Dwarf planet under the magnifying glass
The Dawn spacecraft orbited the dwarf planet Ceres for three and a half years. The images and measurement data show a fascinating world where, despite the freezing cold, there seems to be water and cryo-volcanoes.
On New Year's Eve 1801, the Catholic priest and astronomer Giuseppe Piazzi (1746-1826) discovered something special in the sky: a faintly luminous object that seemed to move a little night after night. Piazzi, then director of the observatory in Palermo, gave the "wandering star" a name: Ceres, like the Roman goddess of fertility and agriculture.
At first he thought Ceres was a comet, other astronomers thought it was a planet. In the mid-19th century it became clear that neither of these was true: the newcomer belonged to a separate class of celestial bodies, the asteroids. As we now know, most of them move around the sun between the orbits of Mars and Jupiter, in the asteroid belt.
Ceres is by far the largest celestial body here with an equatorial diameter of 963 kilometers and combines 90 percent of the mass of all asteroids. And as the only representative, Ceres has enough self-gravity for an almost round shape. In 2006, the International Astronomical Union (IAU) therefore placed the object in the newly created category of dwarf planets, which includes Pluto…