A sonic boom is caused by the change in air pressure, but it wouldn't affect him as he'd be the object creating the shift. For that to happen he would have to accelerate to super sonic, then circle arround at a higher speed, say speed .99c, beat the boom, and come back up behind it. On Earth the acceleration is 9.8m/s^2, terminal Velocity is the maximum speed an object can reach before the resistance is equal to the acceleration, and the fall begins at a constant speed. However If G shifts by different points on the planet, being 20 miles above also much change the G and thus the acceleration. As a(altitude) decreases the acceleration would increase, so he wouldn't be falling at a constant speed, each second into the fall he should be accelerating faster than perviously. At the same time as each second passes, the air pressure would increase. Without too complex physics: Code: Speed Sound = 767m/ph = 1235976m/ph = 343m/s 20 miles = 32186.88 d=Vi(T)+1/2(9.8)(t)^2 t = 81seconds Vf^2=Vi^2+2ad Vf^2 = 2(9.8)(32186.88) Vf = 794 So not counting terminal velosity, resulting from change in a over d, and g over d,plus increased resistance over d. This also doesn't take into account that acceration would be increasing, so the longer he goes the closer to the limit he gets, but he would have to pull a parachute, which would change d. He'd be going twice the speed out sound if he jumped from 20 miles, and crashed staight into Earth.
He'll be wearing a very sophistcated pressurized suit and helmet similar to what astronauts wear. He will probably experience temperatures in the -100F range. The speed of sound varies depending on temperature, atmospheric density and pressure, and some other variables but when Joe Kittenger jumped from 19 miles up in 1960, he reached a speed of 614 mph which translated to Mach .9 or 90% of the speed of sound. To the poster who said the speed of sound = 768mph, that is only for a given set of parameters (temperature, air pressure, altitude, air density ie. water vapor, etc.). There is no exact value for the speed of sound - it's actually a formula so the value depends on the conditions at the exact moment it's being calculated.
I dont think he will hear it because once u break the sound barrier your sound can never catch up to you. Like when the military jets fly over my place I see the jet then a couple secs later i hear the sonic boom. I dont think the guys in the jets can hear their own sonic booms so I dont see why he would hear his.
hasn't this already happened? like during the cold war... [ame="http://www.youtube.com/watch?v=81gn2oLeC_U"]YouTube- First Man in Space - Skydiving From The Edge Of The World[/ame] it's still really cool though and i'd love to do it if i had the chance triple edit: lol i just saw that this was posted on the first page... my bad, i'm really baked right now.
[ame=http://www.youtube.com/watch?v=_lEsLcGB7Vo]YouTube - Boards of Canada - Dayvan Cowboy (High Quality)[/ame] this video is sweet i just found this band and i was instantly like now way i just learned about this jump on grasscity