Gliese 581 is a red dwarf star. A starship traveling at near the speed of light would only take 20.3 years to get there, which is not that much. Until now, astronomers had discovered five planets around this star. Some of them were too close to it, making them too hot to be habitable. Others were too far and too cold. But now, a sixth planet has been discovered right on the "habitable zone", the fourth in distance from the star: Gliese 581g.
If the discoveries from the planet hunters at University of California Santa Cruz and the Carnegie Institution of Washington are right, Gliese 581g could be habitable.
Gliese 581g has three to four times the mass of Earth, orbiting the star at an zippy 37 days. According to data gathered by the Keck I Telescope HIRES spectrometer, it's a rocky planet with a "solid surface and enough gravity to hold to an atmosphere."
More importantly, according to Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz, not only their "findings offer a very compelling case for a potentially habitable planet" but "the fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common."
In other words, the chances of the Universe being bubbling with life of all kinds and forms just jumped beyond our most optimistic hopes.