Skip to comments.Russia meteor virtually impossible to see coming - Current and planned efforts focus on larger...
Posted on 02/17/2013 1:01:22 AM PST by neverdem
Current and planned efforts focus on larger objects
Scientists have begun piecing together the characteristics of the meteor that exploded over Russia on the morning of February 15, using data from seismic instruments that track earthquakes and microphones designed to detect sonic booms from nuclear explosions. Unlike the asteroid DA14, which narrowly but predictably missed Earth later that day, the meteor was too small to detect before its contrail appeared in the dawn skies over the Russian city of Chelyabinsk.
Yet even an object too small to detect can produce an impressive amount of destruction. The meteor was 15 meters across (compared with 50 meters for 2012 DA14) and weighed more than 7,000 metric tons when it entered Earths atmosphere, says Margaret Campbell-Brown, an astronomer at Western University in London, Ontario. She estimates that it was streaking through the sky at supersonic speeds of about 18 kilometers a second before exploding at an altitude of 15 to 20 kilometers, creating a shock wave that shattered glass in a deafening boom once it reached the surface. Various news sources have reported hundreds of buildings damaged and about 1,200 injuries.
Coincidentally, the largest observed meteor to enter the atmosphere since 1908 arrived just hours before a much larger object passed the planet uneventfully at a distance of about 27,000 kilometers.
The fireball is not related in any way to 2012 DA14, says Paul Chodas, a planetary scientist with NASAs Near Earth Object Program at the Jet Propulsion Laboratory in Pasadena, Calif. Among other reasons, the meteor buzzed through the sky from north to south, the opposite trajectory of DA14.
The explosion had the equivalent of up to 500,000 tons of TNT, Campbell-Brown says. Thats about 30 times the energy output of the Hiroshima atomic bomb but only 5 percent of the energy...
(Excerpt) Read more at sciencenews.org ...
I am wondering myself!