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The Astroid Belt is a strip of space rocks between Mars
and Jupiter, it marks the boundary between inner and outer space.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 region is also termed the main belt to distinguish it from other concentrations of minor
planets within the Solar System, such as the Kuiper belt and scattered disc.
More than half the mass of the main belt is contained in the four largest objects: Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea.
All of these have mean diameters of more than 400 km, while Ceres, the main 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 multiple
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. Collisions also produce a
fine dust that forms a major component of the zodiacal light. Individual asteroids within the main 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.
Between Mars and Jupiter, however, gravitational perturbations from the giant planet imbued the planetesimals with too much
orbital energy for them to accrete into a planet. Collisions became too violent, and instead of sticking together, the planetesimals
shattered. As a result, most of the main 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.
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