Talk:Gliese 581c

Microlensing???

What's all this about microlensing? The radial velocity measurements used to detect Gliese 581 have nothing to do with microlensing! 131.111.8.104 (talk) 00:36, 21 February 2008 (UTC)

honestly I don't get it either. While microlensing is a nice technique for observing certain kinds of things, I don't really see how it applies here either.--Marhawkman (talk) 09:30, 18 March 2008 (UTC)

Oh yeah, nice back up of your own sockpuppet.
Just trying to make an issue to make yourself feel important.
It's detection, and it's already in the article: your method is madness.
198.163.53.10 (talk) 20:03, 19 March 2008 (UTC)

Analysis of habitability of Gliese 581 c and d

Check out Selsis et al. (2007), "Habitable planets around the star Gliese 581?" for a discussion of the habitability of this system. 131.111.8.102 (talk) 12:10, 21 February 2008 (UTC)

"Thanks to the greenhouse effect of CO2-ice clouds, also invoked to explain the early Martian climate,
planet “d” might be a better candidate for the first exoplanet known to be potentially habitable."
I agree this is noteworthy and belongs in the article.
GabrielVelasquez (talk) 18:17, 29 February 2008 (UTC)

Artist impressions

I removed these images from the gallery because there was no indication anywhere on their description pages or in their filenames that indicated that they were intended as depictions of Gliese 581 c:

• Desert planet
  Desert planet
• Super-Venus
  Super-Venus
• 
  Terrestrial
• Gas Dwarf
  Gas Dwarf

Simply adding "Gliese 581 c" to the captions doesn't really prove anything. 205.200.236.34, could you provide some sort of evidence that these are in fact intended to be depictions of Gliese 581 c? Bryan Derksen (talk) 09:47, 18 March 2008 (UTC)

This is a joke to me boy'O, the images that you kept there were still there becuase they have the name Gliese 581 c in the file name... it makes no difference as anyone can name a photo with what ever name they like, it's the same as adding the label to the gallery afterward. Your point is usesless, unless it is to get them all deleted.
The important point is that references that say this planet is definately not habitable have been used to support the false idea that it its habitable, and these images simply depict the other possibilities. The other month Dr. Sara Seager wrote an article for Astronomy magazine on extrasolar planets in which she picked up on the term GasDwarf. It's been used in science fiction for a while now, but she is a scientist and she gave it validity once and for all, so if I find a link online I will add it. As for the rest, look beyond the habitable delusion. The file names don't prove anything either sport. 198.163.53.10 (talk) 20:06, 19 March 2008 (UTC)

PS. that Ice Planet is a ripoff of Celestia's Titan texture. 198.163.53.10 (talk) 20:06, 19 March 2008 (UTC)

The point I'm making is that in the case of these four images they don't even have a filename to suggest that they're in any way associated with Gliese 581 c. Whether the others I didn't remove are reasonable to include here is a separate matter, I figured I'd just prune out the obvious ones first. Does anyone have any evidence to present that these images were intended as Gliese 581 c impressions, or whether they've got even the tiniest bit of scientific backing? If not, I'll remove them again. To pretend that they've got something to do with the subject of this article when they don't is simply original research. Bryan Derksen (talk) 17:45, 21 March 2008 (UTC)

I've removed them again, if anyone wants to reinsert them please provide some evidence that they have anything to do with Gliese 581 c in some way. Bryan Derksen (talk) 17:45, 23 March 2008 (UTC)

If you think that your tantrum is going to let you get away with what ever you want in this article you are mistaken. You are stupidly or deliberately ignoring what is referenced for you so you can do what you want: Do you know who Dr. Sara Seager is? Do you know what a GasDwarf is? - Why do I need to repeat these things to you, when this is your tiny bit of proof and far far more and it has already been stated. You, like some spoiled brat ignore the plain evidence that has been provided for you to get your way. Are you the uncle of the kid who ripped of that Celestia Titan textue or something? And you are accepting those images that have the name Gliese in them even though it could be a picture of a chicken! How the f**k did you get to be an administrator??
What part of artistic impression (not scientific) do you not understand??
Look at the graph just above, is not a 88 °C globl average likely to be a desert - that's scientific.
If it is a Chythonian then is it not a ball of rock - that's scientific!
In her article, Dr. Sara Seager talks about a 5 Earth mass ball of gas, why do you use suppose she referred to 5 Earth masses, duh, and then called it a Gas Dwarf, duh?? - is that not scientific??
I think it is Astronomy magazine's February issue, I'll have to dig it up, and I'll replace this line with the referencing code when I find it, though you must be paper-illiterate or you would have check already, Deletionist, Immediatist, Exclusionist, F**k-wit.
198.163.53.10 (talk) 16:17, 26 March 2008 (UTC)

What tantrum? You're the one who's resorted to namecalling. I'm asking for citations. There's nothing on those image's description pages that indicate that they're intended to be artistic impressions of Gliese 581 c, if you're the one drawing that inference de novo then you're doing original research. I suppose I'll put {{fact}} tags on the images now, but this really seems like ridiculous hoops to jump through. Bryan Derksen (talk) 05:08, 8 April 2008 (UTC)

I concur. I would change the labels to remove the impression that they are of C and write it so that it says they're artistic impressions of what those types of planets might look like.--Marhawkman (talk) 07:17, 8 April 2008 (UTC)

Thank you, I will see that gets done. You can stop deleting them. There is a reason that those galleries say artistic impressions. Duely noted that you nephew or friends artistic impression at the top was not deleted by you, you hypocritical slime. 198.163.53.10 (talk) 20:52, 7 June 2008 (UTC)

I'm not going to delete the graphics before seeing what the consensus is, but I question their inclusion in this article on the grounds of WP:RS and WP:V. I would think that they would at the very least need to be artistic impressions of Gl 581 c specifically -- and cited as such. Certainly the images need to be sourced. The fact that Gl 581 c might be a planet of a certain type, and an unnamed artist has created an image of what he thinks such a planet might look like (which may or may not be consistent with the scientific understanding of such a planet) is not grounds for inclusion in the article. Any other thoughts on this?

Additionally, can we try to keep it civil and assume good faith. J. Langton (talk) 06:30, 21 July 2008 (UTC)

You are ignoring everything that has been discussed and concensus that has been built to get your way. How many times do people have to contrast the idea of "Artisitic" and "Scientific" for you to get it. That image at the top of the planet data box has been there forever and no one has questioned it but you have to start far below that at the gallery where no one is fighting to have their individual artistic impression at the top. GabrielVelasquez (talk) 05:17, 24 July 2008 (UTC)

"Artist's impression" section

There is no need to have this section. According to WP:COMMONS, art sections should be confined to Wikimedia Commons (a wiki site). The icon to get to the specific site on commons is found on the bottom of every article here. — NuclearVacuum 01:36, 8 June 2008 (UTC)

Disputed. A problem is that the commons: has more restrictive copyright rules than Wikipedia, so that image galleries could be allowed here and not on commons:. — Arthur Rubin (talk) 03:06, 9 June 2008 (UTC)

Technically, all of the images here are both acceptable in both Wikis. If there were anything wrong with these images (like copyright issues), then they shouldn't be on either Wiki to begin with. — NuclearVacuum 17:58, 9 June 2008 (UTC)

Not really. Wikipedia allows "fair use", and has a more accurate list of things automatically in the public domain, under US law, than commons does. — Arthur Rubin (talk) 19:14, 9 June 2008 (UTC)

This guy got my IP blocked over this "dispute," thanks Arty. Hypocritially, Vacuum deleted the whole gallery and at the same time undid the deletion of the artistic impression above the data box... Not a bias there, would you say (ret.) 24.77.204.120 (talk) 23:42, 11 June 2008 (UTC)

More accurate formula

This chart of possible temperatures for Gliese 581 c uses the formulas at the article " Climate modeling"
http://upload.wikimedia.org/wikipedia/commons/d/d0/Gliese_581_c_Temperatures.jpg

Intro should reflect the errors made by media not excuse them

The intro suggests that there was missing data and so that is why the media blew the (false) idea of habitablility out of proportion. The fact is the data was available and the planet was sensationalized anyway. Five times the heat the earth gets, five times the mass and therefore likely to have five times the greenhouse gas effect is obvious. The intro should admit that this was a mistake not excuse it. 24.77.204.120 (talk) 00:55, 8 June 2008 (UTC)

Proposal: remove the "HO Librae c", "Wolf 562 c", "HIP 74995 c" alternative designations

Is there any record of these designations being in use? SIMBAD lists only the Gliese designation (as GJ, since SIMBAD renders Gliese and GJ both as GJ). Google hits on the other designations seem to be mainly copypaste of Wikipedia. We should not invent designations that are not in use. I propose removing these designations from the article. 131.111.8.104 (talk) 21:41, 11 June 2008 (UTC)

Those are correct designations for the stars,
"Gliese" is not the only Catalog of Stars. People who use other Catalogs will be looking to confirm that they are refering to the same star!
http://www.solstation.com/stars/gl581.htm ...
"Gliese 851 has been previously classified as a variable star with the designation "HO Librae" and NSV 7023. Some other useful star catalogue designations include: HO Lib, Gl 581, Hip 74995, BD-07 4003, G 151-46, G 152-9, LHS 394, LTT 6112, LPM 564, LFT 1195, Vys/MCC 159, and Wolf 562." - You didn't even check, you deletionist piece-of-s**t.

