Astronomers Discover Three Earth-Like Planets

Extrasolar planets are being discovered by the hundreds, but are any of these newfound worlds really like Earth? A planetary system recently discovered by the Kepler spacecraft will help resolve this question. The system of three planets, each just larger than Earth, orbits a nearby star called EPIC 201367065. The three planets are 1.5-2 times the size of Earth, and the outermost planet orbits on the edge of the so-called “habitable zone,” where the temperature may be just right for liquid water, believed necessary to support life, on the planet’s surface. “We’ve learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy,” explains University of Hawaii astronomer Andrew Howard. “We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron.” [...]