One of the holy grails of modern astrophysics is to find a planet orbiting another star that can support life on it. There are all sorts of missions dedicated to searching for habitable worlds.
But with one star system, Gliese 581, we may have hit the jackpot. To look at Gliese 581 in the sky, it doesn't look like much.
It's a red dwarf star, and a much smaller star than our own Sun. It weighs in at only about 30% of the mass and size of our Sun, and it's estimated to be twice as old. But at only 20 light-years from us, it's pretty close, for another star.
So what makes it so important?
It's got at least four planets in its Solar System, including a new record holder: Gliese 581 e -- whose discovery was announced today -- weighs in at less than twice the mass of Earth!
Now, this planet that we found is very close in, just 3% of the distance to its star that the Earth is from the Sun, which makes it like an extreme version of Mercury.
But, planet Gliese 581 d looks like it is habitable, and rocky, just like Earth is. It's at the right distance from its star to get the right temperatures and conditions for life.
And remember, these four planets that we've found are -- probably -- just the four biggest ones. They are, respectively, 16, 7, 5, and 2 times the mass of Earth; the last three are expected to be rocky planets! Who knows how many lower-mass, Earth-sized planets are there, and where they might be located? I would keep an eye on this system if I were you, because it is the closest, best hope we have right now for life outside of our Solar System!
And with a minimum age of these planets of 7 billion years, you can bet that if life did form there, it's probably awfully interesting by now...
Physical Science
Life Science
Comments
It's getting close.
But when we do find an earth-mass planet in a habitable zone, we won't be able to do much meaningful observation of it, not with what we now have and have planned and funded.
We're really going to need some of those interferometers that they tantalized us with a few years back, then whose plans they shelved.
Glen D
http://tinyurl.com/6mb592
Posted by: Glen Davidson | April 21, 2009 1:33 PM
Well, the planets may be at least 7 million years old, but we don't know at what point in that time life formed (assuming it did). Life could be brand new there... but would that be more or less interesting?
I dare you to think up a plausible form of alien life that isn't awfully interesting. :P
Posted by: RJC | April 21, 2009 1:47 PM
So is the seti project monitoring this part of the sky?
Posted by: locksmyth | April 21, 2009 7:52 PM
Locksmyth,
Seti hasn't found anything yet, but I don't know if they've specifically searched at that particular star exhaustively.
I wonder -- could they have been transmitting and monitoring for signals for billions of years?
Posted by: Ethan Siegel | April 21, 2009 10:10 PM
thank youu
Posted by: D_E_R_M_A_N | April 25, 2009 7:24 AM
Wait! I think my TV has been receiving random parts of the Jackie Gliese Show starring a fat alien worm who yells "No-o-r-ton!" at a skinny grasshopper sidekick!
Posted by: yogi-one | April 25, 2009 11:52 PM