ANTIMATTER GALAXIES

You shouldn’t exist. That you do suggests something is very wrong with our best theories in physics. Yet there is a way to both explain your existence and save theorists’ blushes: if bizarre entities called antimatter galaxies also exist.

In the beginning there was nothing, only energy. Our universe burst into existence 13.8 billion years ago in the Big Bang, and soon some of the energy was converted into particles. The kind of particles that are the building blocks of atoms, which in turn are the building blocks of you. We call this stuff matter. Except that’s only half the story. The process of converting energy into stuff is called pair production. Even the name hints at a deeper reality. It creates pairs of particles. Every particle of new matter is joined by another of antimatter.

Antimatter sounds futuristic, and you’ll often see it deployed in science fiction. It may sound made up for dramatic effect, but we know for certain that it exists. A banana, for example, contains traces of radioactive potassium. As the potassium decays