Do aliens exist? Using small spaceships the size of postage stamps, famous physicist Stephen Hawking, Russian billionaire Yuri Milner, and Facebook CEO Mark Zuckerberg plan to find out.
Through their $100-million project named Breakthrough Starshot, the three board members plan to send thousands of light-propelled nanocraft to Alpha Centauri, the closest star system to Earth. Traveling at 20 percent the speed of light, the nanocraft fleet would likely reach Alpha Centauri (which is 4.37 light years away) in the next 20 years.
Equipped with cameras and communication and navigation equipment, the nanocrafts will hopefully answer whether or not habitable planets – and even alien life – exists.
"The probability is low, probably," Dr. Hawking said of the possibility of scientists discovering alien life within the next 20 years. But "the discoveries of the [NASA] Kepler mission suggest that there are billions of habitable planets in our galaxy alone," he said. "There are at least a hundred billion galaxies in the visible universe, so it seems likely that there are others out there."
20 years may seem like a long time to wait for information on habitable areas of Alpha Centauri, but the nanocrafts will use light power to sail through space, traveling far faster than any other conventional spacecraft technology. By comparison, it would take 30,000 years to reach Alpha Centauri on a typical spaceship.
"Using light as a method of propulsion may sound like science fiction, but the concept is rooted in fundamental scientific principles," Anthony Cuthbertson explains in Newsweek. "The theory of relativity states that mass has no mass, however it does have momentum. When light hits a mirror, it therefore exerts a small amount of pressure. If the mirror is light enough, and the light is powerful enough, it will move."
Finding extraterrestrials may excite some space enthusiasts, but Hawking has repeatedly warned against the dangers of alien life.
If aliens were to find humans first, they "would perhaps become nomads, looking to conquer and colonize whatever planets they can reach," Hawking has previously said, arguing that they could take control much like Christopher Columbus and other Europeans took control of the Americas.
Milner and Hawking also warn that the project could take some time: about 20 years to start the mission, then 20 years for the nanocraft fleet to reach Alpha Centauri, and another four years for the information to return home to Earth.
And then there is the cost. Milner, who estimates that the project could cost between $5 and $10 billion, has already invested $100 million of his own money and started looking towards other potential investors.
"The Earth is a wonderful place, but it might not last forever," Hawking said at a Tuesday press conference. "Sooner or later we must look to the stars. Breakthrough Starshot is a very exciting first step on that journey."
"The limit that confronts us now is the great void between us and the stars," he added. "But now we can transcend it, with light beams, light sails, and the lightest spacecraft ever built. Today we commit to this next great leap into the cosmos, because we are human and our nature is to fly."