To date, 1,780 planets have been confirmed to exist beyond our solar system. But how many of these hold the potential to support life? National Geographic have compiled the planets discovered so far into a graph, organizing them by mass and temperature, which are two important limiting factors for the potential to support life. The temperature has to be within a range that can maintain any water present in a liquid state, and the mass needs to be within a range that supports a suitable atmosphere.
Of those 1,780 planets, 16 may have the right conditions to support life. Considering how incredibly vast the universe is it’s certainly likely that many more planets will be discovered over time, but this is a pretty encouraging starting figure. The newly discovered Kepler-186f, the first confirmed Earth-size planet orbiting a star in the habitable zone, was included in the list.
Check out the image below to see the graphic. An interactive version is available on the National Geographic webpage.