S. Jonsell

At CERN's antimatter factory, antiprotons are born with the energy of a bullet from a rifle. You can't just put them in a box: they instantly annihilate upon touching ordinary matter. So physicists devised a way to catch them in electromagnetic traps — invisible cages made of fields.

The antiproton is the mirror twin of the proton: same mass, but negative charge. When it hits matter, it usually annihilates instantly — disappearing in a burst of energy upon colliding with an atomic nucleus.