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Off-Topic Discussion => General Discussion => Topic started by: watsisname on September 30, 2010, 10:21:43 am

Title: First potentially habitable exoplanet discovered
Post by: watsisname on September 30, 2010, 10:21:43 am
Big news in the hunt for exo-earths! :)

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


Personal take:  This planet (http://en.wikipedia.org/wiki/Gliese_581_g) is quite a find.  It's the first terrestrial-sized planet discovered orbiting in its star's habitable zone (http://astro.unl.edu/naap/habitablezones/animations/stellarHabitableZone.html), so this is a very strong indication that it might be habitable.  It was discovered using the radial velocity (http://en.wikipedia.org/wiki/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?
Title: Re: First potentially habitable exoplanet discovered
Post by: Deadly in a Shadow on September 30, 2010, 10:24:46 am
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?
Title: Re: First potentially habitable exoplanet discovered
Post by: T-LoW on September 30, 2010, 10:26:52 am
"20.5 light-years away from Earth"

Only a few subspace-jumps ahead! Who's with me? :D
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on September 30, 2010, 10:30:48 am
Yeah, at only 20 light years away, that's practically one of our cosmic neighbors. :D

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.  :eek:

Yes, I just used a modified form of the Drake equation, but it's still a valid statistical argument. ;)
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on September 30, 2010, 10:45:39 am
Yeah, at only 20 light years away, that's practically one of our cosmic neighbors. :D

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.  :eek:

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.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on September 30, 2010, 10:46:23 am
Binary percent?  :confused:  Can you explain for me?
Title: Re: First potentially habitable exoplanet discovered
Post by: castor on September 30, 2010, 01:00:03 pm
Binary (and so on) star systems?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on September 30, 2010, 01:07:47 pm
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.
Title: Re: First potentially habitable exoplanet discovered
Post by: Mars on September 30, 2010, 01:08:43 pm
Binaries are far less likely to have habitable zones for any significant length of time however.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on September 30, 2010, 01:22:05 pm
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.
Title: Re: First potentially habitable exoplanet discovered
Post by: Mongoose on September 30, 2010, 01:26:37 pm
You forgot this factor (http://xkcd.com/384/), too. :p

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! :(
Title: Re: First potentially habitable exoplanet discovered
Post by: Deadly in a Shadow on September 30, 2010, 01:30:23 pm

Poorly. A Colossus would make many things so easy.

But heh, orbital tourism is under development, that's a start :lol:
Title: Re: First potentially habitable exoplanet discovered
Post by: NGTM-1R on September 30, 2010, 01:39:04 pm
Prep the RKV people, we can't risk it.
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on September 30, 2010, 02:40:47 pm
we better go invade them.
Title: Re: First potentially habitable exoplanet discovered
Post by: FreeSpaceFreak on September 30, 2010, 04:25:40 pm
we better go invade them.

Not Nuke them?? :eek:
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on September 30, 2010, 06:06:03 pm
invading does not exclude the possibility of nukes. we will nuke their cities until they surrender, then we will put them in death camps.
Title: Re: First potentially habitable exoplanet discovered
Post by: Herra Tohtori on September 30, 2010, 06:32:36 pm
<corporate tycoon>

Nevermind potentially habitable exoplanets.

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

</corporate tycoon>
Title: Re: First potentially habitable exoplanet discovered
Post by: Mongoose on September 30, 2010, 06:39:16 pm
I hear it has massive unobtanium deposits!
Title: Re: First potentially habitable exoplanet discovered
Post by: iamzack on September 30, 2010, 06:57:18 pm
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!"
Title: Re: First potentially habitable exoplanet discovered
Post by: Scotty on September 30, 2010, 08:06:53 pm
Being pedantic for a moment, the Bible never said that the Earth was the only habitable planet God made. :P
Title: Re: First potentially habitable exoplanet discovered
Post by: NGTM-1R on September 30, 2010, 08:10:44 pm
Yeah, I don't really see why they need to explain it.

Now if there was actually stuff living there, that might be an issue.
Title: Re: First potentially habitable exoplanet discovered
Post by: SpardaSon21 on September 30, 2010, 08:14:17 pm
And going with Scotty's argument, just because the Bible said Man was made in God's image does not mean God could not have gotten inventive with other creations.

//Pedant
Title: Re: First potentially habitable exoplanet discovered
Post by: iamzack on September 30, 2010, 08:25:41 pm
Yeah, I don't really see why they need to explain it.

Now if there was actually stuff living there, that might be an issue.

Typically, they claim that the earth is so perfectly suited to life that it *must* be by design. If there are tons of other habitable planets... **** makes us so special?

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

Seems like kind of a big thing to leave out.
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on September 30, 2010, 08:34:04 pm
omg i'm dumb
Title: Re: First potentially habitable exoplanet discovered
Post by: Scotty on September 30, 2010, 08:36:34 pm
Seems like kind of a big thing to leave out.

