Posted by Steve Reuland on April 24, 2007 05:58 PM

Are you getting bored with Earth? Maybe you should consider a move to 581 c:

For the first time astronomers have discovered a planet outside our solar system that is potentially habitable, with Earth-like temperatures, a find researchers described Tuesday as a big step in the search for “life in the universe.”

The planet is just the right size, might have water in liquid form, and in galactic terms is relatively nearby at 120 trillion miles away. But the star it closely orbits, known as a “red dwarf,” is much smaller, dimmer and cooler than our sun.

But don’t pack your bags just yet…

There’s still a lot that is unknown about the new planet, which could be deemed inhospitable to life once more is known about it. And it’s worth noting that scientists’ requirements for habitability count Mars in that category: a size relatively similar to Earth’s with temperatures that would permit liquid water.

Still, it’s a neat find. No word yet if the planet is “designed for discovery”, but presumably anyone living there would have discovered those things that are easy to discover, and will therefore conclude that the planet must be situated just right for discovery. At least if their species has creationists.

Below the fold I’ll add some more excerpts from the article. Or you can just read the whole thing.

What they revealed is a planet circling the red dwarf star, Gliese 581. Red dwarfs are low-energy, tiny stars that give off dim red light and last longer than stars like our sun. Until a few years ago, astronomers didn’t consider these stars as possible hosts of planets that might sustain life.

The discovery of the new planet, named 581 c, is sure to fuel studies of planets circling similar dim stars. About 80 percent of the stars near Earth are red dwarfs.

The new planet is about five times heavier than Earth. Its discoverers aren’t certain if it is rocky like Earth or if its a frozen ice ball with liquid water on the surface. If it is rocky like Earth, which is what the prevailing theory proposes, it has a diameter about 1 1/2 times bigger than our planet. If it is an iceball, as Mayor suggests, it would be even bigger.

Based on theory, 581 c should have an atmosphere, but what’s in that atmosphere is still a mystery and if it’s too thick that could make the planet’s surface temperature too hot, Mayor said.

However, the research team believes the average temperature to be somewhere between 32 and 104 degrees and that set off celebrations among astronomers.

Until now, all 220 planets astronomers have found outside our solar system have had the “Goldilocks problem.” They’ve been too hot, too cold or just plain too big and gaseous, like uninhabitable Jupiter. […]

The new planet seems just right — or at least that’s what scientists think.

Eventually astronomers will rack up discoveries of dozens, maybe even hundreds of planets considered habitable, the astronomers said. But this one — simply called “c” by its discoverers when they talk among themselves — will go down in cosmic history as No. 1.

Besides having the right temperature, the new planet is probably full of liquid water, hypothesizes Stephane Udry, the discovery team’s lead author and another Geneva astronomer. But that is based on theory about how planets form, not on any evidence, he said.