Hard bodies pair off. (Astronomy).About one out of every eight 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. orbiting near Earth travels with a companion. Scientists have come up with that estimate by observing near-Earth asteroids, rocks that cross Earth's orbit, with the two most sensitive radar telescopes ever built. Some 16 percent of near-Earth asteroids larger than 200 meters across travel with a companion, report Jean-Luc Margot of the California Institute of Technology California Institute of Technology, at Pasadena, Calif.; originally for men, became coeducational in 1970; founded 1891 as Throop Polytechnic Institute; called Throop College of Technology, 1913–20. in Pasadena and his colleagues in an upcoming issue of Science. During the past 2 years, the astronomers discovered the first five pairings of near-Earth asteroids. To detect those objects, Margot's team used the Arecibo Observatory in Puerto Rico and NASA's Goldstone gold·stone n. An aventurine with gold-colored inclusions. Noun 1. goldstone - aventurine spangled densely with fine gold-colored particles Tracking Facility in California's Mojave Desert. The astronomers found the pairs by beaming precisely tuned radio waves Radio waves Electromagnetic energy of the frequency range corresponding to that used in radio communications, usually 10,000 cycles per second to 300 billion cycles per second. at the space rocks and then measuring the time it took for the waves to bounce back to radio telescopes on Earth. By detecting how far apart the partners are and how rapidly they orbit each other, scientists can determine the mass, volume, and composition of the binary asteroids. Astronomers suspect that many asteroids are relatively fragile, composed of rubble that can range in size from sand grains to kilometer-wide boulders (SN: 7/28/01, p. 61). Simulations suggest that binary asteroids form when a single rock passes so close to either Earth or Mars that the planet's uneven gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. tug on different parts of the asteroid causes it to crumble. --R.C. |
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