Radar Data of Asteroid 1999 JD6 revealed the object is a Contact-Binary, but is the asteroid really a Contact-Binary?
Radar data of the bizarrely-shaped 1.2 miles-long asteroid 1999 JD6 revealed the object is a contact binary consisting of two lobes. And it rotates in just over seven-and-a-half hours and is thought to be a relatively dark object. The data was collected over seven and a half hours on July 25, 2015, when the asteroid was about 4.5 million miles (7.2 million kilometers) from Earth.
Scientists were able to use two Earth-based radio telescopes to capture "images" of the 'Trillion-Dollar Asteroid' asteroid 2011 UW158 as it passed by Earth on July 19.
To obtain the views, researchers paired NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, with the 330-foot (100-meter) National Science Foundation Green Bank Telescope in West Virginia.
Using this approach, the Goldstone antenna beams a radar signal at an asteroid and Green Bank receives the reflections. The technique, referred to as a bistatic observation, dramatically improves the amount of detail that can be seen in radar images.