(CBS) — An asteroid nearly a mile wide with a moon of its own is expected to pass by Earth on Saturday, traveling at 48,000 mph. The unnamed space rock designated as Asteroid (66391) 1999 KW4 is actually a double asteroid or a binary asteroid. That means it’s composed of one large asteroid orbited by a smaller moon. In this case, it’s about a third of a mile wide and orbits around the larger body about once every 16 hours.
The Las Cumbres Observatory describes 1999 KW4 as “slightly squashed at the poles and with a mountain ridge around the equator, which runs all the way around the asteroid. This ridge gives the primary an appearance similar to a walnut or a spinning top.” While 1999 KW4 is classified as a “Potentially Hazardous Asteroid” by the Minor Planet Center, it should clear Earth at a very safe distance of 3,219,955 miles. To put it in perspective, that’s more than 13 times the distance from the Earth to the moon. READ MORE