Asteroids
Asteroids are small bodies in space—the numerous leftover planetesimals from which the planets were made nearly 4.6 billion years ago. Most are in the "main belt," which...
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Small Bodies
For much of history, the solar system was thought to consist of large objects: Earth, the Moon, the Sun, and other planets. However, within the last two centuries astronomers have discove...
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Asteroids
Asteroids are rocky material left over from the formation of the solar system that orbit the Sun, but are too small to be
Asteroid 243 Ida and its moon, photograph. Corbis Corporation. R...
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Asteroid
Johannes Kepler was the first to postulate the existence of a hidden planet between Mars and Jupiter, a theory long pondered by astronomers. Then, in 1766, Johannes Titius (1729-1796), a prof...
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Asteroids
Asteroids
Asteroid