one article i saw in the paper made a distinction between the total energy (presumably, mv^2/2), and the amount of energy that reached the ground. the article said that most of the energy was absorbed by the atmosphere. in any case, video like this: http://www.guardian.co.uk/science/2013/feb/15/meteorite-explodes-over-russia... is pretty amazing! bob baillie --- Hans Havermann wrote:
The NASA release statement is apparently based on calculations by Peter Brown of the University of Western Ontario. I notice that Warren applies the Russian speed estimate to the NASA energy release number but I would guess that Peter Brown elected to use his own number. If his speed was closer to 20 km/s, there is no issue.
On Feb 16, 2013, at 3:13 PM, Warren Smith <warren.wds@gmail.com> wrote:
On 2/16/13, Warren Smith <warren.wds@gmail.com> wrote:
The Russian Academy of Sciences estimates the meteor had a mass of 10,000 tons, entered atmosphere at speed 15 km/s and exploded when 30-50 km up. NASA estimated it was 17 meters diameter and 10,000 tons with an energy release equivalent to roughly 500 kilotons of TNT. --NASA got it wrong, since 500*kiloton = 2.1*10^15 joule = m*v^2 / 2 and with v=15 km/sec, we find m is at least 18666 tonnes ("at least" since not all energy released in the blast).
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