Why would it have mattered to anyone living way back when?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on September 30, 2010, 08:36:43 pm
lololololol, cancel
Title: Re: First potentially habitable exoplanet discovered
Post by: Retsof on September 30, 2010, 08:54:51 pm
did someone hack Batt's account?
Title: Re: First potentially habitable exoplanet discovered
Post by: ssmit132 on September 30, 2010, 10:51:16 pm
Or is it idiottuta?
Title: Re: First potentially habitable exoplanet discovered
Post by: iamzack on September 30, 2010, 11:03:12 pm
Seems like kind of a big thing to leave out.

Why would it have mattered to anyone living way back when?

Same reasons it matters to us now?
Title: Re: First potentially habitable exoplanet discovered
Post by: Dilmah G on September 30, 2010, 11:13:22 pm
Guys, bashing a 2000 year old Religious document is just as productive as waving that 2000 year old document around as fact. Do we need to have this discussion here on the exoplanet thread?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on September 30, 2010, 11:17:56 pm
did someone hack Batt's account?

No, I'm just very dumb.
Title: Re: First potentially habitable exoplanet discovered
Post by: NGTM-1R on October 01, 2010, 12:16:36 am
Typically, they claim that the earth is so perfectly suited to life that it *must* be by design. If there are tons of other habitable planets... **** makes us so special?

That's not actually Biblical in any way, shape, or form, as I like to point out to them.

Also, we're still at one of...I think we've breached the 200-exoplanet mark now.
Title: Re: First potentially habitable exoplanet discovered
Post by: Klaustrophobia on October 01, 2010, 12:45:45 am
Z do you HAVE to continually turn completely unrelated subjects into religion bashing?  really.  give it a rest PLEASE.

ontopic:  cool.  i'll have to see if my astrophysics professor has any thoughts. 

those percentages are probably a wee bit generous.  althought the point remains, the sheer number of stars would suggest there are other habitable/inhabited planets SOMEWHERE.  but unfortunately, unless warp drives/stargates ARE possible, two planetary civilizations will probably never meet (in person).
Title: Re: First potentially habitable exoplanet discovered
Post by: karajorma on October 01, 2010, 12:51:25 am
Seriously? We're still talking habitable zones?

For ****'s sake!
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 01, 2010, 04:36:01 am
What's wrong with talking about habitable zones?  Sure, just because a planet is within the "habitable zone" doesn't mean it is actually habitable, nor does a planet being outside that zone make it necessarily uninhabitable.  But the zone does give us a good indication of whether or not the planet is able to sustain liquid water on the surface.

Quote
Also, we're still at one of...I think we've breached the 200-exoplanet mark now.

490 as of this writing. :)  And that's going to go up a lot with the newer Kepler data.

I also finally found the publication for this one. D:  Hurrrng (http://arxiv.org/PS_cache/arxiv/pdf/1009/1009.5733v1.pdf)
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 01, 2010, 05:14:53 am
im skeptical that a tidally locked planet would be habitable. it suggests that it lacks a molten core and thus magnetic field to protect it from the solar wind and cosmic rays. it would also play havok on the planets weather patterns. so i dont think this planet would be majorly habitable.

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!"

environmentalists are evil. we should be exploiting the earth. not protecting it. a harsher planet could only make better people. sooner we get off this rock the sooner we can bring democracy to other aliens (by nuking them). theology doesnt play into this at all (unless we seed the aliens with a fake religion in order to control them)
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 01, 2010, 05:37:24 am
im skeptical that a tidally locked planet would be habitable. it suggests that it lacks a molten core and thus magnetic field to protect it from the solar wind and cosmic rays.


Not at all.  The reason it is tidally locked is because it is close to its star, so the gravitational tidal forces are stronger -- strong enough to lock the rotation in the amount of time that the planet has existed.  It has nothing to do with it having a molten core or not.  The earth would be tidally locked, too, if it were closer to the sun.

Correction:  Sorry, I misread.  The planet would still have a molten core, but it probably wouldn't be rotating quickly enough (this planet rotates once in 37 days) for that core to produce a magnetic field, so you're right.  That said, habitability at this point depends mainly on whether or not this planet has an atmosphere to block the radiation.  Further study would be needed.


Quote
it would also play havok on the planets weather patterns. so i dont think this planet would be majorly habitable.

Nope, sorry.  This subject has been heavily researched.  I'll quote the publication I had just linked to.

Quote
Gliese 581g is likely to have evolved to a spin-synchronous configuration, leading to
one hemisphere of the planet lying in perpetual darkness. Joshi et al. (1997) presented
three-dimensional simulations of the atmospheres of synchronously rotating planets in the
habitable zones of M dwarfs and concluded that such tidally-locked planets can support
atmospheres over a wide range of conditions, and despite constraints involving stellar
activity, are very likely to remain viable candidates for habitability. Joshi (2003) presented
a more sophisticated three-dimensional global atmospheric circulation model that expanded
on the previous work of Joshi et al. (1997) and evaluated the climate of a spin-synchronous
planet orbiting an M dwarf star. The results of that study reinforced the conclusions of
Joshi et al. (1997) that synchronously rotating planets within the circumstellar habitable
zones of M dwarf stars should be habitable.
Title: Re: First potentially habitable exoplanet discovered
Post by: Liberator on October 01, 2010, 06:04:23 am
Umm, doesn't the rotation of the Earth have a good deal to do with the magnetic field that protects us from the more violent of the suns foibles?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 01, 2010, 07:22:36 am
Umm, doesn't the rotation of the Earth have a good deal to do with the magnetic field that protects us from the more violent of the suns foibles?

