It's been quite a year, with many wondering if 2016 was simply the worst year ever. Cambridge University professor and physicist Stephen Hawking, however, sees a much darker future ahead. "Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or ten thousand years," Hawking, who is 73 and has been living with amyotrophic lateral sclerosis (ALS) for more than half a decade, told BBC News in January. "By that time, we should have spread out in space, and to other stars, so a disaster on Earth would not mean the end of the human race." But, he added, until humanity can live somewhere other than this planet, we're walking on eggshells: "We will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period."

When viewed on a cosmic scale, humanity lives on a tiny grain of sand floating in an unimaginably-deep ocean. Huge expanses of space separate even the closest stars, ensuring that, should any sufficiently intelligent life form want to spread across the galaxy, it would take a momentous effort to launch across the interstellar seas. As we look toward the stars, hoping that we may visit them some day, many would argue that interstellar travel is impossible. After all, the nearest-known star system is over 4 light-years away. Let's think about that for a moment: It takes light 8 minutes and 20 seconds to travel from the sun's surface to our planet's atmosphere.

A new research initiative could provide the building blocks for a program that would send robots trillions of miles into space to better understand our neighboring star system. Billionaire investor Yuri Milner announced the Breakthrough Starshot project, the latest in Mr. Milner's Breakthrough Initiatives started in 2015. Breakthrough Starshot aims to send data-seeking nanocraft to Alpha Centauri, the nearest star system to the solar system, using laser propulsion. While the Breakthrough board of Milner, physicist Stephen Hawking, and entrepreneur Mark Zuckerberg just announced Starshot on Tuesday, they say it may not launch for 20 years, conservatively – and wouldn't reach Alpha Centauri for another 20 after that, despite traveling at one-fifth the speed of light. "We came to the conclusion it can be done: interstellar travel," Milner told The New York Times.