A mountain-sized asteroid zoomed harmlessly past our planet on Monday, and it's not too late to see the space rock online or in the sky.
Radar readings show that the asteroid, known as 2004 BL86, is about two-tenths of a mile wide (300 meters wide), researchers at NASA's Jet Propulsion Laboratory said. They also reported that the asteroid appears to have boulders on its surface — and a tiny moon nearby.
Observers might be able to see 2004 BL86 with binoculars or a small telescope because of its significant size. At about 11 a.m. ET, the asteroid made its closest approach to Earth, coming within about 745,000 miles (1.2 million kilometers). NASA says the asteroid posed no danger to our planet.
"For people who want to look in the right direction you just have to find the brightest 'star' in the sky … and that's Jupiter," Slooh astronomer Bob Berman said. Then, he added, locate the star Procyon, which forms the winter triangle along with Betelgeuse and Sirius. The asteroid will be passing directly between the two stars for most of the evening, he said.
Observers in the Americas, Europe, and Africa will have the best seats during the asteroid's peak brightness, which is expected to last from 8 p.m. ET until about 1 a.m. ET Tuesday [Asteroid Quiz: The Space Rock Challenge]