German astronomer, a founder member of the Celestial Police, a group of astronomers who attempted to locate a supposed missing planet between Mars and Jupiter. During his search he discovered two asteroids, Pallas 1802 and Vesta 1807. Also credited to Olbers are a number of comet discoveries, a new method of calculating cometary orbits, and the stating of Olbers' paradox.
Olbers was born near Bremen and studied medicine at Göttingen. He practised as a physician in Bremen 1781-1823, but was a keen amateur astronomer, with an observatory at the top of his house.
Olbers' main interest was the search for comets, and his efforts were rewarded with the discovery of four more, including one, discovered in 1815, which has an orbit of 72 years, similar to Halley's. Olbers calculated the orbits of 18 other comets. Noticing that comets consist of a starlike nucleus and a parabolic cloud of matter, he suggested that this matter was expelled by the nucleus and repelled by the Sun.