Nope. It's the rotating core that does that. But then again, I don't know whether you'd still have a rotating core on a tidally locked planet (which still rotates, but just does so in phase with its orbit), so you may ultimately be right.
Title: Re: First potentially habitable exoplanet discovered
Post by: iamzack on October 01, 2010, 07:30:24 am
Wasn't a religion bash, was a creationist bash. I really am very curious about what their explanation is going to be.
Title: Re: First potentially habitable exoplanet discovered
Post by: karajorma on October 01, 2010, 10:16:50 am
What's wrong with talking about habitable zones?  Sure, just because a planet is within the "habitable zone" doesn't mean it is actually habitable, nor does a planet being outside that zone make it necessarily uninhabitable.  But the zone does give us a good indication of whether or not the planet is able to sustain liquid water on the surface.

If you're talking about a planet that is suitable for human colonisation that might be an issue. But when people talk about habitable zones they are usually talking about them possibly having life already on them.

When it comes to the Solar System, apart from Earth we have at least a couple of good candidates for life (Mars and Europa) and a few more outliers (Titan, etc). Notice that of those, none are actually in the habitable zone for Sol. So given that we can already envision there being a good possibility of life on bodies outside of the habitable zone within our own system it always confuses me why the hell people insists that they are a requirement for finding life outside of it. :rolleyes:
Title: Re: First potentially habitable exoplanet discovered
Post by: SypheDMar on October 01, 2010, 10:26:28 am
Because, if you're searching for life outside the Earth, you want to increase your chances as much as you can, so you search in highly probably places instead of less probable and less obvious. You can't, for example, find life on a Titan-like exoplanet easily yet. Even if the same is true for the new exoplanet, it gives us hope.
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 01, 2010, 10:54:48 am
say in a hundred years we come up with a feasible engine technology that can go up to 1/4 the speed of light, but only for a small probe, and assume weve solved the problem of extremely long range communications. that would put the journey to the planet in question into the time frame of about 80 years, and another 20 years for the data to return to earth. say such a probe costs 10 trillion dollars. you want to be damn sure you send this probe to somewhere you think to have a high probability of supporting life. otherwise youd be wasting 10 trillion.

of course by the time such a mission were carried out, there would likely be a very long list of potential candidates, from decades of even centuries of exoplanet detection. your first concern would be range, you would go look at closer planets first. the ones at a distance might be beyond your probe's capabilities, or beyond your sphere of interest (too far for human colonization), and would take longer to receive data from them. then you would look at all the factors that seem good for life. is it in the habitable zone? is the gravity close to earth gravity? does it rotate (rotating planets would have a higher probability than non rotating planets perhaps)? does it have a magnetic field? and so on. youd send the probes to the ones which have the most positive results, and not the iffy star systems. that does not mean that any of those had life, or that anything that seemed unlikely would have plenty. its just you want to look at all your options and pick the best one.
Title: Re: First potentially habitable exoplanet discovered
Post by: Liberator on October 01, 2010, 12:23:05 pm
Wasn't a religion bash, was a creationist bash. I really am very curious about what their explanation is going to be.
So because of the laws of physics, chemistry and biology, you reject the concept that it was all created, at some time in the past, by an all knowing, all powerful, ever present, all merciful God?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 01, 2010, 12:29:07 pm
Wasn't a religion bash, was a creationist bash. I really am very curious about what their explanation is going to be.
So because of the laws of physics, chemistry and biology, you reject the concept that it was all created, at some time in the past, by an all knowing, all powerful, ever present, all merciful God?

I don't think there's any reason to say that's impossible; in fact it's thoroughly possible. It's just not testable or useful, and there's no evidence for it (nor will there ever be evidence for or against it).

And the possibility of the act of creation is independent from the possibility that the creating entity was a single, anthropomorphic, merciful God. Unfortunately it's just as possible that it was all created by a disinterested clockmaker entity or entities, or a malevolent entity that feeds on our suffering, or a geek running a server farm in another universe, or a tooth fairy.

All these scenarios are equally likely, equally untestable, and equally irrelevant to the pursuit of scientific progress and the betterment of the human condition.
Title: Re: First potentially habitable exoplanet discovered
Post by: Bobboau on October 01, 2010, 02:19:11 pm
So because of the laws of physics, chemistry and biology, you reject the concept that it was all created, at some time in the past, by an all knowing, all powerful, ever present, all merciful God?

no she rejects it because it's implausible.
Title: Re: First potentially habitable exoplanet discovered
Post by: redsniper on October 01, 2010, 03:18:21 pm
NO! Stop it now! I do NOT want to see such an exciting thread turned into yet another HLP religion flamewar. This should be about Gliese 581g and how we plan to invade. Do NOT **** this up with the same tired old arguments that never end.
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 01, 2010, 03:19:18 pm
I will usher iamzack and Liberator to a private room if they want to continue their foreplay.
Title: Re: First potentially habitable exoplanet discovered
Post by: SpardaSon21 on October 01, 2010, 03:49:05 pm
This should be about Gliese 581g and how we plan to invade.
We should nuke the major population centers from orbit, then deploy a magic anti-radiation nano-swarm and force the remaining inhabitants to bow before the benevolent rule of the Terran Empire with our elite power-armored infantry Heinlein would be jealous of.
Title: Re: First potentially habitable exoplanet discovered
Post by: NGTM-1R on October 01, 2010, 04:55:44 pm
This should be about Gliese 581g and how we plan to invade.

