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From our point of view, no object can fall into a black hole in finite time. The object will seem to be more and more red-shifted to us, but it will never quite pass the schwarzschild-radius / event horizon. (Of course the time frame of the falling object is another thing, but we are well away from any direct effects of black holes on us)

Having said that, how can black holes come to existence? As soon as there would be a schwarzschild radius, nothing can cross it. To me this seems like a chicken-and-egg problem, so no black holes can possibly exist.

Obviously the black holes in our universe do not seem to be aware of this, so what am I missing?

Thanks in advance :-)


marked as duplicate by zibadawa timmy, Mitch Goshorn, Joan.bdm, andy256, called2voyage Jun 26 '15 at 17:00

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    $\begingroup$ The Schwarzschild radius and event horizon are not the same thing. That is probably the source of your confusion. $\endgroup$ – called2voyage Jun 25 '15 at 20:47
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    $\begingroup$ Every mass has a Schwarzschild radius, only black holes have an event horizon. $\endgroup$ – called2voyage Jun 25 '15 at 20:50
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    $\begingroup$ The short answer is that it just isn't true that nothing passes the event horizon, and this 'our point of view' is just the fact that we can use coordinates that aren't defined at the horizon. This is essentially a duplicate of Does matter accumulate just outside the event horizon of a black hole?. $\endgroup$ – Stan Liou Jun 25 '15 at 21:44
  • $\begingroup$ Thanks Stan Liou, this was indeed a duplicate of your link. Didn't find it prior to posting this question :-/ @called2voyage thanks to you, too. I was well aware of that, but didn't mention it for shortness sake, and I don't see how that would have solved the conundrum. $\endgroup$ – Peter Lustig Jun 27 '15 at 20:01

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