Radar images of asteroid 1998 QE2, flying past the Earth today, show that it has its own moon.

Radar images of asteroid 1998 QE2, flying past the Earth today, show that it has its own moon.

When astronomers analyzed radar readings to create their first maps of 1998 QE2, the big asteroid that’s due to sail past Earth on Friday, they were surprised to find that it has a moon twice as big as an ocean liner. 1998 QE2 itself is way bigger: The latest readings from NASA’s Deep Space Network antenna in Goldstone, Calif., are consistent with earlier estimates that the asteroid is about 1.7 miles (2.7 kilometers wide). But the moon is hefty as well. Astronomers estimate its diameter at 2,000 feet (600 meters).

The asteroid is coming! The asteroid is coming!

The asteroid is coming! The asteroid is coming!

The fly-by of the large asteroid 1998 QE2 tomorrow at about 5 pm (Eastern) is causing a lot of hype. It is interesting, but hardly the big news event NASA and others want to make it. The scientists will like it because they get another close look at an asteroid. Others are using it to hype up the threat of asteroids, though that threat is not changed in any way by this fly-by.