A number of the notable science stories of the past year are, quite literally, out of this world.
For me, the story of the year has to be the August discovery of an Earth-like planet orbiting the closest star to our own. The star, Proxima Centauri, is just 4.2 light-years from Earth. The planet circling that star has been named Proxima Centauri b. Proxima Centauri b was discovered by astronomers working on a project called Pale Red Dot, who reported that the planet lies in the star's habitable zone, meaning that it could possess water and, maybe, life.
It's very exciting but it will be a while before we can confirm any of this. The planet can't be directly observed with current telescope technology and, indeed, it was only first discovered by inference through the gravitational wobble a planet generates on a star.