Who said anything about invasion? The RKV has been deployed. The planet will be habitable again, but nicely uninhabited, in approximately 1000 years
Title: Re: First potentially habitable exoplanet discovered
Post by: karajorma on October 01, 2010, 09:37:31 pm
say in a hundred years we come up with a feasible engine technology that can go up to 1/4 the speed of light, but only for a small probe, and assume weve solved the problem of extremely long range communications. that would put the journey to the planet in question into the time frame of about 80 years, and another 20 years for the data to return to earth. say such a probe costs 10 trillion dollars. you want to be damn sure you send this probe to somewhere you think to have a high probability of supporting life. otherwise youd be wasting 10 trillion.

of course by the time such a mission were carried out, there would likely be a very long list of potential candidates, from decades of even centuries of exoplanet detection. your first concern would be range, you would go look at closer planets first. the ones at a distance might be beyond your probe's capabilities, or beyond your sphere of interest (too far for human colonization), and would take longer to receive data from them. then you would look at all the factors that seem good for life. is it in the habitable zone? is the gravity close to earth gravity? does it rotate (rotating planets would have a higher probability than non rotating planets perhaps)? does it have a magnetic field? and so on. youd send the probes to the ones which have the most positive results, and not the iffy star systems. that does not mean that any of those had life, or that anything that seemed unlikely would have plenty. its just you want to look at all your options and pick the best one.

Cart before the horse. We should have checked out both Mars and Europa properly by then. By which point we'd have a much better understanding of exactly where is the best place to find life.

Bear in mind that the possibility exists that Earth-type planets could actually be less likely to have life than cold worlds like Europa. The warmth could make it more likely that self-replicating molecules would be broken down before they could form. It could just as easily mean the opposite.

The point is that it's ridiculously premature to go on about habitable zones being the best place to look for life since our data set on what makes a planet likely consists of one point.
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 02, 2010, 04:00:10 am
say in a hundred years we come up with a feasible engine technology that can go up to 1/4 the speed of light, but only for a small probe, and assume weve solved the problem of extremely long range communications. that would put the journey to the planet in question into the time frame of about 80 years, and another 20 years for the data to return to earth. say such a probe costs 10 trillion dollars. you want to be damn sure you send this probe to somewhere you think to have a high probability of supporting life. otherwise youd be wasting 10 trillion.

of course by the time such a mission were carried out, there would likely be a very long list of potential candidates, from decades of even centuries of exoplanet detection. your first concern would be range, you would go look at closer planets first. the ones at a distance might be beyond your probe's capabilities, or beyond your sphere of interest (too far for human colonization), and would take longer to receive data from them. then you would look at all the factors that seem good for life. is it in the habitable zone? is the gravity close to earth gravity? does it rotate (rotating planets would have a higher probability than non rotating planets perhaps)? does it have a magnetic field? and so on. youd send the probes to the ones which have the most positive results, and not the iffy star systems. that does not mean that any of those had life, or that anything that seemed unlikely would have plenty. its just you want to look at all your options and pick the best one.

Cart before the horse. We should have checked out both Mars and Europa properly by then. By which point we'd have a much better understanding of exactly where is the best place to find life.

Bear in mind that the possibility exists that Earth-type planets could actually be less likely to have life than cold worlds like Europa. The warmth could make it more likely that self-replicating molecules would be broken down before they could form. It could just as easily mean the opposite.

The point is that it's ridiculously premature to go on about habitable zones being the best place to look for life since our data set on what makes a planet likely consists of one point.

we do need more data, its true. but if we find alien germs on mars and alien fishies on europa, its still not that much data to go on. we may have to expand the habitable zone and include moon systems of large gas giants. still mars isnt exactly teeming with life, and we need more data on europa. but as it stands the habitable zone has the highest probability. we need to discover life elsewhere before we can improve upon the known the planetary requirements for life. if we had the technology today to send a probe to a star system like the one discussed in this thread, we would look for a system with a planet much like our own.
Title: Re: First potentially habitable exoplanet discovered
Post by: Bob-san on October 02, 2010, 12:21:51 pm
say in a hundred years we come up with a feasible engine technology that can go up to 1/4 the speed of light, but only for a small probe, and assume weve solved the problem of extremely long range communications. that would put the journey to the planet in question into the time frame of about 80 years, and another 20 years for the data to return to earth. say such a probe costs 10 trillion dollars. you want to be damn sure you send this probe to somewhere you think to have a high probability of supporting life. otherwise youd be wasting 10 trillion.

of course by the time such a mission were carried out, there would likely be a very long list of potential candidates, from decades of even centuries of exoplanet detection. your first concern would be range, you would go look at closer planets first. the ones at a distance might be beyond your probe's capabilities, or beyond your sphere of interest (too far for human colonization), and would take longer to receive data from them. then you would look at all the factors that seem good for life. is it in the habitable zone? is the gravity close to earth gravity? does it rotate (rotating planets would have a higher probability than non rotating planets perhaps)? does it have a magnetic field? and so on. youd send the probes to the ones which have the most positive results, and not the iffy star systems. that does not mean that any of those had life, or that anything that seemed unlikely would have plenty. its just you want to look at all your options and pick the best one.

