Stephen Hawking and Mark Zuckerberg launch $100m alien-hunting mission with Russian billionaire to send fleet of nano-craft to Alpha Centauri at 20% of the speed of light

The project, dubbed Breakthrough Starshot, will rely on tiny so-called 'nanocraft' flying on sails (shown in the background, right) pushed by beams of light through the universe. When in orbit, the tiny craft would unfold thin sails and then be propelled by powerful laser beams from Earth (top inset). Each of these tiny craft would carry cameras and a built in GPS. 

They will travel to the Alpha Centauri star system 25 trillion miles (4.37 light years) away (bottom inset), where astronomers estimate that there is a reasonable chance of an Earth-like planet existing in the 'habitable zones' of Alpha Centauri's three-star system.