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?