Cosmology: Latest theories of everything (Introduction)

by David Turell , Tuesday, November 02, 2010, 17:00 (5134 days ago) @ David Turell
edited by unknown, Tuesday, November 02, 2010, 17:08

The fine structure constant, also called alpha, may not be constant across the universe!! This does not fit relativity:-http://www.newscientist.com/article/mg20827830.900-constant-change-are-there-no-universal-laws.html?page=1-Only available for two more days. Sorry I'm so late with it.-An excerpt:-Webb, who is at the University of New South Wales (UNSW) in Sydney, Australia, first raised physicists' hackles about a decade ago, when he found some strange results after using the Keck telescope in Hawaii. He had been looking at quasars, which are extremely bright galaxies in the far reaches of the cosmos. As the quasar light passed through clouds of magnesium and iron atoms on its 12-billion-year journey to Earth, some of the light had been absorbed by the metal atoms.-Oddly, though, Webb's analysis said the atoms had taken up the wrong kind of light. The wavelengths of light absorbed by magnesium and iron can be predicted using the equations of quantum electrodynamics, but the ones Webb recorded were different. Twelve billion years ago, it seems, iron and magnesium absorbed photons of different energies than the ones they absorb today.-Webb did have an explanation, though. The observations fitted perfectly if he changed one of the fundamental constants of nature, known as the fine-structure constant, or alpha. This is a central pillar in quantum electrodynamics and dictates, among many other things, which photons certain atoms will absorb.-Today's value of alpha is approximately 1/137. But Webb's work showed that, billions of years ago, it must have been around one part in a million smaller.-Nobody believed the result was right, but neither could they find any flaws in Webb's analysis (Physical Review Letters, vol 82, p 884). The only other explanation was that something peculiar to the Keck telescope was to blame. So Webb turned to the Very Large Telescope (VLT) in Chile, and analysed the quasar light that it picked up.-Webb's PhD student, Julian King, has just completed the analysis. "When I started I quietly hoped we'd find the same thing Keck found," says King. "The worst case would have been no effect; then we would have had to start searching for the flaw at Keck."-King's worries were unfounded. There was an effect: as with the Keck observations, the VLT found a slightly different alpha from the accepted value. But the big surprise was that this time the constant was bigger, not smaller (arxiv.org/abs/1008.3907).