Large rocky planets excel at ocean building
Super-Earths are better at keeping water flowing on their surfaces
![Deep oceans on rocky planets, illustration](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/01/cc_alien-waterworld-hires.jpg?fit=860%2C460&ssl=1)
WATER WORLDS Deep oceans on rocky planets a few times as massive as Earth, as seen in this artist’s illustration, may last for billions of years and provide stable environments for alien life.
David A. Aguilar/CfA