Russian billionaire Yuri Milner, best known for early investments in Facebook Inc. and Twitter Inc., has announced plans to spend $100 million hunting for alien civilizations.

Speaking in London on Monday, alongside cosmologist Stephen Hawking, Milner said the “Breakthrough Listen” project would be the biggest scientific search so far for signs of intelligent life beyond Earth.

Milner, 53, made his billions by betting on Internet companies -- including Alibaba Group Holding Ltd. -- but has an interest in astronomy going back to childhood.

Run by a team of researchers at the University of California, Berkeley, the project will span 10 years and will have extensive access to two of the worlds’ most powerful telescopes: the Green Bank telescope in West Virginia, and the Parkes Telescope in New South Wales, Australia.

“We’re committed to bringing the Silicon Valley approach to the search for intelligent life in the universe,” Milner said in a statement. “Our approach to data will be open and taking advantage of the problem-solving power of social networks.”

The project will include a survey of the million stars closest to Earth, covering 10 times more of the sky than previous programs. It will be led by scientists including Martin Rees, the British Astronomer Royal, and Frank Drake, professor emeritus of astronomy and astrophysics at the University of California.

Milner also unveiled a second initiative, Breakthrough Message, which pledges $1 million in prize money to those who can successfully create digital messages to send into the universe that represent humanity and planet Earth.