The find, announced Thursday, excited planet hunters who have been scouring the Milky Way galaxy for years for potentially habitable places outside our solar system.
"This is the best case for a habitable planet yet found. The results are absolutely rock solid," University of California, Berkeley astronomer Geoff Marcy, who had no role in the discovery, said in an email.
The planet was detected by NASA's orbiting Kepler telescope, which examines the heavens for subtle changes in brightness that indicate an orbiting planet is crossing in front of a star. From those changes, scientists can calculate a planet's size and make certain inferences about its makeup.