Astronomers have discovered the lightest exoplanet ever, it's situated in the constellation Libra and orbits star Gliese 581. Three planets were previously detected around this star, but those were far more massive than our own planet. The new planet is named Gliese 581 e and has just 1.9 Earth masses.
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 3.6m telescope at La Silla, Chile.
"This is by far the smallest planet that's ever been detected," said group member Michel Mayor, from the Geneva Observatory, Switzerland.
"This is just one more step in the search for the twin of the Earth.