Prof Stephen Hawking's final research paper suggests that our Universe may be one of many similar to our own.
It also points a way forward for astronomers to find evidence of the existence of parallel universes.
The study was submitted to the Journal of High-Energy Physics 10 days before Prof Hawking died.
In the 1980s, the Cambridge scientist, along with US physicist James Hartle developed a new idea about the beginning of the Universe.
This resolved a difficulty with Einstein's theory that suggested that the Universe began nearly 14 billion years ago but said nothing about how it began.
Instead, the Hartle-Hawking idea used a different theory called quantum mechanics to explain how the Universe arose from nothingness.
Image copyright NASA/SCIENCE PHOTO LIBRARY Image caption Prof Hawking's final paper may help researchers discover evidence of parallel universes. »
