This answer to a question posed a few days ago made me wonder. I made this comment to the answer:

So if we place (as dense as possible) high power lasers on a sphere with a radius of, say, one light year (so we can place very much lasers) and let them all give a high energy pulse at the same time, and directed to the center of the sphere, a black hole will develop at the center of the sphere?

Of course, my suggestion is very hard to realize, and the laser pulses will diverge after traveling one lightyear, but suppose they don't. Now suppose a Black Hole forms (which will, according to the answer in connection with a metric called the Vaidya metric). Will the photons disappear after the Black Hole has formed, can't we answer this question because we are speaking of the very high energy of the photons in a very small spot in spacetime, or is there something meaningful to say about it?

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    $\begingroup$ We cannot answer because photons are quantum mechanical entities and black holes classical relativistic objects. Since gravity has not been definitively quantized yet there can only be speculations from analogies with classical particles . Classically particles just become part of the mass of the black hole,no identity. $\endgroup$ – anna v May 25 '19 at 13:03
  • $\begingroup$ en.wikipedia.org/wiki/Kugelblitz_(astrophysics) - Although personally I don't believe in it. $\endgroup$ – safesphere Jun 20 '19 at 4:49

Will the photons disappear after the Black Hole has formed,

Like any matter that goes into forming a black hole, they will end up at the singularity.

  • $\begingroup$ What exactly do you mean by end up? Do they cease to exist, while their energy fuels the curvature of spacetime? $\endgroup$ – descheleschilder May 25 '19 at 21:57
  • $\begingroup$ @descheleschilder Time starts and matter is created at the Big Bang. The opposite happens at a Black hole singularity. $\endgroup$ – safesphere Jun 20 '19 at 4:24

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