Astronomers found a new planet 20 light years away, one that is 3x the size of Earth, and one that can possibly have water, which is real good for life.
Discover Magazine reports:
If you’re too close to a star, it’s too hot to support liquid water. If you’re too far, it freezes. This defines a rough region from the star — the Goldilocks Zone, for obvious reasons — where liquid water can exist on the surface of a planet. This depends on the star, of course, but also on other factors like the planet’s atmosphere; Venus could have liquid water, but its super-thick atmosphere produces a runaway greenhouse effect which has heated it to 460° C (900° F). If Mars had a thick atmosphere, it might support liquid water! So the planet itself matters here too.
Gliese 581g, as the new planet is called, is in the zone where the temperature is just right. And with a mass of just three times that of the Earth, it’s unlikely to be a gas giant.
Due to the nature of science and evidence based experimentation, the scientists that published their discovery warn that more has to be done. This is not conclusive evidence of a habitable planet only 20 light years away.
From the journal article ms_press-1 [PDF]
Finally, it is important to keep in mind that, though all 6 planets presented here are
well-supported by the calculated reduced chi-squared statistics and also by several different
variants of FAP statistics, and the entire 6-planet system is consistent with the combined
data set from both teams, caution is warranted as most of the signals are small. And there
may yet be unknown systematic errors in either or both data sets.
This is the good news, and not only because it is easier to read: (again from Discover Magazine)
But perhaps the most interesting and exciting aspect of all this is what it implies. The Milky Way galaxy is composed of about 200 billion stars, and is 100,000 light years across. The fact that we found a planet that is even anything like the Earth at all orbiting another star only 20 light years away makes meextremely optimistic that earthlike planets are everywhere in our galaxy. 20 light years is practically in our lap compared to the vast size of our galaxy, so statistically speaking, it seems very likely it’s not unique. I don’t want to extrapolate from a data set of two (us and them), but if this is typical, there could be millions of such planets in the galaxy. Millions.
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