Authored by Eric Mack via Forbes.com,

In Stephen Hawking's universe there was no room for God, because the famous cosmologist came to believe that the entirety of existence was created out of, well... nothing.

As he explains in his final book, "Brief Answers to the Big Questions," before the Big Bang there was nothing, not even a God to create the universe.

"I think the universe was spontaneously created out of nothing according to the laws of science," Hawking writes. "There is no time for a creator to have existed in."

He goes on to explain that the only God who could be consistent with the laws of physics would be a deity who never directly influences the workings of the universe.

"These laws may or may not have been decreed by God, but he cannot intervene to break the laws or they would not be laws."

While the existence of God makes little sense to Hawking, he's more open to the possibility of something that most people might consider much more far-fetched: time travel.

Hawking famously held a party for time travelers but did not send out the invitations until after the party. No one showed up for the festivities. But the scientist writes that there is still some hope that traveling back in time could be possible according to the laws of the universe. He pegs this notion on the promise of something called "M theory" that suggests the universe may contain seven hidden dimensions in addition to the familiar four dimensions of space-time.

"Rapid space travel and travel back in time can't be ruled out according to our present understanding," he writes. "Science fiction fans need not lose heart: there's hope in M theory."

Hawking was working on the book at the time of his death in March and it was completed with the help of his family and vast personal archives.

The relatively brisk read dedicates a chapter to underscoring the frequent public alarms the physicist sounded about the potential perils of artificial intelligence and another on advancing climate change. He also hits several optimistic notes for the future, predicting that science will find a grand unified theory that unites relativity and quantum physics and that humans will be traveling through the solar system within a century.