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Author Topic:   The predictions of Walt Brown
cmanteuf
Member (Idle past 6796 days)
Posts: 92
From: Virginia, USA
Joined: 11-08-2004


Message 86 of 260 (179025)
01-20-2005 5:52 PM
Reply to: Message 74 by johnfolton
01-20-2005 4:07 PM


Re: Parachuters freefall speeds
Tom writes:
the record is 330 mph, though it did say freefall speeds are approximately 120 mph.
This is all a bit off topic, but I'm somewhat pedantic. That is not the record for the fastest fall by a human.
A balloon took Major Joe Kittinger up to 102,000 feet and then he jumped out. With just a small, stabalizing parachute he fell for 4 minutes. At the end of his fall he was travelling 714 miles an hour, fast enough to break the speed of sound with just his falling body. [1]
When he got down to 17,000 feet he activated the main parachute and slowed to a safe, gentle landing. That means that a (roughly) 17 mile free-fall by a human got him up over 700 miles an hour.
The FAI defines the lowest edge of space as 100 km (62 miles). But the lowest orbit that is stable for any length of time is about 90 miles up. At that height, in order to be in orbit (and not simply falling directly down), you need to be going about 18,000 miles per hour. All of that gravitational potential energy and kinetic energy must be dumped *somewhere*.
It can be dumped into the atmosphere[2], but dumping the quantities of matter under discussion (enough to flood the whole earth above Everest) would boil water. I'm not sure where else it could be dumped. Could you suggest a possibility?
[1]: http://www.wpafb.af.mil/museum/history/coldwar/pe.htm
[2]: Note that currently that is what meteorites and returning space capsules and shuttles do- they dump their heat into the atmosphere. We do not boil because even a space shuttle or a dinosaur killer asteroid is insignificant compared to the amount of mass necessary to flood the entire earth to even 10,000 feet above the current MSL, leave alone above the highest mountain.

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