24.77.204.120 (talk) 23:22, 11 June 2008 (UTC)

Let's keep the tone civil, please. Pinkville (talk) 23:31, 11 June 2008 (UTC)

I am not saying the designations are invalid: in fact, according to the SIMBAD database which I linked earlier, Gliese 581 has 26 designations in various catalogues, however most of these are used in the scientific literature very rarely. The article lead-in states that the planet is "also cataloged as HO Librae c, Wolf 562 c, and HIP 74995 c". This means that somewhere, some catalogue lists the planet under these designations. Can you show me where the planet is catalogued under these designations? I did try to check to find the catalogue which contains this listing. Is it a fact that it is actually catalogued under these designations anywhere? If not, what justification is there for a false claim in the article lead-in? 131.111.8.104 (talk) 23:46, 11 June 2008 (UTC)

you are blathering on about the "c" behing each catalog name. I remember when the "c" was not there, and if that's all that is bothering you then take back the "c" but those catalog names are just as valid as the "Gliese" catalog. Typical of deletionist, everyone else has to do the work of referencing and you get to delete it. ( HO Librae c ) Not everyone has access to every catalog, my most current star atlas doesn't even have planets, and many will be slow to publish updates (new versions) because we are still finding planets, you are simply being very narrow minded about the issue.
Wiki Star catalogue
24.77.204.120 (talk) 05:51, 14 June 2008 (UTC)

Struck out comments by troll. Best just to ignore it. kwami (talk) 10:46, 27 June 2008 (UTC)

Those arguments are referenced and have reasoning, it's no more correct for you to be calling it trolling than it is for anyone else to be calling you a sockpuppet. GabrielVelasquez (talk) 21:44, 5 July 2008 (UTC)

Truth is you have a history [1] of making silly edits that get undone by the regulars here. I find your edits and suggestions startling. You may want to help here but you need to stick to what you know, otherwise you are wasting a lot of peoples time. In terms of the space you should reread the reference you started with, it says the first two were blunders. Leave the space there as every news website editor is going be used to having the space there and all the scientific references I read have the space there. I'm am personally so used to it that I can not comprehend what got into you. GabrielVelasquez (talk) 19:09, 11 July 2008 (UTC)

Anything other than some variation on Gliese 581 c (GJ or Gl, etc.) is pretty nonstandard -- it'll be referred to by that name in the literature. I don't have a strong opinion, but could certainly get behind removing the alternative designations.

J. Langton (talk) 07:26, 21 July 2008 (UTC)

Gonna go ahead and remove these now since no one has said anything about it in a while. J. Langton (talk) 02:42, 18 August 2008 (UTC)

The following discussion is an archived debate of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the debate was retracting move of Gliese 581 c.

Requested move

Gliese 581 c → Gliese 581c — Numeral catalogs normally do not have a space between the system and the object. See Extrasolar planets#Nomenclature — NuclearVacuum 20:12, 1 July 2008 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's naming conventions.

• Oppose - "However, when the catalog has mostly numerals (i.e., PSR B1620-26c and HD 209458b), the space is often (astronomically) omitted, but often this is not done in the general public." - Once again you are misinterpreting things to get your way, and as usual it looks like sabotage and vandalism. This quote said for planets that are mostly numerical, and acnowledges that the general public does not use this format. It says nothing that the space has to be omitted. And certainly these plants are written everywhere on the internet with a space between the star number and the planet letter, Everywhere. You have not provided any referencing links to exterior examples for this concoction. You are try to flip this encyclopedia's astromomy articles upside down for some twisted reason, and not everyone sees it as just your editing. Thankfully all of your damage can be undone. And stop adding fantasy to this article with the sci-fi name Yasmir as though it has scientific significance - "unofficially named" is meaningless here when you are just promoting one person's insignificant work of fiction. 198.163.53.11 (talk) 22:13, 9 July 2008 (UTC)

• Opposed: The editor above says it best, the referencing used in the encyclopdia leaves a space in between the star and planet referencing. I makes no sense to change it for the odd ball out, the first odd planets that were miss-named. This guy must have written it incorrectly in his work of science fiction and so he/she wants to change the whole encyclopedia to coinside with his/her published error, the "Yamir" planet. Next he'll be naming each of them. 24.77.204.120 (talk) 02:10, 10 July 2008 (UTC)

• Oppose ...Great another "genius." What is it with all these guys that need express their own importance by changing the entire system. Listen man, this is not your personal play space: The nomenclature reference is very clear that it was just the first two pulsar planets that were named that way and that commonly the space is there. the editors above are correct, you are ignoring and contradicting your own references. You are going to have to change back all the other articles and redirections that you made because they are all wrong. GabrielVelasquez (talk) 02:37, 10 July 2008 (UTC)

Discussion

• Please see Wikipedia:Requested moves#Backlog and search for "Gliese 581". I'll cross-post an extract here:

• I am not sure about this proposal. Google searches give mixed results for the last year:
  Gliese 581 c gives 1030 while Gliese 581c gives 1310 : [2]
  -84user (talk) 22:11, 9 July 2008 (UTC) ]

• I made the move today based on the fact that the main articles for Gliese 581b and Gliese 581d are titled as they are. I went for consistency withing the group. However, I had not looked at the edit histories on those pages—particularly the relatively recent moves. I'm going looking at the astronomy project to see what's been discussed there. —C.Fred (talk) 02:48, 10 July 2008 (UTC)

• Good idea, consensus is best before you flip the encyclopedia's astromomy section on it's head. GabrielVelasquez (talk) 02:55, 10 July 2008 (UTC)

• Unfortunately, I don't think consensus will be reached here. All I see is two editors at odds with each other. —C.Fred (talk) 03:23, 10 July 2008 (UTC)

• NuclearVacuum has already moved the pages back. I've unwound the rest of my move by restoring the old edit history of Gliese 581c, including restoration of Talk:Gliese 581c. —C.Fred (talk) 03:45, 10 July 2008 (UTC)

• Let me see if I can clarify this a little. According to this discussion, the main reason that the Extrasolar Planet Encyclopedia has spaces is due to software limitations. It is because of this that most online sources have a space. However, proper sites (NASA, ESA, and SIMBAD to name a few) all place follow this "unwritten rule." The title of the article should be named by the astronomical community's writing (which is why I requested these to be moved). But some more than others (i.e. the OGLE requests) are never spaced. Also, I do not believe Google is a good reference to be making your claim, because Google holds not just news and facts, it holds speculation and fiction as well (not being a good way to search the science from the art). Please check it out. [3] [4] [5] — NuclearVacuum 01:12, 10 July 2008 (UTC)

No, you are saying ignore the refrencing that you started with (nomentclaure section), and ignore all the referencing of news articles that we will need in the future. You are not making any sense with that line of reasoning. GabrielVelasquez (talk) 03:21, 10 July 2008 (UTC)

I give up! I can't take this anymore. What do you want me to do now? — NuclearVacuum 03:24, 10 July 2008 (UTC)

Listen, what you are doing was never necessary and a large burden in terms of changes. Put it back in each place where it had spaces, like "Gliese 581 c" both in the article titles/redirects and in the article's body. Please and thanks. GabrielVelasquez (talk) 03:31, 10 July 2008 (UTC)

First off, Stop Using My Name. I am titled to privacy, and now you are just trying to annoy me. Unless you know me in real life, don't use my real name. Call me NuclearVacuum (or NV for short). Secondly, I will revert the planet names, but how will I know whether the space should or should not be used? — NuclearVacuum 03:35, 10 July 2008 (UTC)

Various concerns

I don't want to make any changes to the article until I've posted comments here for review. That said, I think there are a number of issues with the article as it now stands.

