Hawking has repeatedly warned that advanced alien civilizations could wipe out the human race, suggesting that rather than searching relentlessly for alien life, we do everything possible to avoid contact. But speaking at the initiatives' media launch at the Royal Society in London, the scientist confessed that his desire to know whether we are really alone in the universe was too strong to hold back even under such threat.
"I am here today because I believe the Breakthrough initiatives are incredibly important," the professor told reporters. "We are alive. We are intelligent. We must know."
Since even the largest extant investigative groups, like the Center for SETI (Search for Extraterrestrial Intelligence), receive no governmental investment, Hawking and Russian tycoon Yuri Milner started their own project.
The initiatives are twofold: Breakthrough Message and Breakthrough Listen. While the first will attempt to transmit signals from Earth to space, the latter endeavour is aimed at searching for any possible evidence of the existence of intelligent alien beings.
While many scientists share Hawking's fears of the aggressive alien invasion that might follow humans' success in catching the attention of outer space civilizations, some were optimistic nonetheless.
"We may get to a period in our future where we outgrow our evolutionary baggage and evolve to become less violent and shortsighted," said Ann Druyan, co-founder and CEO of Cosmos Studios. "My hope is that extraterrestrial civilizations are not only more technologically proficient than we are but more aware of the rarity and preciousness of life in the cosmos."
Astrophysicist Martin Rees added that an advanced civilization "may know we're here already."
Breakthrough Message will include an international grant contest to determine the content of digital messages to alien creatures, whose appearance and disposition can't even be predicted yet.
"A civilization reading one of our messages could be billions of years ahead of us," Hawking said, stressing his cautious stance. "If so, they will be vastly more powerful, and may not see us as any more valuable than we see bacteria."
Breakthrough Listen is a ten-year program that will search for alien communications in radio and laser transmissions. To accomplish its mission, the initiative will inspect 1 million stars closest to Earth in the Milky Way and listen for messages from the 100 closest galaxies.