While I greatly enjoyed this movie, they left physics bruised and bleeding on the floor, even for a Star Trek movie.
First, the black holes were generated using what couldn't have been more than a few grams of "red matter", or a few hundred kilos for the whole set. Thus, any black hole generated would have at most the mass of a few hundred kilos. Such a black hole would be very, very small, and would rapidly evaporate. It probably couldn't consume a planet, or even consume enough to sustain itself.
If you were to try to detonate something inside or just outside a black hole, it would have no appreciable impact on the hole itself. The mass of the explosion would be consumed just like anything else. Active massive black holes are very energetic places, with plasma and x-rays and such out the wazoo. Nothing you could detonate off a starship would have any effect. It would just be consumed.
That is assuming it could even be detonated at all, another pet peeve. If the Enterprise was being pulled backwards into a black hole despite going faster than the speed of light (they said they were at warp) then they would be inside the event horizon. The tidal forces at such a close distance to the black hole would cause massive gravity changes over very short distances. Basically, the Enterprise, everyone in it, and the exploding cores would be very, very long spaghetti. Even after that then, considering they were already going faster than the speed of light inside the event horizon, then no explosion, no matter how energetic, could possibly accelerate them enough to escape. At that point, conventional physics and chemical reactions should be non-functional anyway.
Black holes evaporate and release energy through Hawking radiation very, very slowly. A supermassive black hole like the one in the middle of our galaxy would take several lifetimes of the Universe to evaporate. A small one would evaporate much more quickly, but even then, it only has as much energy to release as it has consumed. If the black holes had the mass of the Romulan mining ship and a few hundred kilos of "red matter", then that is all the energy it would have to release - which would occur slowly anyway. Thus, no big bang.
The real big bang did come from a singularity similar in conception to a black hole, but with two big differences. First, it had the total mass of the entire universe contained within - a lot more than a starship, or even a galaxy or two. Second, unlike standard black holes, this singularity exploded and released all that energy simultaneously. This doesn't happen with regular black holes.
Well, thanks for letting me geek out and vent. Probably more than you wanted to hear.
Pun intended, but truly fascinating. Black hole physics is beyond me and WAY, WAY over my head. Geekness appreciated and ah ... we're not worthy.
:bow: