Astronomers Just Found A Potentially Habitable Earth-Sized Planet, And It’s Nearby – SlashGear

The traditional view of whether a planet counts as habitable is based on the probability water could be present in liquid form on its surface. By seeing how far a planet is from its host star, astronomers can estimate its surface temperature and see whether it is between 0 and 100 degrees Centigrade. This is because liquid water is essential for almost all life as we know it, so we assume it would be needed for an exoplanet to be habitable. Astronomers refer to the area around a star where liquid water could be present as the habitable zone. They typically consider any planet in this zone livable (per The Planetary Society).

However, in practice, this definition is complicated. There can be many factors affecting the surface temperature of a planet, some of which we may not be able to determine from so far away, such as the composition and thickness of the atmosphere. Other factors could make a planet uninhabitable, such as the radiation it receives from its host star. And there could be liquid water on exoplanets outside of this zone due to heat caused by tidal forces.

That’s why even though Earth is the only planet within the habitable zone in our solar system, researchers think that places like Jupiter’s moons Europa, Ganymede, and Enceladus could potentially be livable too (via the European Space Agency).