The search for'another Earth' has been a staple of science fiction for decades, and now a group of astronomers hope to discover one on our galactic doorstep. Alpha Centauri is a triple star system just over four light years from the Earth, split into a pair of sun-like stars known as AB, and a red dwarf called Proxima Centauri. So far planets have only been found orbiting Proxima Centauri, but experts from the University of Sydney and Breakthrough Initiatives believe they will find a world orbiting the larger binary pair using a new privately funded telescope. Known as the Toliman mission, it will launch in 2023 and scan Alpha Centauri AB for worlds in the habitable zone, where liquid water can flow on the surface. The team hope to be able to say whether there are habitable worlds orbiting either or both of the binary stars by the middle of this decade.

An illustration shows what a visitor might see if they could stand on the surface of the Earth-size planet Proxima b. Just a few months ago, astronomers revealed that there is an Earth-size world orbiting Proxima Centauri, the next star over. Now, a team of astrophysicists thinks there's a way to pay that planet a nice long visit sometime in the not-so-distant future. The method involves something similar to the Breakthrough Starshot Initiative, a plan unveiled last year that would send a fleet of small spacecraft toward the three stars in the Alpha Centauri system, which includes Proxima. Propelled by a giant laser, those tiny spacecraft would zip through the system in a matter of moments, furiously snapping photos, gathering data, and somehow relaying that information back to Earth.

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.