Physicist Stephen Hawking baffled by Donald Trump's rise

Renowned theoretical physicist Stephen Hawking may have a good grasp of the workings of the universe, but he says he can't understand Donald Trump's popularity.

Hawking tells ITV's "Good Morning Britain" show Tuesday that he has no explanation for the success of the presumptive Republican Party presidential nominee.

"He is a demagogue who seems to appeal to the lowest common denominator," Hawking said.

Hawking, who speaks through a computer system operated with his cheek, also made a plea for British voters to choose to remain in the European Union in the June 23 referendum.

He said it is important not only for economic and security research but also to further scientific research.

Hawking says: "Gone are the days we could stand on our own, against the world. We need to be part of a larger group of nations, both for our security, and our trade."

Hawking has a form of amyotrophic lateral sclerosis, known as Lou Gehrig's disease, that has gradually paralyzed him since he was first diagnosed at age 21.