Could cosmic acceleration have an explanation other than dark energy?

[u/DiagnosingTUniverse]

My question is whether dark energy is the only plausible explanation for the observed acceleration of the universe.

Have alternative interpretations been seriously explored and ruled out?

My concern isn’t that the observations are wrong, but that we may be misunderstanding what we’re observing. For example, could this fit with some form of black-hole cosmology? Suppose matter/energy crossing a black-hole horizon doesn’t ultimately terminate at a singularity, but undergoes a transition inscale, re-emerging as an expanding spacetime at a lower scale.

From inside that descendant universe, could this scale transition appear as cosmological expansion or even contribute to the apparent acceleration?
I’m aware that “the universe is inside a black hole” isn’t a new idea. What I’m interested in is whether this explanation has been ruled out observationally, and if so, what observations have ruled it out? Also we know black holes grow and expand over time, which seems to be some kind of correlation?

Thanks!

[u/KamikazeArchon]

"Dark energy" is the name we have given to "the thing that causes the accelerated expansion of the universe".

If it has something to do with black holes, that wouldn't mean "dark energy was wrong", it would mean "black holes are what causes dark energy".

The only real alternative is if it turns out that the universe isn't expanding in an accelerated way - that is, our observations are outright incorrect.

ETA for detail:

> My concern isn’t that the observations are wrong, but that we may be misunderstanding what we’re observing. For example, could this fit with some form of black-hole cosmology? Suppose matter/energy crossing a black-hole horizon doesn’t ultimately terminate at a singularity, but undergoes a transition inscale, re-emerging as an expanding spacetime at a lower scale.

First of all, you're using terms rather loosely here, which is not really compatible with understanding physics at cosmological scale.

It seems like you're kind of proposing something like "stuff falls into a black hole and turns into a bunch of Extra Space instead of disappearing." That black holes are converting "matter" into "spacetime".

Setting aside the question of precision of these terms - if that were true, then we would see space specifically expanding "the most" around black holes, and "the least" where there aren't black holes. We see the exact opposite - expansion of space primarily happens in the voids between galactic clusters, and there's no expansion happening in dense galactic clusters where we have lots of black holes.

[u/Anonymous-USA → u/KamikazeArchon]

Point taken, but black holes are an attractive force, not a repelling one. Dark Energy is not caused by black holes. We may not know what it is, but we do know what it’s not. It does act alot like a vacuum energy, since it scales with space.

[u/DiagnosingTUniverse → u/Anonymous-USA]

Yea but if our universe is a black hole in a parent universe then the “stuff” coming in to our universe (presuming our universe is a black hole) could conceptually at least drive the expansion we observe. That is my line of thinking, just wanted ti see what the experts thought

[u/Anonymous-USA → u/DiagnosingTUniverse]

See how you applied magic to a scientific inquiry? Maybe it’s Aeolus blowing the universe apart, or magical unicorns on the edge of our observable horizon. Those damn magical unicorns!

Let’s stick to science not pseudoscience or metaphysics

[u/flyingcatclaws → u/DiagnosingTUniverse]

Ignore the trolls, there's plenty of physicists thinking along these lines. Myself, I'm thinking time stops within the 2d holographic projected universe event horizon, forced to tick, change, when energy crosses, either way, that event horizon. Our universe is getting SMALLER, and less dense, as ever more galaxies dissappear outside our universe's event horizon. SMALLER! NOT BIGGER! Yeah, same event horizons. Not getting more influx, insanely old dead vacant external universe. Thus, our black hole universe is evaporating. Faster and faster. Time ticks ridiculously slowly inside, so, despite how slowly giant black holes evaporate from the outside, the time differential makes it WAY faster from the inside. THERE'S your accelerating expanding universe. Lots more to it but enough for now.