Stephen Hawking submitted a final paper days before his death that could lead to the discovery of parallel universes.
Hawking, who died last week at 76, was listed as a co-author on the paper, which lays the framework for how researchers could someday test the "multiverse" theory, or the existence of an infinite number of universes in addition to our own, The Sunday Times reported.
Arxiv.org, an online distribution system for research papers owned by Cornell University, shows the paper, titled A Smooth Exit from Eternal Inflation, was first submitted by Hawking's fellow co-author Thomas Hertog in July 2017. The latest version of the paper was submitted on March 4, just days before Hawking's death.