Study Finds Super-Earths Have Long Lasting Oceans

Posted on January 9, 2015

A study from researchers at the Harvard-Smithsonian Center for Astrophysics (CfA) has determined that super-Earths likely have long lasting oceans. By long lasting the astronomers mean these oceans can last for billions of years. An artist's interpretation of one of these oceans is pictured above.

Laura Schaefer of the CfA is the lead author of the study. She says these super-Earth oceans could provide great sailing and surfing. Schaefer says in a statement, "When people consider whether a planet is in the habitable zone, they think about its distance from the star and its temperature. However, they should also think about oceans, and look at super-Earths to find a good sailing or surfing destination."

The researchers note that the oceans on Earth are very thin. Water covers about 70% of the Earth's surface but only about a tenth of the Earth is water. Most of our planet is made of rock and iron. Study co-author Dimitar Sasselov says, "Earth's oceans are a very thin film, like fog on a bathroom mirror."

A process on Earth brings water to the surface through volcanism. This process helps keep our oceans full of water. Schaefer used computer simulations to see if this recycling process would also take place on super-Earths. She also examined how long it would take oceans to form after the planet cooled enough for its crust to solidify. The results indicate that planets two to four times the mass of Earth (super-Earths) are even better at establishing and maintaining oceans than our planet. The researchers found some super-Earth oceans could persist for at least 10 billion years. By comparison it is estimated that the oceans on Earth formed about 3.8 billion years ago. The researchers say the long-lasting oceans make super-Earths a good place to look for life.

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