If Black Hole never forms, how important will be to study Black Hole paradoxes? I recently came across a paper Black Hole - Never Forms, or Never Evaporates. It is claimed that under general evaporation conditions, before particles come into the Black Hole, the Black Hole itself will completely evaporate. In other words, Black Hole cannot form from gravitational collapse.
If this paper was correct, (I haven't went through all the details, but did not find a technical error yet. And I would like to know your opinions about this paper, though i am not sure if it will be an opinion-based question), do we still need to study many paradoxes of Black Holes?
 A: The point of the paper is the information lost and singularity problems will be avoided, if black holes do evaporate. Hawking's mechanism of black hole evaporation will solve the information lost problem raised by himself, together with the singularity problem in classical GR. This result suggests that QFT and GR are not only consistent, they requires each other, there are no sharp conflicts between them.
Here is the Mathematica code for verifying the universal spherical solution in the paper: http://zhblog.engic.org/wp-content/uploads/2014/01/BH-Code.zip
PS: As @Christoph said: "black holes are observationally indistinguishable from dark gray ones". So there is no conflict with known astronomical evidences.
--the author of the paper.
A: A common feature of almost all proposals to solve the black hole information loss problem (except horizon complementarity) is that their proponents don't seem to understand the reasoning that led Hawking to conclude that there was a problem in the first place.
Schwarzschild coordinates behave pathologically near the event horizon (and don't cover the horizon itself at all), so if you think about physics near the horizon in Schwarzschild-like coordinates, it's easy to convince yourself that matter gets stuck there and turns into Hawking radiation and there's no problem.
If you consider the same process in local comoving approximately-inertial coordinates, it looks very different. The matter proceeds on its merry way, until suddenly (in a proper time comparable to $GM/c^3$ where $M$ is the mass of the hole that would have formed), it decays into radiation. This decay violates most conservation laws (such as the baryon number conservation that normally prevents proton decay), and it is not isotropic but is concentrated in a beam pointing away from where the black hole would have formed – but that isn't the biggest problem. The biggest problem is that it happens for no reason at all. Even if you imagine that the matter "wants" to avoid forming a black hole, there is nothing in its causal past (past light cone) that reliably indicates that a black hole is about to form. The formation depends on the behavior of matter that is macroscopically far from the light cone. That's the problem.
If the real resolution of the problem looked anything like this paper suggests, it would be a huge deal. It would completely undermine the foundations of quantum gravity, including the assumptions behind the calculation that led to this resolution in the first place. Everything would be up for grabs. It would be an exciting time for theoretical particle physics.
No one is that excited because those who don't understand the problem don't understand the implications, and those who do understand it dismiss these proposals because their proponents clearly don't understand the implications – which means that they probably made some boring error and didn't double-check it because the answer seemed reasonable to them.
