Selasa, 19 Februari 2013

Russian meteor info from Paul Doherty

Exploratorium guru, Paul Doherty, sent this to the PTSOS Yahoo Group this morning. Enjoy!

Here is some info I've scraped together on the Russian meteor.
I'm sure that the numbers will be revised but this will give you a start

Russian Meteor

Latest data

The meteor will probably be named Chebarkul after the lake where the largest fragment is believed to have landed.

The rock was 55 feet across, 17 m in diameter
mass 10,000 tons = 10^7 Kg (given the accuracy of this estimate it doesn't matter if we use english or metric tons)
energy release 500 Kilotons TNT about 30 Hiroshima bombs
entry speed 44,000 mph about 20,000 m/s
breakup at 20 km elevation, or 80,000 feet.

The biggest meteorite found so far is 7 mm across less than 1/4 inch, it was a chondrite meteorite

Scientists made great progress understanding stony meteoroid impacts with the earth's atmosphere tat the time when comet shoemaker Levy hit Jupiter. Stony meteoroids that are the size of the one in Russia or the even larger Tunguska event very quickly encounter thickening air at high mach number. The physical stress of the atmospheric pressure due to high velocity of the meteoroid causes the meteoroid to fracture. The multiple smaller fragments decellerate more quickly than the entire original object object with accompanying surface heating and continued fracturing into smaller pieces. (These small fragments remain cool in the center while the surface is incandescent.) The breakup deposits a great deal of kinetic energy into a shock wave.

Movies of the scientific modelling of the Tunguska event here

and now the same researchers are applying their computer code to the Chebarkul meteoroid

here is the abstract of the Tunguska event article.

Here is an article I co-wrote about another recent near collision

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