The Skeptics' Guide to the Universe > Podcast Episodes
Episode #349
lonely moa:
--- Quote from: wallet55 on Mar 24, 2012, 11:21:01 AM ---So, though I would not hold out my skydiving past as a reason to completely trust my opinion on these high altitude jumps, mainly because what this guy is doing is so radically different from what we sport jumpers do jumping say from 15 thousand feet (my highest jump).
There are really 3 dangers here as i see them and two of them are completely outside of the realm of sport jumping.
1) it is extremely cold
2) there is no air to breath
3) there is no airspeed for a very long time with which to maintain stability in freefall.
The first two items mean that everything about this jump is really about your spacesuit's integrity. Kittinger's glove had problems which nearly cost him his hand. A Russian who did a high altitude hop and pop (opening the chute at the beginning of his jump), died when his suit failed.
the third is similar to what people experience when jumping from any balloon or hovering helicopter, albeit to a much greater degree and longer time. The jumper at high altitude is basically going to rotate and spin for a while until enough air rushes by by which he can stabilized himself either through positioning or a drogue chute.
Lacking any memory of Kittinger describing the deceleration as difficult, I am thinking that Dr. Novella's worry over this is excessive. I know I decelerated from an ultra dive of (what i was told) was close to 300 mph to the normal 120 in just seconds, and it was exhilarating, but not really painful or particularly risky.
The spin and blackout is something that has killed sport jumpers (particularly tandem jumpers before they started using drogues to prevent the passenger from getting them in a spin), and entanglements with their own and others chutes still kill jumpers today.
So when you get down to it, this jump is mainly dangerous because of where they are doing it (at the edge of space) not what they are doing.
--- End quote ---
My sentiments exactly. Going from a full head down dive to the "terminal velocity" in seconds (although one carries a wonderfully huge horizontal component) is just what you do every relative work dive going last from the aircraft. Felix is obviously well practiced at falling at low resistance airspeed.
That would havve been the drogue chute that wrapped around the colonel's neck, wouldn't it? Pilot chutes pull the main or the reserve from their package.
RubberBoots:
One consideration: it seems to me that regardless of what altitude you start at, you're progressing from an altitude at which terminal velocity is higher to one at which it is lower--so regardless of altitude you are *always* going to be decelerating.
At no point in a high altitude jump do you have to shed all that speed suddenly--you would do it gradually as you lost altitude. So the only question is: does the rate at which the atmosphere thins increases as you go higher up? If the answer is no, then there would be no difference in the experience of the jumper. If the answer is yes, then the experienced wind resistence would decrease over time as he lost altitude.
Nuorder:
I think I have a good "skeptical" quote from a cartoon character. It's from one of the BEST shows on television!!! (FUTURAMA!!!)
It's the evolution debate between Professor Farnsworth, a flying spaghetti monster, and a gorilla...this is CLASSIC!!!!
http://www.myvidster.com/embed/316851
<iframe src="http://www.myvidster.com/embed/316851" width="640" height="385" frameborder="0" allowfullscreen></iframe>
I haven't even listened to the entire podcast yet, I just fast forwarded to the WTN; because I'm DETERMINED to win one of these...Nonetheless, thanks for posting this podcast and I literally haven't missed a single episode. Thanks for all you do.
EDIT: How do I embed a video?
superdave:
Steve is right in principle. Hitting the thicker air at a velocity faster than the terminal velocity (TV) would cause an increased drag force relative to the speed. However the effect of this force will depend on the density gradient. If that gradient is relatively smooth I could see this not being a big problem.
Remember the mythbusters episode where they shoot bullets into water. That is sorta similar, but with an extreme change in the density of the environment. There the bullets pretty much exploded because the drag forces were so high. But a more gradual change would produce less extreme results.
Evil Eye:
A GREAT personal interview with Joe Kittenger on my local radio show "Monsters in the Morning". - Here's the mp3.
http://downloads.iheartradio.com/media/station_content/2039/02.09.12_Thursday2.mp3_1328807676_18140.mp3
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