The asteroid 1998 QE2 will pass close by the Earth tonight, but it won't be alone. It's towing its own moon.

Tonight, QE2 will pass within 3.6 million miles of the planet, the closest it will get for the next two hundred years. That's about 15 times further away than the moon.

NASA will be hosting a live Q&A tonight at 8 p.m. EDT here.

The asteroid is less than miles across, large enough to devastate the planet if it had actually hit us. Instead it will simply coast by, orbited by its own little moon, a companion asteroid about less than half a mile across.

"The radar imagery revealed that 1998 QE2 is a binary asteroid. In the near-Earth population, about 16 percent of asteroids that are about 655 feet (200 meters) or larger are binary or triple systems. Radar images suggest that the main body, or primary, is approximately 1.7 miles (2.7 kilometers) in diameter and has a rotation period of less than four hours. Also revealed in the radar imagery of 1998 QE2 are several dark surface features that suggest large concavities. The preliminary estimate for the size of the asteroid's satellite, or moon, is approximately 2,000 feet (600 meters) wide. The radar collage covers a little bit more than two hours," NASA said in a press release.

Recent cuts to NASA and other science programs mean astronomers must eke out as much data from every celestial flyby as possible. While asteroids with their own satellites aren't particularly rare, this will be a relatively unique opportunity for scientists to observe the phenomenon up close.

In addition, many scientists warn that it is important to map near-Earth objects, in case one comes too close and threatens to impact the planet, much like the object that caused the extinction of the dinosaurs. Just three months ago, a much smaller asteroid came only 17,000 miles from Earth, passing well within the moon's orbit.