If I throw a clock towards a black hole, its time slows down, it is redshifted, and according to many theories it never reaches the event horizon from my point of view. How is it then, that a star can fall into a black hole, and be observed to do so by me (by its emission of gravitational waves)?
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1$\begingroup$ I'm speculating, hence a comment instead of an answer, but the statement that we never observe something cross the event horizon is based on an approximation that the infalling body does't move the event horizon. In actuality the gravity of the falling body will pull the event horizon out to meet it in finite time (when the body is about its own Schwarzschild radius of the event horizon). $\endgroup$– Sean E. LakeMar 4, 2019 at 5:55
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The LIGO results are about the merging of two black holes, and gravitational waves are expected mathematically to be emitted due to the great distortions of space as the two massive black holes merge. One has to remember it is general relativity at work here.
Something similar will happen when a star is absorbed, again space distortions will be great. A clock falling into a black hole distorts space in so tiny a quantity, due to the small gravitational constant its mass is insignificant with respect to the black hole mass, that any gravitational waves of its disappearance ( or not depending on the observer) cannot be recorded. It took the order of sun masses size of the two merging black holes to be detected by LIGO.
