An asteroid half the size of a football field buzzed Earth in a historic flyby today (Feb. 15), barely missing our planet just hours after a much smaller object exploded above Russia, injuring perhaps 1,000 people.
The 150-foot-wide (45 meters) near-Earth asteroid 2012 DA14 cruised within 17,200 miles (27,000 kilometers) of Earth at 2:24 p.m. EST (1924 GMT) today, coming closer than many communications satellites circling our planet.
The flyby marked the closest approach by such a large asteroid that astronomers have ever known about in advance. But it wasn't even the most dramatic space-rock event of the day.
That distinction goes to a brilliant fireball that exploded early this morning in the skies over Russia's Chelyabinsk region, which is about 930 miles (1,500 km) east of Moscow. The blast damaged hundreds of buildings and wounded perhaps 1,000 people, according to media reports. [Fireball Explodes Over Russia (Video)]
Scientists think the Russian fireball was caused by a object that was about 50 feet wide (15 m) and weighed about 7,000 tons before it hit Earth's atmosphere. For comparison, 2012 DA14 tips the scales at 140,000 tons or so. The two space rocks are completely unrelated, NASA researchers say, making the dual events a spooky cosmic coincidence.
Astronomers had been looking forward to 2012 DA14's flyby for a while, since it gave them the rare chance to study a decent-size asteroid up close.
"We're going to use our radars to bounce radio waves off this asteroid, watch it spin, look at the reflections and understand its size, its shape and perhaps even a little bit about what it's made of," Jim Green, director of NASA's planetary science division, said in a video released by the space agency Thursday (Feb. 14).
Indeed, researchers around the world trained instruments on 2012 DA14, tracking the space rock as it cruised toward Earth, gave our planet a historically close shave and then slipped silently off into the depths of space once again.