Cart before the horse. We should have checked out both Mars and Europa properly by then. By which point we'd have a much better understanding of exactly where is the best place to find life.

Bear in mind that the possibility exists that Earth-type planets could actually be less likely to have life than cold worlds like Europa. The warmth could make it more likely that self-replicating molecules would be broken down before they could form. It could just as easily mean the opposite.

The point is that it's ridiculously premature to go on about habitable zones being the best place to look for life since our data set on what makes a planet likely consists of one point.

we do need more data, its true. but if we find alien germs on mars and alien fishies on europa, its still not that much data to go on. we may have to expand the habitable zone and include moon systems of large gas giants. still mars isnt exactly teeming with life, and we need more data on europa. but as it stands the habitable zone has the highest probability. we need to discover life elsewhere before we can improve upon the known the planetary requirements for life. if we had the technology today to send a probe to a star system like the one discussed in this thread, we would look for a system with a planet much like our own.
There's also the question of adapting the planet for our exploitation. We'll be introducing Earth people, things, and problems to the new planet and, in turn, will have alien factors introduced to ourselves. Nuking the planet and starting over is one rather shoddy method. To eviscerate the planet of all forms of life as well as viruses would be virtually impossible to do though perhaps easier to recover from.
Title: Re: First potentially habitable exoplanet discovered
Post by: Grizzly on October 02, 2010, 02:41:48 pm

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?

The Star Wars mUltiverse has such a planet :P.
Title: Re: First potentially habitable exoplanet discovered
Post by: Turambar on October 02, 2010, 02:56:30 pm
Wouldn't it be extremely windy along the terminator?
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 02, 2010, 05:08:14 pm

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?

The Star Wars mUltiverse has such a planet :P.

So does Metroid, actually. :P
Title: Re: First potentially habitable exoplanet discovered
Post by: Bob-san on October 02, 2010, 05:23:19 pm
Wouldn't it be extremely windy along the terminator?
It would depend on the atmospheric model. I'd assume no since there'd be few global wind currents: the sun-facing side would be high-pressure while the dark side would be low-pressure. In addition, the far side would likely have much more solid or liquid water.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 02, 2010, 07:15:55 pm
Mmm, interesting.  From a study in 2003 (http://www.liebertonline.com/doi/abs/10.1089/153110703769016488):

Quote
M stars constitute 75% of main sequence stars though, until recently, their star systems have not been considered suitable places for habitable planets to exist. In this study the climate of a synchronously rotating planet around an M dwarf star is evaluated using a three-dimensional global atmospheric circulation model. The presence of clouds and evaporative cooling at the surface of the planet result in a cooler surface temperature at the subsolar point. Water ice forms at the polar regions and on the dark side, where the minimum temperature lies between -30°C and 0°C. As expected, rainfall is extremely high on the starlit side and extremely low on the dark side. The presence of a dry continent causes higher temperatures on the dayside, and allows accumulation of snow on the nightside. The absence of any oceans leads to higher day-night temperature differences, consistent with previous work. The present study reinforces recent conclusions that synchronously rotating planets within the circumstellar habitable zones of M dwarf stars should be habitable, and therefore M dwarf systems should not be excluded in future searches for exoplanets.


Doesn't say much about surface winds, unfortunately, but I think I'd agree that there would be a strong flow of wind across the terminator.  The cooler temperatures at the subsolar point was surprising though.
Title: Re: First potentially habitable exoplanet discovered
Post by: Bobboau on October 02, 2010, 07:47:30 pm
if I was trying to determine which planet to visit I think I would care less about the position it had in the system and more about the composition of it's atmosphere, and I would not hold water as vital.
Title: Re: First potentially habitable exoplanet discovered
Post by: FUBAR-BDHR on October 02, 2010, 09:51:04 pm
Yea we can create the water supply as we drink the shipments of beer.
Title: Re: First potentially habitable exoplanet discovered
Post by: Klaustrophobia on October 02, 2010, 09:55:06 pm
we can't even model our own climate, how can we have anything the least bit reliable on planets 20 lightyears away?
Title: Re: First potentially habitable exoplanet discovered
Post by: redsniper on October 02, 2010, 11:58:09 pm
Because we actually can model our climate, even if the model isn't perfectly accurate. Therefore we can make some general guesses at how similar planets would behave too. But you knew that...

In other words, because we know SCIENCE. :p
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 03, 2010, 12:44:06 am
We can model our climate well enough to know what the typical temperatures and prevailing winds are like at any latitude, and that's pretty much exactly all we're doing with this extrasolar planet.

Just because we can't be sure if Moscow will receive rain next Thursday doesn't affect our ability to predict a global climatology.

