The idea that other universes – as well as our own – lie within “bubbles” of space and time has received a boost. Studies of the low-temperature glow left from the Big Bang suggest that several of these “bubble universes” may have left marks on our own.
This “multiverse” idea is popular in modern physics, but experimental tests have been hard to come by.
Hiranya Peiris, a cosmologist at University College London, and her colleagues have now worked out that when these universes are created adjacent to our own, they may leave a characteristic pattern in the CMB.
Dr Peiris’ team first proposed these disc-shaped signatures in the CMB in a paper published in Physical Review Letters, and the new work fleshes out the idea, putting numbers to how many bubble universes we may be able to see now. Crucially, they used a computer program that looked for these discs automatically – reducing the chance that one of the collaborators would see the expected shape in the data when it was not in fact there.
The program found four particular areas that look likely to be signatures of the bubble universes – where the bubbles were 10 times more likely than the standard theory to explain the variations that the team saw in the CMB. However, Dr Peiris stressed that the four regions were “not at a high statistical significance” – that more data would be needed to be assured of the existence of the “multiverse”.