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From: FIRTH@TL-20B.ARPA
Newsgroups: net.space
Subject: making parabolas
Message-ID: <8512040205.AA22545@s1-b.arpa>
Date: Tue, 3-Dec-85 21:04:08 EST
Article-I.D.: s1-b.8512040205.AA22545
Posted: Tue Dec  3 21:04:08 1985
Date-Received: Thu, 5-Dec-85 08:02:28 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 15

Don Barry is correct.

If a film with adequate surface tension is rotated and subjected to
a pressure difference, it deforms into a surface that is a paraboloid
of revolution.  Of course, if the surface tension is inadequate, you
get a disgusting blow-out.

Alas, I don't think this is going to work in near-Earth orbit: the
basic frame of reference is not inertial, being subjected to either
a gravity gradient (radial to the planet) or Coriolis forces (tangential
to it), and my back-of-the-VDU-screen calculation says that this is enough
to cause a significant distortion.

Robert Firth
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