Scientists have found two Earth-sized planets orbiting a star outside the solar system, an encouraging sign for prospects of finding life elsewhere.
The discovery shows that such planets exist and that they can be detected by the Kepler spacecraft, said Francois Fressin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. They’re the smallest planets found so far that orbit a star resembling our sun.
Scientists are seeking Earth-sized planets as potential homes for extraterrestrial life, said Fressin, who reports the new findings in a paper published online Tuesday by the journal Nature. One planet’s diameter is only 3 percent larger than Earth’s, while the other’s diameter is about nine-tenths that of Earth. They appear to be rocky, like our planet.
But they are too hot to contain life as we know it, with calculated temperatures of about 1,400 degrees and 800 degrees Fahrenheit, he said.
Any life found on another plant may not be intelligent; it could be bacteria or mold or some completely unknown form.
Since it was launched in 2009, NASA’s planet-hunting Kepler telescope has found evidence of dozens of possible Earth-sized planets. But Fressin’s report is the first to provide confirmation, said Alan Boss of the Carnegie Institution for Science in Washington. He’s a member of the Kepler science team but not an author of the paper.