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Asteroid Belt, Asteroid-belt
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type (carbonaceous), M-type (metallic), or S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in a region known as the main asteroid belt. The total mass of all the asteroids combined is only 3% that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minor Planets And Comets Visited By Spacecraft
The following tables list all minor planets and comets that have been visited by robotic spacecraft. List of minor planets visited by spacecraft A total of 19 minor planets (asteroids, dwarf planets, and Kuiper belt objects) have been visited by space probes. natural satellite, Moons (not directly orbiting the Sun) and planets are not minor planets and thus are not included in the table below. File:Small Asteroids and Comets Visited by Spacecraft.jpg, Minor planets and comets visited by spacecraft as of 2019 (except Pluto, Ceres, and Vesta), to scale File:Asteroidsscale.jpg, The comparative sizes of the first eight asteroids visited by spacecraft Incidental flybys In addition to the above listed objects, three asteroids have been imaged by spacecraft at distances too large to resolve features (over 100,000 km). List of comets visited by spacecraft Incidental flybys Spacecraft visited by comets Comet C/2013 A1 passed close by planet Mars in October 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
