Stephen Hawking submitted his final academic work days before he passed away containing a groundbreaking mathematical explanation that would allow humans to test the existence of other universes.
Thomas Hertog, who co-authored the paper, told Euronews that "A Smooth Exit from Eternal Inflation" sets out a mathematical formula to build a probe that could find evidence for the existence of "multiverses".
Cosmologists define this phenomenon as an ensemble of universes that exist in parallel — this paper provides a way of proving that the Big Bang created a multiverse and that our universe is just one of many.
An improved version of an old model
It is "an improved version of Hawking’s original 'no-boundary' model of the big bang," which he and James Hartle put forward back in 1983, according to Hertog, professor of theoretical physics at KU Leuven University in Belgium.
For many years it had remained unclear what kind of universe came out of the Big Bang but physicists gradually realised that the model described not one but infinitely many universes.
Hawking was not satisfied with this unresolved conundrum: "Let’s try to tame the multiverse," he told Hertog a year ago.
So the pair set out to develop a method to transform the idea of a multiverse into a coherent, testable scientific framework.
"In this paper, we put Stephen's original no-boundary model on a more solid mathematical footing. We find this appears to restrict the multiverse down to a manageable finite set (of universes), thereby enabling the model to be tested."
Some cosmologists have argued against the multiverse on the basis it can’t be tested. However, the new model "shows that observations in our own universe can provide strong evidence for the existence of other universes," according to Hertog.
The universe will eventually go dark
Not only does Hawking's final theory put forward the exciting prospect of finding evidence that other universes exist, it also makes a dark prediction that the universe will eventually go dark as stars burn out of energy.
Fellow researchers have claimed if the work had been released when Hawking was alive it could have won him a Nobel Prize — he was nominated on multiple occasions but never won.
Hawking met with Hertog just two weeks prior to his death to finalise the paper and submit it for publication.
It is currently under review and soon to be published in a leading academic journal.
"Hawking should have been awarded the Nobel Prize long ago."
"In my opinion, Hawking should have been awarded the Nobel Prize long ago," said Hertog, referring to the physicist's famous studies on black holes and relativity, which revolutionised the way we view the universe.
Hawking died aged 76 at his home in Cambridge last week having suffered from a rare form of motor neurone disease since 1964.