Well, I'd say predictions about the future of the universe are sometimes based on the Mediocrity Principle



....such as the assumption that the observable universe is homogenous....

Homogeneous. Yes, the part of the universe beyond the visible universe is typically thought to be much like the part we can see. I guess that's the Mediocrity Principle, meaning common, ordinary (not low quality!). With respect to just the visible universe alone, we know it's not really homogeneous except on a very large scale, which we can verify with observations.


My question is, since we only see a very small percentage of the whole universe, isn't it possible that the Mediocrity Principle doesn't apply, and perhaps things such as the geometry or fate of the universe aren't what we think them to be?

Sure. Could be. But we have no specific reason to think the part of the universe beyond our light horizon is much different than the part we can see. Plus, it apparently all came from the same event, and the CMB that we detect in every direction of the sky is very uniform. Because just prior to that, all was in thermal equilibrium.


My specific thought is: what if there wasn't an inflationary epoch, but instead inflation is just always present on the "edge" of the universe and we interpret that as dark energy...

I'm not sure how that would work. You'll have to think of the implications of such a scheme and see if they square with what we see.