Meteor -- a small object from space observable as it enters the earth's atmosphere
A meteorite crashed in Chelyabinsk, in the Russian Urals at 9:20am local time on 15 Feb (7:20pm California time), just after sunrise.. The Russian Academy of Sciences initially said that the space rock had a diameter of “a few meters” and a mass of approximately 10 tons. They said that it was probably made of iron, a very common substance for meteorites. Other sources said the diameter was probably about 30 meters, probably about the size of a This meteorite generated a sonic boom, as it streaked through the early morning traveling more than five times the speed of sound.
Chelyabinsk, a city of over one million people, and a major industrial and transportation centre since World War II is farther north than the Canadian cities of Edmonton, Alberta and Goose Bay-Happy Valley, Labrador, so it was a very sizeable population that witnessed the meteorite. More than one thousand people were injured, mostly by flying glass and debris.
The National Aeronautics and Space Administration (NASA) estimated the size of the meteorite as 55 feet-and 10,000 tons. This would be equivalent to cramming the mass of 20 times the maximum take-off weight of a 747 jumbo jet into a commercial long-haul truck trailer. They also estimated the amount of energy released by the meteorite to be equivalent to about 500 thousand tons or kilotons. This is about 33 times the energy radiated by the Hiroshima nuclear blast.
California was reportedly visited by a much smaller meteorite the day after the Chelyabinsk—about 22 hours after. This meteorite was spotted in the San Francisco area. The San Francisco Chronicle quoted the operations manager for the American Meteor Society, Mike Hanley, as saying "fireballs happen every single night, all around the world.". The American Meteor Society reported 35 sightings of the San Francisco meteorite.
California was also hit by a meteorite in October 2012 near Novato. The 17 October fireball was reported by the San Francisco Chronicle, and a piece of it was found three days later by a Novato home owner, Lisa Webber, who contacted Cameras for Allsky Meteor Surveillance (CAMS), which had issued a call for information on the California fireball.
There was another California fireball spotted by CAMS about a month ago on 17 January. This fireball was apparently the result of an impact between a meteor and another object, perhaps a small comet, according to CAMS. The meteorite came from the direction of the constellation Virgo, and was struck by a the comet over Lake Tahoe. The comet, about 1 meter wide was totally destroyed. There were no meteorites as a result of this collision.
As it turns out, meteorites land on earth frequently, but the kind of event that happened in Russia on Friday is rare.
Meteoroid -- a small object from space
Meteor -- a meteoroid that enters the earth's atmosphere
Meteorite -- a meteoroid that hits the ground