Antimatter?

Quote

Weird as it sounds, antimatter is a normal feature of the real, unfictional universe. Scientists see the creation of anti-hydrogen atoms as the first step toward testing some physicists' deepest notions about nature, which hold that antimatter should look and behave identically to ordinary matter.

For example, any violation of the expected symmetry between hydrogen and anti-hydrogen would rock physics to its core.

The new research was conducted by physicists at CERN, the particle physics laboratory outside Geneva.

By corralling clouds of antimatter particles in a cylindrical chamber laced with detectors and electric and magnetic fields, the physicists assembled anti-hydrogen atoms, the looking glass equivalent of hydrogen, the most simple atom in nature. Whereas hydrogen consists of a positively charged proton circled by a negatively charged electron, in anti-hydrogen the proton's counterpart, a negatively charged anti-proton, is circled by an anti-electron, otherwise known as a positron.