September 21 – Discovery of Asteroid 149 Medusa (1875)

Henri Joseph Anastase Perrotin discovered today’s first asteroid, 149 Medusa, on September 21st 1875, at which time I believe he was working at Toulouse Observatory. His name is quite impressive,  so his discoveries are normally just credited to J Perrotin.

Medusa, despite being a bright stony asteroid, was a good catch for Perrotin, as it was the smallest to have been found at the time.


Medusa, of course, was the hideous female gorgon with snakes for hair who turned to stone anyone who met her gaze. She was one of three sisters (the others being Stheno and Euryale) who were the children of the marine deitiesPhorkys and Keto. Medusa was killed by Perseus, who then presented her head to Athene to attach to her shield. The word gorgon, incidentally, comes from the same root as the Sanskrit word “garg”, meaning a monster (from the noise they generally make).

Twelve years later, on September 21st 1887, Johann Palisa discovered 269 Justitia, a much larger main belt asteroid which was named after the Roman goddess whose Greek equivalent was Themis.

Themis, the personification of divine law and order, was one of the original twelve Titans, descendants of Gaia and Uranus, who ran the world until the Olympian gods showed up and overthrew them.