What keeps mass from turning into energy that we can use?

Question

What keeps mass from turning into energy that we can use?

In: 3

Answer 1

There are several things in our universe that are conserved. These are quantum numbers.

So long as these things do not change, mass *can* become energy, but it’s hard to turn mass into energy without these changing.

For instance, take a proton. It has some mass, but if it became energy (like a photon) it would lose its charge. This is not allowed, so until it can combine with an electron this proton cannot become energy.

Combining a proton with an electron has its own issues – I was just giving an example. Even when a proton *does* combine with an electron it forms a neutron and only releases a bit of energy.