I don’t have time for a post, but man, this is exciting.
Astronomers have discovered an Earth-like planet in the “Goldilocks Zone” of its solar system. Gliese 581g is the sixth planet of the Gliese 581 system discovered to date, and the most promising of them all (others have received media attention for their size/composition, or location, but until now none have been squarely in the middle of the habitable zone).
More info from Science magazine; the paper itself will be in the next Astrophysical Journal.
In my opinion, Steve Vogt is getting carried away, misquoted, or just trying to make a name for himself with that “100% chance” soundbite; I haven’t heard anybody claim that the *only* prerequisite for life is a water-friendly temperature, and (although I’m no xenobiologist) the fact that 581g is a ribbon world doesn’t inspire confidence.
Still, this is the best shot at finding extraterrestrial life we’ve ever had. In the words of a friend-of-a-friend: “This is the coolest f***ing time to be alive.”
[EDIT] The fact that Gliese 581g is tidally locked is probably a good sign, as Vogt explains in the Space.com article. This provides more of a range of temperatures, from the blazingly-hot side facing the star to the frozen dark side. In between, there must therefore exist a fairly wide zone of Earthlike “Goldilocks” temperatures. A planet that rotates with respect to its sun has a much narrower range of temperatures, lowering the odds (although there is variation from the poles to the equator, of course!)
By the way, Space.com needs to work on their fact-checking. Mercury isn’t tide-locked, as scientists have known for decades [NASA].