The planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to our Solar System, is seen in an undated artist's impression released by the European Southern Observatory Aug. 24, 2016. The planet is in the star’s “Goldilocks zone,” where it may not be too hot nor too cold. That means liquid water could exist at the surface, raising the possibility for life. It’s 4.2 light-years, or 25 trillion miles, away from Earth, which is extremely close in cosmic terms. (Photo/Agencies)
