’Super-Earths’ likely have oceans and continents

Massive terrestrial planets, called "super-Earths," are known to be common in Earth's galaxy, the Milky Way. Now a Northwestern University astrophysicist and a University of Chicago geophysicist report the odds of these planets having an Earth-like climate are much greater than previously thought. Nicolas B. Cowan and Dorian Abbot's new model challenges the conventional wisdom, which says super-Earths actually would be very unlike Earth—each would be a waterworld, with its surface completely covered in water. They conclude that most tectonically active super-Earths—regardless of mass—store most of their water in the mantle and will have both oceans and exposed continents, enabling a stable climate such as Earth's. Cowan is a postdoctoral fellow at Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics, and Abbot is an assistant professor in geophysical sciences at UChicago. "Are the surfaces of super-Earths totally dry or covered in water?" Cowan said. "We tackled this question by applying known geophysics to astronomy.