What a lie, you have already made changes and they are offensive to some of us. GabrielVelasquez (talk) 00:29, 24 July 2008 (UTC)

No changes were made until this section had been up for at least a day. Sorry if that wasn't long enough. J. Langton (talk) 00:30, 24 July 2008 (UTC)

Okay, went through the record, and it might've not been a full day. Still, there was a pretty substantial window of time to comment before I started messing with stuff. Again, sorry if it wasn't long enough. J. Langton (talk) 01:02, 24 July 2008 (UTC)

1.) I think the "Derivation" section in "Climate and habitability" is probably unnecessary. If Udry et al, etc., published equilibrium calculations of $T_{\rm {eff}}$, then citation of these results should be sufficient, as interested readers could refer to the papers for details of the calculations. It's also worth noting that one has to be a bit careful when the planet is on an eccentric orbit -- the time-averaged insolation received by the planet is not the same as the insolation when the planet is at its average distance from the star (i.e. the semi-major axis) -- it turns out it's increased by a factor of ${\sqrt {1-e^{2}}}$. (The derivation is a little tricky, and outside the scope of the article itself, so please excuse the lack of elaboration here.)

The Urdy paper is definately not enough, god-damn-it, are you on their team? - the fact that there are contradictory scientific papers means that you are violating Wikipedia policy on Neutral points of view; Wikipedia:NPOV. As for your opinion that they are not necessary, you are incorrect as the habitability of this planet has long history of being disputed and those paragraphs tell that history. You make is sound as thought it's a little too much for our little minds to comprehend, but he eccentricity matters because the heat matters. Toronto, Ontario got up to +15°C this past mid-winter at Earth's Perhelion, did you know that?! That is why the perihelion distance is definately important here, it shows planet is not habitable! I just found another reference that says this planet is out of the habitable zone by about 17.5% before factoring in eccentricity, it cites the zone as starting at 0.08 AU and Gliese 581c at 0.073 AU average. [6]. GabrielVelasquez (talk) 00:29, 24 July 2008 (UTC)

2.) The chart of $T_{\rm {eff}}$ with respect to albedo and emissivity doesn't appear to take this into account. Furthermore, it's hard to justify it's inclusion in light of Wikipedia's prohibition on original research. Someone obviously spent a good deal of time preparing it, and it is certainly interesting, but unfortunately it probably shouldn't be in the article. (Sorry!)

So presumptuous, I can't believe you are defending removing this chart using the reasons it is there in the first place. Nothing else in the article suggests that the eccentricity is important, yet it is when you think of how much heat this planet gets at perihelion. The chart makes fools of the Urdy discovery team that only used possible Albedos to misrepresent habitiablity, completely missing the other side of the coin, the Emissivity. The formula there is from the Climate model article and is used in it's basic sense with the data on the planet and star. Mathematicaly, it is like saying words are "original research" because no one has referenced the use individual letters to make words. The referencing for this chart is there. The chart shows all possibilities of combinations of Albedo and Emissivity not like the biased Urdy team. It disproves your team's idea that this planet must be habitiable so it "has to go right away," that's all. GabrielVelasquez (talk) 03:35, 24 July 2008 (UTC)

3.) I'm not sure why the text in "Greenhouse effect" warrants its own section. Is there a reason why this couldn't be included in "Temperature"?

4.) The calculations of the solar constants for Earth, Venus, and Gl 581 c do not appear to be germane, and should probably be considered original research as well. Also, the label is incorrect, as the solar constant is four times the globally-averaged incident flux. I would suggest that this chart be removed as well.

This chart that you removed is of importance

5.) The unequivocal statement in "Liquid Water" that the planet is "outside the habitable zone" is stronger than is justified in the literature. See, for example, Selsis et al. 2007. The von Bloh paper does not appear to have been accepted to a peer-reviewed journal, and is therefore superceded. And even if equal weight is assigned to both papers, the overall body of literature does not rule out the presense of liquid water on Gl 581 c. As a practical matter, I think it's probably unlikely to have surface water, but the cleaest statement of the current knowledge is that liquid water is unlikely but possible.

6.) The planet is unlikely to be tidally locked, due to its non-circular orbit. Instead, eccentric planets are believed to be pseudo-synchronous. See, for example, Hut (1981) or Ivanov & Papaloizou (2001, I think -- also, might have spelled Papaloizou wrong). The basic idea is that the rotation rate of the planet is primarily determined by the orbital speed at periastron, when tidal effects are strongest. In the Hut theory, the planet's rotation is approximately synchronous at periastron. In the I&P theory, the rotation rate ends up being about 1.55 times the orbital angular velocity at periastron.

While the claim of tidal locking is sourced to a Princeton astrophysicist interviewed in an SF Chronicle article, I'd suggest that the peer-reviewed literature would supersede this source. Of course, explaining pseudo-synchronous rotation in sufficiently accessible terms might be a bit problematic. Would it be better to attempt to rewrite the section along these lines, or to delete the "Tidal Locking" section entirely.

7.) For reasons given earlier on the talk page, I think that the "Artists Impressions" section should be deleted.

I have not made any changes to the article itself, and I won't until interested editors have a chance to respond to discuss these issues. —Preceding unsigned comment added by J. Langton (talk • contribs) 07:12, 21 July 2008 (UTC)

Okay, I've looked into this a little bit further, and it looks like the von Bloh paper is in A&A: see http://www.aanda.org/index.php?option=article&access=bibcode&bibcode=2007A%2526A...476.1365VPDF

Tomorrow, I'll try to go through and update this reference, as it appears in more than a few articles. I still maintain that it's too strong to claim that gl 581 c has been "shown" to lie outside the habitable zone, in light of the other reference, although a more thorough lit search is probably in order.
J. Langton (talk) 10:17, 21 July 2008 (UTC)

Hi J.Langton -are you the guy from oklo.org? It's an honour to have you here and I agree with your concerns. I just wanted to say that, about 6), shouldn't mentioning Mercury pseudo-synchronous rotation be enough to give a concrete example of that to the reader? --Cyclopia (talk) 16:05, 21 July 2008 (UTC)

Hi, and thanks for the warm welcome! I don't post at oklo, but I work for the guy who runs it, and he posts my stuff up there from time to time. Regarding Mercury: that is technically not pseudo-synchronous rotation, wherein the ratio of orbital to rotation periods is irrational. Rather, it's a spin-orbit resonance, wherein this ratio is rational (i.e. 2:1, 3:2, etc.). As I understand it -- and I certainly can't claim to be any kind of expert in tidal theory -- there are significant differences in the mechanism, or at least the mathematics that describe the mechanism, in each case.

As far as other editing stuff goes, the von Bloh article has been used as a reference for statements which are not in actuality supported by this article, and which are furthermore of dubious veracity. I'm gonna go ahead and delete those statements.

J. Langton (talk) 18:38, 21 July 2008 (UTC)

Okay, rereading the Hut paper. Mercury's 3:2 orbit actual isand example of pseudosynchronization. Since it's a rocky body, it can maintain a permanent deformation (unlike a gas giant), and that's the reason for the 3:2 resonance as opposed to what you'd expect with a jovian planet. The Ivanov and Papaloizou analysis applies to "fully convective planets" (i.e. gas giants) and therefore it's questionable whether it applies to Gl 581 c. More stuff below. J. Langton (talk) 15:01, 16 August 2008 (UTC)

First of all, it has to be made clear you are so full of yourself. You are either a sockpuppet of this user:Cyclopia or you are a research competitor of this "von Bloh" and want to minimise the use of that paper as a reference. Before you ever came along this article was full of suggestions that the planet was habitable and like the Earth. There was all kinds of discussion that is now archive and that you think you can get away with bushing aside. It was given a balancing point of view, and a non-media hyped realistic view of the planet's habitiablility. As for you precious points, just reading your first point above tells me you are false. That this planet is not habitable is one of the easiest things to prove. And that von Bloh reference is a scientific paper that is thoroughly reference. I think rather that your presence here is what is "dubious." The eccentricity of the planet is very important, especially important to the fact that the planet gets more than twice as much heat as Venus, so your removing all the references to is very "dubious." --GabrielVelasquez (talk) 00:01, 24 July 2008 (UTC)

I intend to get to everyone of your points after I have discussed this as a sockpuppet case in the proper venue. GabrielVelasquez (talk) 00:01, 24 July 2008 (UTC)

GabrielVelasquez, I'm not sure what I've done to rub you the wrong way, but whatever it is, I'm sorry. That said, please bear in mind WP:CIV, WP:AGF, and WP:NPA.

