[watsisname]

Big news in the hunt for exo-earths!

Astronomers at the University of California, Santa Cruz may have stumbled upon something rather special. Following 11 years of telescopic observations, the planet hunters claim to have found the most feasibly habitable exoplanet yet discovered.

http://www.wired.co.uk/news/archive/2010-09/30/gliese-581g


Personal take:  This planet is quite a find.  It's the first terrestrial-sized planet discovered orbiting in its star's habitable zone, so this is a very strong indication that it might be habitable.  It was discovered using the radial velocity technique, so unfortunately we only have a lower limit for its mass, which is estimated at 3 to 4 times more massive than the earth.

Also interesting is that it is very probably tidally locked with the star (like the moon is with the earth), meaning it has one side which is perpetually in daylight, while the other side is in perpetual night.  This implies a scorching hot dayside, a frozen cold nightside, and a region in between where the temperature is just right to maintain liquid water and possibly even life.  Would make a great setting for a sci-fi, wouldn't it?

[Deadly in a Shadow]

Huh,so many blue planets, so far far away...

How long is the distance between our earth and this planet?

BTW: I heard often rumors about "habitable-planet-sightings", how many planets like these (or earth of course) exist?

[T-LoW]

"20.5 light-years away from Earth"

Only a few subspace-jumps ahead! Who's with me?

[watsisname]

Yeah, at only 20 light years away, that's practically one of our cosmic neighbors.

BTW: I heard often rumors about "habitable-planet-sightings", how many planets like these (or earth of course) exist?

Short answer:  *shrug*  Probably billions of them, spread through our universe.

Long answer:  Statistical argument using our best data and lower-limit estimations:
1:  Assume 100 billion stars in our galaxy.
2:  Assume 75% of those stars are low mass and are thus stable for billions of years.
2:  Assume 25% of those stars form a planetary system
3:  Assume 5% of those planetary systems have a planet in the habitable zone.
4:  Assume 10% of those planets in the habitable zone have actual habitable characteristics (terrestrial size, solid surface, liquid water, breathable atmosphere, etc)

Then (1x10¹¹)(0.75)(0.25)(0.05)(0.1) = ~93 million habitable planets in our galaxy alone.  

Yes, I just used a modified form of the Drake equation, but it's still a valid statistical argument.

[General Battuta]

Yeah, at only 20 light years away, that's practically one of our cosmic neighbors.

BTW: I heard often rumors about "habitable-planet-sightings", how many planets like these (or earth of course) exist?

Short answer:  *shrug*  Probably billions of them, spread through our universe.

Long answer:  Statistical argument using our best data and lower-limit estimations:
1:  Assume 100 billion stars in our galaxy.
2:  Assume 75% of those stars are low mass and are thus stable for billions of years.
2:  Assume 25% of those stars form a planetary system
3:  Assume 5% of those planetary systems have a planet in the habitable zone.
4:  Assume 10% of those planets in the habitable zone have actual habitable characteristics (terrestrial size, solid surface, liquid water, breathable atmosphere, etc)

Then (1x10¹¹)(0.75)(0.25)(0.05)(0.1) = ~93 million habitable planets in our galaxy alone.  

Yes, I just used a modified form of the Drake equation, but it's still a valid statistical argument.

You forgot the binary percent, which is gonna make things trickier in some cases.

[watsisname]

Binary percent?    Can you explain for me?

[castor]

Binary (and so on) star systems?

[General Battuta]

Yeah, most systems are binary or trinary or more. Now you could consider that to be folded into the 'planet in habitable zone' percent, since binaries can still have habitable orbits.

[Mars]

Binaries are far less likely to have habitable zones for any significant length of time however.

[watsisname]

Oh, durr, multiple-star systems would indeed be another factor to consider.  Location in the galactic disk might be important too -- too much radiation around the core; not as much metals in the outer rim, so forth.

[Mongoose]

You forgot this factor, too.

But seriously, news like this is really really awesome until you realize that we'll never get the chance to visit these places ourselves.  I want a warp drive, dammit!

[Deadly in a Shadow]

Poorly. A Colossus would make many things so easy.

But heh, orbital tourism is under development, that's a start

[NGTM-1R]

Prep the RKV people, we can't risk it.

[Nuke]

we better go invade them.

[FreeSpaceFreak]

we better go invade them.

Not Nuke them??

[Nuke]

invading does not exclude the possibility of nukes. we will nuke their cities until they surrender, then we will put them in death camps.

[Herra Tohtori]

<corporate tycoon>

Nevermind potentially habitable exoplanets.

Gimme potentially exploitable planets, habitable or not and we're talking business.

</corporate tycoon>

[Mongoose]

I hear it has massive unobtanium deposits!

[iamzack]

How are creationists going explain this away? "God made more planets because he knew we'd use this one up and would need a new home. Therefore environmentalists are evil!"

[Scotty]

Being pedantic for a moment, the Bible never said that the Earth was the only habitable planet God made.