(February 1, 2019 at 2:01 pm)Anomalocaris Wrote: No. Sagittarius A* ‘s Star denoted the notation used to mark the object, not the nature of the object. A black star’s star denotes the blackish object’s nature. A black star is not a black hole into which things can fall but never come back out. A black star has no event horizon. Things falling onto a black star can in theory come back out. But that happens rarely enough that our power of observation is not precise enough to see it. So we can’t tell the difference through observation yet.
The debate between black hole and black star is not what happens inside the event horizon. It is about whether there in fact is a event horizon.
Meh. When quantum effects are brought into play, that definition of a black hole fails. It is quite possible that any object approximated by the 'black hole' concept from geeral relativity actually evaporates over time. In fact, that is considered quite likely.
At the very least, we have incredibly massive objects that we cannot otherwise see that agree with the theoretical predictions concerning black holes. We have gravitational waves that have the signature of merging black holes as predicted by GR. We have the accretion disks and other phenomena as predicted for black holes.
So, for at least a second order of approximation, we have black holes. The existence or non-existence of an event horizon that likely wouldn't have the properties predicted by GR because of quantum effects is rather trivial against what we already have.
So, it is quite reasonable to call the objects we have found 'black holes'. If, later, our theories or observations change a bit, we may have to change our designation.
