# E=mc2 is more complicated that I originally thought

Wow, it all makes sense! Thank you everyone. So the reason for the decrease in mass is not because it is being converted to energy, but because there is less matter. True? Also, what about the strong nuclear force, where does that energy come from? Does it also come form matter?

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Drakkith
Staff Emeritus
Wow, it all makes sense! Thank you everyone. So the reason for the decrease in mass is not because it is being converted to energy, but because there is less matter. True?
No, the amount of particles is the pretty much the same, so I wouldn't say you had less matter. The difference is that BINDING ENERGY has been released. Energy has mass, and when you release it, that mass goes with it.

Look at it this way. The total mass is the same before and after the reaction. The difference is that the reaction moves mass and energy around.

Also, what about the strong nuclear force, where does that energy come from? Does it also come form matter?
That is not energy, it is a force. Fundamental forces are the cause of energy, they do not result from it.

Wow, it all makes sense! Thank you everyone. So the reason for the decrease in mass is not because it is being converted to energy, but because there is less matter. True? [..]
As Drakkith says, often the amount of particles doesn't change. In Einstein's calculation the atom keeps the same number of protons and neutrons. So in such cases one usually doesn't say that matter is converted in radiation but that its mass is reduced. However, such things can be done in particle accelerators: sub-atomic particles ("matter") can be completely converted into gamma radiation - and even the other way round!
- http://en.wikipedia.org/wiki/Mass–energy_equivalence
- http://en.wikipedia.org/wiki/Electron–positron_annihilation