Harvard-Smithsonian Center for Astrophysics: Super-earths have long-lasting oceans
Harvard-Smithsonian Center for Astrophysics: Super-earths have long-lasting oceans
Saturday, January 10, 2015
CAMBRIDGE, MASS.- For life as we know it to develop on other planets, those planets would need liquid water, or oceans. Geologic evidence suggests that Earth’s oceans have existed for nearly the entire history of our world. But would that be true of other planets, particularly super-Earths? New research suggests the answer is yes and that oceans on super-Earths, once established, can last for billions of years.
“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,” says lead author Laura Schaefer of the Harvard-Smithsonian Center for Astrophysics.
Schaefer presented her findings today in a press conference at a meeting of the American Astronomical Society.
Even though water covers 70 percent of Earth’s surface, it makes up a very small fraction of the planet’s overall bulk. Earth is mostly rock and iron; only about a tenth of a percent is water.
“Earth’s oceans are a very thin film, like fog on a bathroom mirror,” explains study co-author Dimitar Sasselov (CfA).
However, Earth’s water isn’t just on the surface. Studies have shown that Earth’s mantle holds several oceans’ worth of water that was dragged underground by plate tectonics and subduction of the ocean seafloor. Earth’s oceans would disappear due to this process, if it weren’t for water returning to the surface via volcanism (mainly at mid-ocean ridges). Earth maintains its oceans through this planet-wide recycling.
More:
http://artdaily.com/news/75630/Harvard-Smithsonian-Center-for-Astrophysics--Super-earths-have-long-lasting-oceans#.VLD9B2ctCbw
