The strange case of 4179 Toutatis.Sporting a complex tumbling motion and a chaotic orbit that defies long-term prediction, the potato-shaped near-Earth asteroid Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earth's orbit. Some NEAs' orbits intersect Earth's so they pose a collision danger. On the other hand, NEAs are most easily accessible for spacecraft from Earth; in fact, some can be reached with much less fuel 4179 Toutatis ranks as one of the stranger objects in the solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. . That's what planetary scientists conclude from a computer analysis of radio images obtained in 1992, when Toutatis came within 3.2 million kilometers of Earth. "The vast majority of asteroids This is a list of numbered minor planets, nearly all of them asteroids, in sequential order. As of late September 2007 there are 164,612 numbered minor planets, and many more not yet numbered. Most asteroids are ordinary and not particularly noteworthy. , and all the planets, spin about a single axis like a football thrown in a perfect spiral, but Toutatis tumbles like a flubbed pass," says R. Scott Hudson of Washington State University Washington State University, at Pullman; land-grant and state supported; chartered 1890, opened 1892 as an agriculture college. From 1905 to 1959 it was the State College of Washington. in Pullman. In the Oct. 6 Science, he and Steven J. Ostro Steven J. Ostro is an astronomer at the Jet Propulsion Laboratory of the National Aeronautics and Space Administration. Ostro was part of the team of astronomers that observed asteroid 1998 KY26 in 1998. of NASA's Jet Propulsion Laboratory “JPL” redirects here. For other uses, see JPL (disambiguation). Jet Propulsion Laboratory (JPL) is a NASA research center located in the cities of Pasadena and La Cañada Flintridge, near Los Angeles, California, USA. in Pasadena, Calif., note that the tumbling stems from a combination of two different rotations, one with a period of 5.4 days and the other with a period of 7.3 days. Together, these motions ensure that Toutatis never repeats its orientation. Even though all asteroids are thought to have suffered violent collisions that could set them tumbling, most of the known ones rotate about a single, fixed axis. Tumbling stresses an asteroid, creating a source of internal friction, or heat, that ultimately damps out the erratic motion. But because Toutatis tumbles so slowly--over a period of about 6 days rather than several hours--the asteroid won't generate enough heat to damp the motion for another trillion years, Hudson notes. Thus, its rotation represents a well-preserved relic of impacts that most asteroids have undergone. |
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