Hints of 'time before Big Bang'

The inspiration for their theory isn't just an explanation for the Big Bang our Universe experienced 13.7 billion years ago, but lies in an attempt to explain one of the largest mysteries in physics - why time seems to move in one direction. The laws that govern physics on a microscopic scale are completely reversible, and yet, as Professor Carroll commented, "no one gets confused about which is yesterday and which is tomorrow". Physicists have long blamed this one-way movement, known as the "arrow of time" on a physical rule known as the second law of thermodynamics, which insists that systems move over time from order to disorder. This rule is so fundamental to physics that pioneering astronomer Arthur Eddington insisted that "if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation". The second law cannot be escaped, but Professor Carroll pointed out that it depends on a major assumption - that the Universe began its life in an ordered state.

In the meantime, the team have turned to the results from WMAP. Detailed measurements made by the satellite have shown that the fluctuations in the microwave background are about 10% stronger on one side of the sky than those on the other. Sean Carroll conceded that this might just be a coincidence, but pointed out that a natural explanation for this discrepancy would be if it represented a structure inherited from our universe's parent. Meanwhile, Professor Carroll urged cosmologists to broaden their horizons: "We're trained to say there was no time before the Big Bang, when we should say that we don't know whether there was anything - or if there was, what it was." If the Caltech team's work is correct, we may already have the first information about what came before our own Universe.

Date

20080606