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or minor planet,
small body orbiting the sun. More than 300,000 asteroids have been identified and cataloged; more than a million are believed to exist in the main belt between Mars and Jupiter, with many more in the Kuiper belt
..... Click the link for more information. that revolve about the sun in the same orbit as a planet, occupying stable positions (known as Lagrangian points) either about 60° ahead of the planet in the orbit or about 60° behind it. Such asteroids were first discovered (1906) in Jupiter's orbit. In 1990, a similar asteroid, Eureka, was found in the orbit of Mars, and several others have since been discovered. Similar asteroids also have been found in Neptune's orbit since 2001, and a Trojan asteroid in earth's orbit was confirmed in 2011.
The Trojan asteroids represent one possible special solution to the famous three-body problem (see also celestial mechanicscelestial mechanics,
the study of the motions of astronomical bodies as they move under the influence of their mutual gravitation. Celestial mechanics analyzes the orbital motions of planets, dwarf planets, comets, asteroids, and natural and artificial satellites within the
..... Click the link for more information. ), with each group forming an equilateral triangle with the planet whose orbit they share and the sun. Some Trojan asteroids are composed of ice and dirt, rather than rock, making it possible that they are captured comets. The first Trojan asteroid discovered was Achilles, observed by the German astronomer Max Wolf; all of Jupiter's Trojan asteroids are named for heroes of the Trojan WarTrojan War,
in Greek mythology, war between the Greeks and the people of Troy. The strife began after the Trojan prince Paris abducted Helen, wife of Menelaus of Sparta. When Menelaus demanded her return, the Trojans refused.
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