After weeks of rumors and unconfirmed reports, European scientists have officially announced the discovery of an Earth-sized world around the closest star to the Sun, Proxima Centauri. Although the planet theoretically orbits its star in a region where water could exist as a liquid on its surface, no direct information can be gleaned about whether Proxima b has an atmosphere, water, or other characteristics that would increase its habitability. Nonetheless, it is tantalizing to imagine a habitable world so close to home.

The existence of a likely terrestrial world orbiting Proxima Centauri, which is 4.2 light years from the Sun and part of a three-star system that includes two distant members, Alpha Centauri A and B, has been speculated about for some time. That’s because Guillem Anglada-Escudé, an astronomer at the Queen Mary University of London, and colleagues used spectrograph data from the European Southern Observatory in Chile during the 2000s to discern a wobble in the star’s movement.