G is for Goldilocks - Gliese 581g could be habitable

http://news.discovery.com/space/earth-like-planet-life.html

Damn, it's too bad the solar system is aligned wrong to ever see g transit the star.

If it does turn out to have life, it's going to need a better name than Gliese 581g. Maybe "Gliese IV"

The Gliese 581 name comes from being the 581st star listed in the Gliese Catalogue of Nearby Stars, so if it was going to be renamed it would need a new name entirely.

When we are eventually able to analyse the atmosphere of planets such as this one (although I don't expect it to happen in any of our lifetimes) it will certainly be a very interesting time. Red dwarf stars last a long longer than ours, with Gliese 581 estimated to be between 7 and 11 billion years old. That means Gliese 581g was likely habitable before our solar system even formed.

If Gliese 581g has life, it has had billions of years longer than life on Earth to develop. If it doesn't have life then that has significant implications for how dead the universe at large might be.

This guy makes a lot of pretty big leaps in his argument that the chances for life are "about 100%", but it's an encouraging find.

And if we are finding planets like this only 20 LY away (next to nothing on the cosmic scale), then the odds of more life-bearing, earthlike planets out there in the black really goes beyond certainty, statistically speaking.

...

I would bet almost anything that this is just another dead space rock.

Yeah, everybody already knows the aliens are at Zeta Reticuli.

If this pans out . . . an earthlike planet. Holy moly!

Bailey, if I remember correctly, projections are that we should be able to analyze atmospheres on extrasolar planets within the next 20 or so years.

What we need is a space or moon-based interferometry array. Then we'd be able to scan chemical lines (like oxygen and chlorophyll) from nearby planets.

At three times the size of Earth (dependent on the amount of the planet's mass) we'd find it pretty much unlivable- Nobody is going to be walking around comfy under 2-3 G's.

Well, actually since gravity DECREASES with the square of the size (radius, not mass), a planet 2-3 time larger in diameter might not be so bad at all.

True. The gravitational force is directly proportional to mass but inversely proportional to the square of the radius, so radius will have a big effect. Right now, however, we don't really know either. I guess surface gravity would depend on how dense the planet's mass is.

A habitable (to us) planet 20 LY away would be quite a prize. Some might even call it an incentive.

I'd call it a goal. Or even better - a destination.

Bring it on.

It'll help me work on my hugeness.

Good Lord. We've never seen life anywhere but earth, and this guy is seriously claiming we have to prove there isn't life here? What a pompous ass.

According to Wikipedia (which presumably got the figures out of the original paper) the best estimate is that the mass is 3.1-4.3x Earth, but the radius is 1.3-2x Earth, giving a surface gravity of 1.1-1.7g. You might feel like you're wearing lead weights all the time, but it wouldn't be unlivable, and after a few months you'd probably not notice it.

^^^ But I think you'd still wind up a) in great muscular shape and b) with lower back problems.

So it'd be a "Ribbon world", where the only truly livable surface space would be the ribbon of twilight between the light-side and dark-side...?!

Presumably by the mass, age, and distance. Conservation of angular momentum, and all that.

Not really, you would get some interesting specialization though, as life would undergo 'banding' with the 'day' side dominated by plant analogues and the 'night' side by fungal analogues.

You'd see definite changes as you crossed from one side to another, with even the animal analogues having photosynthetic elements - they can derive energy while resting, radically altering the kind of energy expense you get on Earth as they would need much lower levels of food intake.

Although that would depend on tectonic activity as well, if the crust was static - more like Venus than Earth - then you'd have some long term stability, if it's a bit more mobile like ours than you would get mass extinctions from an inability of some life to adapt to moving from the 'day' side to the 'night' side. The plant life may even have two distinct phases to handle the shift between environments.

Such a planet would definitely throw up some interesting adaptations.

Tidal locking is inevitable due to compression and torque of the not-quite-rigid bodies, it's just a matter of time. Eccentricity determines whether the lock is 1:1 or another ratio (as with Mercury). Given that Gliese 581 is a main sequence red dwarf, it's probable ALL of it's planets are tidally locked. http://en.wikipedia.org/wiki/Tidally_locked

Hello people of Gliese 581g, we're from a government on a planet called Earth, and we're here to help!

We are considering what it would be like on us humans.....but life on 581g planet would have evolved to meet the conditions there. Maybe to them Earth would be unlivable, because we evolved along totally different lines entirely. Considering the diversity of life here, imagine what could have evolved with billions of years of stability. Intelligent life could be leaps and bounds ahead of us!

Or, due to any number of factors (for the terrestrial version, read Guns, Germs, and Steel) there may be 'intelligent' life there that has existed for eons but never progressed beyond the spear-throwing stage.

Every intelligent species needs two things to develop industrial-level technology:

1. Manipulative digits similar in function to our fingers and opposable thumbs.

2. A Newton-equivalent to decipher basic physical laws and break them down mathematically so they can be used in engineering technology.

Take away either of those, and you'll have a pre-19th Century civilization at best, at least technologically speaking.

^Plus intelligence isn't a given, intelligence isn't a target for evolution, it's just one of many strategies.

If it was that much of bonus to life in general, we'd see other species having adopted it to the lengths we have.

I wonder how much oil they have?

Oh, shit they've got WMD!!!!!

Send in the 101st Mobile Infantry!!!

The cool thing is for all we know, the planed was destroyed 15 years ago, after sending their only surviving son in an escape rocket.

Or if we zapped off a message right now it would take 20 years to get to them and another 20 to get a message back.

I can think of a few companies who may have already outsourced their call centres there...

But once they achieve this.....they would progress exponentially.
On a long enough timeline mankind's mastery of engineering really kicked in much later in our 70,000 year (give or take) journey.

So if we landed on 581 today and saw a crude civilization, many generations later who knows what they could accomplish? It could progress much, much faster than on Earth - or slower.

Imagine if all the countries on Earth pooled their ideas and resources from the beginning. We (as a planet) could be on 581 by now!