Kepler-186f, a planet 500 light years away from Earth has the properties of a planet that could sustain life.

Using the Kepler Space Telescope, astronomers have discovered a planet slightly larger than Earth orbiting a star in what is called the “habitable zone” -- the range of distance from a star where it is just right for the temperature on the surface of the planet to be not too hot and not too cold for life and for reservoirs of liquid water to exist -- NASA announced on April 17.

The alien planet’s identity was determined by an international research team at the SETI Institute and NASA’s Ames Research Center in Mountain View, as well as scientists from many other research institutions, according to the San Francisco Gate.

The research team was led by Elisa V. Quintana, a SETI postdoctoral physicist at the Ames Center, according to NASA.

“We know just one planet where life exists-- Earth. When we search for life outside our planet we focus on finding planets with characteristic that mimic that of Earth,” Quintana said. “Finding a habitable zone planet comparable to Earth in size is a major step forward.”

The San Francisco Gate reported that it has taken the team of scientists four years to insure that Kepler-186f is indeed the most Earth-like exoplanet ever discovered.

“There must be so many small bodies close to stars like this one, and with so many stars in the galaxy, we should be finding more and more,” Quintana told the San Francisco Gate.

According to the New York Daily News, NASA is now focusing on finding Earth-size planets with habitable zones that are close enough to Earth to study their atmospheres.

If scientist start finding planets around stars that are 50 light years away from Earth they could check if the atmosphere is amenable to life, Jason Rowe, research scientist at the SETI Institute and member of the Kepler team at NASA, told the New York Daily News.

NASA said, “The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun.”

Watch a video about the discovery below: