English: After more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile, astronomers discovered the lightest exoplanet found so far. The planet, “e”, in the famous system Gliese 581, is only about twice the mass of our Earth. The Gliese 581 planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days, while Gliese 581 e completes its orbit in 3.15 days. This Video News Release is targeted especially at broadcasters for further editing. In order to keep the audio tracks editable, different sound information has been recorded on two separate tracks at optimal volumes as is common standard in professional post production. This video is not meant for on screen viewing — on ESOcasts are better suited for that.