Stephen Hawking had multiple universes on his mind when he died

Stephen Hawking had multiple universes on his mind when he died
From Mashable - March 19, 2018

Before his death on March 14, theoretical physicist Stephen Hawking was deep in thought about the possibility of universes that exist well beyond our ownplaces with completely unknown galaxies, stars, and planets.

While there's no evidence yet of any such parallel universes, also known as a multiverse, Hawking had been working with fellow theorist Thomas Hertog to prove that it's possible to observe the cosmos and find evidence of these mysterious places. Hertog continues to research the deeper questions of the universe at the Institute for Theoretical Physics at the University of Leuven in Belgium.

Their paper, which Hertog says has been sent to a leading journal for formal review, is available online and was last updated by Hawking and Hertog on March 4. It builds upon Hawking's 1983 theory about the Big Bangthe event many scientists believe prompted the beginning of our 13.8 billion-year-old universe.

But this earlier theory did not satisfy Hawking because it was untestable, requiring an experiment that would account for an infinite number of potential universes. So Hawking sought a solution.

"'Lets try to tame the multiverse', he told me a year ago," said Hertog, over email, about Hawking's research plans.

This paper creates a "coherent testable scientific framework," said Hertog, which will guide scientists on their quest to find evidence of other universes, something that currently only exists in the realm of science fiction. Using complex mathematics, Hawking and Hertog assert that future research missionswhether using assets on Earth or in spaceshould be able to pick up evidence of powerful gravitational waves from the Big Bang.

Observatories on Earth have detected gravitational waves from colliding black holes and stars, but not yet from the Big Bang.

According to Hertog, finding evidence of the Big Bang would lend critical support to the idea that other such events created other universesa reality that would momentously alter our understanding of space, and ourselves.

"That constitutes a significant extension of our notion of physical reality," Hertog said.


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