A new member in a family of planets circling a red dwarf star 20 light-years away has just been found. It's called Gliese 581g, and the 'g' may very well stand for Goldilocks.
Gliese 581g is the first world discovered beyond Earth that's the right size and location for life.
"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say that the chances for life on this planet are 100 percent. I have almost no doubt about it," Steven Vogt, professor of astronomy and astrophysics at University of California Santa Cruz, told Discovery News.
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The discovery caps an 11-year effort to tease out information from instruments on ground-based telescopes that measure minute variations in starlight caused by the gravitational tugs of orbiting planets.
Planet G -- the sixth member in Gliese 581's family -- orbits right in the middle of that system's habitable region, where temperatures would be suitable for liquid water to pool on the planet's surface.
"This is really the first 'Goldilocks' planet, the first planet that is roughly the right size and just at the right distance to have liquid water on the surface," astronomer Paul Butler, with the Carnegie Institution in Washington, D.C., told reporters during a conference call Wednesday.
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"Everything we know about life is that it absolutely requires liquid water," he added. "The planet has to be the right distance from the star so it's not too hot, not too cold... and then it has to have surface gravity so that it can hold on to a substantial atmosphere and allow the water to pool."