The Planets

Ceres Facts

Located in the asteroid belt between the orbits of Mars and Jupiter, Ceres is the closest dwarf planet to the Sun and the only one located in the inner solar system. It's the smallest of the known dwarf planets at 950 km (590 mi) in diameter.

Size of Ceres compared with the Earth

Side by side size comparison of the size of Ceres vs Earth
Side by side size comparison of the size of Ceres vs Earth

Facts about the dwarf planet Ceres

  • Ceres was the first object to be considered an asteroid in the solar system. In early 1801, an Italian astronomer by the name of Giuseppe Piazzi discovered and named Ceres. He originally classified it as a planet, but it has since been reclassified as a dwarf planet.
  • Ceres accounts for approximately one third of the mass of the entire asteroid belt but it cannot be classified as planet since it does not “dominate its orbit” – sharing it instead with many thousands of asteroids.
  • The unmanned spacecraft Dawn is scheduled to arrive at Ceres in early 2015. This probe was launched by NASA on 27th September, 2007 and should it complete it complete its mission, it will be the only craft to successfully orbit two separate extraterrestrial bodies – having completed a fourteen month survey mission of the protoplanet Vesta in late 2012.
  • Ceres was named for the Roman God of agriculture, Ceres (or Cerere in Italian) – also known as Demeter in Greek mythology. The original name of Cerere Ferdinandea was changed after there were objections to Ferdinandea.
  • Ceres was classified as a planet for half a century – from 1801 until the 1850s – when it was reclassified as an asteroid. In 2006, it was subsequently classified as a dwarf planet.
  • The presence of water ice on Ceres has led to speculation that life may exist there. Discussions about life on Ceres are not as active as those for Mars and Europa, however.
  • Ceres is believed to have a rocky core with an icy inner mantle that is 100km thick. Scientists have calculated that this ice mantle may contain as much as 200 million cubic kilometres of water – that’s more fresh water than can be found on planet Earth.
  • Ceres is generally regarded as too dim to be seen with the naked eye but a viewer with exceptional eyesight under the right conditions might be able to see the dwarf planet.
  • Ceres completes its orbit once every 4.6 Earth years and completes a full rotation every nine hours and four minutes.