Astronomers have discovered what they say is the most Earth-like planet yet detected – a distant, rocky world that’s similar in size to our own and exists in the Goldilocks zone where it’s not too hot and not too cold for life.
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.
The planet was detected by NASA’s orbiting Kepler telescope, which studies 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.
The newfound object, dubbed Kepler-186f, circles a red dwarf star 500 light-years from Earth in the constellation Cygnus. A light-year is almost 6 trillion miles.
The planet is about 10 percent larger than Earth and may very well have liquid water – a key ingredient for life – on its surface, scientists said.
The find “is special because we already know that a planet of this size and in the habitable zone is capable of supporting life as we know it,” lead researcher Elisa Quintana of NASA’s Ames Research Center said at a news conference.
The discovery was detailed in Friday’s issue of the journal Science. It was based on observations that were made before the Kepler telescope was crippled by a mechanical failure last year.
Quintana said she considers the planet to be more of an “Earth cousin” than a twin because it circles a star that is smaller and dimmer than our sun. While Earth revolves around the sun in 365 days, this planet completes an orbit of its star every 130 days.
Since its launch in 2009, Kepler has confirmed 961 planets, but only a few dozen are in the habitable zone.
Most are giant gas balls like Jupiter and Saturn, and not ideal places for life.
