Kepler-186f: A NASA artist's concept of the first validated Earth-size planet to orbit a distant star in the habitable zone. Photo: Reuters
For decades, astronomers have scanned the sky looking for planets like our own, rocky worlds that orbit a star at just the right distance to harbour liquid water, and possibly, life.
Scientists on Friday announced the discovery of a planet outside our solar system that is, so far, the closest contender for Earth 2.0.
The exoplanet, named Kepler-186f, is roughly the same size as Earth and orbits its star in the habitable zone – the region around a star within which a planet can sustain liquid water on its surface.
The planet was observed using NASA's planet-hunting space telescope Kepler, which has discovered 961 planets orbiting other stars since it began operating in May 2009.