The first thing we learn in science is that matter cannot be created nor destroyed. The same with energy. Just like in Einstein's E=MC^2.
I believe that energy and matter cannot be destroyed. Even when an atom is split, the matter is converted from matter to energy. If we could capture the explosion and convert it back to matter, it would still be the same mass as it was before.
Some say that the energy after the explosion dissapates into nothing.. not true it just dissapates to the point of unmeasurability. Like if you wind a watch it becomes a trillionth of an milligram heavier. It gets so close to zero it might as well be nothing.
None of this changes the fact that the mass and energy levels remain at a constant ratio making up for one another as they convert back and forth.
What do you think?