You often hear that black holes are so strong in their gravitational pull that matter, even light cannot escape. But this seems to contradict the laws of conservation of energy. Is it possible that perhaps light (photons) are not themselves elementary particles, and within the immense gravity of black holes decompose into some other sub-particle or dark matter that we cannot yet measure/see? I know there is no way, yet, to measure or determine this, but it seems like there is a more simple explanation than matter just "disappearing". Thoughts?


closed as unclear what you're asking by ACuriousMind, Martin, Kyle Kanos, Qmechanic May 5 '15 at 19:00

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    $\begingroup$ "But this seems to contradict the laws of conservation of energy."...where do you see the contradiction? I'm not sure what your question is. $\endgroup$ – ACuriousMind May 5 '15 at 15:05

The matter doesn't disappear - it still exists, but we can't access it without entering the black hole ourselves, and then we'd be trapped. Due to Hawking radiation, over time (assuming the black hole is small enough) all of the energy that went into the black hole will be released again as the black hole evaporates.

The bigger conservation issue at stake is the information paradox, which deals with what happens to the information contained in matter that gets thrown into the black hole. This is not necessarily preserved by the Hawking radiation (that is, by observing the particles radiating out of the black hole, you may not be able to predict what went in). Resolving this paradox is still an open field of research.

It is possible that elementary particles are indeed not actually elementary, but this doesn't follow (AFAIK) from black holes. Supposing that photons were made of smaller particles, what would happen to those particles when they fell into a black hole? It's turtles all the way down at that point. :-)


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