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FINDINGS STRESS VITAL ROLE OF CORNELL-MANAGED TELESCOPE IN DETECTING DANGER
13 February 2007 - Cornell University
| The Arecibo Observatory's powerful radar, a keen eye aimed into the sky, has made the most detailed observations ever of a binary near-Earth asteroid. This information provides clues about asteroid formation, properties and motion dynamics. |
The observations, led by Steve Ostro, senior research scientist at the NASA/Caltech Jet Propulsion Laboratory in Pasadena and who earned his master's degree in engineering physics at Cornell; and Jean-Luc Margot, Cornell University assistant professor of astronomy; and their colleagues describe asteroid (66391) 1999 KW4 (called KW4). The report is at http://www.sciencemag.org/sciencexpress/recent.dtl. The Arecibo Observatory is managed by the National Astronomy and Ionosphere Center at Cornell University for the National Science Foundation. KW4, the astronomers say, is actually a pair of light, porous clusters of rubble that circle each other as they orbit from a point closer to the Sun than Mercury and then outward, occasionally passing very close to Earth along the way. The bodies were discovered in 1999, but not known to be binary until they were observed in May 2001, when they came to within 3 million miles of Earth, this asteroid's closest pass until 2036. KW4 is a valuable source of information for planetary scientists studying the formation and evolution of near-Earth asteroids - as well as for researchers studying how to mitigate the potential threat they pose to Earth. KW4 is classified as a Potentially Hazardous Asteroid, but data show that its path will not intersect Earth's for at least 1,000 years. Unlike single asteroids, where physical properties are impossible to determine from Earth-based observations, binaries can reveal information about their mass and density by their interaction with each other. Using both the Arecibo Observatory in Arecibo, Puerto Rico, and the Goldstone Deep Space Communications Complex, located in California's Mojave Desert, the only telescopes with the radar capability for such observations, the researchers could reconstruct the orbit, mass, shape and density of KW4's two components, Alpha and Beta. They found an oddly shaped pair of dance partners, with the much larger (1.5 km, or .93 miles in diameter) Alpha spinning as fast as possible without breaking apart, and the smaller and denser Beta wobbling noticeably as it orbits its partner. The study also involved the most precise tracking of an irregularly shaped binary system's motion, information vital in learning how they formed. As a whole, the Arecibo/Goldstone data on KW4 take the understanding of near-Earth asteroids to a new level of precision, say researchers. The study also highlights the value of both telescopes involved: NASA's Goldstone, which is more steerable, and Arecibo, whose radar is an order of magnitude more powerful.
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About: Cornell University
Once called "the first American university" by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.Today's Cornell reflects this heritage of egalitarian excellence. It is home to the nation's first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League. On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over. In his first inaugural address, at the Weill Cornell Medical College campus in Qatar in October 2004, Jeffrey Lehman, the first Cornell alumnus to become its president, articulated a vision projecting Cornell as "the transnational university of the future." |
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