Chasing the Sound Barrier, in a Leap From 23 Miles Up

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.

“Fearless” is right; wow…

[thanks to Tom M. for the link; more at MetaFilter]