Who knows? Maybe this discovery will have a part to play in the evolution of a theory of quantum gravity. Whether that happens or not, the universe just keeps getting stranger and stranger....

...and also more interesting.

Fundamental constant swells

... With collaborators in Australia, England and the United States, John Webb of the University of New South Wales in Sydney has looked back in time using a powerful telescope at the Keck Observatory in Hawaii. Analysing the light from distant astrophysical objects called quasars, the team concludes that billions of years ago the fine-structure constant was about 0.001 per cent smaller than it is now.

The fine-structure constant sets the strength of the interaction between light and matter, just as the gravitational constant determines the tug between the Earth and the Moon. If the fine-structure constant had a very different value, stable atoms might not exist; a small difference would alter their properties slightly.

In other words, fundamental constants determine how the universe is put together. Scientists have wondered for decades whether their values were set at the beginning of time, or whether they have shifted slowly as the universe aged. The latter possibility has been highlighted in recent years by theories invoking extra, hidden dimensions to unify gravity with the other fundamental forces of nature.

These unified theories pack away the extra dimensions by curling them up very tightly. If this curling up happened gradually, it would have led to a slow change in the fundamental constants....

In 1999, Webb and others measured 30 quasar spectra, focusing on absorption lines caused by magnesium and iron atoms. The lines seemed to have shifted slightly relative to measurements made in the laboratory, implying a small change in the fine-structure constant2.

It was a provocative and controversial result. This second survey embraces more quasar sources and looks at absorption lines from a range of other elements. It gives the researchers four independent sets of data from which to extract values of the fine-structure constant, as well as increasing the precision of the measurements.

A change of the same order of magnitude persists in all the data, indicating that the 'constant' has indeed increased over time. If confirmed by other measurements, the finding will overturn the idea that the fundamental constants define the canvas on which the universe was painted. The picture and the canvas, it seems, may have evolved together.

References

Webb, J.K et al.Further evidence for cosmological evolution of the fine structure constant. Physical Review Letters, 87, 091301-1, (2001).

Webb, J. K., Flambaum, V. V., Churchill, C. W., Drinkwater, M. J.. & Barrow, J. D.Search for time variation of the fine structure constant. Physical Review Letters, 82, 884 - 887, (1999).

© Nature News Service / Macmillan Magazines Ltd 2001