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Asteroid (film), Asteroid
An asteroid is a minor planet—an object that is neither a true planet nor a comet—that orbits within the inner Solar System. They are rocky, metallic or icy bodies with no atmosphere. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter. 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 the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, re ... [...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 17 minor planets ( asteroids, dwarf planets, and Kuiper belt objects) have been visited by space probes. 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, four asteroids have been imaged by spacecraft at distances too large to resolve features (over 100,000 km), and are labeled as such. List of comets visited by spacecraft Spacecraft visited by comets Comet C/2013 A1 passed close by planet Mars in October 2014, closer than t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
