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Scientists finetune asteroid earth6/7/2023 ![]() How did these two cold, hard bodies come to be fellow travelers? ![]() They are rotating counterclockwise in the images, and it takes 4.1 hours for them to complete one rotation. The asteroid was 3.4 million miles away, 14 times as far away as the moon, a tiny object racing across the sky as it was nailed by a radar beam from Earth.īy studying the images, Ostro has determined that the twin asteroids have a rough, irregular surface. 22, the last day that Ostro had reserved at Arecibo, Ostro captured the historic images. Meanwhile, other astronomers in Australia were able to make precise measurements, permitting the Arecibo team to fine-tune the great telescope. This made it possible for two scientists in Great Britain to zero in on the asteroid. 17, a total lunar eclipse occurred, as the moon passed through the shadow of the Earth. Then, something most extraordinary happened. But astronomers were hampered by the fact that the asteroid was in the same part of the sky as the moon, and the moon was full, making observations of the dim object extremely difficult. Ostro sent out an urgent message to other astronomers around the world, asking for help in pinpointing the position of the asteroid. And since radar images depend on bouncing the signal off the object as it speeds across the sky, the position had to be known exactly. The project was extremely difficult because asteroids traveling through the inner solar system follow orbits that are hard to predict due to the gravitational influence of various planets. Hine of Arecibo, Ostro decided to abandon his earlier target and shoot instead for the approaching asteroid, named 1989 PB. ![]() ![]() Shapiro of the Harvard-Smithsonian Center for Astrophysics and A.A. Quick calculations told Ostro that the asteroid would pass over Arecibo at exactly the time that he was scheduled to be studying another distant asteroid. So in order to study anything, the object must pass through its field of view. That in turn provides an image of the object much the same as light from an electronic flash returns from a photographic target to create an image on light-sensitive film.īut Arecibo’s 1,000-foot-diameter dish is mounted in a bowl-shaped valley and cannot be moved to track objects across the sky. But for now, Ostro is just savoring a moment that comes rarely to an astronomer.Īrecibo can bounce a radar beam off a target and then capture the echo when it returns to Earth. It will take several years, and improvements that are now under way at the Arecibo observatory, for scientists to answer that question. “Or did we just with a stroke of luck see something that is extremely rare?” “We’ve never seen anything this small,” Ostro said.īut what is particularly astonishing to Ostro and his colleagues is that the images reveal that the asteroid is two small bodies, each less than a mile in diameter, and they appear to be touching as they rotate around each other during their long journey through the solar system.ĭoes that mean that “paired asteroids” are common in the solar system? Ostro said he doesn’t know. Halley’s Comet, which was photographed by five spacecraft as it made its rare approach to the sun in 1986, is 10 times bigger than the asteroid captured by Ostro’s team.
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