Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Satellite or Moon

  • Ralf Jaumann
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1403-4


The term satellite refers to a natural object that orbits another (larger) body or to an artificial object placed into orbit by human action. Thus, planets that orbit a star may also be considered natural satellites. However, the basic definition of a natural satellite is a celestial body that orbits a planet or a small body and is classically also called a moon. The sizes of natural satellites in our Solar System range from 5,268 km for the Jovian moon Ganymede to objects of less than 1 km in diameter. Among the objects classified as natural satellites are 172 objects that orbit planets, 169 of which are in the outer Solar System. Eight satellites orbit dwarf planets. A significant number of satellites are known to orbit asteroids (186) and trans-Neptunian objects (TNOs) (84).

See Also


Human Action Bioorganic Chemistry Solar System System Formation Small Body 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.DLRInstitut für PlanetenforschungBerlinGermany