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Super-Earth Exoplanets Could Be Better for Life

Dimitar Sasselov, director of Harvard's Origins of Life Initiative, explains how rocky exoplanets larger than Earth could have greater potential for life than Earth did. Steve Mirsky reports

Earth is the only planet we know of that harbors life. But could some exoplanets be even better for life?

“It just happened that in our own solar system, the Earth is the largest rocky planet.” Astronomer Dimitar Sasselov directs the Harvard Origins of Life Initiative and wrote the new book The Life of Super-Earths.

“Now we know that planets which are rocky but bigger than the Earth are plentiful, they’re around other stars in big numbers. And we certainly know that if you’re smaller than the Earth a lot of things go wrong. Your climate is less stable, your atmosphere can go away, like Mars, plate tectonic activity and chemical enrichment goes away as well.

“The Earth is great. But if you’re a little bit bigger than the Earth, all those things are the same or even better—more active, more chemistry, more stability—and nothing is worse. That you have a little bit higher G? That’s not a big deal, especially for the microbes.”

—Steve Mirsky 

[The above text is a transcript of this podcast.]

[Look for the full interview with Dimitar Sasselov on an upcoming edition of the Scientific American Science Talk podcast.]

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