[catfish1957]

He really should change his title from daredevil to Darwin candidate. Two points come to mind. How sure he that the parachute will open at over 600 mph, and (2)what will be the effect of the abrupt reduction in speed? I am not a Physicist, but say you suddenly and instantly go from 600 to 200 mph, won't that be like like a shift mass that would have a terrible effect on the body?

A real simple much smaller scale is what we see in a elevator. As it is dropping, it's probably go what maybe 20 mph? Notice the sensation as the elevator stops. Well now multiply it times 20.

[mlocher]

Your points are interesting ones. The effects of going the speed of sound are nothing compared to the G-forces generated by velocity changes.

One thing in his favor is that as he drops, the atmosphere increases and his speed will naturally slow down (more atmosphere means more air friction). I think there is a terminal velocity at 1 atmospheric pressure unit that is about 125 mph if I remember correctly from HS physics. He will therefore go from 600 mph to 125 mph in a gradual manner. His parachute will open as it normally would -- provided he does not pull the rip cord too soon.