* Astronomy

The positron was discovered by Carl D. Anderson on August 2, 1932, for which he won the Nobel Prize for Physics in 1936.
Read more

This is a video showing positrons (and gamma rays) from a Fluorine-18 source made visible via a cloud chamber. The tracks coming directly from the source are (most likely) positrons stopping and then annihilating. Tracks not pointing to the source are either gamma rays scattering electrons (Compton scattering). The final even shows what is possibly a positron annihilating (without first generating a visible track) followed by both photons scattering electrons. A few events (ones with fuzzy cloud tracks) are likely Cosmic rays striking the chamber from above.