From: scerir (scerir@libero.it)
Date: Sun Jun 24 2001 - 13:09:38 MDT
> Mike Lorrey <mlorrey@datamann.com>
> Just got this off another list:
> "An intriguing theoretical discovery which has applications for new
> phenomena and insights"
> http://www.academicpress.com/inscight/06202001/grapha.htm
http://xxx.lanl.gov/abs/astro-ph/0012345
Magnetic tension and the geometry of the universe
-Christos G. Tsagas (University of Portsmouth)
The vector nature of magnetic fields and the geometrical interpretation of
gravity introduced by general relativity, guarantee a special coupling
between magnetism and spacetime curvature. This magneto-geometrical
interaction effectively transfers the tension properties of the field into
the spacetime fabric, triggering a variety of effects with profound
implications. Given the ubiquity of magnetic fields in the universe, these
effects could prove critical. We discuss the nature of the magneto-curvature
coupling and illustrate some of its potential implications for cosmology.
http://xxx.lanl.gov/abs/astro-ph/0101151
Magnetized gravitational waves
-Roy Maartens, Christos Tsagas, Carlo Ungarelli (Portsmouth)
We investigate the influence of cosmic magnetic fields on gravitational wave
perturbations, and find exact solutions on large scales. We show that a
large-scale magnetic field can generate large-scale non-decaying
gravitational waves. In the general case where gravitational waves are
generated by other mechanisms, a large-scale magnetic field introduces a new
decaying tensor mode and modifies the non-decaying mode. The direct effect
of the magnetic field is to damp the gravitational waves, while an indirect
magneto-curvature effect can either damp or boost the waves. A magnetic
field also leads to a breaking of statistical isotropy, and the magnetic
imprint on the tensor spectrum in principle provides a means of detecting a
primordial field.
> Question: what does this mean for the possibility of magnetic 'surf
> boards' for spacecraft propulsion?
Difficult to say.
Tsagas writes:
"Given the ubiquity of magnetic fields in the
universe, this unconventional behaviour deserves further
investigation as it could reflect a deeper inter-connection
between electromagnetism and geometry. This in turn
could drastically change our views on the role of cosmic
magnetism not only only in cosmology but also in astro-
physics. It is the aim of this letter to bring these issues to
light and draw attention to *their potential implications*"
This archive was generated by hypermail 2.1.5 : Sat Nov 02 2002 - 08:08:16 MST