BEYOND THE SOLAR SYSTEM
These exoplanets might mimic Earth enough to support life of their own
An artist’s concept of Kepler-186f, the first validated Earth-size planet
KEPLER-186F
558 LIGHT YEARS AWAY
The first of Earth’s exoplanet ‘cousins’ was discovered in 2014 in the constellation of Cygnus. Like Earth, this exoplanet has a rocky surface, may have liquid water and an atmosphere. However, the planet lives at the edge of a region of space known as the ‘Goldilocks zone’, meaning it receives just a third of the energy that Earth receives from the Sun, casting doubt over its likelihood of supporting life. There are countless planets in the universe zipping around stars like the eight major planets that orbit the Sun. Some have comparable compositions to the planets in our Solar System. The best chance exoplanets have of supporting life is to orbit within their parent star’s Goldilocks zone, named because its distance from its star is ‘just right’ for life. Earth exists within the habitable zone of the Solar System, where it’s not too hot or too cold for water to remain liquid and its atmosphere stable. The hope is that exoplanets in a similar zone in their own systems could look like Earth and share its life-supporting properties.