The warm smugness that a physicist often feels when he/she says that a phenomenon or a law is universal’ may be an illusion. If a team of researchers from Swinburne University of Technology is to be believed, then their data shows that the laws of physics might actually vary throughout the Universe. They have measured the value of the fine-structure constant, a fundamental dimensionless parameter occurring frequently in Quantum Electrodynamics, and have found that this varies throughout the Universe.
What is the Fine-Structure Constant?
The fine-structure constant, commonly called alpha’, is exactly 1/137 in its value. The constant manifests itself in the expansion parameter as one tries to expand in the theory of Quantum Electrodynamics, the physics explaining electrons, light and their interaction. The constancy of the value of alpha is crucial in establishing the universal strength of the electromagnetic force. It would mean that the strength of coupling (or interactions) between the photons (particles of light) and electrons varies throughout the Universe.
The Research Team
A team of researchers comprising Professor John Webb, Professor Victor Flambaum and colleagues, all from University of South Wales (UNSW), Swinburne University of Technology and the University of Cambridge, had already got a hint of the supposed deviation from the accepted value of alpha as early as a decade ago. While they had used the Keck telescope in Hawaii to obtain all their data then, they’ve used the Very Large Telescope (VLT) in Chile this time. They’ve more than double their number of data points and it seems to support what they had initially thought. The confidence level has grown to a respectable 3 sigma. Professor Webb shares his excitement:
In one direction – from our location in the Universe – alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger.
What Are The Consequences?
It is always the habit of scientists to back up initial observations with enough observations to fully confirm the fact. It is, thus, too early to comment what implication this will have on our understanding of the cosmos, As far as we know, the Universe is spatially homogenous (same from all points in space) and isotropic (looks the same in all directions there is no preferred direction) on a large scale (bigger than the length scale of galaxies). This is one of the basic principles of
Einstein’s General Theory of Relativity Cosmology (i.e. application of Einstein’s General Relativity – the modern theory of gravity- on the scale of the Universe). If alpha varies from point to point, then the homogeneity of space is destroyed. We can still have a weaker’ version of the homogeneity condition and General Relativity will still be true, but, having worked so well, we would like the homogeneity principle to be rigidly true. Only further observations, backed up by theory, can tell us more.
A pre-print of the arXiv paper by Webb et al is available here: http://arxiv.org/abs/1008.3907v1
Astrophysicist Sean Carroll says that the value of alpha is probably constant. Here’s an article from him written a year ago: http://blogs.discovermagazine.com/cosmicvariance/2010/10/18/the-fine-structure-constant-is-probably-constant/