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Original Date: Sun, 3 Mar 2002 16:17:51 +0100
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Space clocks test 'super theory'
Published 3/2/2002 10:23 AM
WATERVILLE, Maine, March 2 (UPI) -- Experiments performed in space
using lasers and clocks may help scientists forge a unified theory of
everything in the near future.
Scientists hope to use high-speed deep space probes and the
International Space Station to discover mysterious links that can
marry all of the known forces of the universe with a theory that could
prove as deeply profound for society as the unification of electricity
and magnetism did.
"The effort that people put in 150 years ago to combine the two
mysterious forces of electricity and magnetism together ultimately
have led to all the technological breakthroughs we've had with
electricity and computers, with light and lasers," said researcher V.
Alan Kostelecky, a theoretical physicist at Indiana University in
Bloomington. "It's very difficult to foresee what the practical
consequences would be of anything like this, but they are certainly
likely to be substantial in the far future."
The researchers believe experiments conducted in space may prove
sensitive enough to detect minuscule violations of conventional
physics. Scientists believe these scant discrepancies may provide
evidence for new laws of physics that can explain how gravity
interacts with elementary particles, something currently held physics
models are incapable of doing.
"What the space station allows us to do is open a whole new realm of
tests that are either inaccessible or would be very difficult to
conduct down on Earth," said lead researcher Robert Bluhm, a
theoretical physicist at Colby College in Waterville, Maine.
The experiments analyze how clocks tick. Conventional physics is
"symmetrical" -- it says the laws of physics apply the same way for
different observers, regardless of how fast they move or what
direction they go in. The scientists are looking for a violation of
this so-called Lorentz symmetry -- in theory there are exceedingly
tiny changes in ticking rates as one clock rotates relative to another
The experiments require incredibly sensitive clocks -- clocks that use
microwaves and lasers to bounce atoms or electrons around as their
ticker mechanism. Since rotating such clocks is impractical, most
scientists simply let the Earth perform the rotation for them.
"As the Earth rotates, the orientation of the clock changes relative
to the stars," Kostelecky explained in an interview with United Press
Scientists on the ground, however, can only measure eight or nine
factors involving energy and velocity changes tied to symmetry
violation, because the Earth only rotates in one direction. In space,
clocks can rotate in different or varying directions, so researchers
may look at more than 20 additional factors.
Another advantage of space experiments is that the International Space
Station orbits 16 times more quickly than Earth does.
"An experiment like this on ground usually takes months to more than a
year," Kostelecky said. "You can knock that down to weeks or days."
The researchers also hope to help develop a deep space probe named the
Space-Time experiment, which would send a satellite with three clocks
in it out to Jupiter. The probe would then drop back towards the sun
at a maximum velocity of a more than 1 million kilometers per hour --
a thousandth of the speed of light.
"Since these clocks are moving so fast, that allows you to test this
notion that physics is independent of velocity much more exactly,"
said Lute Maleki, principal investigator for the Space-Time experiment
at the Jet Propulsion Laboratory in Pasadena, Calif. "Our job is to
sort of push the edge and see where some of our most cherished beliefs
in physics break down, and every time they break down they point to
different features of the universe we didn't know before. This is very
exciting -- this is what gaining knowledge is all about."
A series of clock experiments for the International Space Station are
already funded and under construction to run several years from now.
The Space-Time mission is currently under consideration at NASA.
The researchers reported their ideas in the journal Physical Review
(Reported by Charles Choi in New York.)
Copyright � 2002 United Press International
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