With that out of the way, to address your substantive points: (unindenting now)

1.) Habitability. To my knowledge, two studies of the habilitability of planets in the Gl 581 system have been published in peer-reviewed journals: van Bloh et al. (2007) and Selsis et al. (2007). There may be others, but I'm unaware of them, and they haven't been cited here. I'll certainly do a more thorough search at some point in the next few weeks.

Van Bloh simply assumes, much as you do, that since the top of the atmosphere of Gl 581 c receives more insolation than Venus, it must be inhabitable. The rest of his paper focuses on Gl 581 d, which they consider to be a more promising candidate. Selsis, by contrast, looks at 581 c in more detail, and calculates that if the day side of the planet has >75% cloud cover, sufficient insolation would be blocked to admit the presence of liquid water. Whether you or I or any other editor disagrees with that conclusion is irrelevant; it's only what has been published in the peer-reviewed literature that matters. If you can find another reliable source that takes issue with the Selsis results, then feel free to include that. Unfortunately, even if you or I personally feel that they're wrong, there's nothing that we can do to prevent the Selsis result from being worthy of inclusion into the wikipedia article, short of publishing contravening calculations in a peer-reviewed journal. Otherwise, you're violating WP:NOR,WP:RS, and WP:SPS.

This is just not true, I have read the van Bloh paper and it thoroughly covers both planets with their data, theories, and thorough referencing. The paper says in it "Received June 15, 2007; accepted October 26, 2007" and I don't kow the specifics of peer-reviewing papers but that statement seems obvious to me. GabrielVelasquez (talk) 05:43, 24 July 2008 (UTC)

2.) Eccentricity. I never said the eccentricity didn't matter. It does, and your calculations did not properly take it into account. (Disclaimer: the following is WP:OR, so I'm not advocating that it be added to the article. It is, however, pertinent to the discussion in the talk page.) Because the eccentricity is fairly small, the radiative time-scale at STP is on the order of a week, and the orbit is 12 days, the actual time-variation insolation over the orbit is not likely to be a first-order effect. The relevant question, then, is the time-averaged solar constant, and it turns out that this is not equal to the solar constant at the average planet-star separation except when the orbit is circular. The higher the eccentricity, the higher the time-averaged insolation -- as I said before (although I was a bit unclear), you get this by multiplying what you're calling the "average insolation" by $1/{\sqrt {1-e^{2}}}$.

And you have the nerve to talk about other peoples original research. Again, from above:
"I just found another reference that says this planet is out of the habitable zone by about 17.5% before factoring in eccentricity, it cites the zone as starting at 0.08 AU and Gliese 581c at 0.073 AU average. [7]."
I want you to know that "time-averaged solar constant" was the next step in my research and I was going to look at all 307 planets again to factor in the orbit periods to more realistically look at the habitability of those planets (planet's moons). But I don't like how you are ignoring the obvious, 505% of the heat the Earth receives is not insignificant.
GabrielVelasquez (talk) 05:26, 24 July 2008 (UTC)

I'm not trying to put my original research into the article, that's the difference. Also, I don't know that I'd consider your reference to be WP:RS. Blogs, web pages, etc., generally fall under the purview of WP:SPS -- there's no evidence that the planetarybiology.com website has at any point been subject to any peer-review or editing process.

Also, any chance of adding new replies to the bottom? I'm getting a bit confused looking for stuff in the middle of my great big wall o' text.
J. Langton (talk) 05:44, 24 July 2008 (UTC)

I find this so annoying, I would be willing to bet you didn't even read all the discussions on the talkpage on these topics that have been re-organized and archived. GabrielVelasquez (talk) 22:17, 27 July 2008 (UTC)

3.) Udry et al. I'm not on the Udry team. I have professional respect for Udry's work -- he's a good planet finder -- and that's the extent of the relationship. I'd be surprised if he'd even heard of me.

With that said, the numbers he published are equilibrium temperatures, ignoring the effects of atmospheres. Without having looked carefully at the Udry et al. paper yet, I'd be pretty surprised if they weren't clear on this point. Like you, I think that their calculations probably didn't take eccentricity into account -- they were probably missing that $1/{\sqrt {1-e^{2}}}$ factor. (Since temp goes as the fourth root of luminosity, the effect of this omission is probably small.) However, since I haven't published these finding in a reliable non-self-published source, I can't put my objections into the article. It's really nothing personal with you -- I'm just trying to follow WP's guidelines for what can and cannot be included in articles.

4.) The albedo/emissivity chart. This is a pretty clear case of synthesis. The formulae are reliably sourced, but as I understand it, actually plugging in numbers and applying it to a particular planet would be considered "synthesis of published materials," which is verboten. In that sense, it's considered original research and shouldn't be in the article.

I also have to point out that the "albedo/emissivity chart" doesn't really "make fools out of the Udry team." The equations used don't really give any information about temperature variation with altitude -- it's basically giving you an effective temperature: if you had a spherical body with some known albedo and some known emissivity and no atmosphere, then the formula would give you the surface temperature of such a sphere. In the presence of an atmosphere, the problem becomes way more complex; you actually have to start using the equations of radiative transfer.

As a matter of fact, it's quite easy to construct a plausible scenario in which the surface might be cool: Due to internal heating by eccentricity tides, if the planet is terrestrial, you would expect a great deal of geological activity -- earthquakes, volcanoes, the like. Volcanic eruptions, while known to emit carbon dioxide, also add a lot of dust to the atmosphere. Sufficient dust in the atmosphere would block much of the incoming sunlight, reducing surface temperatures to a more comfortable level that one might ordinarily expect. There are plenty of other possibilities: clouds, photochemical haze (unlikely because Gl 581 is a red dwarf, which emits little UV), very high albedo -- if the planet were entirely frozen, it wouldn't heat up because the icy surface would reflect too much incident sunlight. I don't think any of these scenarios are likely, but they're not ruled out by current information.

In the absence of any information regarding the atmospheric composition and structure, the claim that Gl 581 c is definitely not habitable is unsupportable. The strongest position that one should take is that it is unlikely to be habitable. This just happens to be the same position held by the body of literature on the subject.

J. Langton (talk) 05:36, 24 July 2008 (UTC)

I haven't read all of your typing yet but I have to sign off for the night, I am not opposed to "unlikely to be habitable," I'm just tired of seeing e-newspaper articles referenced here that practically have a picture of a fucking fire-trucking hotel and with a reservations accepted sign. 505% of the heat the Earth recieves man, what does that mean to you. GabrielVelasquez (talk) 05:46, 24 July 2008 (UTC)

Um, yeah, sorry about the wall o' text... I get a bit carried away with this stuff.

The problem with the whole "505%" thing is that 5x the insolation at the top of the atmosphere does not necessarily equate to 5x the insolation at the surface. The effect the atmosphere has as far as where that energy ends up -- scattered back into space, absorbed and reradiated in the upper atmosphere, trapped near the surface via a runaway greenhouse effect, etc. -- is huuuuuuuge. We don't know anything about the atmosphere, so it's not really as cut and dried as you might initially think. I agree with you that some of the media coverage has been a bit more cheerleader-ish than is warranted, and don't particularly want to see that stuff in the article either. What would be useful to incorporate is a presentation of the literature's discussion of what would be required for Gl 581 c to actually be habitable. The Selsis paper has a pretty nice treatment, although it's a bit scattered here and there -- still worth a pretty close look if you get a chance. G'nite; I'll look forward to continuing this tomorrow!

