alt Hacker NewsThe event horizon radius grows linearly, so it's possible for a black hole to have a lower density than water (around 7 billion solar masses). Another curiosity is that if you plug in the mass of the regular matter in the observable universe into the schwarzchild radius equation (R = 2GM/(c^2)) you get a black hole event horizon larger than the the observable universe.
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AnimalMuppet • today at 12:33 AM
Therefore... what? The universe is a black hole? (If so, what if anything does that change? Is there a singularity that we hit within a finite proper time?)
Or the universe is not a black hole? If that's the case, why isn't it?
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> it's possible for a black hole to have a lower density than water
But that density is not homogeneous. It's much denser in the middle. As you cross the event horizon you wouldn't notice anything happening (as long as the BH is big enough that the tidal forces were small so you didnt get spaghettified). But things would feel very weird as you got closer to the middle.
Probably. Nobody has proved any of this but it seems likely.