ps418

There is an interesting new article on Physicsweb about the use of geological and astrophysical data to reconstruct changes in physical "constants" during the history of the universe. Its an interesting article, especially the explanation of quasar absorption spectra as a tool for "paleophysics."

Are the laws of nature changing with time?

In particular, the article discusses evidence for changes in the fine-structure constant:

First, geologic data are examined. Both the Oklo reactor phenomenon and the results of rhenium dating allow only very small changes in ¦Á over the past 4.5 billion years:

Next, astrophysical data are discussed, particularly the use of quasar absorption spectra. It is argued on the basis of these spectra that ¦Á may have changed by a very small amount over time:


Patrick

Shadowy Man

Perhaps the group has a more recent paper out, but I checked out the paper entitled "Search for Time Variation of the Fine Structure Constant" (Physical Review Letters 82:884, 1999) by John K. Webb (University of New South Wales), et al.

Their data is essentially consistent with zero change of the fine structure constant out to redshift of 1.6. They even state:

Their upper limit is in the range of delta alpha/alpha = 1--2 x 10^-5.

Sauron

I *knew* it!

The speed of light really has slowed down since Creation!

SULPHUR

A more thorough investigation of the spectra from different areas has led some scientists to believe the speed of light is not consant throught time especially in the more distant areas of the universe.The alpha constant 1/137 dictates what can live as we know it.

Calzaer

I was gonna say, it's a good damn thing that Creationists don't actually give enough of a shit about science to follow it, or they'd start using this one against us.

SULPHUR

Some of webb and associates work does appear in Nature,2002

ps418

There are both new papers and new quasar data. The impression I get from the PhysicsWeb article is that while the data for change is stronger than it was 1999, it is still somewhat inconclusive. At any rate, any change of of the FSC, if it exists at all, is constrained by observational data to be very small indeed. To me this is interesting in that it refutes empirically the notion that 'constants' have changed in some dramatic way over recent time.

Here are the papers cited by the PhysicsWeb article. The last one is written by the same group that wrote the PRL paper you cite above.

Does the fine-structure constant vary with cosmological epoch?

Fine-structure constant variability: surprises for laboratory atomic spectroscopy and cosmological evolution of quasar spectra

WMAP Constraints on varying $\alpha$ and the Promise of Reionization

A Search for Variations of Fundamental Constants using Atomic Fountain Clocks

Does the fine structure constant vary? A detailed investigation into systematic effects

Constraints on the Variations of the Fundamental Couplings

The fundamental constants and their variation: observational status and theoretical motivations

Does the fine structure constant vary? A third quasar absorption sample consistent with varying alpha

SULPHUR

The earlier work by Webb and others was not a definite statement on the variation of the speed of light and was always open to further investigation. From the information given seems still to be fully investigated.