Russian Meteor Blast Bigger Than Thought, NASA Says

The meteor that exploded over Russia Friday was slightly larger than previously thought and more powerful, too, NASA scientists say.

The Russian meteor explosion over the city of Chelyabinsk, on Friday (Feb. 15), injured more than 1,000 people and blew out windows across the region in a massive blast captured on cameras by frightened witnesses. Friday afternoon, NASA scientists estimated the meteor was space rock about 50 feet (15 meters) and sparked a blast equivalent of a 300-kiloton explosion. The energy estimate was later increased to 470 kilotons.

But late Friday, NASA revised its estimates on the size and power of the devastating meteor explosion. The meteor's size is now thought to be slightly larger — about 55 feet (17 m) wide — with the power of the blast estimate of about 500 kilotons, 30 kilotons higher than before, NASA officials said in a statement.

The meteor was also substantially more massive than thought as well. Initial estimated pegged the space rock's mass at about 7,000 tons. Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., now say the meteor weighed about 10,000 tons and was travelling 40,000 mph (64,373 km/h) when it exploded.

"These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world - the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk," JPL officials explained in the statement. The infrasound stations detect low-frequency sound waves that accompany exploding meteors, known as bolides.

more here: http://www.space.com/19838-russian-meteor-blast-bigger-size.html