system
Given the following post, respond as if you're commenting on Reddit:
human
I've read several times that particles and their corresponding antiparticles are constantly being created and annihilated. Why doesn't that violate the conservation of matter?
gpt
By the relation E=mc^2 (energy equals mass times the speed of light squared).

For instance, you may hear of a positron annhilating an electron.  What actually happens is that when a positron and an electron meet, they give off two gamma rays (which are photons, and as such have no mass), and a lot of energy.  If you take the energy generated and divide it by the speed of light squared, you will get the missing amount of mass.

In everyday calculations, it's convenient to say that mass is conserved, since very few things in our everyday experience give off enough energy to change mass significantly.  However, it is really energy, and not mass, that is being conserved.

Edited for Science!