Put simply, matter certainly falls into a black hole in finite time. Black holes merge, as LIGO recently observed gravitational waves from, if that helps give some "direct" evidence.
Yes, studying the exact formation for a black hole is a subject under investigation. From what little I've heard in the past, there is nothing surprising happening, but I guess people are hoping that could lead to some understanding. Not sure what they do, numerical GR I suppose, maybe compare to alternative gravity theories to see if any differences are predicted.
Yes, studying the exact formation for a black hole is a subject under investigation. From what little I've heard in the past, there is nothing surprising happening, but I guess people are hoping that could lead to some understanding. Not sure what they do, numerical GR I suppose, maybe compare to alternative gravity theories to see if any differences are predicted.