The first planet orbiting another sun, 51 Pegasi b, is discovered.

51 Pegasi b, officially named Dimidium, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the Sun-like 51 Pegasi, and marked a breakthrough in astronomical research. It is the prototype for a class of planets called hot Jupiters.