J. Langton (talk) 05:55, 24 July 2008 (UTC)

(unindent) GV, I reverted your edits, as the material that was added was unsourced OR. If you can provide sources for the material you re-inserted, then I'm happy to let it stand pending resolution of outstanding issues on this talk page. Unsourced material, whether correct or not, I have to take down immediately. I hope you understand that this isn't a matter of me enforcing my personal views, but Wikipedia policy. J. Langton (talk) 14:45, 24 July 2008 (UTC)

Upon reflection, I realized that adding synthesis and OR tags was a better course of action than simply reverting, so I reverted my revert and added the tags, pending the outcome of this discussion. J. Langton (talk) 15:39, 24 July 2008 (UTC)

Re: van Bloh et al.
GV said:

This is just not true, I have read the van Bloh paper and it thoroughly covers both planets with their data, theories, and thorough referencing. The paper says in it "Received June 15, 2007; accepted October 26, 2007" and I don't kow the specifics of peer-reviewing papers but that statement seems obvious to me. GabrielVelasquez (talk) 05:43, 24 July 2008 (UTC)

The relevant paragraph in the paper (2nd parapgraph, section 3) reads

"The planet Gl 581 c is clearly outside the habitable zone for all three luminosities. The luminosity of the central star would have to be as low as L=0.0045 L_sun to yield habitable solutions for this planet. It should be pointed out that Gl 581 c is closer to its parent star than Venus to the Sun, even with the stellar luminosity scaled accordingly. The results for Gl 581 d are much more encouraging..."

Further discussion focuses on Gl 581 d. For a thorough discussion of the habitability of Gl 581 c, Selsis is the more useful paper. However, since we have used von Bloh as a reference, I'm not sure what the issue here is.
J. Langton (talk) 14:56, 24 July 2008 (UTC)

Reasonable Conclusions that have not been published (my own wall of text)

J.Langton,
I was just going to keep adding comments indented between the paragraphs that you have written but after reading the later parts of what you have written I thought I should seperate this to cover all the points at once and to resign myself to the facts of the matter.
It is easy for you to wield these concepts and blend them with hypothesis to point this article where you want it to be for whatever purpose as there doesn't seem to be alot of interest in getting to the serious study of the planet Gliese 581 c. But as a layman hobbiest I have invested a lot of time in understanding extra solar planet science because of my interest in extra solar planets and random solar system generators. I am not going to dispute the issue that what I have added should not be there without proper referencing, but I am very disappointed when someone like yourself, a professed professional in the field, who should know better starts using their bias and training to get there way. I will stand by the fact that the Urdy team do not know the albedo of the planet and so their speculations are not any better than someone elses speculations who uses both albedo and emissivity. I made that chart, I added it to the article, and for what it's worth it works out to 14°C if you plug in the numbers for the Sun and the Earth, as well as for Venus' figures, and the others I am sure, so I trust the results, much more than I trust the Urdy's team's simplistic speculations. I think your arguments are admmitedly weak, "I don't think any of these scenarios are likely, but they're not ruled out by current information" you wrote above. I reconsider that period-balanced-eccentricity-heat idea as it is extremely hot perihelion to average to aphelion, through and through. Now you want to consider possible cooling situations but these factors complicate things on the concommitant dimensions, being that if the albedo where high enough to reflect the enormous amount of heat then that kind of atmosphere would itself be toxic and not at all habitable. for me whichever way you present it, you tip it, the balance, of flip side of the argument adds up to it not being habitable. I am sorry to say I have not put the effort into finding more reliable references that support this fact. I keep relearning that intelligent concusions are not enough, they have to be published intelligent conclusions that have been peer-reviewed for them to be accepted in wikipedia. I added the insolation/irridiance chart as well in case you didn't guess, and those calculations are also sound. But they won't be used here because no respectable scientist is willing to shoot themselves in the foot and contradict speculation that brings more prestege to their particular field. The hope that Gliese 581 c is habitable sells more copy and brings more funding so why bother to publish anything to the contrary. I got the 505% from combining two different luminosity formulas and solving for the irradiance, and that one did factor in the eccentricity. If you are a professional in the field then take an honest look at the formulas and see if you don't know anyone who might be interested in publishing them. I don't take credit for them, they are basic and general enough that they speak for themselves. It doesn't matter that the Albedo/Emmisivity chart/formula doesn't factor in eccentricity, it is there to show all possibilities for the average distance and it is as good an estimate as can generally be made given that it results in Earth's global average with that data. I am not arguing that they should be used without referencing. I am just saying that they are useful tools that do say something about Gliese 581 c, and that someone should have published those figures by now. Hopefully someone will and they can be returned to the article. GabrielVelasquez (talk) 22:17, 27 July 2008 (UTC)

Wall? more like brick. :P But I agree people who don't favor the habitable hypothesis have no real incentive to publish their findings. Maybe you could volunteer to write an article for Scientific american about it?--Marhawkman (talk) 10:08, 28 July 2008 (UTC)

You are mocking me both ways after what I wrote. I was not the first to use the term wall. And, as I said I don't even have any university background in the area so no one is going to publish me. GabrielVelasquez (talk) 21:03, 30 July 2008 (UTC)

Just as a point of clarification: neither of the habitability studies published so far "favor" the habitable hypothesis. It's just that there simply isn't enough information to rule out habitability at this stage. Therefore, the scientifically responsible position -- and this is well reflected in the literature, and in the article as well now, is that habitability is highly unlikely, but is not impossible.

@GV: Your calculations of the solar constant -- barring a few more decimal places than they should have, you do have to pay attention to sig figs! -- are basically correct. (It's not correct to refer to the solar constant as "average flux" and that's what I was complaining about.) The time-averaging, as I discussed above, is something that you haven't yet successfully accounted for, due to the difficulties posed by eccentric orbits. Unfortunately, the albedo/emissivity formulation doesn't really capture the whole picture, and therefore you can't use the insolation charts to draw any firm conclusions regarding habitability. As a "professional in the field," I can tell you that merely calculating incoming irradiation is not publishable -- to produce something that a journal would be interested in publishing, you would need to develop some kind of habitability model, the way that van Bloh and Selsis do. The time-varying insolation is merely the input to the model, you don't a priori know what the response of the model to that input is going to be. It depends on a lot of other factors, like cloud cover, geological activity, etc. I'm not saying this to discourage you from contributing to the field; just trying to give you a sense of what you'll need to do if you want to contribute.

FWIW, I don't think that anyone is making their entire career based on Gl 581 c. It's obviously a more interesting planet if it's habitable, but right now we simply don't have enough data on any one exoplanet that anybody can spend their entire lives studying that one world to the exclusion of all others. So the implication that there's some kind of a cabal of astronomers that are interested in squelching any analysis that shows Gl 581 c to be inhospitable is completely unfounded. Personally, Gl 581 c is a world that I have very little professional interest in -- my atmosphere models are geared towards gas giants, and so nothing that I can do with Gl 581 c at this point is likely to be useful. J. Langton (talk) 00:01, 29 July 2008 (UTC)

I will say it again a different way. "Habitable zone" is one dimensional for the most part, so far. I don't see that so many places hyping that these planets may be in the "habitable zone" when they are not (AANDA press release) is so much better than going out on limb and using two or more dimensions (ie. albedo and emissivity) to make a simple (but not too simple) comparision between Earth and Gliese 581 c. I personally would like to see as many dimensions to the puzzle factored in as possible (all planets) and the whole range of possibilities explored but that's not easy to display. I think that these two dimensions cover enough and when the calculations works out to nearly exacly Earth's global average (14°C) the comparision is worth making. You keep putting it down as too simplistic, but the habitable zone speculation is worse. You keep mentioning that it should be more dimensions because your work biases your view of what is simple good and what is simple bad. You keep saying time averaging is important but I know that's not going to make the result less hot than Venus, so may be not 505% but more than 265% when Venus averages 191% is not any less hot. I am for including that chart in the article [8],and I believe we can if we credit them using a link as a reference. Also, please explain to me why you left some artistic impressions and deleted others, without telling me please it was somthing as irrelevant as the (changable) file name. Also, did you or did you not read what has been archived from here before you started editing? by the way, NASA is teaching that Albedo/Emissivity formula to kids in grade NINE ("Clouds and the Earth's Radiant Energy System").GabrielVelasquez (talk) 21:03, 30 July 2008 (UTC)

Quick reply: The artist impression that I left seemed to me to be more properly sourced (after following the links). With that said, "artist's impressions" of exoplanets are renowned for being unreliable, so I don't have a problem with it's removal -- I think you're correct that constency demands that all artist's impressions be removed.

