How the Falling Meteor Packed a Sonic Punch


A 10,000-ton meteor that entered the atmosphere over Russia on Friday triggered a powerful sonic boom. So what causes a sonic boom?

The huge sound is the result of colliding pressure waves in the atmosphere generated by an object moving faster than the speed of sound, which varies depending on altitude and temperature.

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At sea level and 68 degrees Fahrenheit, sound travels at about 761 mph.

The meteor blazing  through the skies over Central Russia on Friday was traveling a heck of a lot faster than that.  As it moved, the rock generated pressure waves in the air, similar to how a boat creates waves from its bow and stern as it moves through water.

Because the meteor is supersonic, the waves, which travel at the speed of sound, can’t get out of the way fast enough. The waves build up, compress and eventually become a single shock wave moving at the speed of sound.

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The meteor  vaporized as it tore through the skies, but not before building up a powerful shock wave.  When the pressure changed, kaboom! A sonic boom was heard on the ground, one that in this case was powerful enough to break windows.

It’s not the first time it has happened and it won’t be the last.

“Meteorites hit the Earth all the time,” Tufts University chemist Samuel Kounaves, who studies Mars meteorites, told reporters at a press conference on planetary exploration at the American Association for the Advancement of Science meeting in Boston on Friday.

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Fortunately, asteroid 2012 DA14, which is passing by Earth later today, won’t come any closer than about 17,200 miles. If that rock, which is about as wide as the length of an Olympic-sized swimming pool, hit it would have about the force of a similarly sized asteroid that exploded over Siberia in 1908. That blast leveled trees over 830 square miles.

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