List Of Planet–satellite Systems
A natural satellite, moon, or secondary planet is a celestial body that orbits a planet or smaller body, which is called its primary.
Formally classified natural satellites, or moons, include 176 planetary satellites orbiting six of the eight planets, and eight orbiting three of the five IAU-listed dwarf planets. As of January 2012, over 200 minor-planet moons have been discovered. There are 76 objects in the asteroid belt with satellites (five with two satellites each), four Jupiter trojans, 39 near-Earth objects (two with two satellites each), and 14 Mars-crossers. There are also 84 known natural satellites of trans-Neptunian objects. Some 150 additional small bodies were observed within rings of Saturn, but they were not tracked long enough to establish orbits. Planets around other stars are likely to have natural satellites as well, although none have yet been observed.
Of the inner planets, Mercury and Venus have no natural satellites; Earth has one large natural satellite, known as the Moon; and Mars has two tiny natural satellites, Phobos and Deimos. The large gas giants have extensive systems of natural satellites, including half a dozen comparable in size to Earth's Moon: the four Galilean moons, Saturn's Titan, and Neptune's Triton. Saturn has an additional six mid-sized natural satellites massive enough to have achieved hydrostatic equilibrium, and Uranus has five. It has been suggested that some satellites may potentially harbour life, though there is currently no direct evidence of life.
The Earth–Moon system is unique in that the ratio of the mass of the Moon to the mass of the Earth is much greater than that of any other natural satellite:planet ratio in the Solar System, and the Moon's orbit with respect to the Sun is always concave.
Among the dwarf planets, Ceres and Makemake have no natural satellites. Pluto has the relatively large natural satellite Charon and four smaller natural satellites. Haumea has two natural satellites, and Eris has one. The Pluto–Charon system is unusual in that the center of mass lies in open space between the two, a characteristic sometimes associated with a double-planet system.
Read more about List Of Planet–satellite Systems: Origin and Orbital Characteristics, Tidal Locking, Satellites of Satellites, Trojan Satellites, Asteroid Satellites, Shape, Geological Activity, Natural Satellites of The Solar System, Terminology, Visual Summary
Other articles related to "system":
... Solar System moons Ganymede Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Umbriel Ariel Dione Tethys Enceladus Miranda Proteus Mimas Hyperion Phoebe Janus Amalthea ...
Famous quotes containing the words list of, systems and/or list:
“Sheathey call him Scholar Jack
Went down the list of the dead.
Officers, seamen, gunners, marines,
The crews of the gig and yawl,
The bearded man and the lad in his teens,
—Joseph I. C. Clarke (18461925)
“Not out of those, on whom systems of education have exhausted their culture, comes the helpful giant to destroy the old or to build the new, but out of unhandselled savage nature, out of terrible Druids and Berserkirs, come at last Alfred and Shakespeare.”
—Ralph Waldo Emerson (18031882)
“I am opposed to writing about the private lives of living authors and psychoanalyzing them while they are alive. Criticism is getting all mixed up with a combination of the Junior F.B.I.- men, discards from Freud and Jung and a sort of Columnist peep- hole and missing laundry list school.... Every young English professor sees gold in them dirty sheets now. Imagine what they can do with the soiled sheets of four legal beds by the same writer and you can see why their tongues are slavering.”
—Ernest Hemingway (18991961)