British scientists are looking for signs that we live in a multiverse - with multiple alternative universes existing in their own individual bubbles.
They're searching for disk-like patterns in the cosmic microwave background (CMB) radiation - heat radiation left over from the Big Bang – which could provide evidence of collisions between other universes and our own.
"The work represents an opportunity to test a theory that is truly mind-blowing: that we exist within a vast multiverse, where other universes are constantly popping into existence," says UCL PhD student Stephen Feeney.
In these other universes, the fundamental constants, and thus even the basic laws of nature, could be different from our own.
Until now, there's been no efficient way of searching for signs of collisions, as they could show up anywhere in the sky. And the physicists would also need to be able to test whether any patterns they detected were the result of collisions, or just random noise.
But cosmologists at University College London, Imperial College London and the Perimeter Institute for Theoretical Physics reckon they may have an answer.
They ran simulations of what the sky would look like with and without cosmic collisions and developed a new algorithm to determine which fits better with the wealth of CMB data from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP). It imposes very strict rules on whether the data fits a pattern or whether the pattern is down to chance.
"It's all too easy to over-interpret interesting patterns in random data (like the 'face on Mars' that, when viewed more closely, turned out to just a normal mountain), so we took great care to assess how likely it was that the possible bubble collision signatures we found could have arisen by chance," says Imperial's Dr Daniel Mortlock.
The first results are ambiguous, unfortunately, and can't prove or disproce the existence of the multiverse either way. But, says the team, new data currently coming in from the European Space Agency’s Planck satellite should help solve the puzzle.