The size of a city block, Asteroid 2005 YU55 buzzed past Earth with just 201,700 miles of room to spare.
An asteroid the size of a city block zoomed inside the moon's orbit today (Nov. 8) in a rare flyby that marked the closest approach to Earth by such a big space rock in 35 years.
The asteroid 2005 YU55 came within 201,700 miles (324,600 kilometers) of Earth at 6:28 p.m. EST (2328 GMT) Tuesday evening before speeding off into deep space once again at about 29,000 mph (46,700 kph).
The space rock is about 1,300 feet (400 meters) wide. An asteroid this large hasn't come so near to Earth since 1976 and won't again until 2028, researchers said.
The asteroid encounter brought 2005 YU55 closer than the moon, which orbits Earth at an average distance of 238,864 miles (384,499 km). But there was never any danger that 2005 YU55 would slam into Earth today.
Scientists eagerly awaited the close encounter all the same, since it's providing an unprecedented opportunity to learn more about the asteroid and its orbit.
"We would really like to characterize it as much as possible, and learn about its past and about its future," said Marina Brozovic, a scientist with NASA's Near-Earth Object Office at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., before today's flyby. "I really can't wait to see the images."
Photos and videos of asteroid 2005 YU55 released by NASA just before and during the flyby revealed the space rock to be a relatively round but lumpy object. [See the latest photos and videos of asteroid 2005 YU55]