"Scientists who have been hunting for another Earth beyond our solar system have come across a planet that's remarkably similar to our world."

"It's almost the same size as Earth, and it orbits in its star's "Goldilocks zone" — where temperatures are not too hot, not too cold, and maybe just right for life."

"But a lot about this planet is going to remain a mystery, because it's 500 light-years away."

"Researchers detected the planet while poring over data collected by NASA's Kepler Space Telescope. The telescope spent years staring at 150,000 stars, watching for telltale dips in brightness that might mean a planet was circling around a star."