Subject:
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Re: Hypothetical design question
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Newsgroups:
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lugnet.space
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Date:
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Mon, 23 Jun 2003 23:53:32 GMT
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Viewed:
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545 times
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In lugnet.space, Shaun Sullivan wrote:
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But then, to counter what I just said: Has anybody done any calculations to
show that the density of particles in space is *not* high enough to produce
fluidic interactions at near-light speed?
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It does behave more like a fluid at extremely high speeds. However, have you
seen what happens to an airplane when it hits water at mach speeds? It’s not
pretty, and that’s essentially what you’d have to be dealing with in a near
vacuum. By the time you’re going fast enough for the particle impacts to
collectively behave like a fluid, the amount of inertial energy involved would
have quite a few options as for how best to destroy your vessel.
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The space between particles is huge in space ... but then again, it’s also
huge on the molecular scale in regular air. Could it be that going fast
enough in space allows you to build up boundary layer effects even with the
scanty molecular density, arguing for an aerodynamic shape?
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I believe that boundary layer effect relies in large part on molecular cohesion
in the travel medium. Water molecules tend to cling to each other when in close
proximity, so they’ll flow around you like a horde of teeny little trains. The
denser the medium is, the slower your maximum speed will be, but the more sparse
it is, the more destructive it will be when you reach the point where it behaves
like a liquid. Atmospheric reentry involves speeds that exceed what you can
achieve in the lower atmosphere, but it’s also a rather toasty affair.
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Message is in Reply To:
 | | Re: Hypothetical design question
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| (...) Well, in the space-ish situation, the number of particles you're hitting will only come down to size; regardless of its shape, a ship shaped like a perfect lozenge will hit the same number of particles as a ship shaped like a cube, if their (...) (21 years ago, 23-Jun-03, to lugnet.space, FTX)
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