(1) Interlineated for simplicity. [Image:Gliese_581_c_-_Sarah_Seagers_GAS_DWARF_Example.gif] - I hope this is not what you were originally refering to when you wanted to leave some images and remove others. I just changed the name of the file to whatever I want. Incidentally, I think it was january or feburary Sky & Telescope that Dr. Sarah Seager published and article that illustrated several possibilities of a five Earth-mass planet.

Second, the repeated claim of bias is unwarranted, as I have explained several times, and violates WP:AGF. Please don't make this accusation again. Once more, for clarity: I have nothing at stake in the discovery of a potentially habitable exoplanet. I think it would be awesome, but from a professional standpoint, I don't really have anything to gain by trying to convince people that a planet is habitable when it's not.

(2) I disagree. I'm sorry it bothers you, but I have been told at least once while editing by and administrator that I was too close to the subject matter and I should back off from editing a particular article. My general overview of your edits tells me to watch out for your angle of approch, I just don't trust you. I don't see you doing a rewrite of the article that re-check all the referencing, just what conflicts with your time-factored doctoral thesis maybe. And I don't see anything wrong with neutrality reminders.

Thirdly, the main point I've been trying to make regarding your insolation chart is that the mere fact that the top of the planet's atmosphere receives more irradiation than the top of the Venusian atmosphere is not sufficient reason for concluding that the planet must be hotter than Venus. Even if it were, it would count as WP:OR or WP:SPS unless you got your findings published in a WP:RS. The unpublishability of your work has nothing to do with your credentials, and everything to do with the fact that you're not properly considering the effects of the atmosphere.

(3) I would like to consider the effects of the atmosphere, and I believe I am in agreement with NASA that the formula they use and are teaching to grade nine students does factor in the atmosphere. This is the kind of thing I am talking about with trust, it is easy to quote policy like WP:AGF and then give me reason to distrust. I trust NASA, you contradict NASA, I must distrust you, simple logic. I don't mean to be agrivating, there is my intuition's warning crystalized by simple logic.

Fourthly, "emissivity" is, in this context, basically a parametrization of the greenhouse effect. To actually determine what the emissivity is for a given planet, you'd need to do some pretty detailed atmospheric modeling -- using a line-by-line radiative transfer code, perhaps. This is a highly non-trivial project. —Preceding unsigned comment added by J. Langton (talk • contribs) 22:40, 30 July 2008 (UTC)

(4) I don't mean to go in circles here, I believe the emissivity factor includes or covers the greenhouse gas effect or I wouldn't be getting absoulte zero across the board for all Albedos when I set that variable in the formula (sorry NASA's formula) to zero. I appreciate that you could get really specific data with your computations, maybe even weather simulations, but something as simple as a global average temperature, as that formula correctly results in (14°) for the Earth (what a fluke for NASA) is enough for a simple comparision. I personally don't need a Cray computer to crunch the numbers for me. For a professional in the field I guess you need to qualify the numbers from 0.0 to 1.0 (emissivity) but I think that it speaks for it self as 0% and 100% and I am satisfied with that for a simple comparison of global average temperatures using all possibilies of Albedo and Emissivity, thank you NASA. Again, I hope someone publishes it specifically on Gliese 581 c so we can return it to the article. GabrielVelasquez (talk) 00:52, 31 July 2008 (UTC)

(Unindent)

In response to the numbered points above:

1.) My recollection from the earlier discussion on the talk page was that no proper source had been provided for the images that I removed. If I was mistaken -- and please make sure that an actual link is available, as they really need to be cited in the article -- then the issue could be revisited. As a matter of principle, though, I'd still prefer not to have artist's impressions in the article. I think that they're generally not very good -- even the ones in S&T. That's just my opinion, though; I'm happy to go with whatever the consensus ends up being regarding the inclusion of well-sourced illustrations.

2.) I'm going to remand further discussion of this issue to our talk pages, as it's not immediately relevant to the topic at hand. I'll respond to this when I get around to it.

3, 4.) I'm not contradicting the NASA equation; I just think you've misapplied it. It's useful if and only if you have a pretty good idea what the emissivity and albedo are. The trouble is that the emissivity could literally be anything between 0 (for a super-Venus) and 1 (for a Chthonian with no atmosphere). The albedo is somewhat more constrained, but could vary dramatically depending on if the planet is, for example, an ice world (see Snowball Earth) or is covered in highly reflective clouds, or if it has a lot of dark dust in the atmosphere. So that equation doesn't really give you useful information about the temperature, and you unfortunately have to turn to the type of model that I was talking about to figure out what the surface of the planet might be like.

Putting this in slightly different terms: the reason the NASA formula works so well for Earth's temperature is that the emissivity has been chosen to give the correct temperature. Emissivity is defined as the ratio of energy radiated by an object to the energy radiated by a blackbody at the same temperature. So if you measure Earth's temperature and then use that to calculate the emissivity, it's entirely unsurprising that when you go back and plug that emissivity into the equation, you get the correct temperature. Now, if you use a model atmosphere to figure out what the emissivity should be, and that gives you the right temperature, that's a different story.

None of this invalidates the primary point I've been trying to make all along, which is that the insolation, in the absence of any other considerations, is not sufficient to place useful whatsoever on the surface temperature in this case.

Actually, that's the secondary point. The primary point is that none of this discussion can go into the article unless it's included in a reliable source. Unfortunately, any of the unpublished musings that you or I, or anyone else, for that matter, might come up with, no matter how intelligent, no matter how correct, do not rise to this level.

J. Langton (talk) 04:42, 31 July 2008 (UTC)

Aside from the referencing issue, which I acknowledge a while ago, I don't agree with you because in part we are talking around eachother. my perspective is that when you have scientist stating their assumptions as important probabilities, then you have situations where the general public and the media do a "touchdown dance" because they find a planet that they think will probably be in the so-called "Habitable Zone" and then you get all this hype and nonsensical points with useless referencing being added to this article. All on the basis of weak assumption and speculation on "habitability." I have never disagree with you that atmosphere models are great, I wish I had one, I am working to broadly in all aspects at my own pace to have finish any one thing, but when you say it is all important and no simple conclusions can be made, that they have to be complex analysis then you are contradicting every other scientist who has hyped (added to the hype) that this planet is a twin of Earth (is that reference still there), that the the single dimensional idea of "Habitable zone" (too simple) is of prime importance, that the size of the planet is like Earth (when the sane perspective is that it is just farther from Jupiter size) (also too simple) is of prime importance. I don't disagree that this planet could be a Chthonian, but I would never suggest that it could be an ice planet. I don't see that ignoring the amount of heat that this planet gets, averaged or not, is something that any (or any "habitable") atmosphere will abate, otherwise it's like saying that Venus could be an Ice Ball after all under that thick carbon dioxide atmosphere, and I don't mean to throw that in your face but you really are ignoring that. I won't argue with the possibilities of the composition of atmosphere, but simple disagree that on whether those possibilites can or can not be represented simply. I see your point that if you had a complex atmosphere model and the figures covered many dimensions over broad areas in each dimension of factoring in what takes place in an atmosphere that you may or may not come up with an over all emissivity factor of 0.62 for the Earth. But because NASA has done (that fomula is incomplete and I may have gotten mine elsewhere) that it looks to me that it can be used as a standard to represent all possibilities of at least the percentage of greehouse gases or just the percent of the effect of the greenhouse gases, and I will say once again that don't think that is such a small and too simplistic thing given all the other hype that has been generated using mono-dimensional parameterization. I don't think we are talking about the same thing. One is all the things that go on in an atmosphere and one is the single number representation of all of that as mearly on factor in formula. It doesn't invalidate the idea that you don't include the entire computer models worth of figureing behind that one range of numbers. I won't re-add it to the article because no one has published it, but I don't see anything wrong with showing all of the possibilies of temperature in line with all Albedos and all Emissivity possibilities. For me it says the atmosphere would have to have this percent of greenhouse gases or a precent of a greenhouse gas effect along with that albedo to have a given temperature. Show me that those temperatures in the chart (which is still above if not in the article) are not at all the probable range of the planet's surface temperature (Ice planet is there, just to me not a probable combination) and I will concede that I am wrong.GabrielVelasquez (talk) 16:50, 2 August 2008 (UTC)

Using that simple formula, if you plug in the Albedo of Venus and the Emissivity of Earth you end up with 31°C (sill habitable), which is not my issue, my issue is how probable is that atmosphere, that combination, and wouldn't it be toxic to breath??GabrielVelasquez (talk) 16:57, 2 August 2008 (UTC)

"Xavier Delfosse of the research team admits possible greenhouse gases in the planet's atmosphere are not being considered and so expects that the actual surface temperatures will be hotter; for instance, the corresponding calculation for Earth yields an "effective surface temperature" of 256 K/−17.15°C/1.13°F, yet Earth's true surface is 32 K warmer (an average of 288 K/14.85°C/58.73°F) due to the greenhouse effect." - I think it is worth noting that you are not taking issue with this atmosphere model, or lack of atmosphere model by your argumentation. GabrielVelasquez (talk) 17:48, 2 August 2008 (UTC)

I've not read your comments here thoroughly, as I have important video games to play this afternoon! I'll come back to it later if need be. A couple quick points:

1.) I agree that hyping Gl 581 c as a "twin" of Earth is irresponsible. I've not been doing so, and I don't advocate doing so in this article. However, claiming that it's definitely got a Venusian runaway greenhouse is no more responsible. The article should reflect the imperfect knowledge that we currently possess.