BTW I'm blasted drunk so I'll find out how legible this post is tomorrow.
Title: Re: First potentially habitable exoplanet discovered
Post by: Liberator on October 03, 2010, 02:44:07 am
We can model our climate well enough to know what the typical temperatures and prevailing winds are like at any latitude, and that's pretty much exactly all we're doing with this extrasolar planet.

Just because we can't be sure if Moscow will receive rain next Thursday doesn't affect our ability to predict a global climatology.

Then we can't model our climate can we?
Title: Re: First potentially habitable exoplanet discovered
Post by: Ravenholme on October 03, 2010, 03:09:45 am
We can model our climate well enough to know what the typical temperatures and prevailing winds are like at any latitude, and that's pretty much exactly all we're doing with this extrasolar planet.

Just because we can't be sure if Moscow will receive rain next Thursday doesn't affect our ability to predict a global climatology.

Then we can't model our climate can we?

You can model general conditions and trends, which is what the climate is.

That's modelling the climate. You're talking about weather, which is a specific and capricious function of climate. Not the climate itself.

Speaking of which, I attended a fascinating seminar by my university's environmental modelling team.
Title: Re: First potentially habitable exoplanet discovered
Post by: Klaustrophobia on October 03, 2010, 04:03:48 am
no, that's fitting a trend line over some data points.  which is rather horrendously inaccurate, since the global temperature is actually trending down during our supposed global warming.  climate modeling would suggest understanding the basic driving forces and physics behind the climate and using that to project.  the researchers at my university admit what a tremendous headache climatology really is, and that their best attempts at a simulation take 4 months to run on a supercomputer.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 03, 2010, 04:18:38 am
Quote
...since the global temperature is actually trending down during our supposed global warming...

Lol, what?  Source, please.
Title: Re: First potentially habitable exoplanet discovered
Post by: Ravenholme on October 03, 2010, 04:28:38 am
no, that's fitting a trend line over some data points.  which is rather horrendously inaccurate, since the global temperature is actually trending down during our supposed global warming.  climate modeling would suggest understanding the basic driving forces and physics behind the climate and using that to project.  the researchers at my university admit what a tremendous headache climatology really is, and that their best attempts at a simulation take 4 months to run on a supercomputer.

Oh dear (http://www.youtube.com/watch?v=YkS3rImqADI)

But more seriously, that's not what I've heard, and that's with a girlfriend who is an environmentalist (as in, degree wise) and myself being a Zoologist, so being somewhat concerned with the global climate.

It would, I reckon, depend very much on the modelling team and their agenda, if they have any. I know that my universities' one is very well respected in the field, being answerable to the EU parliament, the UK parliament, and the UN on occasion. (So much so that the project leader, a really nice guy - Professor Pete Smith - never gets to spend time at home with his kids) Climate modelling doesn't require a supercomputer if you're gathering data over the long term and identifying trends and extrapolating them into the long term. If you were intending to do absolute specific forecasts for the future, then you'd need a supercomputer, or possibly an AI.
Title: Re: First potentially habitable exoplanet discovered
Post by: Bobboau on October 03, 2010, 04:37:09 am
googleing I found this thing
(http://c3headlines.typepad.com/.a/6a010536b58035970c0133f32f363f970b-pi)

the site I found it on did not seem unbiased, but I doubt they would outright fabricate the raw data.
Title: Re: First potentially habitable exoplanet discovered
Post by: Ravenholme on October 03, 2010, 04:48:09 am
the site I found it on did not seem unbiased, but I doubt they would outright fabricate the raw data.

Do not fall into the trap of believing that. It happens a lot more than we like.

And it usually depends on who's funding the study.

Edit:

Not that I'm saying this isn't true. It could be. But it contradicts what I've seen and researched myself. And, more importantly, am living with. Here in Scotland, we're having warmer and wetter summers (But conversely, colder winters) - at least in the North East.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 03, 2010, 04:54:46 am
When responding to a specific line of text from the post above yours, could you please snip the image out of the quote so it's not needlessly posted twice in a row?  Thanks. :)

Edit:  I'm also going to post this (http://www.msnbc.msn.com/id/38263788/) for the sake of the climate-change debate. :P
Title: Re: First potentially habitable exoplanet discovered
Post by: Ravenholme on October 03, 2010, 05:08:04 am
When responding to a specific line of text from the post above yours, could you please snip the image out of the quote so it's not needlessly posted twice in a row?  Thanks. :)

Edit:  I'm also going to post this (http://www.msnbc.msn.com/id/38263788/) for the sake of the climate-change debate. :P

Done, was in a rush when I made the post.

And, yeah, which rather proves my point about it really depends on who's reporting it and what their agenda (or the agenda of their sponsor) is
Title: Re: First potentially habitable exoplanet discovered
Post by: Bobboau on October 03, 2010, 05:17:44 am
Do not fall into the trap of believing that. It happens a lot more than we like.

I doubt it because it would be trivial to disprove, it does not look like their data, they are siteing someone else in the data, and I'm not really into it, it was just the first graph I found with data from the last two years in it. you say this graph is false show me another one with data for the last two years, pics or GTFO.
Title: Re: First potentially habitable exoplanet discovered
Post by: Ravenholme on October 03, 2010, 05:20:14 am
Do not fall into the trap of believing that. It happens a lot more than we like.

