astroengine writes, quoting Discovery: "The source of loud 'booms' accompanied by a bright object traveling through the skies of Nevada and California on Sunday morning has been confirmed: it was a meteor. A big one. It is thought to have been a small asteroid that slammed into the atmosphere at a speed of 15 kilometers per second (33,500 mph), turning into a fireball, delivering an energy of 3.8 kilotons of TNT as it broke up over California's Sierra Nevada mountains. Bill Cooke, head of NASA's Meteoroid Environment Office, classified it as a 'big event.' 'I am not saying there was a 3.8 kiloton explosion on the ground in California,' Cooke told Spaceweather.com. 'I am saying that the meteor possessed this amount of energy before it broke apart in the atmosphere. (The map) shows the location of the atmospheric breakup, not impact with the ground.' Interestingly, this event was bigger than asteroid 2008 TC3 that exploded over the skies of Sudan in 2008 after being detected before it hit."