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Dark comet’s flyby of Earth observed with radar and infrared

25 March 2016 Astronomy Now

Astronomers were watching when comet P/2016 BA14 flew close by Earth on 22 March at a distance of slightly more than nine times the distance of the Moon. Radar images from the flyby indicate that the body is about a kilometre in diameter, while infrared spectra indicate that the comet’s nucleus is as dark as fresh asphalt.

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Asteroid looks even better second time around

18 December 2015 Astronomy Now

Asteroid 1998 WT24 safely flew past Earth on 11 December at a distance of about 2.6 million miles (11 lunar distances). During its flyby, NASA scientists used the 230-foot (70-metre) DSS-14 antenna at Goldstone, California, to probe it with microwave transmissions. Using this technique, they created the highest-resolution radar pictures of the asteroid — 2.5 times better than when it was last imaged, 14 years ago.

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Radar images provide new details on Halloween asteroid

4 November 2015 Astronomy Now

The highest-resolution radar images of 600 metre-wide asteroid 2015 TB145‘s safe flyby of Earth have been processed. NASA scientists used giant, Earth-based radio telescopes to bounce radar signals off the asteroid as it flew past Earth on 31 October at 17:00 UTC (~5pm GMT) at about 1.3 lunar distances (302,500 miles, or 486,800 kilometres) from Earth.