SuperEarths And Life

Harvard astronomy professor Dimitar Sasselov coined the term "SuperEarth" to refer to worlds similar to Earth, but with two to ten times the mass. Now, Sasselov is arguing such worlds might be better able to support life than our own.

He bases his argument principally on increased geologic energy on the more massive planets-- especially more efficient plate tectonics. That's important because tectonic shifts release carbon into the environment, and carbon is essential for life. Sasselov goes on to speculate that most civilizations might, therefore, be found on SuperEarths, and suggests that might explain why Earth hasn't been visited by aliens. Either the aliens haven't developed the technology to allow them to escape the deep gravity well of their home planet, or they see smal worlds like Earth as unikely homes of life.

Not to question a Harvard astronomy professor, but an extremely active planet geologically-- with volcanoes constantly erupting and the surface in a constant state of change-- doesn't seem like a good place for advanced civilization to rise and thrive. Life, perhaps; civilization capable of space travel, maybe not. There is also the matter of that strong gravitational field. Surely such a planet would tend to bring even more comets and asteroids to itself than Earth does, and we know life on Earth could be extinguished under such a bombardment. Increase the number of objects coming in, and the speed with which they hit the surface under the stronger gravity, and sustaining life might be problematical.