Heinrich Olbers
The Bremen doctor and astronomer who discovered the asteroids Pallas in 1802 and Vesta in 1807.
Key facts
- Born
- 1758
- Died
- 1840
- Nationality
- German
- Field
- Physician and astronomer
Heinrich Wilhelm Matthias Olbers worked as a physician in Bremen by day and observed the sky at night from an observatory in the upper floors of his house. He became one of the leading astronomers of his time without ever holding a university post.
In 1801 the Italian astronomer Giuseppe Piazzi discovered Ceres, a small body orbiting between Mars and Jupiter. Olbers helped find it again later that year, using an orbit calculated by the young mathematician Carl Friedrich Gauss. While watching that part of the sky on 28 March 1802, Olbers found a second such body, which he named Pallas. On 29 March 1807 he found a third, which Gauss named Vesta after the Roman goddess of the hearth.
Vesta is the brightest asteroid as seen from Earth and one of the largest, about 525 kilometres across. It is now known to be the source of the howardite, eucrite and diogenite meteorites, which are pieces of its crust and mantle blasted off by impacts.
Olbers suggested that the asteroids might be fragments of a single planet that had broken apart. That idea has since been abandoned: the asteroids are leftover building blocks that never formed a planet, largely because of Jupiter's pull. Olbers is also remembered for asking why the night sky is dark if the universe is filled with stars, a puzzle now called Olbers' paradox.
Did you know?
Vesta was discovered in Olbers' own house, using a small telescope.
Olbers also worked out a widely used method for calculating the orbits of comets.
On the timeline
- 28 March 1802Olbers finds Pallas
- 29 March 1807Olbers discovers Vesta