Science

Laws of physics vary throughout universe, study finds

John Webb
Thursday, 9 September, 2010

The laws of physics are different in different parts of the universe, according to new evidence uncovered by a team of Australian and British astrophysicists.

One of the supposed fundamental constants of Nature appears not to be constant after all, the team says in a report of the discovery submitted for publication in the journal Physical Review Letters.

The report describes how the "magic number" known as the fine-structure constant – dubbed alpha for short – appears to vary throughout the universe, says the team from the University of New South Wales, Swinburne University of Technology and the University of Cambridge. The work is currently under peer review (a preliminary version is available here).

“After measuring alpha in around 300 distant galaxies, a consistency emerged: this magic number, which tells us the strength of electromagnetism, is not the same everywhere as it is here on Earth, and seems to vary continuously along a preferred axis through the universe,” says Professor John Webb of the UNSW School of Physics.

“The implications for our current understanding of science are profound. If the laws of physics turn out to be merely “local by-laws”, it might be that whilst our observable part of the universe favours the existence of life and human beings, other far more distant regions may exist where different laws preclude the formation of life, at least as we know it.

“If our results are correct, clearly we shall need new physical theories to satisfactorily describe them.”

The researchers' conclusions are based on new measurements taken with the Very Large Telescope (VLT) in Chile, along with their previous measurements from the world’s largest optical telescopes at the Keck Observatory, in Hawaii.

Co-author Julian King, a UNSW doctoral student, says that after combining the two sets of measurements, the new result "struck" them: "The Keck telescopes and the VLT are in different hemispheres; they look in different directions through the universe. Looking to the north with Keck we see, on average, a smaller alpha in distant galaxies, but when looking south with the VLT we see a larger alpha.

"It varies by only a tiny amount – about one part in 100,000 – over most of the observable universe, but it's possible that much larger variations could occur beyond our observable horizon."

Co-author Dr Michael Murphy, of Swinburne University of Technology, says the discovery will force scientists to rethink their understanding of Nature's laws.

"The fine structure constant, and other fundamental constants, are absolutely central to our current theory of physics. If they really do vary, we'll need a better, deeper theory," Dr Murphy says.

While a "varying constant" would shake our understanding of the world around us, Dr Murphy notes: "Extraordinary claims require extraordinary evidence. What we're finding is extraordinary, no doubt about that.

"It's one of the biggest questions of modern science – are the laws of physics the same everywhere in the universe and throughout its entire history? We're determined to answer this burning question one way or the other."

Other researchers involved in the research are Professor Victor Flambaum and doctoral student Matthew Bainbridge, from UNSW, and Professor Bob Carswell at the University of Cambridge.

Media contacts:

John Webb (UNSW) - jkw@phys.unsw.edu.au

UNSW Faculty of Science media liaison: Bob Beale bbeale@unsw.edu.au 0411 705 435