That was one of the questions in which I was "retarded" because even though I kind of knew what Einstein's equations were exactly saying in the middle of the high school, it was unclear to me how can someone ever manage to cross the horizon. Fortunately, CommunistSocialistSwine, pretending to be CapitalistImperialistPig in order to damage the capitalists' image, has repeated the same question.
The (wrong) argument that nothing ever manages to get inside the black hole goes as follows. The observer at infinity, Paolo, never sees the infalling observer - that will be referred to as a beer can to preserve the standard conventions here - crossing the horizon because the final moments of the can's live before the horizon crossing are infinitely stretched.
That's fine but even the observer who lives closer to the event horizon, Julio, seems to see the can's moments right before the horizon crossing stretched to infinite time intervals. At some moment, this expansion gets really extreme. Microseconds of the can's life can get stretched to times that are longer than the lifetime of the black hole (that evaporates by the Hawking radiation).
Moreover, as you choose Julio's base to be ever closer to the horizon, he seems to see the black hole evaporate ever faster, as measured by his proper time. You may put him so close to the horizon that it only takes a microsecond of his proper time to see the whole black hole evaporation process.
It's such a short time that you must conclude that the beer can, which is really close to Julio, simply can't have enough time to cross the horizon. Before the beer can manage to cross the horizon, the black hole must surely evaporate, so the beer can (or parts of the stars that is supposed to collapse into a black hole) can never get inside. Or can it?
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