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- Path: sparky!uunet!portal!cup.portal.com!lordSnooty
- From: lordSnooty@cup.portal.com (Andrew - Palfreyman)
- Newsgroups: sci.physics
- Subject: Re: Another antigravity device
- Message-ID: <71716@cup.portal.com>
- Date: Tue, 15 Dec 92 01:28:44 PST
- Organization: The Portal System (TM)
- Distribution: world
- References: <1992Dec15.013620.24161@galois.mit.edu>
- Lines: 29
-
- John Baez poses:
- : Imagine an extremely (although not infinitely) rigid crystal. It takes
- : a huge amount of energy to deform the crystal lattice ever so slightly.
- : Thus if this crystal is placed in the earth's gravitational field at sea
- : level, the curvature of space due to the gravity prevents the
- : lattice from being perfectly regular, at the cost of a large amount of
- : energy. The crystal would have much less energy if it were far away
- : from the earth where the curvature of space is less. If we make the
- : crystal rigid enough it will actually be energetically favorable for the
- : crystal to float upwards - since the decrease in its internal energy
- : will more than compensate for the increase in gravitational potential
- : energy.
- :
- : Now, I *know* that this material would have to be insanely rigid for
- : this effect to be noticeable at all -- far more rigid than any actual
- : stuff. However, we're talking questions of principle here. Is there
- : any reason *in principle* why a sufficiently rigid material wouldn't
- : levitate to get out of the earth's gravitational field - that's what I'm
- : asking.
-
- I usually get this stuff wrong, but here's my answer.
- The rod will flex infinitessimally, offsetting its internal energy gain
- by the reduction in gravitational potential energy. This is a local energy
- minimum, and that's where it'll be trapped. The space stuff is a red
- herring, since there is no mechanism to get it there.
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- | lord snooty @the giant | Would You Like Space Potatoes With That? |
- | poisoned electric head | andrew_-_palfreyman@cup.portal.com |
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