Has Stephen Hawking changed his tune on extraterrestrials?

Renowned physicist Stephen Hawking has long cautioned that we may not want to meet any extraterrestrial neighbors. However, on Monday, Dr. Hawking threw his support behind Russian tycoon Yuri Milner’s $100-million Breakthrough Listen project, which plans to scour space for signs of communication from extraterrestrial life.

That's a very different perspective from that of his previous statements, in which he cautioned that contact with aliens, should they exist, could be disastrous. It seems, however, that curiosity has since gotten the better of him.

"There is no bigger question. It's time to commit to finding the answer – to search for life beyond Earth," Dr. Hawking said Monday at the launch of Breakthrough Listen in London.

Of course listening is very different from speaking. The Breakthrough Listen project does not include any new plans to broadcast signals into space that would invite any extraterrestrials to find us. 

Hawking and Mr. Milner announced their 10-year project will involve scanning for radio signals out in space with some of the world’s largest radio telescopes and listening to signals from star systems near earth and its 100 closest galaxies, as The Christian Science Monitor’s Pete Spotts reported,

The scale of the effort, known as Breakthrough Listen, is unprecedented. Until now, the hunt for signals generated by intelligent life elsewhere in the universe has operated on a shoestring and, at least early on, was widely seen as quixotic.

But evidence on Earth that simple forms of life can thrive in environments hostile to humans, as well as the discovery of thousands of planets orbiting other stars, has added energy to the effort. The discovery of these extrasolar planets has led to estimates that the Milky Way alone holds billions of Earth-mass planets orbiting within their host star's habitable zone – a distance at which liquid water, essential for organic life, can persist on a planet's surface.”

Hawking said it was likely that some form of simple life existed on other planets, but continued to urge caution about what finding intelligent life could mean.

"A civilization reading one of our messages could be billions of years ahead. If so, they will be vastly more powerful and may not see us as any more valuable than we see bacteria," he said.

In a 2010 Discovery Channel documentary, Hawkins put it more plainly: "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans."

On a more hopeful note, Milner conjectured that civilizations more advanced than us could teach us something about allocating natural resources. And even if 10 years and $100 million leads to the potentially disappointing discovery that there is no such thing as aliens, Milner said the information will be invaluable for our conception of life on Earth.

"If we're alone, we need to cherish what we have," he said. "The message is, the universe has no backup."