I have a question. I was awake stupidly early in the morning a few weeks ago, and watching the Discovery Channel. I faintly remember them discussing a man who jumped from a balloon/plane (i think at 90,000 ft., but im not postive) and broke the speed of sound on his way down. I thought this was fairly amazing. I shared this with some of my science-minded friends, and they all told me I was wrong and that it was impossible for this to happen. Google searches haven’t turned up the desired evidence. So, my question, in short, is, has it been done? Is it possible? Examples would be wonderful. Thank-you
Col. Joseph Kittinger.
cite?
You mean you don’t know how to use the SDMB search engine for “Kittinger” or Google for it?:dubious:
Here is a website that has all the relevant details (Kittenger’s velocity is listed as unreliable) and physics:
I think the two basic principles are:
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The air is thinner the higher up you go, so the less wind resistance you’re going to get from falling (even less resistance if you’re pointed feet down or head down).
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The speed of sound is slower in a medium that is less dense.
However, going to this site:
http://hypertextbook.com/facts/JianHuang.shtml
and this site:
http://www.military-art.com/sb5.htm
suggests that Kittenger’s own journal lists him as only hitting 9/10 of the local speed of sound (at his altitude).
There are countless examples of both the 614 mph value (agrees with Kittenger’s journal apparently) and the incorrect 714 mph value.
Seems like almost every other article suggests he did break the speed of sound, showing potentially how ignorance and urban legend can spread through ‘learned channels’.
Under the circumstances, based on Kittenger’s own journal, I’ll go with him not actually breaking the sound barrier, although it certainly seems that it would be possible.
A small nitpick.
The speed of sound is is greater as the density of air decreases. Specifically, it varies as the square root of local temperature.
Actually, to nitpick my own nitpick:
The speed of sound can go up or down with a decrease of density.
Great links though on the Kittinger thing.
However, breaking the speed of sound by falling is not impossible, whether Kittinger did it or not. As long as the force that the air is putting on you is less than your weight, you’ll still accelerate. I bet that if Kittinger had assumed a head-down, feet up position with his arms to his side, he would have broken the sound barrier, but I think that would have been harder to control.
Would this have generated any significant heat from friction with the atmosphere? At what speed does this begin to occur?