Tuesday, October 12, 2010
Recently Discovered Habitable World May Not Exist - ScienceNOW: "But at this week's Astrophysics of Planetary Systems meeting, astronomer Francesco Pepe of the Geneva Observatory and the Swiss group reported that he and his colleagues could find no reliable sign of a fifth planet in Gliese 581's habitable zone. They used only their own observations, but they expanded their published data set from what the U.S. group included in its analysis to a length of 6.5 years and 180 measurements. 'We do not see any evidence for a fifth planet ... as announced by Vogt et al.,' Pepe wrote Science in an e-mail from the meeting. On the other hand, 'we can't prove there is no fifth planet.' No one yet has the required precision in their observations to prove the absence of such a small exoplanet, he notes."