Near Earth-sized planet found in habitable zone: Gliese 581C

keermalec · May 7, 2007

This planet is really really cool. To make some not so scientific theories but simply to throw in some ideas about what this planet could possibly be like: 1). Does it have an atmosphere. It probably does, haveing a mass 5x the Earth's it probably has attracted more volatiles than the Earth has. Odds are it has a very thick massive atmosphere, way more than 5x times the Earth's atmospheric mass. Therefore higher pressures and higher temperatures (NB an atmosphere 5x the Earth's in mass on this planet would exert a pressure 10x the Earth's, due to its 2x gravity). 2). Is it tidally locked to Gleise 581 (i.e keep the same face turned towards its Red Dwarf sun)? It probably is, considering Io is tidally locked to Jupiter. If we consider Jupitar's attraction at Io's distance to be 1, then Gliese 581's attraction at G581c's distance will be 0.6, just slightly less. If we consider Mercury, which is ALMOST tidally locked with the sun (very slow rotation), the sun's attraction at that distance (using same Jupiter-Io units) is 0.05. i would say G581C is most probably tidally locked. Coupling this with the thick atmosphere theory, there would probably be very violent and permanent winds at the day-night cut-off line and temperatures would be substantially similar on day ot night side (compared to an airless body). 3). Is it geologically active (have volcanoes, tectonics, or is it dead & covered in impact craters)? Lets compare it to io again. Io is geologically active because it is closely surrounded by Jupiter, Europa and Ganymede which interact gravitationally with it, exerting huge tidal forces which create heat in its mantle by friction. At first glance it seems the proximities and masses of G581, G581B and G581D must certainly exert similar forces on poor G581C. Considering it is larger than the Earth and slightly younger, its crust has had less time to cool and covers more mantle per sq km: the cr <div class="Discussion_UserSignature"> “An error does not become a mistake until you refuse to correct it.” John F. Kennedy </div>

robnissen · May 7, 2007

Very well thought-out post. Unfortunately, we probably won't know whether your speculations are right for a very long time . . . hopefully some of them will be answered within our life times.

3488 · May 8, 2007

I agree RobNissen. A very thought out post. Thank you Keermalec for your answers & welcome to SDC. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

mithridates · May 8, 2007

Yes, that's a nice post. I'm not sure about the night side being the same temperature as the other side for two reasons: though Venus is the prime example of a planet where the atmosphere is so thick that the day and night side have pretty much the same temperature in spite of the 200+ Earth-day year, Gliese 581 c has two major differences: 1) For all practical purposes the night side has never seen the sun, and 2) The planet is much larger, and the heat on the day side has a lot more ground to cover as it flows to the other side. Perhaps this would depend on the speed of the winds. I am just guessing though. <div class="Discussion_UserSignature"> ----- http://mithridates.blogspot.com </div>

heyscottie · May 8, 2007

Keermalec: Good speculation here! Of course, we are almost assured of being surprised in at least one aspect, and probably about more of them. Our assumptions are still too earth-centric to necessarily be valid everywhere. That is one of the reasons this topic is so exciting -- we have a chance to prove ourselves wrong. Once we start getting some hard data back from systems like these, we will probably find ourselves rethinking many of these assumptions. On the whole, good list with good guesses...

dragon04 · May 8, 2007

If its interior is differentiated and liquid, as it probably is, then it probably has a magnetosphere as this is created by the rotation of a metallic core. If 581c is tidally locked with 581, how could a molten core generate a significant magnetic field? IOW, what would make the core rotate faster relative to the mantle and crust of 581c? <div class="Discussion_UserSignature"> "2012.. Year of the Dragon!! Get on the Dragon Wagon!". </div>

heyscottie · May 8, 2007

If it IS tidally locked, it likely was rotating faster in the past. I see no reason that the core could not still be spinning faster than the tidally slowed crust.

