A large asteroid, called 2004 BL86 by astronomers, swept just outside 3 lunar distances of Earth on January 26, 2014. It’s the closest asteroid of its size known to pass Earth between now and 2027. It was close enough that observers on Earth could see it fleeing in front of the fixed star background. It was close enough that observers noticed a moon orbiting the asteroid! Here are some of the best images so far.
The movie of the asteroid’s pass – above – is from Alessandro Marchini of the Osservatorio Astronomico Università di Siena, in Italy. He emailed EarthSky with word of this video, saying:
… A video of the ride of asteroid 2004 BL86 through the stars. It’s the animation of 71 frames just captured in 16 minutes by our telescope, with the asteroid crossing our field of view (40 arc minutes). Taken from 20:28 to 20:44 UTC.
Telescope Maksutov-Cassegrain 30cm f/5.6, CCD Sbig STL-6303, field of view 58×39 arcmin.
Thank you, Alessandro!
The two videos above are really cool. They relate to the announcement on the afternoon of January 26 that asteroid 2004 BL86 has a moon! Astronomers discovered the small moon this past weekend, and the discovery was confirmed by scientists working with NASA’s Deep Space Network antenna at Goldstone, California. The radar images show the primary asteroid as 1,100 feet (325 meters) across with a small moon 230 feet (70 meters) across.
Bottom line: Images and video of asteroid 2004 BL86, which swept about 3 times the moon’s distance from Earth on Monday, January 26.