Why do matter and antimatter annihilate each other?

That's a very good question. You see, if there's one thing Nature loves the most, it's a vacuum. More precisely, the electron field - the field from which both electrons and positrons are created -- really loves to be in a vacuum state, which is the state of lowest energy, in which there are no particles. read more

So when a particle annihilates its own antiparticle, it cancels out both the electric charge AND the parity. So you could say that matter and antimatter annihilate each other because they have opposite electric charge and opposite parity. Parity is the conjugate property to chirality. Parity is conserved by all forces except the weak nuclear force. read more

So. when we say matter and antimatter annihilate, what is meant is, the matter and antimatter particles combine and the resultant burst of energy is a violent consequence. An article in NEW SCIENTIST was about matter and anti-matter combining in a chemical reaction. read more

I'm almost certain it's the latter as mass can't be destroyed. Energy can't be destroyed, mass is destroyed in annihilation. when speaking of the big bang it's said if there were equal amounts of both matter and antimatter there would be nothing left. read more