I doubt it because it would be trivial to disprove, it does not look like their data, they are siteing someone else in the data, and I'm not really into it, it was just the first graph I found with data from the last two years in it. you say this graph is false show me another one with data for the last two years, pics or GTFO.

Except I didn't say it was false. I just said "Do not fall into the trap of believing that data is never falsified."

Indeed, I even said it "could" be true. However, look at Watsisname's post, his link has a wee bit more credibility as it is a study done by a government agency. (But only a little bit more)


And, actually, it's not trivial to disprove anything like that - it's usually very hard to do without a.) asking them to redo their experiment and figures and show how they did it - because the method and location and sources of their data will influence their readings or b.) Like that climatology group that was caught falsifying data to fill gaps, get your hands on their internal communications.

If you really want Bobboau, I'm going to the library tomorrow with some friends, and I'll see if I can't use my uni's account to raid some scientific journal sites to present you with evidence that shows the opposite of your graph. And then I could probably find some that show the same as your graph.

You might want to look into the differences in models where only natural factors are considered, and where human factors are also considered, as well, as that's a huge issue and divisive factor in the CM community.


Also, importantly, all you've done is pull a graph off the internet from some site - which is hardly the most accurate of sources. Rule number one of science - don't trust the internet unless it's an accredited scientific journal site and you're looking at an actual paper and cited study.

Edit:

But we're getting massively offtopic.

Habitable exoplanet? Colony ship pls.
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 03, 2010, 08:57:10 am
yea, if i start seeing environmentalist mudslinging, im locking this thing.
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 03, 2010, 10:22:44 am
omg someone said 'model climate'

global warming argument
Title: Re: First potentially habitable exoplanet discovered
Post by: Mobius on October 03, 2010, 10:26:05 am
No, please, no more Antropocene-related arguments... :ick:
Title: Re: First potentially habitable exoplanet discovered
Post by: Bobboau on October 03, 2010, 01:08:31 pm
all you've done is pull a graph off the internet from some site - which is hardly the most accurate of sources. Rule number one of science - don't trust the internet unless it's an accredited scientific journal site and you're looking at an actual paper and cited study.

yeah, I've only said that like three times now.

If you really want Bobboau, I'm going to the library tomorrow with some friends, and I'll see if I can't use my uni's account to raid some scientific journal sites to present you with evidence that shows the opposite of your graph. And then I could probably find some that show the same as your graph.

You might want to look into the differences in models where only natural factors are considered, and where human factors are also considered, as well, as that's a huge issue and divisive factor in the CM community.

it's not a model, its measurements, yes find some measurements, without anything contradicting what I found, all I can do is assume the graph I found is right. by all means find me some other better sourced evidence.
Title: Re: First potentially habitable exoplanet discovered
Post by: SpardaSon21 on October 03, 2010, 01:20:28 pm
Aren't most of the surface stations in the U.S. absolute crap when it comes to positioning, such as being right next to asphalt, A/C exhaust vents, and other heat sources?
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 03, 2010, 01:36:05 pm
THIS THREAD IS ABOUT BATTUTA'S WORLD, NOT THIS MISERABLE MUDBALL YOU'RE SO CONCERNED ABOUT OVERHEATING

:mad:

battuta: not so much a 'moderator' as an 'excessinator'
Title: Re: First potentially habitable exoplanet discovered
Post by: qazwsx on October 03, 2010, 01:57:15 pm
****ing religion/climate change debates, buggering up interesting threads, pisses me off D:<
Title: Re: First potentially habitable exoplanet discovered
Post by: redsniper on October 03, 2010, 02:19:45 pm
What color would plants be on Gliese?
Title: Re: First potentially habitable exoplanet discovered
Post by: qazwsx on October 03, 2010, 02:23:03 pm
Octarine
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 03, 2010, 10:01:31 pm
Black, actually, in order to take full advantage of the mostly infrared sunlight.

Interesting article on it here (http://www.scientificamerican.com/article.cfm?id=the-color-of-plants-on-other-worlds)
Title: Re: First potentially habitable exoplanet discovered
Post by: Topgun on October 04, 2010, 11:09:37 am
Aren't most of the surface stations in the U.S. absolute crap when it comes to positioning, such as being right next to asphalt, A/C exhaust vents, and other heat sources?
Using surface stations is stupid anyway. The only reliable way to tell if the world is heating up is with satellite data that includes the temperature of the oceans. Unfortunately, we only have that data since the 70's and 80's, and thats way too early to tell if global warming is factual or not.
Title: Re: First potentially habitable exoplanet discovered
Post by: Topgun on October 04, 2010, 11:14:05 am
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?

So basically its not habitable at all :p
At least not for us anyway.
Title: Re: First potentially habitable exoplanet discovered
Post by: General Battuta on October 04, 2010, 11:26:48 am
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?

So basically its not habitable at all :p
At least not for us anyway.

le wrong!

