In this concluding episode, our hero Cooper is reeling from the fact that he just (willingly) jumped into a supermassive black hole. Amelia is watching the daring jump from the safety of a spaceship far away from the black hole.
Cooper is alright as far as he can tell. According to Amelia, however, Cooper is not alright. Rather, his now incinerated body is seemingly frozen just outside the event horizon.
We are told by the laws of physics that Cooper is required to remain outside the black hole so that information is not lost (which in this case means Cooper’s body remain outside the event horizon in the form of either atoms or radiation). Indeed Amelia sees Cooper’s remains and even collects them.
Meanwhile, there is a perfectly healthy and happy copy of Cooper existing inside the supermassive black hole. We are further informed by the laws of physics that Cooper’s body is not allowed to exist (alive or otherwise) both outside and inside the black hole at the same time. So what is going on here? After puzzling physicists for a while, the simplest solution is that Cooper’s duplicated body does not break any laws of physics because no one can know of the existence of the other ‘person.’
Amelia can never see inside the black hole, and Cooper can never see (or go) outside the black hole. We were more or less okay with that explanation, until recently. Then the following question came up of what if it turns out that information of Cooper’s existence inside the black hole can in principle be discerned by Amelia?
It turns out that it may be possible for information in Cooper’s atoms outside the black hole to be connected to Cooper’s atoms inside the black hole. They would be connected by a kind of invisible piece of string called ‘action at a distance.’ If so, then we will have to worry about the implications for physics after all.
One is not sure if it helps, but it is at least useful to know that at the moment, even if such a computation were possible, it would so long to run that the black hole itself would have died before we had the answer (or rather, evaporated, which is how black holes reach their end).
But, what we all want to know is what will happen to Cooper?! While Cooper can possibly survive the fall through the event horizon, he will not be happy for much longer. Cooper’s free-falling self would have to meet its end once he reaches the the infinitely-twisted space and time at the black hole’s center, or singularity. At least according to his perspective he will have died valiantly in the field.
One can recommend now going to see the film “Interstellar,” in which this thrilling thought experiment is carried out!