This content from Wikipedia is licensed under the GNU Free Documentation License.
HOME - Help build the worlds largest free encyclopedia.
Natural satellite
The term moon (never capitalized) is used to mean any natural satellite of the other planets. There are, at least, 102 moons within Earth's solar system, and presumably many others orbiting the planets of other stars. Typically the larger gas giants have extensive systems of moons. Mercury and Venus have no moons at all, Earth has one large moon, Mars has two tiny moons, and Pluto a large companion called Charon (sometimes considered to be a double planet). Most moons are assumed to have been formed out of the same collapsing region of protoplanetary disk that gave rise to its primary. However, there are many exceptions and variations to this standard model of moon formation that are known or theorized. Several moons are thought to be captured foreign objects, fragments of larger moons shattered by large impacts, or (in the case of Earth's moon) a portion of the planet itself blasted into orbit by a large impact. As most moons are known only through a few distant observations through probes or telescopes, most theories about them are still uncertain. Most moons in the solar system are tidally locked to their primaries; an exception is Saturn's moon Hyperion, which rotates chaotically due to a variety of external influences. No moons have moons of their own; the tidal effects of their primaries make orbits around them unstable. However, several moons have companions in their Lagrangian points (eg, Saturn's moons Tethys and Dione). The recent discovery of Ida's moon Dactyl confirms that some asteroids also have moons. The largest moons in the solar system (those bigger than about 3000 km across) are Earth's Moon, Jupiter's Galilean moons Io, Europa, Ganymede, and Callisto, Saturn's moon Titan, and Neptune's captured moon Triton. For smaller moons see the appropriate planets. A comparative table classifying the moons of the solar system by diameter, also including a column for some notable asteroids: Diameter(km) Earth Mars Asteroids Jupiter Saturn Uranus Neptune Pluto 5000+ Ganymede Titan 4000-5000 Callisto 3000-4000 Luna Europa Io 2000-3000 Triton Iapetus Ariel 1000-2000 1 Ceres Rhea Umbriel Charon Dione Titania Tethys Oberon 500-1000 4 Vesta 2 Pallas Phoebe Hyperion Sycorax Proteus Nereid 100-500 (Too many Amalthea Enceladus Miranda Larissa to list) Mimas Puck Janus Portia Galatea Epimetheus Despina Setebos Prospero Stephano Caliban 1986U10 Belinda 50-100 (Too many Himalia Pandora Rosalind Thalassa to list) Thebe Prometheus Naiad Juliet Desdemona Cressida Bianca Cordelia Ophelia Sinope Pasiphae Carme Helene Ananke Calypso 10-50 Phobos (Too many Elara Telesto Trinculo Deimos to list) Lysithea Atlas Leda Pan Adrastea Metis S/2000ÊJ11 S/2000ÊJ1 Iocaste Praxidike Harpalyke Isonoe Erinome Taygete Chaldene S/2002ÊJ1 Kalyke Megaclite Callirrhoe Euporie Kale Orthosie Thyone Euanthe Hermippe Pasithee Eurydome Aitne less than 10Cruithne¹ Sponde Autonoe S/2001ÊJ11 S/2003ÊJ2 S/2003ÊJ3 S/2003ÊJ4 S/2003ÊJ5 S/2003ÊJ6 S/2003ÊJ7 S/2003ÊJ8 S/2003ÊJ9 S/2003ÊJ10 S/2003ÊJ11 S/2003ÊJ12 S/2003ÊJ13 S/2003ÊJ14 S/2003ÊJ15 S/2003ÊJ16 S/2003ÊJ17 S/2003ÊJ18 S/2003ÊJ19 S/2003ÊJ20 S/2003ÊJ21 Ymir Paaliaq Siarnaq Tarvos Kiviuq Ijiraq S/2002ÊN1 unknown Themisto Thrym S/2002ÊN2 Skadi S/2002ÊN3 Mundilfari Erriapo Albiorix Suttung S/2003ÊS1 ¹ It is debatable whether Cruithne counts as a real moon; it is mainly placed here for comparison's sake.
How to - Physics - History - Companies - Internet - Video Games - List of Phobias - September 11, 2001
Radio - Timelines - Chemistry - Genealogy - Family - Film - SARS - Cancer - Medicine - DVD - Calendar
Countries - Disease - Health Science - Dentistry - Economics - AIDS - Law - Autism - Statistics - Bible
Recipes - Architecture - Computers - History of the Internet - Personal computer - Apple Macintosh
War - Presidents of the United States - United States Constitution - Universe - Philosophy - Animals
Biology - United States Constitution - Marketing Topics - Sports - Television - History of Computing
This content from Wikipedia is licensed under the GNU Free Documentation License.
HOME - Help build the worlds largest free encyclopedia.
