Hawking is backing Breakthrough Starshot, a venture to reach this system within two decades using a tiny aircraft that could travel at the speed of light. "It could bring great disruption to our economy", Hawking said, adding that creators of AI need to "employ best practice and effective management" before it's too late.
"The rise of AI could be the worst or the best thing that has happened for humanity", Hawking said via video link at the opening night of the summit on Monday.
The idea of a "killer AI", or artificially intelligent machines enslaving mankind is one that has been used and abused by Hollywood for decades.
"We cannot know if we will be infinitely helped by AI or ignored by it and sidelined, or conceivably destroyed by it", he said.
Then last November, he gave us about 1,000 years to leave Earth. "Perhaps we should all stop for a moment and focus not only on making our AI better and more successful, but also on the benefit of humanity".
In May, he decided that 1,000 was a bit generous and reduced it to just 100 years. However, Hawking said humans just don't know yet what the outcome of AI will be.
"I believe we have reached the point of no return".
"Unless we learn how to prepare for, and avoid, the potential risks, AI could be the worst event in the history of our civilisation".
In what has become a bit of a morbid running joke, physicist Stephen Hawking has returned to his new favourite pastime: doomsday predictions.
Stephen Hawking is the most renowned cosmologist, English theoretical physicist and Research Director at the Theoretical Cosmology Centre of the University of Cambridge. We stand on the threshold of a brave new world.
The scientist highlighted some of the legislative work being carried out in Europe, particularly proposals put forward by lawmakers earlier this year to establish new rules around AI and robotics.
Hawking expects AI to transform every part of our lives, with the potential to undo damage done to the Earth and cure diseases. Have we abandoned our planet and colonized far away planets and remote solar systems?
"The so-called control problem that Elon is worried about isn't something that people should feel is imminent", said Gates.
The address set the scene for three days of talks between high profile tech, business and government leaders grappling with ethical implications of everything from self-driving cars to sex dolls. And he joins a chorus of other major voices in science and technology to speak about their concerns.