(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

CBS News is the news division of American television and radio service CBS. CBS News’ broadcasts include the CBS Evening News, CBS This Morning, news magazine programs CBS Sunday Morning, 60 Minutes and 48 Hours, and Sunday morning political affairs program Face the Nation.