Spaceweather.com updated with a statement from NASA’s Meteoroid Environment Office.
The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth’s atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth’s surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT.
A shock wave propagated down and struck the city below, causing large numbers of windows to break, some walls to collapse, and minor damage throughout the city,” he continued. “When you hear about injuries, those are undoubtedly due to the effects of the shock wave, not due to fragments striking the ground. There are undoubtedly fragments on the ground, but as of this time we know of no recovered fragments that we can verify.
A collection of videos is here. They also said the meteorite is not related to asteroid 2012 DA14 because they were traveling in opposite directions.
Good thing it wasn’t any lower when it exploded or there would have been even more injuries.
Craig Swain
dgharvey
ultimaratioregis
roamingfirehydrant
themavf14d
xbradtc
Hey, this NASA page updates the size of the meteorite to 17m, the mass to about 10000 tons, and the energy release to about a 500 kt during the event – http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html
I’ll razz Bill Cooke the next time I see him.
I looked up the Tunguska event, and most estimates put that at 10 – 15 megaton equivalent of TNT.