2.) Aside from OR concerns, the other problem with the emissivity/albedo chart is that it doesn't really constrain the temperature range at all. With an albedo of 1, the planet is at absolute zero. As emissivity approaches zero, the temperature increases without bound. Since the planetary albedo could be anywhere from ~0 to 0.9, and the emissivity could be between 0.01 and 1. That doesn't tell you much about what the temperature is -- I don't have the numbers handy, but I'm sure you could plug in and you'd find a very large range of possible temperatures. J. Langton (talk) 20:24, 2 August 2008 (UTC)

http://en.wikipedia.org/wiki/Talk:Gliese_581_c#More_accurate_formula

No Kidding, wide range? - what I said was all possible, rather than two.

GabrielVelasquez (talk) 02:55, 18 September 2008 (UTC)

Chart from Astonomy and Astrophysics

File:Gliese 581 Planets and Zones www.aanda.org 275-42.gif

http://www.aanda.org/content/view/275/42/lang,en/
show me what you mean by proper referencing?
GabrielVelasquez (talk) 17:30, 2 August 2008 (UTC)

Well, in this context, it would probably refer to peer-reviewed articles rather than to press releases. I would have no objection to including the graphic in the article -- it's a pretty decent one. Still, Selsis's calculation that Gl 581 c could have liquid water given 75% or greater cloud cover supercedes any blanket claim to the contrary made in the press release. The scientifically responsible position, as I've said numerous times, is that Gl 581 c is unlikely to be habitable, but habitability cannot be ruled out without a more detailed understanding of the planet's atmosphere. Do you disagree with this assessment? J. Langton (talk) 20:13, 2 August 2008 (UTC)

Bah... It's not our job to "decide" what to write. Merely to represent what others have written. thus the article needs to examine all possibilities that have been seriously considered in scientific literature.--Marhawkman (talk) 07:11, 3 August 2008 (UTC)

I don't disagree that that is scientifically responsible, but since you have several times reminded me, we have to be Wikipedia responsible first. Although I dislike it very much, this "Encyclopedia" does pander to the popular press/media and popular ideas. As I said before, clean out all the crap referencing and you can quote what ever is left. GabrielVelasquez (talk) 21:36, 12 August 2008 (UTC)

There is a balance between the two. While we need to cover everything, we also need to do so from an objective point of view. In otherwords, even though we need to cover the habitability aspect we should also write it to indicate that it is now considered to be almost certainly uninhabitable. So, in short, why did people think it might be habitable, and why it's beleived to be uninhabitable. "Pandering" is the result of crappy article writing. Feel free to cite any journals you want. It's just that we can't simply ignore the press reports. Honestly the way it's written right now looks pretty good to me.--Marhawkman (talk) 10:55, 14 August 2008 (UTC)

Apparently, there is an unspoken consensus in some circles is that only peer-reviewed literature provides appropriate sources for scientific topics on wikipedia. I think that's too restrictive, but I do think one needs to be very careful when dealing with press releases and newspaper summaries, etc., instead of journal publications -- the "popular media" sources at the very least miss the nuances, and sometimes outright get stuff wrong.

Regarding the question of habitability -- and I'm sorry to keep repeating myself, but apparently it bears repeating -- to say that Gl 581 c is "almost certainly uninhabitable" is not justified. It is "probably" uninhabitable. While neither Selsis nor von Bloh are particularly sanguine about the prospects for habitability, Selsis give specific conditions under which the planet would be inhabitable, namely, thick cloud cover. They also consider the possibility of an "ice planet" scenario, where the entire surface of the planet is covered in highly reflective ice, which prevents the planet from absorbing incident sunlight. So the possibility that the planet is to cold to be habitable hasn't been ruled out.

I think the current wording (or at least, last I checked) accurately reflects the current situation, although it could perhaps be made a bit more explicit. There are some other issues (tidal locking) that need to be looked at; just haven't had the time to work on it yet. Also, GV, apparently the A&A picture got deleted from WM commons. I don't think we need both habitability diagrams, but the A&A one is probably preferable to the one that's currently up there. J. Langton (talk) 18:13, 14 August 2008 (UTC)

Yeah, press reports have little if any useful information. They'd probably be best used as "inspiration" for the topics the article should cover.

As for Tidal locking, I think it's a bit premature to go indepth there. We simply don't know enough to do more than make a few wild guesses.--Marhawkman (talk) 09:10, 16 August 2008 (UTC)

There's actually a fair amount of literature on tidal theory as it relates to planetary rotation rates. The downside is that it's really, really hard to follow -- more math than you can shake a stick at. According to Hut (1981), due to the fact that tidal strength is stronger near periastron than elsewhere in the orbit, an eccentric orbit will always lead to a pseudosynchronous rotation period which is shorter than the orbital period. Mercury may well be the best example of a rocky planet in pseudosynchronous orbit. If I understand Hut correctly, 1:1 synchronization is unlikely, but I should spend more time looking through the paper to check. Incidentally, it's available here. J. Langton (talk) 15:23, 16 August 2008 (UTC)

I didn't mean tidal locking itself, I meant Tidal locking as it applies to C. We don't know enough about c to calculate what sort of lock there might be. We do know there probably is one, but not what.--Marhawkman (talk) 04:00, 17 August 2008 (UTC)

I think citation of Hut's paper would be appropriate, as well as a reference to the fact that orbits with significant eccentricity are generally pseudosynchronous (also courtesy of Hut) would be appropriate. I agree that any specific claim as to the rotation period would be out of place, if that's what you meant. I bet it's right around 5:4, though. :) J. Langton (talk) 01:55, 18 August 2008 (UTC)

Globalize tag

I'm not sure exactly why it's up there. GV, would you mind explaining what needs to be fixed? J. Langton (talk) 00:56, 15 August 2008 (UTC)

Who put up the tag saying that the article doesn't represent a worldwide view? I think it's absurd. If no one can justify it, it should be removed. I also disagree with the tag saying that the article is too technical. And while we're at it, why did the discussion in this article, which is light-years away from the usual controversial topics on Earth that people flame about, get so nasty? It really makes Wikipedia look bad. Vegasprof (talk) 08:18, 17 August 2008 (UTC)

Since GV hasn't responded here, I'm going to go ahead and remove the worldwide view tag. I agree that the technical tag is out of place as well; if nobody objects within the next 24 hours, I'll take that down as well.

