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NASA’s Kepler space telescope celebrated its 1,000th exoplanet discovery this month, an impressive milestone in the search for life on other

Now astronomers are homing in on those exoplanets that may have liquid water, which is thought to be essential for life. And according to new research, so-called “-Earths” may host vast oceans that last for billions of years. 

A super-Earth is an extrasolar planet whose mass is greater than Earth’s but smaller than that of giants like Neptune and Uranus.

Earth’s mantle holds vast amounts of water, which returns to to the surface through volcanism. Since this “recycling” is crucial for maintaining our planet’s oceans, researchers from the Harvard-Smithsonian For Astronomy (CfA) wondered if a similar might occur on super-Earths.

The researchers used computer simulations on various super-Earths to find out how long it would take oceans to form on them, and whether the oceans could be sustained.

What did they find? Super-Earths between two and four times Earth’s mass seem to be even better than Earth at establishing and maintaining oceans. In , the water on these could last for at least 10 years, the research suggested.

The findings were presented in Seattle on Jan. 8 at the annual meeting of the Astronomical Society.