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I have a theory I think might explain why the universe has accelerated in a way that doesn't require dark energy. I'm wondering if someone has proposed this theory before (did some research and couldn't find anything).

The theory is that the big bang was essentially a huge super-nova-like eruption inside an even larger universe. Just like the visible universe has super novae that happen inside much much larger galaxies and dust clouds, so could the Big Bang have been a huge explosion in a much huger universe. The acceleration we have seen evidence of could, then, have been caused if the big bang was off center in the huge amount of matter in the outer universe - ie if one side exerted more gravity than the other, mass closer to that side would accelerate away from mass closer to the center of the big bang.

I imagine a huge black-hole sucking in a giant swath of matter from the greater universe, coalescing into a small area that leaves a large space around it rather empty. Then when it explodes (or perhaps it just emitted large amounts of matter out of it via something like hawking radiation), it fills this space again with what we now see as our universe.

This theory doesn't seem to require any sort of bizarre unknown physics, like dark energy, singularities or anything else that causes divide by 0 errors in established physical equations. Has it been proposed before? Also, I'd be interested to know if anyone has any concrete reasons why this theory wouldn't work.

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    $\begingroup$ The big bang is more than just an explosion, it is spacetime itself that is singular there. Please also have a look at our mainstream policy. $\endgroup$ – ACuriousMind Aug 8 '14 at 21:35
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    $\begingroup$ @ACuriousMind Well so my primary question is whether my theory (or a theory like it) has been proposed in the mainstream. Is that not acceptable? Where would you suggest I post a question like this? $\endgroup$ – B T Aug 8 '14 at 22:10
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    $\begingroup$ As far as I know, the policy of reviewing non-mainstream theories (e.g., why X isn't accepted, evidence against X) is actually on topic here. $\endgroup$ – Kyle Kanos Aug 9 '14 at 1:58
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    $\begingroup$ I would not call this a theory unless it's falsifiable and testable by observations, and presents what the observations should be. What specifically would be observed if this was correct - and more importantly what would be observed if it isn't correct? $\endgroup$ – paisanco Aug 9 '14 at 2:03
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    $\begingroup$ Most of this idea is realized by the Lemaitre-Tolman-Bondi models representing a spherically symmetric but inhomogeneous universe. This may not be a "standard" model of cosmology, but it is a serious proposition studied in peer-reviewed journals so I don't understand the "non-mainstream" label. (But yes, the third paragraph of the question goes too far into fantasizing.) $\endgroup$ – Void Oct 20 '14 at 8:41
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There are two immediate problems with this idea. First, the acceleration due to the dark energy appears to be the same in all directions. In general relativity (and Newtonian gravity for that matter) the influence of distant matter can only cause a tidal acceleration that expands matter in some directions and compresses it in others. A uniform expansion has to be due to something present locally.

Second, gravitational influences travel at the same speed as light, which means we can see the most distant matter that could gravitationally influence any of the other matter we can see. What we actually see (in the cosmic microwave background) is remarkable uniformity in all directions, to within about 0.01%. So there's no density fluctuation close enough to have an effect.

Dark energy is not as strange as you think; it's actually quite natural in quantum field theory, and the biggest mystery is why the dark energy is so small, not that it exists. And modern big bang cosmology starts with inflation, not with a singularity.

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  • $\begingroup$ So saying we "can see" the most distant matter that could gravitationally influence any of the other matter we can see isn't correct. There is matter beyond our visual horizon that was influencing the matter near the horizon when the photons of that matter left toward us. Also, there is plenty of matter we can't see, that is within our theoretical visibility simply because it doesn't emit enough light for us to see it. $\endgroup$ – B T Apr 30 '15 at 10:18
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The main problem with this hypothesis is that Penrose–Hawking singularity theorems state existence of cosmological singularity at the beginning of time, unless (at great matter densities) either some mysterious fields intervene or General Relativity fails at all. Cosmological singularity is a thing definitely distinct from a supernova explosion, whichever huge power could the latter release. Given that the modern scientific Big Bang cosmogony (also known as FLRW cosmology) crucially depends on General Relativity, it is a big trouble for such a theory.

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  • $\begingroup$ Anything involving a singularity is outside the bounds of where semiclassical physics is reliable. Its almost a certainty that General Relativity fails where singularities arise in the theory. $\endgroup$ – B T Apr 30 '15 at 10:14

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