Asteroid 2004 BL86 Has Its Own Moon, Reveals NASA

You've likely heard of the big asteroid that zipped by our planet today, and if you were particularly lucky you might have even spotted it when it was its closest point. NASA dished all the details on the fly-by ahead of time, and now it is back with more, this time with some info about the space rock itself: namely that it has a moon of its own. The moon was spotted on radar images as the asteroid neared the Earth earlier today, and as such it is a somewhat more rare occurrence than the average asteroid hurling past us.

The discovery was made earlier today via NASA's massive Deep Space Network antenna in California, with the resulting radar images (there are 20 of them) being assembled into the video below. The asteroid itself measures in at about 1,100ft. across, while the second body — its little moon — is smaller at about 230ft. across.

This makes asteroid 2004 BL86 a bit unique, in that only 16-percent or so of asteroids measuring in at 200 meters or more are a binary (or triple) system. To get an idea of the size of it all, NASA says its radar images represent 13ft. per pixel. The use of radar allowed the space agency to get an idea of the asteroid's size, shape, and more as well.

The video above, comprised of the 20 radar images, gives a view of the moon and asteroid both in motion, with the asteroid rotating and the moon appearing to lower down behind it. Says the space agency, this is the closest 2004 BL86 will be to our planet for the next couple hundred years, at least.

SOURCE: NASA