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Rockets in Space
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by
on 2008-08-10 16:57:42 (edited 2008-08-10 16:58:24)
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I've been thinking something recently: If space shuttles and such are propelled by expanding gases pressing against other matter, and the flaps on planes' wings allow them to rotate because air presses against them, how is it that these actions are still possible in space, a supposed vacuum? Unless, of course, it's pushing against that elusive 'dark matter'. That, or it's not a vacuum at all. So, who's got thoughts or links to share?  |
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Re: Rockets in Space
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on 2008-08-10 21:08:29 |
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An airplane achieves lift by taking advantage of the differential pressure on the wing. This pressure is actually a result of many molecules of air bouncing off the wing. In space, thrust is achieved by throwing off mass in one direction to move in the opposite direction. This mass is thrown off at a the maximum possible speed, so as to maximize the resulting thrust. Your connection to dark matter makes no sense. Space is an effective vacuum. Trust me. 
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Re: Rockets in Space
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by kudoushinichi
on 2008-08-10 21:19:40
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Lol, yeah... Rockets can move in vacuum due to the conservation of momentum. What gendou is trying to say is that when the rocket shoots out gas from its butt at high speed, it causes the rocket to move forwards. Much like you blow into a balloon and let it go. The baloon can fly even if there is no air surrounding it (there's air in the baloon though). Other examples include the recoil of a gun/rifle when you shoot it. Actually, before anyone sent a rocket out into space, they were doubts whether or not rockets can fly in space. It was an amusing story... But I've forgotten the name of the scientists involved.
Shinjitsu wa itsumo hitotsu!
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Re: Rockets in Space
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by
on 2008-08-10 21:29:42 |
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Excuse me. I did not try to say anyone shot gas out their butt. That's just gross. That is a patronizing reduction that narrow-mindedly constricts the wonderful possibilities physics allows. Yes, gun kickback and flying balloons are wonderful examples that illustrate conservation of momentum.
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