“It was a meteor strike–the most powerful since the Tunguska event of 1908”

ScienceAtNasa has a sobering video on the latest information about the visitation by the god Ogdy unexpected meteor strike in the Chelyabinsk region of Russia on 15 February.  Video credit: ScienceAtNasa.

From the accompanying ScienceAtNasa press release

The Russian meteor’s infrasound signal was was the strongest ever detected by the CTBTO network. The furthest station to record the sub-audible sound was 15,000km away in Antarctica.

Western Ontario Professor of Physics Peter Brown analyzed the data: “The asteroid was about 17 meters in diameter and weighed approximately 10,000 metric tons,” he reports. “It struck Earth’s atmosphere at 40,000 mph and broke apart about 12 to 15 miles above Earth’s surface. The energy of the resulting explosion exceeded 470 kilotons of TNT.” For comparison, the first atomic bombs produced only 15 to 20 kilotons.

Based on the trajectory of the fireball, analysts have also plotted its orbit. “It came from the asteroid belt, about 2.5 times farther from the sun than Earth,” says Cooke.

Comparing the orbit of the Russian meteor to that of 2012 DA14, Cooke has shown that there is no connection between the two. “These are independent objects,” he says. “The fact that they reached Earth on the same day, one just a little closer than the other, appears to be a complete coincidence.” [orbit diagram]

Infrasound records confirm that the meteor entered the atmosphere at a shallow angle of about 20 degrees and lasted more than 30 seconds before it exploded. The loud report, which was heard and felt for hundreds of miles, marked the beginning of a scientific scavenger hunt. Thousands of fragments of the meteor are now scattered across the Ural countryside, and a small fraction have already been found.

Preliminary reports, mainly communicated through the media, suggest that the asteroid was made mostly of stone with a bit of iron–“in other words, a typical asteroid from beyond the orbit of Mars,” says Cooke. “There are millions more just like it.”

And that is something to think about as the cleanup in Chelyabinsk continues.

Indeed.