Hawking's last theory: parallel universes and how to find them
A final theory explaining how mankind might detect parallel universes was completed by Stephen Hawking shortly before he died, it has emerged.
Colleagues have revealed the renowned theoretical physicist's final academic work was to set out the ground-breaking mathematics needed for a spacecraft to find traces of multiple big bangs.
Currently being reviewed by a leading scientific journal, the paper - 'A Smooth Exit from Eternal Inflation' - may turn out to be Hawking's most important scientific legacy.
Fellow researchers have said that if the evidence which the new theory promises had been discovered before Hawking died last week, it may have secured the Nobel Prize that eluded him.
The new paper seeks to resolve an issue thrown up by Hawking's 1983 "no-boundary" theory which described how the universe burst into existence with the Big Bang.
According to that account, the universe instantaneously expanded from a tiny point into a prototype of what we live in today, a process known as inflation.
But the theory also predicted an infinite number of big bangs, each creating their own universe, a 'multiverse' which presented a mathematical paradox because it is seemingly impossible to measure.
Carlos Frenk, professor of cosmology at Durham University, told the 'Sunday Times': "The intriguing idea in Hawking's paper is that [the multiverse] left its imprint on the background radiation permeating our universe and we could measure it with a detector on a spaceship.
"These ideas offer the breathtaking prospect of finding evidence for the existence of other universes."
Professor Thomas Hertog, from KU Leuven University in Belgium, worked with Hawking on the new theory and said he met the Cambridge scientist two weeks ago to discuss its final approval.
"This was Stephen: to boldly go where 'Star Trek' fears to tread," he said. "He has often been nominated for the Nobel and should have won it. Now he never can."
Hawking's final work also has the depressing prediction that the universe will ultimately fade into blackness as stars simply run out of energy.
Hawking died last Wednesday in Cambridge at the age of 76, having suffered from a rare form of motor neurone disease since 1964. That disease left him reliant upon people or technology for virtually every part of his life, including eating, bathing, dressing and even speaking.
To communicate with others, Hawking used a speech synthesiser that allowed him to speak with a computerised voice that had an American accent.
He was perhaps best known for his landmark book 'A Brief History of Time'. Published in 1988, it went on to sell more than 10 million copies.