Video: Radar imagery of approaching asteroid
BY STEPHEN CLARK
Posted: November 9, 2011
NASA released a six-frame video clip of asteroid 2005 YU55 on Tuesday, but the best imagery is still yet to come.
The 1,300-foot-wide asteroid passed approximately 201,700 miles from Earth at 2328 GMT (6:28 p.m. EST) Tuesday, but the video shows imagery collected Monday when the asteroid was about 860,000 miles away.
A 230-foot dish antenna at NASA's Goldstone tracking site in California created the images using radar. They are the highest-resolution images every generated by radar of a near-Earth object, according to NASA.
"The movie shows the small subset of images obtained at Goldstone on Nov. 7 that have finished processing," said Lance Benner, a radar astronomer from NASA's Jet Propulsion Laboratory leading the 2005 YU55 observations. "By animating a sequence of radar images, we can see more surface detail
than is visible otherwise."
The video does not include frames taken as the asteroid was closest to Earth.
"The animation reveals a number of puzzling structures on the surface that we don't yet understand," Benner said. "To date, we've seen less than one half of the surface, so we expect more surprises."
Other observatories, including the 1,000-foot Arecibo radio telescope in Puerto Rico, were tracking the asteroid's flyby of Earth.
Discovered in 2005, the asteroid is in an orbit that regularly passes near Earth and the moon. Tuesday's flyby was inside the orbit of the moon and was the closest approach of an asteroid to Earth since 1976.
The next known flyby this close will be in 2028.