Approaching Asteroid 1998 QE2 has a satellite Moon

First radar images of asteroid 1998 QE2 were obtained when the asteroid was about 3.75 million miles (6 million kilometers) from Earth.

CREDIT: NASA/JPL-Caltech/GSSR

A huge asteroid set to sail past Earth on Friday has its own moon, NASA scientists have just discovered.

Researchers obtained a series of radar images of the approaching asteroid 1998 QE2 late Wednesday (May 29) using the Deep Space Network antenna at Goldstone, Calif.

Images captured over the course of two hours showed that the asteroid is actually a binary system.

The main space rock is the size of nine ocean liners, roughly 1.7 miles (2.7 kilometers) across, and the satellite that orbits it is estimated to be 2,000 feet (600 meters) wide, according to NASA.

Binary systems are quite common among near-Earth asteroids. Of space rocks at least 655 feet (200 meters) across, about 16 percent are binary or triple systems, NASA officials said.

1998 QE2 poses no threat of hitting Earth during the flyby, space agency officials assure. Its closest approach will occur at 4:59 EDT on Friday (May 31) and it is expected to pass at least 3.6 million miles (5.8 million kilometers) away from the planet.

The asteroid won't be visible to the unaided eye as it zips by.

Though harmlessly far away, this will be the nearest 1998 QE2 gets to Earth in the next two centuries.

As it passes, the asteroid will be closely watched by astronomers. In addition to the 230-foot-wide (70 meter) Deep Space Network antenna, astronomers will also be using the Arecibo Observatory in Puerto Rico to observe 1998 QE2 until June 9.