Microscopic spaceships powered by Earth-based lasers are being developed to hunt for extra-terrestrial life in Alpha Centauri, the closest star system to ours.
The £70m Breakthrough Starshot concept involves creating a tiny robotic spacecraft, no larger than a mobile phone chip, which would carry cameras, thrusters, a power supply and navigation and communication equipment.
Physicist Stephen Hawking, Facebook founder Mark Zuckerberg and Russian internet billionaire Yuri Milner have all joined the project’s board giving it major backing.
The Alpha Centauri star system is 25 trillion miles (4.37 light years) away, so far that even with today’s fastest spacecraft, it would take about 30,000 years to get there.
But Breakthrough Starshot aims to establish whether a gramme-scale nanocraft that could be pushed faster into space on a tiny light-catching sail can fly over a thousand times faster.
A ‘mothership’ carrying thousands of the nanocraft would be sent into a high-altitude with laser beams focusing on each light sail to give the tiny craft a strong push, theoretically launching them to 20 per cent of the speed of light within minutes.
Once at their destination they would send back images of any planets and scientific data via an on-board laser communications system. The same beam of light that launched them would receive the information - taking over four years to get home.
The project capitalises on exponential advances in certain areas of technology since the beginning of the 21st century.
Announcing the venture at the One World Observatory in New York, Hawking said: "What makes human beings unique? There are many theories.
"Some say it’s language or tools, others say it’s logical reasoning. They obviously haven't met many humans. I believe what makes us unique is transcending our limits.
"Gravity pins us to the ground but I just flew to America. I lost my voice but I can still speak thanks to my voice synthesiser. How do we transcend these limits? With our minds and our machines.
"The limit that confronts us now is the great void between us and the stars, but now we can transcend it.
"With light beams, light sails and the lightest spacecraft ever built we can launch a mission to Alpha Centauri within a generation.
"Today we commit to this next great leap into the cosmos because we are human and our nature is to fly."
Years of research and development stand in the way before the first spacecraft could be launched to other stars.
Project backer Yuri Milner believes the nanocraft could eventually be mass-produced at the cost of an iPhone and launched for less than £700,000.