[90148] in Cypherpunks
Anti-Grav?
daemon@ATHENA.MIT.EDU (Steve Schear)
Sun Nov 16 08:05:53 1997
Date: Sat, 15 Nov 1997 21:57:24 -0800
To: cypherpunks@cyberpass.net
From: Steve Schear <schear@lvdi.net>
Reply-To: Steve Schear <schear@lvdi.net>
I must have been sleeping, but it appears I missed the emergence of another=
Fleischman-Pons ("cold fusion") style episode, this time having to do with=
antigravity. Experiments in 1992 in Finland seemed to show that the=
Earth's gravity could be shielded with a superconductor. This experiment,=
by Eugene Podkletnov, at Finland's Tampere University of Technology,=
apparently displayed a reduction in the weight of objects placed above a=
levitating, rotating high Tc superconducting disk, exposed to high=
frequency magnetic fields.=20
http://www.virtualpet.com/rbbi/folders/tech/basic/gravity.htm
http://www.inetarena.com/~noetic/pls/gravity.html#pandb
There are at least three different theoretical models for the effect --=
gravitomagnetism, local change to cosmological constant, and outright=
shielding. Detractors have pointed to possible experimental errors as the=
cause for the apparent levitation. =20
Gravitomagnetism
The coupling of supercurrents to the classical gravitational field is=
extremely weak. The reason, of course, stems from the smallness of the=
coupling between gravity and the energy-momentum tensor of matter. One=
might wonder whether in a quantum theory of gravity - or at least in an=
approximation of the theory for weak fields - the Bose condensate of the=
Cooper pairs, due to its macroscopic quantum character, can play a more=
subtle role than as a simple contribution to the energy-momentum tensor.=20
In other words, we wonder if the macroscopic quantum coherence of the=
condensate can be taken into account at a fundamental level in computing=
the interaction between the superconductor and the external gravitational=
field. Results might then differ from those obtained for the gravitational=
coupling of "regular", incoherent matter.
Shielding
It appears that a theory is being developed for simple shielding of gravity,=
in analogy with the shielding of microwaves by metal. Different materials=
shield or don't shield EM ratiation at various frequencies; metal shields=
microwaves, but plastic does not. Pure YBCO superconductors do not shield=
microwaves, but YBCO doped with small amounts of lead or silver does. =
They relate this to gravity shielding by virtue of two ideas -- that=
gravity might have a frequency (very high, on the order of the Planck=
length, or 10^34) -- a very speculative idea -- and that the bose=
condensate within a superconductor could radically lower the effective=
interaction frequency of gravity so that it could be shielded by ordinary=
matter.=20
On a related note, NASA has Breakthrough Propusion page http://www.lerc.nasa=
=2Egov/WWW/bpp which outlines their plans and activities to explore (and=
hopefully perfect) non-mass based propusion technologies. They seem to be=
taking this seriously enough to form a Delta-G group at their Marshall=
Space Flight Center to try and reproduce Podkletnov's (and others)=
experiments. =20
--Steve
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