New Celestial Census: 17 Billion Earth-sized Worlds Out There!
At least one in six stars has an Earth-sized planet – that’s the word from Francois Fressin of the Harvard-Smithsonian Center for Astrophysics (CfA).
Fressin and his colleagues have been sifting through data gleaned by NASA’s Kepler spacecraft. A new analysis of Kepler data shows that about 17 percent of stars have an Earth-sized planet in an orbit closer than Mercury.
Since the Milky Way has about 100 billion stars, there are at least 17 billion Earth-sized worlds out there.
Altogether, the researchers found that 50 percent of stars have a planet of Earth-size or larger in a close orbit. By adding larger planets, which have been detected in wider orbits up to the orbital distance of the Earth, this number reaches 70 percent.
“Earths and super-Earths aren’t picky. We’re finding them in all kinds of neighborhoods,” says co-author Guillermo Torres of the CfA. More good news.
The Kepler spacecraft’s extended mission should allow it to spot Earth-sized planets at greater distances, including Earth-like orbits in the habitable zone.
Fressin presented the analysis today in a press conference at a meeting of the American Astronomical Society in Long Beach, Calif.
By Leonard David