- Scientists claim they have broken the ultimate speed
barrier: the speed of light.
- In research carried out in the United States, particle
physicists have shown that light pulses can be accelerated to up to 300
times their normal velocity of 186,000 miles per second.
- The implications, like the speed, are mind-boggling.
On one interpretation it means that light will arrive at its destination
almost before it has started its journey. In effect, it is leaping forward
- Exact details of the findings remain confidential because
they have been submitted to Nature, the international scientific journal,
for review prior to possible publication.
- The work was carried out by Dr Lijun Wang, of the NEC
research institute in Princeton, who transmitted a pulse of light towards
a chamber filled with specially treated caesium gas.
- Before the pulse had fully entered the chamber it had
gone right through it and travelled a further 60ft across the laboratory.
In effect it existed in two places at once, a phenomenon that Wang explains
by saying it travelled 300 times faster than light.
- The research is already causing controversy among physicists.
What bothers them is that if light could travel forward in time it could
carry information. This would breach one of the basic principles in physics
- causality, which says that a cause must come before an effect. It would
also shatter Einstein's theory of relativity since it depends in part on
the speed of light being unbreachable.
- This weekend Wang said he could not give details but
confirmed: "Our light pulses did indeed travel faster than the accepted
speed of light. I hope it will give us a much better understanding of the
nature of light and how it behaves."
- Dr Raymond Chiao, professor of physics at the University
of California at Berkeley, who is familiar with Wang's work, said he was
impressedby the findings. "This is a fascinating experiment,"
- In Italy, another group of physicists has also succeeded
in breaking the light speed barrier. In a newly published paper, physicists
at the Italian National Research Council described how they propagated
microwaves at 25% above normal light speed. The group speculates that it
could be possible to transmit information faster than light.
- Dr Guenter Nimtz, of Cologne University, an expert in
the field, agrees. He believes that information can be sent faster than
light and last week gave a paper describing how it could be done to a conference
in Edinburgh. He believes, however, that this will not breach the principle
of causality because the time taken to interpret the signal would fritter
away all the savings.
- "The most likely application for this is not in
time travel but in speeding up the way signals move through computer circuits,"
- Wang's experiment is the latest and possibly the most
important evidence that the physical world may not operate according to
any of the accepted conventions.
- In the new world that modern science is beginning to
perceive, sub-atomic particles can apparently exist in two places at the
same time - making no distinction between space and time.
- Separate experiments carried out by Chiao illustrate
this. He showed that in certain circumstances photons - the particles of
which light is made - could apparently jump between two points separated
by a barrier in what appears to be zero time. The process, known as tunnelling,
has been used to make some of the most sensitive electron microscopes.
- The implications of Wang's experiments will arouse fierce
debate. Many will question whether his work can be interpreted as proving
that light can exceed its normal speed - suggesting that another mechanism
may be at work.
- Neil Turok, professor of mathematical physics at Cambridge
University, said he awaited the details with interest, but added: "I
doubt this will change our view of the fundamental laws of physics."
- Wang emphasises that his experiments are relevant only
to light and may not apply to other physical entities. But scientists are
beginning to accept that man may eventually exploit some of these characteristics
for inter-stellar space travel.
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