Edward Lovett and Ned Potter Report on ABC News:
We have a visitor — a large asteroid called 2005 YU55 that is expected to come within approximately 201,700 miles of Earth on Tuesday, according to NASA. That’s slightly less than the distance from Earth to the moon.
Asteroids often pass this close, but most are tiny. Countless thousands of pieces come plunging into the atmosphere, but they burn up without doing any harm. If they’re as large as grains of sand, we may, if we’re lucky, see them in the night sky as shooting stars.
But 2005 YU55 is at least 1,300 feet wide — larger than an aircraft carrier, according to radar measurements. The last time an asteroid this big passed by was in 1976, and the next one scientists know of won’t be until 2028, NASA says. (There have been some rude surprises in between, but not involving anything remotely as large.)
Don Yeomans, manager of NASA’s Near-Earth Object Program Office at Jet Propulsion Laboratory, in Pasadena, Calif., said this fly-by is an opportunity to learn more about c-type — that is, carbon-based — asteroids, to find “clues as to what it was like when our solar system was forming.”
More: ABC News