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Science - Reuters - Thursday August 16 6:57 AM ET

Laws of Nature May Change as Universe Ages

``The theoretical implications are potentially enormous if this is right, and it's a big if,'' said University of New South Wales astrophysicist John Webb, who headed the research team.

``But if it's right then the theoretical implications are possibly quite profound,'' Webb told Reuters on Thursday.

The findings by the Australian, U.S. and British researchers may also provide fodder for adherents of new theories, such as super string theory, which postulates that there may be extra dimensions in the cosmos that we know nothing about.

Scientists based their findings on observation of light from a quasar -- an extremely bright object that produces 10 trillion times as much energy per second as our sun -- passing through a cosmic gas cloud.

They first took a spectrum pattern as elements such as magnesium, zinc and hydrogen, which were present in the cloud, absorbed the quasar's light. This was then compared with a spectrum pattern created down on Earth -- and they found small unexplained differences.

Those differences suggested that something, possibly the speed of light, had changed by the time it reached the Earth, trillions upon trillions of miles from the cloud.

GLIMPSE INTO PAST

The experimental results suggesting the laws of nature may not be constant came from observations of the quasar, 14 billion light years away, through Hawaii's 10-meter-wide Keck telescope.

Because they are extremely distant and, assuming that light travels at a finite speed, quasars can provide a glimpse of what happened during the Big Bang in which many believe the universe was formed.

Webb's team measured what is known as the fine structure constant, a concept involving a ratio of three quantities -- the charge on electrons, Planck's constant (a factor used in calculating measurements of energy) and the accepted speed of light.

Webb said they found a very small difference between the spectrum in the quasar and the one back in the laboratory, suggesting that one of the elements that made up the fine structure constant had changed.

``We don't know what is changed, we don't know whether it's the speed of light or the electron charge or Planck's constant,'' Webb said, but he added:

``There are other theoretical reasons for preferring a change in the speed of light.'' He did not elaborate.

The findings do not prove the existence of extra dimensions, which are thought to be subatomic and may determine the forces of nature -- gravity, electromagnetism and the strong and weak nuclear forces.

But theories that the laws of nature may be altered by any change in the size of these tiny extra dimensions, possibly through the expansion of the universe, could explain the observations the team made with the quasar, Webb said.

The findings of the international scientists are due to be published later this month.

Webb said it was early days and scientists would have to make sure the observations were correct before rushing off to invent new physical theories.

The team itself had already begun to go over a far larger amount of data from optical telescopes and preliminary results still showed the same difference.

``In a time scale of maybe two to three years, we would know whether this is right or wrong,'' he said.

``But if it is right, then the impact on fundamental physics is huge and we will need new physics to explain what we've seen.''