A new asteroid discovered in late January made a favorable pass of Earth, allowing astronomers to bounce radio waves off it to determine its shape, size, rotation period and the fact that it has a tiny companion asteroid in orbit around it. Arecibo / NASA / NSF
New radar images from the Arecibo Observatory in Puerto Rico reveal that a recently-discovered, near-Earth is really two asteroids in one! The images were created by bouncing radio waves off the asteroid on Feb. 4-5 when it passed near the Earth. By studying the returning radar echoes astronomers can deduce an asteroid’s shape, surface features, size and more. The larger or primary asteroid was discovered on January 27 by the ATLAS survey on Mauna Loa, Hawaii. Based on its size and the minimum separation of its orbit from Earth’s orbit (only 188,000 miles or 302,000 km) astronomers classified it as a potentially hazardous asteroid (PHA).
Single images of the binary asteroid were used to make this short video sequence. The bright spot is the main asteroid’s moon or satellite. Arecibo / NASA / NSF
While that means it could conceivably pass closer to the Earth than the moon and even potentially threaten the ...