Suppose you were in the exact center of a sphere of mass large enough and dense enough to undergo gravitational collapse. Someone releases whatever’s been holding it and the sphere collapses, with you inside. Since you’re not falling into a singularity that’s already there, what exactly would you observe (before your presumed annihlation)?
You would see nothing of the formation of the Black Hole. Your extinction is assured LONG before the black hole singularity forms (even supposing some sci-fi gizmo to keep you alive longer than necessary). The densities at the center would be staggering. Remember the mass would pass through densities of a Neutron star and Quark star on its way to singularity.
However, you can ask what the view is like from the inside of a black hole (that is inside the event horizon). For a sufficiently large black hole you could easily survive passing that threshold (although you are now ultimately doomed). Unfortunately I don’t know the answer to this but I suppose someone will be along soon who does.
nobody knows what it looks like inside a black hole. according to relativity, if the center is actually a singularity, then the laws of physics and probability would completely break down. you wouldn’t get much of a glimpse anyway. once you pass the event horizon the gravitational difference between your head and your feet will turn you into human spaghetti!
Ok…here’s a page with an animated ride into a black hole…all the way to just before the singularity. It’s crude but there are explanations.
Come on guys, lets try and answer. The obvious answer is “nothing, but you’d be crushed,” so let’s suppose that:
- You are in an incompressable shell.
- The matter arround it is transparent.
Then either:
- This prevents a singularity forming.
- A singularity forms at some point on the edge of the shell
- A singularity forms at all points round the edge, ie. it gets infinitely thin.
2 would just be you next to a singularity (being crushed against the edge of the shell) and probably within the event horizon. 3 sounds very cool but very unstable and would probably become 2. But you’d experience no gravity (some calculus shows a uniform mass round you cancels out), and nothing could get in as it would be absorbed by the singularity. In 1, you’d still be stuck in a black hole.
Any physicists want to weigh in with a clearer explanation, and explain any time-dilation effects?
If you were in a sufficiently massive black hole, you would feel nothing special and there is no reason to think you would be crushed. In fact, the density of a black hole is IIRC inversely proportional to its mass. As far as I know, there is no way we could know that our observable universe is not a black hole. On the other hand if somehow the sun could be compressed into a black hole it would be incredibly dense.
That’s only for a stellar-mass black hole. For bigger ones, not necessarily so. A body of water the mass of the galaxy is dense enough to be a black hole.
Darn you beat me to it. The only thing is…
should be “inversely proportional to the square of its mass.”
Sorry, I should have been clearer. I meant a spherical hollow shell, so that none of the matter reaches you until after (from an outside observer’s viewpoint) the shell has fallen past the event horizon.
I know that calculated strictly Newtonian, someone inside a spherically symmetrical shell feels no net gravitational pull, but presumably you need to take General Relativity into account. My own intuitive guess was that the inrush of matter would generate a tremendous gravity wave that would exert enough pressure on you to crush you into a singularity.
BUT: what if the “shell” was a stupendously dense sphere of photons? If it collapsed at lighspeed, then the gravitational force couldn’t reach you untill the wall of photons hit you. But I admit that my grasp of “when” events inside an event horizon can be said to have happened is pretty shaky.