Two weeks before his death, Stephen Hawking predicted 'the end of the universe'

• The world-famous physicist, who died last Wednesday aged 76, was a co-author to a mathematical paper in which he sought to prove the so-called "multiverse" theory, according to a report by U.K. newspaper The Sunday Times.
• Hawking's final work — titled "A Smooth Exit From Eternal Inflation" — is being reviewed by a leading scientific journal.
• In it, he predicted how our universe would eventually fade to darkness as the stars run out of energy.

Stephen Hawking completed a theory outlining his prediction for the end of the world just two weeks before his death, it has emerged.

The world-famous physicist, who died last Wednesday aged 76, was a co-author to a mathematical paper in which he sought to prove the so-called "multiverse" theory, according to a report by U.K. newspaper The Sunday Times. This theory imagines the existence of many separate universes other than our own.

Hawking's final work — titled "A Smooth Exit From Eternal Inflation" — is being reviewed by a leading scientific journal. In it, he predicted how our universe would eventually fade to darkness as the stars run out of energy.

Alongside Professor Thomas Hertog of Belgium's KU Leuven University, Hawking also proposed a way in which scientists might be able to find alternate universes by using probes on space ships. This would allow humans to attain a more accurate understanding of our own universe, decipher what else is out there and ultimately realize our place in the cosmos.

"He has often been nominated for the Nobel and should have won it. Now he never can," Hertog told The Sunday Times in an interview published Sunday.

'Intelligent life may be watching'

Hawking, who was perhaps best known for his work on black holes and the theory of relativity, had previously posited the idea that Earth would turn into a giant ball of fire by 2600. Therefore, humans would eventually need to colonize another planet or face extinction, he said.

In 2015, Hawking joined Russian billionaire Yuri Milner to launch a project that aimed to use high-powered computers to listen for aliens. The project, known as Breakthrough Initiatives, supports SETI@home, a scientific experiment based at the University of California, Berkeley. It uses computers to scan the skies to look for life.

"Somewhere in the cosmos, perhaps, intelligent life may be watching these lights of ours aware of what they mean," Hawking said. "Or do our lights wander a lifeless cosmos, unseen beacons announcing that here on our rock, the universe discovered its existence?"

— CNBC's Arjun Kharpal contributed to this report.