Kepler-186f is more like a cousin than a twin to our Earth.
This week, NASA announced the discovery of an earth-like planet about 500 light-years away from Earth. NASA calls it the Kepler-186f, which is situated in the Kepler-186 system, a dwarf star in the Cygnus constellation.
According to NASA, Kepler-186f is the first Earth-size planet orbiting in a "habitable zone."
In astronomy, the habitable zone is the region around a star in which planets, with the right atmospheric pressure, can support liquid water. The discovery confirms that Earth-like planets exist.
The previous record holder for the most Earth-like planet title went to Kepler-62f, a super-Earth exoplanet in the constellation of Lyra. However, it was 40 percent larger than Earth.
Kepler-186f, on the other hand, is less than 10 percent larger than Earth. But its mass, composition, and density are still unknown.
NASA said that the planet orbits its star - an M dwarf - once every 130 days. Its system is also home to four other planets, namely the Kepler-186b, Kepler-186c, Kepler-186d, and the Kepler-186e. The planets orbit their sun every 4, 7, 13, and 22 days, respectively.
Kepler-186f is the farthest of the four, located near the outer edge of the habitable zone. The brightnes of its star at high noon, NASA said, is as bright as our sun before sunset.
The next step will be to discover the chemical compositions of the planet, which is more like an Earth-cousin than a twin.
"The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth," said Paul Hertz, NASA's Astrophysics Division director at the agency's headquarters in Washington. "Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind's quest to find truly Earth-like worlds."