Stephen Hawking launches biggest-ever search for alien life

British cosmologist Stephen Hawking on Monday launched the biggest-ever search for intelligent life in the universe in a 10-year, $100-million (143-million-euro) project to scan the heavens.

The Breakthrough Listen project, backed by Russian Silicon Valley entrepreneur Yuri Milner, will be the most powerful, comprehensive and intensive scientific search ever undertaken for signs of extra-terrestrial intelligent life.

"In an infinite universe, there must be other occurrences of life. Somewhere in the cosmos, perhaps, intelligent life may be watching," Hawking said at the launch event at the Royal Society science academy in London.

"Either way, there is no bigger question. It's time to commit to finding the answer, to search for life beyond Earth. We must know."

The project will use some of the biggest telescopes on Earth, searching far deeper into the universe than before for radio spectrum and laser signals.

The initiative is allied with the Breakthrough Message project, an international competition to create digital messages that represent humanity.

There is no commitment to send any messages into space, and the project should spark discussion about whether humans should be sending messages at all out into the void.