system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How black holes and anti-matter work.
gpt
Black holes: All stuff (matter) in the universe pulls on everything else. This force is called gravity. If you bring enough matter together in one place it will clump together. This is why planets and stars don't just fall apart. The more stuff you put in one place the stronger that it will pull itself together. Eventually the effect of all of the pulling will cause the stuff to collapse in on itself. Once you reach a critical limit it will keep pulling until the stuff is condensed into such a small space that not even light can escape its pull. The area around it will look black because light can't escape. Hence, black hole.

Anti-matter: Everything in the universe is made of a handful of fundamental particles: proton, neutron, electron, etc. These particles have an electric charge. Electrons have a negative charge, protons a positive charge and neutrons have a charge of zero. Each of these particles have a pair that is identical in every way (mass, spin) except it has the opposite charge. So, a positron looks exactly like an electron except it has a positive charge. If an electron and a positron meet they will destroy each other and generate pure energy.