A second “Earth”?
This exoplanet – as astronomers call planets around a star other than the Sun – is the smallest ever found up to now and it completes a full orbit in 13 days. It is 14 times closer to its star than the Earth is from the Sun. However, given that its host star, the red dwarf Gliese 581, is smaller and colder than the Sun – and thus less luminous – the planet nevertheless lies in the habitable zone, the region around a star where water could be liquid! The planet’s name is Gliese 581 c.