X-Message-Number: 22150
From: "John de Rivaz" <>
Subject: Time and Relative Dimensions in Space
Date: Mon, 7 Jul 2003 11:42:04 +0100

[message to CryoNet and bcc to others]

Time and Relative Dimensions in Space is a loose description of a famous
fictional time machine, originally developed for use in a BBC television
Children's programme Dr Who. There are few people on the planet who have not
heard of this series.

When shown for the first in a home for the mentally ill, one patient
proclaimed "I am a Temperature Traveller".

I wonder whether that remark is more profound than its originator realised
or intended.

However, Ronald Mallett, a professor of theoretical physics at Connecticut
University,  proposes a device using lasers to send a particle a few
nanoseconds back in time. If it can be proved possible, then it demonstrates
that time travel is not the domain of lunatics who claim to be able to
travel "in temperature" or any other measurable quantity.

Sometime within the next few years, Mallett hopes his theory will get a
critical test. Perhaps he and a colleague will light up a laser device
designed to twist space. If it works, then he feels confident the resources
to advance the concept will quickly follow. more on
http://www.advance.uconn.edu/01091012.htm

Has anyone read his paper and does anyone think this can actually work?

If it doesn't, does it mean that GR has some serious flaws?

more on http://w4.lns.cornell.edu/spr/2002-04/msg0040840.html

On
http://archive.newscientist.com/secure/article/article.jsp?id=mg17022914.500
if you have s subscription to New Scientist, you can find an article which
includes the following. If you have not done it before, you can get a free 7
days trial to this service from http://www.newscientist.com


Time twister

New Scientist vol 170 issue 2291 - 19 May 2001, page 26

(excerpt that focuses on the actual practicalities and slightly edited for
context)
>>>
"People forget that light, even though it has no mass, causes space to
bend," Mallett says. Light that has been reflected or refracted to follow a
circular path has particularly strange effects. In 2000, Mallett published a
paper describing how a circulating beam of laser light would create a vortex
in space within its circle (Physics Letters A, vol 269, p 214). Then he had
a eureka moment. "I realised that time, as well as space, might be twisted
by circulating light beams," Mallett says.

To twist time into a loop, Mallett worked out that he would have to add a
second light beam, circulating in the opposite direction. Then if you
increase the intensity of the light enough, space and time swap roles:
inside the circulating light beam, time runs round and round, while what to
an outsider looks like time becomes like an ordinary dimension of space. A
person walking along in the right direction could actually be walking
backwards in time-as measured outside the circle. So after walking for a
while, you could leave the circle and meet yourself before you have entered
it .

The energy needed to twist time into a loop is enormous, however. Perhaps
this wouldn't be a practical time machine after all? But when Mallett took
another look at his solutions, he saw that the effect of circulating light
depends on its velocity: the slower the light, the stronger the distortion
in space-time. Though it seems counter-intuitive, light gains inertia as it
is slowed down. "Increasing its inertia increases its energy, and this
increases the effect," Mallett says.

As luck would have it, slowing light down has just become a practical
possibility. Lene Hau of Harvard University has slowed light from the usual
300,000 kilometres per second to just a few metres per second-and even to a
standstill (New Scientist, 27 January 2001, p 4). "Prior to this, I wouldn't
have thought time travel this way was a practical possibility," Mallett
says. "But the slow light opens up a domain we just haven't had before."

To slow light down, Hau uses an ultra-cold bath of atoms known as a
Bose-Einstein condensate. "All you need is to have the light circulate in
one of these media," Mallett says. "It's a technological problem. I'm not
saying it's easy, but we're not talking about exotic technology here; we're
not talking about creating wormholes in space."

Mallett has already caught the interest of his head of department, William
Stwalley,  at Connecticut University, who leads a group of cold-atom
researchers. Their first experiment will be designed only to observe the
twisting of space, by looking for its effect on the spin of a particle
trapped in the light circle. If they can then add a second beam, Mallett
believes evidence of time travel will eventually appear.

<<<

That was in 2001. It is now 2003. Anyone known how they are getting on?

-- 
Sincerely, John de Rivaz:  http://John.deRivaz.com for websites including
Cryonics Europe, Longevity Report, The Venturists, Porthtowan, Alec Harley
Reeves - inventor, Arthur Bowker - potter, de Rivaz genealogy,  Nomad .. and
more

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=22150