© Arecibo Observatory/NASA/Ellen HowellRadar image of asteroid 1998 QE2 and its moon taken on June 7, 2013, by the Arecibo Observatory. Several craters are visible on the asteroid, and the moon appears as a bright streak. Each pixel is 7.5 meters (25 feet).
Asteroid 1998 QE2 and its moon sailed within 3.6 million miles (5.8 million kilometers) of Earth on May 31, making their closest approach to our planet for at least the next two centuries. New radar images captured by the Arecibo Observatory in Puerto Rico are revealing just how unique this binary asteroid is, researchers say.
"Asteroid QE2 is dark, red, and primitive - that is, it hasn't been heated or melted as much as other asteroids," Arecibo's Ellen Howell said in a statement. "QE2 is nothing like any asteroid we've visited with a spacecraft, or plan to, or that we have meteorites from. It's an entirely new beast in the menagerie of asteroids near Earth."
The 1000-foot-wide (305 meters) Arecibo dish and NASA's 230-foot (70 m) Deep Space Network antenna in Goldstone, Calif., tracked 1998 QE2 as it approached Earth last month, then kept following the near-Earth asteroid as it receded into the depths of space.
The resulting radar images have helped researchers take 1998 QE2's measure. The dark, cratered main asteroid is 1.9 miles (3 km) wide, and it has a 2,500-foot (750 m) moon that orbits it once every 32 hours.
Comment: No mystery here. Just go over articles in the Fire in the Sky category to get an idea.