Everyone's been talking about asteroid 1998 QE2 recently as it flies by our planet, but the 1.7-mile giant has a little friend that was only recently discovered by NASA. Turns out that 1998 QE2 has a traveling companion: a moon of its own.
Radar imaging of the asteroid when it was 3.75 million miles from Earth using the 230-foot Deep Space Network antenna at Goldstone, Calif. showed that the asteroid was part of a binary system.
"Radar really helps to pin down the orbit of an asteroid as well as the size of it," said Paul Chodas of NASA's Near-Earth Object Program office during a JPL webcast about the asteroid May 30. "We now know our size estimates were pretty good, but finding it was a binary was surprising."
It is estimated that 16 percent of near-Earth asteroids with a diameter greater than 655 feet are part of a binary or even a triple system. Asteroid 1998 QE2 and its 2,000-foot moon, it seems, are not so unique.
Radar imaging is an important tool in studying asteroids, and is frequently used by NASA's Near-Earth Object Program, which tracks any potentially-dangerous cosmic objects . NASA does not consider Asteroid 1998 QE2 a threat to Earth.
Asteroid 1998 QE2 will be at its closest to Earth at approximately 4:59 p.m. EDT, when it will be 3.6 million miles from us. The asteroid won't be visible in broad daylight, but a live stream of the event can be viewed at the Slooh online telescope. Parties interested in scoping out the asteroid from a public observatory can find a full list of places open for viewing here.