Kepler telescope spots Earth-like planet

This artist's concept released April 17, 2014, by NASA/JPL-CALTECH depicts Kepler186f, the first validated Earth-size planet to orbit a distant star in the habitable zone. An international team of researchers has confirmed the existence of the first Earth-sized planet within the "habitable" zone of a star. AFP PHOTO HANDOUT-NASA/JPL-CALTECH/ T. PYLE

What you need to know:

  • The planet was spotted by the Kepler telescope, which has found nearly 1,000 new worlds since its launch in 2009.
  • Kepler 186f travels around a small and cool star, and its orbit is furthest out and lasts about 130 days.

San Franscisco, Friday

The most Earth-like planet yet has been discovered, scientists report in the journal Science.

The rocky planet, Kepler 186f, is close to the size of Earth and has the potential to hold liquid water, which is critical for life, the team says.

Nestled in the Milky Way, it is part of a five-planet system that orbits around a cool dwarf star.

It was spotted by the Kepler telescope, which has found nearly 1,000 new worlds since its launch in 2009.

“This is the smallest planet we’ve found so far in the habitable zone. The kind of star it does orbit - which is a very small star - are amongst the most common in the galaxy,” said Prof Stephen Kane, an astrophysicist from San Francisco State University, in the United States.

500 LIGHT YEARS AWAY

Kepler 186f is about 500 light-years away from the Earth.

The researchers estimate that it is a little bigger than our planet, with a radius that is about 10 per cent larger than ours.

Because of its size, the team believes it is a rocky planet.

Prof Kane explained: “There seems to be a transition that occurs at about 1.5 times the Earth’s radius, such that if the planet is larger, then it starts to develop a very substantial atmosphere very similar to what we see in the gas giant planets in our own Solar System. And so anything less than 1.5 is probably more like a rocky planet that we are familiar with.”

Kepler 186f travels around a small and cool star. Of the five planets in the system, its orbit is furthest out and lasts about 130 days.

The team believes that it has the potential to hold water because with this orbital path, it does not journey too close to its star for the liquid to boil away or so far out that it would freeze. Scientists call this region the “habitable zone”. (BBC)