Doubt cast on existence of possibly habitable alien planet

[IDemo]

Astronomers no longer sure about Gliese 581g

Last month, astronomers announced the discovery of the first potentially habitable extrasolar planet. But this week at an International Astronomical Union meeting, doubts were raised about the existence of this exciting new planet said to be orbiting the star Gliese 581.

Called Gliese 581g, the planet was determined to be about three times the mass of Earth, meaning it was a rocky world, not a gas giant like Jupiter.

Rocky extrasolar planets have been found before, but the unique trait about this planet was that it orbited within the red dwarf stars habitable zone, that region of space where temperatures are sufficient for water to remain as a liquid on a planetary surface.

Discovery of planet Gliese 581g
Astrobiologists were thrilled at the news, since liquid water is considered necessary for the origin and evolution of life. In fact, NASA has made it a primary aim to follow the water in the search for life elsewhere in the galaxy.

http://www.msnbc.msn.com/id/39640401/ns/technology_and_science-space/