Is energy conserved when things fall into a black hole? 
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*We all know in physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it transforms from one form to another. What happens when said energy ie planets, stars, light etc..enter a black hole? 

*Does it simply change form or does it disappear from this universe into another?

*I know many physicists have said all laws start to break down once something enters a black hole but are there any new theories on this? Is it possible it simply turns the energy into a new form like dark matter?
 A: Energy (in any form) falling into a black hole contributes to the mass of the hole, and mass is one of the many forms that energy can take, using the usual conversion factor: $E = mc^2$.
A: *

*It loses organization, e.g. matter changes into pure energy or some such thing. It's not entirely clear what form there is (some suggest there is no form at all, but it's obvious that it doesn't follow Pauli's exclusion principle). This is nothing special, it happens all the time - when you burn carbon, for example, you get a bit of disorganised energy (heat) and a molecule of carbon dioxide that has the energy of the free carbon and oxygen molecule, minus the lost heat.

*There's no reason to believe that the matter is lost - for one, the mass of the black hole is exactly the same as of the matter that formed the black hole, so both the mass and energy must still be there. Second, we have good reasons to believe that black holes emit radiation and "evaporate" over time - for microscopic black holes, this is so important that they don't exist for very long. This is lucky for us, since we have pretty good evidence that microscopic black holes are created all the time in Earth's upper atmosphere. EDIT: My fault, this isn't actually true. String theory predicts that this might be true, but it seems we don't have solid evidence of this yet. When they evaporate, all the trapped energy is released back into our environment. If the universe gets cold enough, this will eventually happen to all black holes, even those gigantic ones in the center of galaxies - but it's going to take a long, long time, and even then only if the universe keeps expanding.

*Laws don't break, and there's little reason to believe they would. What breaks is some models - but most physicist you ask will tell you that when the model breaks down, it's a problem of the model, not of reality. We know black holes are real, therefore any model that breaks down when describing a black hole is wrong. That doesn't mean the model is useless - it just means you can't use it to describe black holes (and presumably other, possibly yet undiscovered phenomena).

A: To expand on @dmckee's answer, if we have a speacetime that has the matter concentrated in a central area, we can definte an overall conserved energy-momentum vector called the ADM energy.  It can be further shown that the ADM energy does not change when the matter falls into the black hole.
