Artist Conception of Kepler-22b
Kepler-22b is an extrasolar planet orbiting the star Kepler-22 that may potentially be capable of supporting life.
Description[]
Located 638 light years away from Earth, Kepler-22b is probably the likeliest candidate for a habitable exoplanet. It is located in the habitable zone of its star, the only "Super-Earth" discovered to have this characteristic as of yet.
Its estimated average surface temperature is 295 K (or 22 °C or 71 °F), similar to that of Hawaii (and hotter than Earth's average temperature).
Terraforming it would therefore be easy, perhaps even unnecessary. All it would involve is ensuring a proper atmosphere of oxygen and nitrogen as well as the presence of water, and the addition of life.
The gravity of Kepler-22b is uncertain, but likely to be higher than Earth's gravity, which could pose a problem for settlement. Kepler-22b has 2.4 times the diameter of Earth, which would result in 2.4 times the gravity if its composition is also similar to Earth's.
Controversies[]
In the unlikely scenario of Kepler 22b already being inhabited, ethical issues would arise. If the life is microbial or otherwise primitive, nature reserves could be built to preserve it. If sapient life is found, we could form reservations or attempt to make diplomatic contact.