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Yes, absolutely - black holes don’t need singularities inside them in order to be black holes. Just enough mass in a small enough volume. (Of course, we don’t
by pja 10y ago
Yes, absolutely - black holes don’t need singularities inside them in order to be black holes. Just enough mass in a small enough volume.
(Of course, we don’t actually know whether stellar or galactic centre black holes have singularities inside them - we just don’t know of any process that will prevent one from forming in current physics.)
- BurningFrog 10y agoIf our universe is a very big black hole, that means light cannot leave it. So where does it go? My intuition - which is almost certainly wrong - says it would turn back around, and be visible as a faint background radiation.
- pdonis 10y ago> black holes don’t need singularities inside them in order to be black holes. They do according to the standard GR model. Speculations about holes not having singularities inside them are quantum gravity speculations and we have no way of testing them experimentally any time soon.
- pja 10y agoTrue! Hmm. I retract my statement: Penrose/Hawking predict that all GR black holes contain singularities. In our universe, it looks like inflation is the fly in that particular prediction: The universe is going to tear itself apart instead.
- pdonis 10y ago> In our universe, it looks like inflation is the fly in that particular prediction: The universe is going to tear itself apart instead. reply I assume you're referring to the "Big Rip" scenario? That's not considered very likely, at least according to our best current data.
- pja 10y agoNo, just inflation taking the rest of the universe over the horizon - I believe it’s the dynamic effects of being in an inflationary universe that mean that the standard GR results for black holes don’t apply, at least according to the references I read. (I can’t pretend to be able to derive this stuff personally.)