For the first time, NASA has found an Earth-sized planet that could support life as we know it

GlobalPost

We've long suspected it, and now we may have proof.

In a historic first, NASA on Thursday confirmed the existence of an Earth-sized planet that could support life as we know it.

The planet, known as Kepler-186f, sits about 500 million light years away and is orbiting a red dwarf sun at a distance that would allow it to support liquid water, researchers with the SETI Institute and NASA Ames Research Center said in a new study published in the journal Science.

Part of a five-planet solar system, it also likely has a rocky surface much like Earth.

This diagram compares the planets of the inner solar system to Kepler-186, a five-planet system about 500 light years from Earth in the constellation Cygnus. (NASA Ames/SETI Institute/JPL-CalTech Courtesy)

Earth-like planets have been discovered before, but none have met both of the criteria — a rocky, solid surface and the potential for water — that are necessary for life, the study said.

The solar system, first discovered in 2009, is located in the constellation Cygnus.

Kepler-186f is the outermost planet and measures about 1.1 times the size of Earth.

Although it receives just a third of the heat that the Earth does from the sun, scientists hope its larger size would result in a thicker atmosphere that would provide extra insulation.

More than 1,700 confirmed planets have been discovered outside our solar system so far, including 961 by the Kepler Space Telescope, according to NASA.

Who knows what else is out there?

This artist's concept depicts Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zone (Danielle Futselaar Courtesy)

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