Astronomers have announced Tuesday the discovery of the lightest planet ever detected outside our Solar System.

It is only about twice as massive as the Earth, and is situated in the constellation Libra, BBC reported. Most other planets identified outside our Solar System have been far bigger.

"This is just one more step in the search for the twin of the Earth... At the beginning, we discovered Jupiter-like planets several hundred times the mass of the Earth; and now we have the sensitivity with new instruments to detect very small planets very close to that of the Earth", Michel Mayor, from the Geneva Observatory, Switzerland, said.

The scientists say the planet's orbit takes it far too close to its star Gliese 581 for life to be possible.

The detection was made by an international team of researchers using a 3,6 meters  telescope at La Silla, Chile.