# Black holes and conversation of energy

1. Aug 14, 2009

### Oh the irony

Alright, According to the law of Conversation of Energy states that, Energy in a system may take on various forms (e.g. kinetic, potential, heat, light). The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant.

So, When a black hole is formed the compressed matter that has been crushed down to it's nuclei is destroyed and gone after the black hole itself is formed. Doesn't that contradict said law stated above?

2. Aug 14, 2009

### humanino

The black hole has a very large mass, equal to all the fallen energy content according to $E=mc^{2}$

3. Aug 14, 2009

### Oh the irony

Yes, I understand that but what I'm saying is the mass that created it. When all that packet up matter goes further then the mass of a neutron star, down too the point that it's crushed down to litterly nothing. How can that be? It's destroyed and that violates that law.

4. Aug 14, 2009

### Naty1

No. By "gone" I assume you mean "destroyed forever" or "hidden forever" from our observation.
Neither is accurate. A simple answer is that black holes radiate energy and unless they are swallowing other energy faster than they are radiating, eventually shrink down to a tiny size. When that happens they get hotter, radiate more energy and it's believed end in a cataclysmic explosion. So the energy is hidden for a long long time and eventually returned to our universe as equivalent energy.

As I see humano just posted the mass remains as energy...yes...the mass is not literally destroyed, it's form is changed to a singularity...No one knows what's actually there....

When an atomic bomb is detonated mass is also "destroyed"....a small proportion changes form to energy....

Last edited: Aug 14, 2009
5. Aug 15, 2009

### qraal

It's not literally nothing. It's a point of infinite density - more "something" than anything in our Universe. If quantum information is preserved somehow then the "point" probably has a finite, but very high density, that stores the information in a very compact form. But there's no generally agreed theory about what happens. General relativity merely predicts that for a certain concentration of mass there's nothing that can stop its self-collapse into that "infinitesimal" size.