The article reports on the move of astronomers to study planets around other stars. Stéphane Udry and his colleagues at the Geneva Observatory announces that they had found a planet in the "habitable zone" of the red dwarf Gliese 581. It states that the only way to find out whether Gliese 581c is larger version of Earth or Neptune, is by observing cross the face of Gliese 581 and working out its radius.