RUSSIAN METEOR UPDATE: On Friday, February 15th at 9:30 am local time in Russia, a small asteroid struck the atmosphere over the city of Chelyabinsk and exploded. According to reports from news organizations and Russian authorities, as many as 1000 people received minor injuries from the shock wave. This is the most energetic recorded meteor strike since the Tunguska impact of 1908.

Researchers have conducted a preliminary analysis of the event. “Here is what we know so far,” says Bill Cooke, head of 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.” (continued below)

“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.”

Videos of the event may be found here and here. In many of the videos you can hear the sound of windows shattering as the meteor’s loud shock wave reaches the ground. Onlookers cry out in Russian as alarms and sirens sound in the background. This pair of wide-angle gif animations is also worth watching: #1, #2.

It is natural to wonder if this event has any connection to today’s record-setting flyby of asteroid 2012 DA14. Paul Chodas of the Near Earth Object Program at JPL says no. “The Russian fireball is not related to 2012 DA14 in any way. It’s an incredible coincidence that we have had these two rare events in one day.”

fr/spaceweather.com