nexium · May 8, 2007

One reason is a large friction loss between the core and mantel producing near zero speed difference a few hours after a planet becomes tide locked. Neil

keermalec · May 13, 2007

You are right Nexium, I was under the illusion that the Earth's magnetic field came from a differential rotation between the core and mantle. This is wrong and robably induced by some dumb movie... There seems to be a small differential rotation between the inner and outer cores, and also some convective movements in the outer core, but the main origine of the Earth's magnetic field is widely regarded as being its rotation, as you noted. This theory is supported by the very weak magnetic field of Venus, which rotates only once every 243 days, but is not supported by the also very weak magnetic field of Mars, which rotates once every 25 days, almost like Earth... It is a probable guess that a magnetic field is induced by the rotation of a liquid metallic core, however that functions is another story (we could use the help of a geologist here). In this case the weakness of Mars' magnetic field is explained by postulating that its core is solid, or feebly metallic. Coming back to our G-planet, even if it is tidally locked, it does rotate once every 12.9 days, as it completes its revolution around the star. As its metallic core is probably larger than Earth's (2.5x?) it probably does have a magnetic field, weaker but comparable to Earth's. <div class="Discussion_UserSignature"> “An error does not become a mistake until you refuse to correct it.” John F. Kennedy </div>

bdewoody · May 13, 2007

After reading most of the post's on this thread I can't help but wonder how many members in here think that even if all the technology currently under investigation works we could reach these planets any time in the foreseeable future, and for what purpose if we did? Don't get me wrong I grew up on Star Trek and Star Wars and would be the happiest person alive if warp drive, hyperdrive or any FTL means of propulsion is discovered or invented. But I believe interstellar travel is a very long way off if ever. The biggest reason other than curiosity for all the exploration that went on here on earth in the 1500-1900's was commerce and expansion. What good does it do the people that put up the money for these ventures if even the outcome won't be known for 5 or 6 hundred years? We've all gotten so used to TV shows and movies where interstellar travel is like going to work in the morning and coming home that night that we believe we can do it now. I really hope there is something like the hyperspace in Bab5 where you can pop into it somewhere around Mars fly to a beacon and pop out at Alpha Cetauri 2 days later conduct your business and then fly back to earth in time for Sunday's NASCAR race. If it don't happen then I think we'll have to be happy with travelling to Mars or Titan and missing a few NASCAR races. So it's good to be enthusiastic about all these planetary finds but I'd hold off on planning the trip ticket for a while. <div class="Discussion_UserSignature"> Bob DeWoody </div>

Kalstang · May 13, 2007

bdewoody: What good does it do the people that put up the money for these ventures if even the outcome won't be known for 5 or 6 hundred years? Ahh yes the ole "why do it if it does us no good now" question. Ansewr...They are looking out for their childrens, childrens, children etc etc. Imagine just how rich someone would be if they were the first to discover FTL travel. (thru what ever means). Not only would they be rich beyond thier imaginings but they would have one heck of a monopoly on the market. And then theres the possibility of actually achieving it in our lifetimes and being the first to visit another solar system. So much for the lunar landing. <div class="Discussion_UserSignature"> I have an answer for everything...you may not like the answer or it may not satisfy your curiosity..but it will still be an answer. "Imagination is more important then Knowledge" ~Albert Einstien~ Guns dont kill people. People kill people.Solar System </div>

bdewoody · May 13, 2007

You totally missed my point It's one thing to finance and invent/discover FTL travel and I really hope it gets done. The sooner the better. It's another thing to finance a trip to planets in a system 20 LY away when even if there is a planet in the goldilocks zone, has a 70% nitrogen-30% oxygen atmosphere has friendly inhabitants who would like to trade with us but are still looking for FTL propulsion too. Could meaningful, ie profitable commerce be established when a round trip would take 3 or 4 hundred years. <div class="Discussion_UserSignature"> Bob DeWoody </div>

brellis · May 13, 2007

Could meaningful, ie profitable commerce be established when a round trip would take 3 or 4 hundred years. The commerce happens along the way. The pyramids weren't build in a day, but there they stand as a monument to every individual who helped undertake their massive construction. Similarly, our contributions to the knowledge of other star systems and the ability to get there will one day stand like stones in a modern-day pyramid - you know, like Stargate <img src="/images/icons/wink.gif" /> Much of 21st C commerce is already built from and around technology derived from space exploration. There is a viable economic need for interstellar travel - the natural expansion of the human population. Paul Ehrlich, in The Population Bomb, cites famine, disease and war as suppressors of the human population that keep us - barely! - on the confines of earth. One day, we will build massive arks and set sail for distant star systems as a matter of survival. Our knowledge of our own planet's fragile ecosystem tells us we've got a better chance to survive as a species if we continue to pursue the frontiers of the solar system and the universe. Everything we're doing technologically, from the internet to innovative propulsion systems to arrays of space telescopes, is preparing us for the next stage. It's gonna happen, because it has to! <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

