Planet hunters say they've identified the first planet orbiting
a distant star with conditions right to sustain liquid water
and, perhaps, life. The planet, Gliese 581g, is about 3 to 4
times the mass of Earth and circles Gliese 581, a red dwarf star
located 20 light years away from Earth in the constellation
Libra. The astronomers say it likely has a rocky surface,
gravity enough to sustain an atmosphere, and lies in a
temperature range in which liquid water could exist. The planet
is no paradise, however. The researchers believe the planet is
tidally locked to the star, with one side always facing the star
and the other in constant night. The side of the planet facing
its star would likely be blazing hot, while the side pointed
away from the star would be freezing cold. Still, with stable
temperatures, the possibility exists that extremophiles of some
sort could survive on the planet's surface. Intriguingly, the
planet was found relatively rapidly, raising the possibility
that such planets might be relative