Asteroid Belt

The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish its members from other asteroids in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids, Ceres, Vesta, Pallas, and Hygiea. These have mean diameters of more than 400 km, while Ceres, the asteroid belt's only dwarf planet, is about 950 km in diameter. The remaining bodies range down to the size of a dust particle. The asteroid material is so thinly distributed that numerous unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, and these can form an asteroid family whose members have similar orbital characteristics and compositions. Nesvorny and Jenniskens (2010 Astrophysical Journal) attributed 85 percent of the Zodiacal Light dust to fragmentations of Jupiter-family comets, rather than from comets and collisions between asteroids in the asteroid belt. It was once thought that collisions of asteroids produce a fine dust that forms a major component of the zodiacal light. Individual asteroids within the asteroid belt are categorized by their spectra, with most falling into three basic groups: carbonaceous (C-type), silicate (S-type), and metal-rich (M-type).

The asteroid belt formed from the primordial solar nebula as a group of planetesimals, the smaller precursors of the planets, which in turn formed protoplanets. Between Mars and Jupiter, however, gravitational perturbations from the giant planet imbued the protoplanets with too much orbital energy for them to accrete into a planet. Collisions became too violent, and instead of fusing together, the planetesimals and most of the protoplanets shattered. As a result, most of the asteroid belt's mass has been lost since the formation of the Solar System. Some fragments can eventually find their way into the inner Solar System, leading to meteorite impacts with the inner planets. Asteroid orbits continue to be appreciably perturbed whenever their period of revolution about the Sun forms an orbital resonance with Jupiter. At these orbital distances, a Kirkwood gap occurs as they are swept into other orbits.

Classes of small Solar System bodies in other regions include the centaurs, Kuiper belt and scattered disk objects, and Oort cloud comets.

Read more about Asteroid BeltHistory of Observation, Characteristics, Collisions, Families and Groups, Exploration

Other articles related to "asteroids, asteroid belt, asteroid, belt":

Ceres In Fiction - Literature
... in the juvenile novel Lucky Starr and the Pirates of the Asteroids (1953) and the Wendell Urth mystery "The Dying Night" ... In Larry Niven's Known Space stories (1964 onward), the asteroid belt has a government based on Ceres. 2007) Ceres is the site of an interplanetary mystery involving the theft of asteroid-mined super-heavy metals ...
Physics And Star Wars - Specific Phenomena - Asteroid Field in Episode V
... pursued by imperial ships through a dense asteroid field ... Ordinarily, an asteroid field or belt is unlikely to be so densely packed with large objects, because collisions reduce large objects to rubble ... About the only way for an asteroid belt to maintain itself would be to "balance destructive high-speed collisions with constructive soft collisions", but ...
Nice Model - Solar System Features - Trojans and The Asteroid Belt
... Trojan populations are then these acquired scattered planetesimals of the primordial asteroid belt ... planetesimals would have also been captured in the outer asteroid belt, at distances greater than 2.6 AU, and in the region of the Hilda family ... This suggests that the Jupiter Trojans, Hildas and some of the outer asteroid belt, all spectral D-type asteroids, are the remnant planetesimals from this capture and erosion ...
Asteroid Belt - Exploration
... The first spacecraft to traverse the asteroid belt was Pioneer 10, which entered the region on July 16, 1972 ... At the time there was some concern that the debris in the belt would pose a hazard to the spacecraft, but it has since been safely traversed by 11 Earth-based craft ... Pioneer 11, Voyagers 1 and 2 and Ulysses passed through the belt without imaging any asteroids ...
E-type Asteroid
... E-type asteroids are asteroids thought to have enstatite (MgSiO3) achondrite surfaces ... They form a large proportion of asteroids inward of the asteroid belt known as Hungaria asteroids, but rapidly become very rare as the asteroid belt proper is entered ... some that are quite far from the inner edge of the asteroid belt, such as 64 Angelina ...

Famous quotes containing the word belt:

    Names on a list, whose faces I do not recall
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    Distinguished the belt feed lever from the belt holding pawl.
    Richard Eberhart (b. 1904)