robnissen · May 13, 2007

One day, we will build massive arks and set sail for distant star systems as a matter of survival. Probably. But if we need to do that in the next thousand years or so, I'm afraid we are totally screwed. Fortunately, humans don't only do things to make money. There is no money to be made in studying super nova 10+ B light years away. Now certainly there is a limit to what can be done when there is no financial gain. But hopefully we will have the technology in the near future to reach .1c. Once we reach that point, we could probably get funding for a 40 year mission to Alpha Centauri. (We already have funding for a mission to Pluto that takes 10 plus years). We probably could not fund a 200+ year trip to Gliese, however. But if we can ever get to .1c, maybe some day we could get to .4c, if so we might be able to fund a 50+ year trip to Glieses.

keermalec · May 13, 2007

I believe bdewoody means "why waste time conjecturing on a planet 20 ly away if we won't reach it in our lifetimes". Well maybe we like to discuss this precisely BECAUSE we will not reach it in our lifetimes. If we could, why discuss it? Simply go there and see. Actually there is also another reason to conjecture on things like Gliese 581c, and that is simply curiosity, and the fascination of obtaining knowledge by deduction. I personnally have a strong interest in discovering things which have been around for billions of years. You may remember being fascinated when you discovered the unique properties of the number PI, or the natural logarithm e, or the golden proportion: all things which had been around long before our times and were simply waiting to be discovered. I felt the same fascination on discovering the nature of our planetary neighborhood: the clouds of Jupiter, the deserts of Mars, the seas of Titan, and now, other planets around other stars. There does not need to be a financial, or political reason for ressearch. You only need such reasons when you are spending money, which we aren't. We talk about Glilese 581c simply because we like to. You may argue that doing something for no practical purpose serves no end, and I would remind you that life itself serves no practical purpose. <div class="Discussion_UserSignature"> “An error does not become a mistake until you refuse to correct it.” John F. Kennedy </div>

dragon04 · May 13, 2007

The discovery of 581c (and hopefully many more worlds more like ours) does something that can't be defined in terms of dollars. In incites the need to investigate, and and provides a shot in the arm for renewed vigor in the area of manned space exploration. It's a place. It's the New World all over again 5 centuries later. It's right up our alley. We explore. We expand. We tame a new and wild environment to make our homes. It's what we do. It's what we've done ever since we came down out of the trees 3 million years ago. We have a deeply rooted need to find new things. We have a curiosity with quite an appetite. We can never stop growing. The biggest danger to us as a species is not having a challenge, I think. While it serves no "practical purpose" in terms of the mundane, everyday things that we require to make us run, not all things can be properly measured in those terms. Besides (and very unscientifically), it's just plain cool. <div class="Discussion_UserSignature"> "2012.. Year of the Dragon!! Get on the Dragon Wagon!". </div>

MeteorWayne · May 13, 2007

Well summarized, Dragoon <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

bdewoody · May 13, 2007

Maybe I didn't express myself properly. As I tried to say I'm as enthusiastic about space travel and boldly going where no man has gone before as say Gene Roddenberry, but now that I have reached 57 years of age I just don't see manned interstellar flight happening unless some new undiscovered means of getting from here to there is found. I check the progress of spirit and opportunity every day, I check Cassini's discoveries at least once a week. I even watch for the occasional Venus express update. I watch more hours of the science channel than all others combined (even the Sci-Fi channel and sports). I'm willing to volunteer to be a permanent crew member of the space station or moon base. The point is I'm NOT one of those people who think we are wasting money exploring space, heck I wish we could get over our petty religious and political differences here on earth so we could divert our military budget to space and along the way provide a job to everyone willing to work (I don't have much sympathy for those who just want a free ride). Maybe its just that my health has not been that good lately or that since my enthusiastic youth, old age and a sense of reality has crept in. My bottom line thought is before we dilute our resources spending money on extra-solar systems we should first plant ourselves firmly on the moon and Mars from which space exploration can much more easily be initiated. <div class="Discussion_UserSignature"> Bob DeWoody </div>

