Physical constants are the cornerstones of physics - sacred numbers that we know about their constancy - but what if some of these constants change?
Physical constants are the cornerstones of physics - sacred numbers that we know about their constancy - but what if some of these constants change? At the Institute of Physics conference "Physics 2005", Dr. Michael Murphy from the University of Cambridge spoke about the "fine structure constant" - one of the critical numbers in the universe that seems to be tuned with great precision for the existence of life - and will suggest that it is not constant after all .
Dr. Murphy used the world's largest optical (visible light) telescope, the Keck telescope on Mauna Kea in Hawaii, to study light from distant quasars. This light moves through the expanses of the universe for billions of years, and seems to show that the constant of the fine structure, which is sometimes called "alpha", changes over time.
The fine structure constant is governed by the electromagnetic force, which holds all atoms and molecules together. Scientists have known for many years that if its value was slightly different, life could not exist. Only the tiny changes over time could be tolerated, and most scientists believe that alpha is the same today as it has always been.
The constant also affects the absorbed fingerprint of atoms, which can be detected when light shines through gas clouds. Murphy used quasars as extremely distant light sources, whose light meets gas clouds on its way to Earth. Light takes time to reach Earth, so Murphy sees the fingerprints as they were billions of years ago. By comparing these fingerprints with those taken in experiments on the DNA, he concludes that alpha has changed by 1/200,000 over the past ten billion years.
Other researchers have published results which have shown that alpha does not change. In any case, Dr. Murphy's work is the most detailed review ever conducted. He says the internal tests in his method, which other research groups have not used, make this study the most authoritative measurement to date.
Murphy is careful not to claim that the matter is closed, saying that no one can say that alpha is changing until another kind of experiment proves it. "We're claiming something extraordinary here," says Murphy, "and the proof, despite its rigor, is not yet extraordinary enough."
Dr. Michael Murphy is a Research Associate at the Institute of Astronomy at the University of Cambridge, and a Research Fellow at Darwin College, Cambridge.