Read what you quoted again.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 04, 2010, 05:48:33 pm
Well.... probably not habitable for us, yes.  But who cares, it's by far the best chance of life outside the solar system we've found so far. :yes:

AND SRSLY, BLACK PLANTS!  BLACK PLANTS PLACK BLANTS BLAACK BLANTS.  BLAACK PLANTS, BLACK PLAAAANTS, BLACKLANTS, BLACKPANTS, BACKPLANTS, BACKPLANS, BLAHBLAMS B:ABJE<S
Title: Re: First potentially habitable exoplanet discovered
Post by: redsniper on October 04, 2010, 10:48:30 pm
Actually I read somewhere that even though it's more massive than Earth, it's also larger (diameter-wise) so the acceleration due to gravity on the surface isn't that far off from Earth's. Though that might have just been someone's wishful thinking, I don't know.
Title: Re: First potentially habitable exoplanet discovered
Post by: Klaustrophobia on October 04, 2010, 11:11:25 pm
if they know the mass and diameter of the planet, that's a really basic calculation.
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 04, 2010, 11:27:20 pm
i think gravity follows the inverse square law. so if you have a known surface gravity acceleration value, its not hard to extrapolate gravity at whatever altitude. i dont know how to figure out what a planet's gravity is with only its mass and and radius. i do know the density of a planet is the major factor of how hard gravity pulls, a massive planet like saturn only pulls 0.9 gs. even though it has way more mass than earth does.
Title: Re: First potentially habitable exoplanet discovered
Post by: redsniper on October 04, 2010, 11:28:46 pm
Oh yeah, I know. I just don't know if we can tell the diameters of planets so far away. I think I saw it in a forum post somewhere, I just don't remember if it was fact or speculation.
Title: Re: First potentially habitable exoplanet discovered
Post by: karajorma on October 05, 2010, 12:05:34 am
Try it yourselves (http://www.ericjamesstone.com/weird_stuff/gravitator.htm).

Using the figures they give in the article (around 1.3x diameter of Earth) and the same density as Earth 5.5g/cm3 I ended up with a surface gravity of around 1.3G. Perfectly tolerable.
Title: Re: First potentially habitable exoplanet discovered
Post by: Klaustrophobia on October 05, 2010, 03:36:48 am
i think gravity follows the inverse square law. so if you have a known surface gravity acceleration value, its not hard to extrapolate gravity at whatever altitude. i dont know how to figure out what a planet's gravity is with only its mass and and radius. i do know the density of a planet is the major factor of how hard gravity pulls, a massive planet like saturn only pulls 0.9 gs. even though it has way more mass than earth does.

Newton's law of gravity.  F= G*[m1*m2/r^2].  divide by m1 and you get A=G*M/r^2

as for how they figured out its radius, that probably depends on how they found the planet (if the article says i don't remeber).  if the planet's orbital plane is in line with us, the radius can be determined by the dimming of the star as the planet passes in front.  otherwise, since they determined it is a rocky, earth-like planet they may have done the same as kara and assumed a similar density to get an estimate of size (knowing mass from observing its orbit).
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 05, 2010, 06:12:42 am
Yeah, the planet was discovered with the radial velocity technique (can't use transit method since the orbital inclination doesn't bring it in front of the star from our vantage point -- unfortunate), so they only know the mass (3 to 4 Earth masses iirc) and orbital period.  They can come up with estimates for the radius by guessing what the planet's composition is like and then applying physics to figure out how much it'd be compressed.
Title: Re: First potentially habitable exoplanet discovered
Post by: JGZinv on October 05, 2010, 11:17:06 am
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?


*ahem*

http://en.wikipedia.org/wiki/List_of_Star_Wars_planets_%28R%E2%80%93S%29#Ryloth

Covered in the YJK books.
Title: Re: First potentially habitable exoplanet discovered
Post by: watsisname on October 05, 2010, 01:53:06 pm
Quote
The Nightlands have an eerie beauty, strange crystal-like plants have evolved here, glowing from within, having to produce their own light from which to make energy due to the absence of natural light.

Producing energy from which to make energy?  lolwut
Title: Re: First potentially habitable exoplanet discovered
Post by: Solatar on October 05, 2010, 02:21:36 pm
Perpetual Motion plant? :P
Title: Re: First potentially habitable exoplanet discovered
Post by: JGZinv on October 05, 2010, 02:51:57 pm
It has a sister species that is used as a light fixture.... known as the Clapper Fern.  ;)
Title: Re: First potentially habitable exoplanet discovered
Post by: Nuke on October 06, 2010, 12:37:38 pm
i think gravity follows the inverse square law. so if you have a known surface gravity acceleration value, its not hard to extrapolate gravity at whatever altitude. i dont know how to figure out what a planet's gravity is with only its mass and and radius. i do know the density of a planet is the major factor of how hard gravity pulls, a massive planet like saturn only pulls 0.9 gs. even though it has way more mass than earth does.

Newton's law of gravity.  F= G*[m1*m2/r^2].  divide by m1 and you get A=G*M/r^2

as for how they figured out its radius, that probably depends on how they found the planet (if the article says i don't remeber).  if the planet's orbital plane is in line with us, the radius can be determined by the dimming of the star as the planet passes in front.  otherwise, since they determined it is a rocky, earth-like planet they may have done the same as kara and assumed a similar density to get an estimate of size (knowing mass from observing its orbit).

thats the equation i was looking for.