dragon04 · May 13, 2007

but now that I have reached 57 years of age I just don't see manned interstellar flight happening unless some new undiscovered means of getting from here to there is found. I'm certainly not advocating the immediate pursuit of interstellar travel manned, or robotic. I just am of the opinion that discoveries like these are the fuel that drives the pursuit of advanced propulsion and better space based observation instruments. The desire of one scientist to get to the Gliese 581 system before he dies just might be the thing that inspires him or her to invent that remarkable star drive we don't have. It's inspiration value that I'm talking about. Wait till we find a terrestrial planet closely similar to our own. Brilliant and bright people will be on fire. Throughout history, we've had various technological revolutions. It always takes a spark to set them off. I think Gliese 581c and future discoveries like it aare that spark. Why, the Universe just got a little smaller I think. We're no longer talking about some nondescript point of light a whole 20LY away now, but rather a planet somewhat like our own in the neighborhood. This is just the kind of stuff that we can deliver to our kids in our schools to make science popular again. Now all we need is another Champion. Another Carl Sagan to be the spokesperson for the Next Great Thing. I see this as an opportunity we can ill-afford to squander. <div class="Discussion_UserSignature"> "2012.. Year of the Dragon!! Get on the Dragon Wagon!". </div>

brellis · May 13, 2007

The discovery of Gliese 581c is a product of an emerging technology that has and will create jobs and economic opportunities as we build an array of instruments and the ability to immediately share the information gleaned from those instruments. As we build a matrix of outposts, cyclers, etc. around the moon, Mars and the rest of the solar system, we will be building toward a human interstellar presence. Some craft can be sent out quickly, like the record-breaking New Horizons mission. Some can be sent out more slowly and gradually, like Hyabusa or SMART-1. Just designing, assembling and maintaining these craft creates an economy and improves our technological standards here on earth. As to getting there quickly, who knows? Perhaps as we unravel the mysteries of our DNA, we'll discover a way to instantaneously communicate on some innate level with alien creatures living in another star system like Gliese 581c. Perhaps we'll be like the aliens in Sagan's "Contact". A step towards that may be the invention of an instrument that can detect the level of consciousness or brain wave activity on a distant planet. Currently, we can wrap a sensor around our heads and control the player on a video game with our eyes and foreheads. Tomorrow, why not mount a sensor on a telescope pointed at Gliese 581c and get into someone's head over there? Granted, a conversation with a Gliesian (sic) 20ly away would be more along the lines of "The Lake House", hopefully without Keanu Reeves or Sandra Bullock involved! <img src="/images/icons/tongue.gif" /> <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

MeteorWayne · Jun 14, 2007

No transit was observed. See this post from Serak <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

heyscottie · Jun 14, 2007

Thanks -- it is too bad, but not unexpected, that we are not in a geometry to observe transits from the Gliese system. I noticed at the bottom of the post some good news, though: That the output of the star seems to be nicely constant. That raises hopes that the climates on these planets are not subjected to wild swings with a variable or flare star.

qso1 · Jun 15, 2007

Maybe the constant output is suggesting that Gliese581 is not a traditional flare star. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

3488 · Jun 15, 2007

Hi qso1. Yes, that is very true. Because Gliese 581 is an older red dwarf, it has left its tempestuous youth behind. Proxima Centauri on the other hand, is thought be be young, only 800 million years old, although Alpha Centauri A & B are thought to be about 6.4 GYO, considerably older than Sol. This means that if Proxima IS gravitaionallly bound to the A B pair, than it is an imposter captured later on. AFAIK, Barnards Star is also an older red dwarf & does not flare. It is clearly age related. The Gliese 581 system MUST be studied further. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

qso1 · Jun 15, 2007

Hows it goin 3488? I wasn't sure what the age of Gliese581 was. You cleared that one up for me, thanks. I was kind of just guessing when I said it might not be a flare star. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Near Earth-sized planet found in habitable zone: Gliese 581C

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