At one New York City press conference, Yuri Milner held up a postage stamp-sized device. This, he said, was an early version of the StarChip, a miniature space probe that will hunt for signs of extraterrestrial intelligence.

TheStreet notes that Milner, a Russian billionaire and physicist, has invested in many tech startups, being one of the earliest buyers of shares in Facebook, Groupon and Twitter. But his most audacious investment to date has him aiming for the stars - literally.

Breakthrough Starshot is a $100 million initiative that hopes to build extremely lightweight robotic probes that can travel to Alpha Centauri, the star closest to our solar system. It is 4.37 light-years away. The StarChip probes are intended to arrive there after a journey of 20 years.

The idea is for each StarChip to be carried aloft through interstellar space by a lightsail, which looks a lot like a kite. With no wind in space to push the sail, it will be moved using concentrated laser light beamed from the Earth. Propelled in this fashion, the tiny "nanocraft" will supposedly achieve a speed of 100 million miles an hour.

Milner attended the Brainstorm Tech 2016 conference in Aspen, Colorado, where he spoke Tuesday on his reasons for investing in the $100 million nanocraft scheme. Fortune reports that he highlighted his personal need to know - which he thought reflected humanity's need to know - the answer to the mystery of whether we are alone in the universe.

"According to the latest NASA data, there are about 20 billion planets like ours, with water, just in our galaxy... and there are 100 billion other galaxies. It's hard to believe that we're alone," Milner said, adding that there's a good chance that alien civilizations would use technology like ours, therefore generating radio signals that we can detect.

Milner is not alone in his need to know, or his support of the Starshot project. The famous physicist Stephen Hawking is part of the initiative, and so are mathematician Freeman Dyson, former astronaut Mae Jemison and Pete Worden, the recently retired Director of NASA's Ames Research Center.