A school bus–sized meteor that exploded over Earth with a force of 10 atomic bombs on Dec. 18 just came to the public’s attention last week during a presentation at the Lunar and Planetary Science Conference in Texas. The celestial event, the second largest meteor explosion recorded since NASA started tracking them 30 years ago, went largely unnoticed because the fireball exploded over the Bering Sea between Russia and Alaska, many miles from inhabited land, Live Science reported.
U.S. Air Force missile-monitoring satellites detected the event and reported the meteor weighed about 1,500 tons, had a diameter of about 32 feet, and traveled through the atmosphere at 71,500 mph before shattering about 16 miles above the sea, according to NASA.
World asteroid-monitoring groups did not see the fireball coming because most modern telescopes only detect objects measuring at least several hundred meters in diameter. NASA mostly focuses on identifying near-Earth objects with a diameter of at least 460 feet.
In 2013, the largest recorded meteorite explosion occurred over mainland Russia with a force 2½ times greater than that of the recent fireball. That meteor measured 62 feet across, and its shockwaves injured more than 1,200 people.
NASA said fireball events happen frequently and the recent December meteor posed no threat to anyone on the ground. —J.B.