Artistic representations of all known potentially habitable exoplanets (including newly-discovered Kepler-438b, Kepler-440b, Kepler-442b, and Kepler-443b), ranked from best to worst by the Earth Similarity Index - a measure of Earth-likeness based on stellar flux and planet size. Our planet, Mars, Jupiter, and Neptune are shown for scale. Image credit: PHL / UPR Arecibo.
Kepler 438b: Most Earth-like planet ever discovered could be home for alien life
Caption: Kepler-186f is part of five-planet system 795 lights years away. The find is described in the journal Science as ‘a landmark on the road to discovering habitable planets’. Photograph: Nasa Ames/SETI Institute/JPL-Cal/PA