Scientists Call for a Conservative Approach in Looking for Earth-like Planets

A study published this week in the Proceedings of the National Academy of the Sciences suggests that astronomers, in their quest to find planets that could possibly sustain life, should take a more conservative approach. By that the researchers mean the search for planets with a star's habitable zone should be restricted to those that have liquid water or solid or liquid surfaces, rather than gaseous planets such as Jupiter or Saturn.