Scientists working with NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, have released the first radar images of asteroid 2004 BL86. (These are also the folks responsible for the New Horizons mission to Pluto, which arrives soon!)
The resolution on the radar images is 13 feet (4 meters) per pixel. It made its closest approach yesterday (January 26, 2015, 10:19 am Central time) just 745,000 miles (1.2 million kilometers) from us, about 3.1 times the distance as far away as the Moon.
Best part? The images reveal that asteroid 2004 BL86 has its own small moon.
The asteroid is approximately 1,100 feet (325 meters) across and has a small moon approximately 230 feet (70 meters) across. In the near-Earth-object (NEO) population, about 16 percent of asteroids larger than 650 feet (200 meters) or larger have one - or even two! - small moons orbiting them.
The trajectory of the asteroid is well understood. Monday's flyby was the closest approach the asteroid will make to Earth for at least the next two centuries. It is also the closest a known asteroid this size will come to Earth until asteroid 1999 AN10 flies past our planet in 2027.</p>
Asteroid 2004 BL86 was discovered on Jan. 30, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.
NASA places a high priority on tracking asteroids and protecting our home planet from them, the most robust and productive survey and detection program for discovering NEOs in the world. NASA partners with government agencies, university-based astronomers, space science institutes across the country, and amateur astronomers, plus international space agencies and institutions working to track and better understand these objects. (I helped with the NEO search, too, back in the mid-1990s, as part of the Hobbs Observatory mission. That was frakkin' cool, except the part where I had to use an Apple II to run the telescope.)
Snips from a couple of amateur vids:
This tiny little world has a moon of its own! Space exploration is awesome.
Speaking of, The Galactic Adventures of Jack & Stella progress: