particle/antiparticle "annihilation" This has been bugging me for quite some time now. Why is it called "annihilation" when a particle and an antiparticle collide, when in fact they don't annihilate at all, but simply transform into photons with the original energy conserved? Since "annihilate" literally means "turn into nothing," the two particles (and their energy) would actually have to disappear from existence in order for us to be able to apply this term properly. Are there any plans to do away with this terminology so that this kind of confusion can be avoided? Or am I missing some more specific reason that the word "annihilate" is used?