[froeb]

A lot of crazy sounding physics theories involve some non-trivial tweak to the laws of physics as we know them (e.g. the Alcubierre drive, many exotic dark matter theories, ...) so I usually dismiss them as unlikely. However, from what I have read about this so far, it seems to a natural consequence of black hole solutions in an expanding spacetime, no new physics needed. Am I missing something? If that's really the case, the odds of this being real are much higher than most typical hyped up physics fare. Would love an expert take.

[T-A]

> no new physics needed. Am I missing something?

Unfortunately, yes. The black holes in question are not the textbook ones, they need to be full of something which acts like dark energy.

[froeb]

The textbook black hole is unphysical though, it assumes spacetime is asymptotically flat. As far as I can tell, the paper's claim is that if you do black holes more realistically, including better boundary conditions, then you can find solutions that have dark energy inside them, purely from GR. I wouldn't call that new physics exactly, I would call that a better understanding of physics we already have.