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Comment by causi | Hacker News Reader

Something I've always been curious about is how energy relates to black hole formation with regards to Schwarzschild radius and the early universe. How did the early universe not collapse into one giant black hole? Are mass-energy and density the only factors affecting formation or does the type of energy have an effect? For example, suppose I have a mass more than sufficient to collapse into a black hole. Now suppose that the mass is split in half and each half has a very high momentum energy directly away from the other half. Do they fly apart or does the momentum energy simply increase the mass-energy of the black hole?

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Space is "able to" expand/inflate faster than light. So, the universe started as a black hole, but space expanded/inflated fast enough to push almost everything out past the event horizon. Maybe there wasn't enough matter left in any one place to be a black hole anymore? Or, any already sufficiently dense clumps kept their event horizons, and became the primordial black holes.

Or, maybe there wasn't anything until there was enough room for it to be in. Then you don't need a black hole.

Cosmologists like to toss about "expanding universe" and "inflation" as if they mean something, but they really are like gravity to Newton: a name for a process that can be described, but is otherwise wholly incomprehensible.

Not an expert; please correct me if anything is wrong.

My understanding is:

1. there needs to be somewhere to escape to, for the schwarzschild radius to make sense, and there's no "outside" to the universe

2. we don't know how big the universe is or what it looks like; if it's infinite and uniform then there won't be any central point for a singularity

3. as others have mentioned, inflation is a get-out-of-black-hole card

4. the physics of the early universe aren't necessarily the same as physics now

Put a pile of sand on large deflated ballon. Inflate ballon. Stuff will get further apart and thinned out.

It’s more that we had infinite density. Then space itself spread out.

Oversimplified disclaimer.

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