From: Mike Lorrey (mlorrey@datamann.com)
Date: Sun Jun 24 2001 - 07:36:44 MDT
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
Magnetism Stiffens Space-Time - by CHARLES SEIFE
Albert Einstein's rubber sheets--his metaphor for thinking of space and
time as a stretchy membrane--may be due for a dose of starch. By
reanalyzing the basic equations of general relativity, a researcher has
discovered that magnetic fields tend to flatten and stiffen the fabric
of space-time.
The finding might force cosmologists and astronomers to reexamine how
magnetic fields have shaped the evolution of the cosmos.
According to Einstein, a hunk of matter such as a star bends space-time
just as a bowling ball weighs down a rubber sheet. The result, described
in relativistic terms, is gravity. That much has been known for the
better part of a century.
But physicist Christos Tsagas of Portsmouth University in the United
Kingdom looked at the equation in an unusual way, switching the roles of
space and time -- a swap that makes no mathematical difference but
changes the form of the equation.
Tsagas spotted something no one had seen before: A term in the equation
showed that magnetic fields transfer their properties to the very fabric
of space-time itself.
Like rubber bands under tension, magnetic field lines try to remain as
straight as possible. The fields transmit that tension to space-time,
Tsagas writes in the 11 June issue of Physical Review Letters, making
nearby space like a rubber sheet that has been stretched a little bit
tighter.
According to Tsagas, such a region becomes stiffer and flattens out
somewhat.
"The normal assumption is to neglect magnetic fields in the early
universe, mostly for simplicity," says Bernard Carr, a physicist at
Queen Mary's College in London.
But if the finding pans out, cosmologists will have to rethink the role
of magnetic fields in shaping the cosmos. And black hole theorists --
who deal with sharply curved space near strong magnetic fields -- might
need to revise some pet notions as well. Astrophysicists in general,
it's safe to say, could lose a little sleep over stiff sheets.>>
end quote
Question: what does this mean for the possibility of magnetic 'surf
boards' for spacecraft propulsion?
Mike
This archive was generated by hypermail 2.1.5 : Sat Nov 02 2002 - 08:08:16 MST