Researchers Discover First Earth-Sized Planets That Could Support Life

Researchers have discovered five Earth-sized planets, two of which are circling a sun-like star at a distance that would allow those planets to support life.

NASA will hold a news briefing at 2 p.m. EDT to discuss the findings. We'll add more information here based on what they say.

The five planets orbit a star called Kepler 62. They were detected by the Kepler spacecraft, launched in 2009 to look for Earth-sized planets near stars like our sun.

The two outermost most planets in the five-planet system, named Kepler-62e and Kepler-62f, are super-Earths. They are 1.61 and 1.41 times the radius of Earth, respectively.

The planets are of great interest because they are the smallest planets detected by the Kepler mission that orbit within the "habitable zone" of a star other than our sun (that planet in our solar system is Earth).

The "habitable zone" is the area in space that is the right distance from the star for a planet to support life. On planets that are too close to their star, liquid water boils away. Those that are too far don't get enough energy from their star to support a climate and atmosphere similar to Earth.

Researchers are cautious about the discovery.

"We do not know if Kepler-62e and -62f have a rocky composition, an atmosphere, or water," they wrote in a paper, published online Thursday, April 18, in ScienceExpress. "Until we get suitable spectra of their atmospheres we cannot determine whether they are in fact habitable."

Kepler-62 e and Kepler 62-f receive 1.2 and .41 times the amount of solar radiation that Earth does from our sun, which is similar to the energy received from the sun by Venus and Mars.