Of course, as somebody else said, for an outside observer the time to reach the horizon is infinite, you never see anything crossing it.
This actually has interesting consequences about what the black hole is, if you think about it a little more. Consider that you throw a 10 tonne spaceship into a black hole (let's say supermassive, so that we needn't bother with tides) and watch it from the outside. As it approaches the event horizon, you will see it slow down, flatten, get red and dark, its transmissions will slow down ("... and now, I'm about to crooosss ttthheeee evvvvvvvvv....v...") to an apparent halt; its time will appear to freeze as the spaceship appears to get compressed into a flat cake slapped onto the existing black hole. (This is just how it appears to you who are far away; the traveller will actually be doing fine and won't notice any flattening.) You will wait and wait, but you'll see nothing more. The flattened spaceship will seem to hang just above the event horizon forever - or rather, so you'll figure, because eventually it will get so red-shifted and dark that you won't see it anymore. Disappointed, you leave. Another experimenter then comes and sees just a black hole, 10 tonnes heavier and a fraction of an inch larger than you first saw it. He'll never figure out that the outermost fraction of an inch is a spaceship hovering just above the black hole. Just as you didn't figure out that the last 3 km of the black hole that
you saw was actually a star that had been falling towards the black hole some time before you came and had gotten stuck above the horizon, trying to fall into it.
Every single inch of the black hole's radius, all the way down to the central singularity, can be accounted for as some matter that had fallen into the black hole earlier and got frozen above the "previous" horizon. From the outside observer's point of view, the event horizon is packed full of matter rushing into the singularity, compressed, frozen and blackened from where you see it. In the center of the black hole, presumably there is the matter of the star that initially formed it, frozen in its collapse as it reached the apparent density c
2/6Gr
2. Classically, this is all there is; in the time of the outside observer, the singularity never formed, because the infalling matter never quite reached it and is frozen in its fall towards it forever.
The infalling observer's experience would presumably be different; he would finish his sentence, "... and now, I'm about to cross the event horizon - okay, you shouldn't be able to hear me now. It was me who ate your cookie, ha-ha!" From his point of view, the event horizon would recede from him as he falls further towards the singularity. He could even be allowed to hear
some of the transmissions by someone who fell in
just before him. But most of the matter that had fallen in earlier would always remain frozen ahead of him and he would never "hit" it. He would keep falling towards the shrinking (from his viewpoint) black hole, until it shrinks so much that the tidal forces will tear him to bits, and then his remnants would approach the singularity until the physical laws change so much that we can't predict what happens next.
Enter Hawking radiation. If Hawking's hypothesis is correct, black holes will eventually evaporate, so the infalling matter is not actually frozen in its fall forever. If he waits ridiculously long, even the outside observer will see the event horizon shrink - infalling matter will be allowed to fall beyond where the horizon used to be. Would this allow the infalling observer to transmit something outside? It might, or it might not; it depends on how the black hole information paradox is resolved. Classically, if black holes truly "have no hair", Hawking radiation could be truly random, information could be allowed to actually disappear from the universe and no transmissions will ever reach the outside observer. Or, as some suggest, Hawking radiation could be affected by information contents of the black hole, and an outside observer could theoretically be allowed to decipher the contents of the transmission from inside the black hole by carefully observing the radiation over time. Frankly, we don't know. All we can say so far is that from the outside observer's perspective, at some point during their fall into the singularity, the mass of the infalling observer's remnants is transformed into radiation and allowed to leave the black hole - ultimately, gravitational collapse results simply in 100% conversion of matter to radiation. What this implies about the experience of the infalling observer - whether perhaps his remnants are allowed to travel into their past as laws of physics break at the singularity, or something entirely different happens from his perspective - is not known. And to be really fair, we haven't even confirmed yet that Hawking radiation actually exists in the real universe. But theoretical physics is advancing, and if you wait for a few dozen years, there might be much better answers for you about what is going on inside black holes.
(Note: The above has been intentionally simplified for the sake of a layman reader.)
but at best all we can do is speculate. Interesting phenomena and they were always the stuff of science fiction until recently.
