A Supersonic Jump, From 23 Miles In The Air

From New York Times:

Ordinarily, Felix Baumgartner would not need a lot of practice in the science of falling.

He has jumped off two of the tallest buildings in the world, as well as the statue of Christ in Rio de Janeiro (a 95-foot leap for which he claimed a low-altitude record for parachuting). He has sky-dived across the English Channel. He once plunged into the black void of a 623-foot-deep cave, which he formerly considered the most difficult jump of his career.

But now Fearless Felix, as his fans call him, has something more difficult on the agenda: jumping from a helium balloon in the stratosphere at least 120,000 feet above Earth. Within about half a minute, he figures, he would be going 690 miles per hour and become the first skydiver to break the speed of sound. After a free fall lasting five and a half minutes, his parachute would open and land him about 23 miles below the balloon.

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