"A black asteroid as big as an aircraft carrier zoomed past Earth on Tuesday, delighting astronomers who trained telescopes on the ancient body in hopes of learning more about its composition and origin."
"With a diameter estimated at 400 meters, or about a quarter of a mile, Asteroid 2005 YU 55 is the biggest asteroid to make a close pass by Earth since 1976.
During its closest approach, which occurred at 6:28 p.m. EST, it was inside the orbit of the moon, about 200,000 miles above the planet. It posed no threat to either.
Thousands of professional and amateur astronomers were tracking the asteroid with telescopes, seeking to learn more about what it is made of, how fast it spins and ultimately, where it came from."
Irene Klotz reports for Reuters November 9, 2011.