New research rewrites history from the Big Bang onwards, says Roger Highfield for The Telegraph
Every now and again, cosmologists decide that the universe needs a rethink. For example, for the past century, they have likened it to an inflating balloon, decorated with galaxies. Now one theoretical physicist has pricked this textbook idea by coming up with an heretical suggestion – namely, that the universe is not expanding at all.
The idea that the universe is unchanging – a constant backdrop that alters only with our parochial view of the heavens – was long ago consigned to the dustbin, thanks to the work of astronomers such as Edwin Hubble in the 1920s.
Because the frequency or “pitch” of light increases with mass, Prof Wetterich argues that masses could have been lower long ago. If they had been constantly increasing, the colours of old galaxies would look red-shifted – and the degree of red shift would depend on how far away they were from Earth. “None of my colleagues has so far found any fault [with this],” he says.
Although his research has yet to be published in a peer-reviewed publication, Nature reports that the idea that the universe is not expanding at all – or even contracting – is being taken seriously by some experts, such as Dr HongSheng Zhao, a cosmologist at the University of St Andrews who has worked on an alternative theory of gravity.
“I see no fault in [Prof Wetterich’s] mathematical treatment,” he says. “There were rudimentary versions of this idea two decades ago, and I think it is fascinating to explore this alternative representation of the cosmic expansion, where the evolution of the universe is like a piano keyboard played out from low to high pitch.”
Harry Cliff, a physicist working at CERN who is the Science Museum’s fellow of modern science, thinks it striking that a universe where particles are getting heavier could look identical to one where space/time is expanding. “Finding two different ways of thinking about the same problem often leads to new insights,” he says. “String theory, for instance, is full of 'dualities’ like this, which allow theorists to pick whichever view makes their calculations simpler.”