SPACE
NASA identifies 17 planets with possible subsurface oceans
WORDS CONOR FEEHLY
An artist’s illustration of Proxima Centauri b, one of the watery exoplanet candidates
© Getty / E. Dubovtseva
As far as we know, life needs water.
Astronomers and astrobiologists
have naturally focused their efforts on identifying exoplanets that might harbour liquid oceans. Water in its liquid form can exist on a planet’s surface, where direct heat from its host star can keep the substance from freezing, but it can also exist beneath a planet’s surface, where internal sources of heat can sustain flowing subsurface oceans. In a new analysis, NASA has revealed that 17 discovered exoplanets could house subsurface oceans buried below thick sheets of ice. These worlds, much like the icy moons of Jupiter, could therefore be promising places to search for biosignatures, or chemical signs of life. While the exact composition of these worlds remains unclear, estimates of their surface temperatures from previous studies point at them being significantly colder than Earth. They’re also each less dense than Earth, despite being roughly the same size as our planet.