As to the other question, well, I don't really know. I made some rather bold edits and I think it rubbed GV the wrong way. J. Langton (talk) 01:58, 18 August 2008 (UTC)

Sorry, I was camping in BC for two weeks. I added the tag just because I came across it and found it ironic, and thought it said something of the idea of having as many (verifiable) persectives in the article as possible. that's all. GabrielVelasquez (talk) 18:36, 18 August 2008 (UTC)

Heh, okay. I though it was more of a worldwide perspective kind of thing... Also, do we still need the technical tag on the talk page? I think it's pretty straightforward at the moment. J. Langton (talk) 19:26, 18 August 2008 (UTC)

Technical tag gone. Do we still need the ActiveDiscuss tag on the front page? I think most of the contentious issues have been resolved at this point. J. Langton (talk) 13:47, 19 August 2008 (UTC)

De-emphasize Habitability

The reason for the habitability hype over Gliese 581c is that the word "Habitable" appeared in the origintal title of the paper. Udry changed the title about 2 days later, which shows that he realizes it was a mistake. (Nothing against you personally, Stephane. You and your team are to be congratulated for finding the planet.) There is now no particular reason to have a long discussion about habitability of this planet in particular, as opposed to extrasolar planets in general. (A short discussion, pershaps.) The references to interstellar travel are silly, since Gliese 581c is now very far down the list (if there is a list) of planets to visit, since it is not that promising (in the search for life sense) and much farther away than some others. In the initial burst of excitement after the original article, people got carried away. Let's clean the article up and make it what it should be: just a matter-of-fact scientific article about a more-interesting-than-average member of a large class of interesting things. Vegasprof (talk) 08:38, 17 August 2008 (UTC)

well.... this planet has had more indepth habitability studies done than most. The current wording of this article does not convey the impression that it might be habitable. 581D might still be worth visiting. So if people do start exploring the vast reaches of space they might go there anyways. oops... --Marhawkman (talk) 07:14, 18 August 2008 (UTC)

I think that a fair amount of discussion of habitability is warranted, for two reasons. First, there actually is a reasonable amount of scientific literature analyzing the habitability; discussion of these articles (von Bloh 2007 and Selsis 2007, I believe) is worthwhile and adds to the WP article as a whole. Secondly, and perhaps most importantly, the amount of media attention this planet has received is due to purported (and ill-advised) claims of habitability in press releases, newspaper stories, and other non-peer-reviewed sources. Because of that, I think additional emphasis on presenting the results of scientific studies of habitability is a good idea. I also think that for the most part, the content of the article accurately presents the current scientific understanding of the habitability, although the organization and such might leave something to be desired. (I've been meaning to muck around with that, but I've been too lazy.) J. Langton (talk) 02:07, 18 August 2008 (UTC)

alternative designations

HO Librae C is from a designation as a variable. Wolf(something or other) c is from the wolf catalog of stars. It's rarely used as the Wolf catalog is obsolete. Ymir is pointless as it was only used by the dimwits who forgot to double check their data and thought it was habitable. I'd still keep them and metion that it has these other names, just kinda push it off to the side.--Marhawkman (talk) 07:17, 18 August 2008 (UTC)

I don't have strong feelings here one way or the other. With that said, just because the star has alternative designations doesn't mean that those also apply to the planet. Gliese 581 c is universally used as the planet's name in the literature, from what I can see. The reliable exoplanet catalogs (exoplanet.eu, for example) don't list any alternative designations. So I'd probably lean towards excluding the alternative designations entirely. If they are included, they certainly shouldn't be right in the first sentence! J. Langton (talk) 13:25, 18 August 2008 (UTC)

Ymir is a joke, Notability reqirement not met at all, three paragraph piece of lame fiction trying to get attention by using the planet designation Gliese 581 c. I find it offensive that anyone ever let that crap in this article. The catalog names should at least be in the star article page and redirected in case anyone comes looking for them (either) by that name. GabrielVelasquez (talk) 18:45, 18 August 2008 (UTC)

It looks like alternative designations are already on the Gliese 581 page. Setting up redirects might be a good idea; I'll leave that for someone else to actually do, though. J. Langton (talk) 18:53, 18 August 2008 (UTC)

there's alrady redirects for some of them. I tried searching it under the Wolf name and got redirected here. :) Ymir, yeah, let's forget we ever heard of that one.--Marhawkman (talk) 11:42, 21 August 2008 (UTC)

Stability of Iceball State

It wasn't clear to me from Selsis et al. that volcanic CO₂ emission would cause a runaway greenhouse affect in general, or simply in the case that the albedo is in the very small range where local habitability might be possible. I would suggest that the wording here be less strong: "is expected to be unstable" -> "may be unstable" and "would trigger" -> "could trigger."

Incidentally, I'd argue that the Selsis analysis here may be flawed, on the grounds that he neglects the (significant!) potential for heat redistribution by surface winds. There's some pretty good indication that a slowly rotating (as it would have to be in 1:1 synchronization) planet is close to isothermal due to winds. Such an effect would tend to increase the stability of a snowball state. This is, of course, blatant OR, so it doesn't belong in the article -- but still interesting. J. Langton (talk) 13:06, 18 August 2008 (UTC)

It is not interesting to me precisely because it is blatant Original Research. You continue to insist on referencing of scientific papers and then turn around and critisize the ones that conflict with your own version of reality. It's getting old; If it has be superceded fine, otherwise stick to quoting the scientific paper rather than critisizing it. GabrielVelasquez (talk)

I'm retracting that on the basis that "FUNDAMENTALS OF ASTRONOMY" (QB43.3.B37 2006) by Dr.Cesare Barbieri, professor of Astronomy at the university of Pauda, Italy has a different planet Equilibium Temperature formula than the Selsis et al paper (very different) and is more accurate. It is on page 318, and it works out to over 306°K (333°K perihelion)/60°C with out the GHG effect (Earth is +33°C)for Gliese 581 c, with the Earth's minumum it would put it at 99°C! The formula is pretty simple when reduced: Tp=Ts[((Rs/d)^2)*((1-0.3)/4)]^(1/4). Sorry used the full reduction (for Sol/Earth) the first time, and using the same Albedos as they did for Earth, but nowhere near habitable. I was never in support of the original Equilibrium Temperature formula in the article, I in fact removed it as false given the admission that planets are not perfect black bodies. User:GabrielVelasquez|GabrielVelasquez]] (talk) 15:59, 10 September 2008 (UTC)

You do realise that that is the same formula that was used to support the habitability claims of Udry et al. in the original version of the discovery paper? I don't know where you get the 4100 from because the temperature of the star is around 3480 K (according to Bean, Benedict and Endl, 2006 - used in the Gliese 581 article). I note also that elsewhere on this talk page you are arguing strongly against Udry et al. for being too simplistic an analysis! But I guess when you change the numbers and it supports your POV that there is no way this planet is habitable, it becomes ok. However you note that in your formula you have a (1-A) term, this basically means you can make the temperature as low as you want as A - an unknown quantity - tends to 1 (and high albedos are possible - witness Enceladus for example). Please stop POV-pushing - we all agree here that Gliese 581c is likely a runaway greenhouse world, but fact is we do not know -- essentially, all we have for this planet is a minimum mass and an orbital period -- and making it seem more certain than it is is dishonest to the reader. Icalanise (talk) 22:14, 12 September 2008 (UTC)

What is the purpose of your comment here GabrielVelasquez? This is a discussion of how the paper should be interpreted, yet you just use this as an excuse to launch another one of your attacks on J. Langton. This is getting quite tedious and making the discussions on this article needlessly unpleasant. If you read J. Langton's comment you would see he is NOT advocating putting his own criticisms into the article - in fact it looks like it is you who is being dogmatic about the version of reality in this article by launching attacks on editors who advocate viewpoints different from your own. Please calm down a bit. 86.171.72.213 (talk) 19:18, 18 August 2008 (UTC)

In the same section, it is described that the conditions at the substellar point are inconsistent with a snowball state anyway unless the albedo is extremely high, comparable to Enceladus in our solar system. Same for the case with a habitable substellar point. Much of the discussion of the iceball state in the Selsis paper seems to suggest that the conditions at the substellar point end up outside the parameters that the iceball requires. From the Selsis paper: "This means that temperature and vapor pressure are expected to diverge rapidly from this assumed starting point." - this is before volcanic CO₂ release is even considered. From this, I would suggest wording the iceball hypothesis very sceptically indeed. 86.171.72.213 (talk) 15:36, 18 August 2008 (UTC)

As you note, Selsis's analysis depends on the albedo: he claims that the iceball "is stable" for A>0.95. The way I read it is that it's unconditionally unstable for lower albedos (forget the exact numbers; I think it was A~0.8) because of the high temperature at the substellar point. For A=0.89-0.90, he's saying that you might have a state where pockets can support liquid water, but this state is unstable to volcanic CO₂ emission.

I agree that the iceball state is unlikely, but should be presented as an alternative possibility to the (much more probable) super-Venus scenario. The current wording I think basically does that honestly, although the absolute assertion of iceball instability is probably a bit stronger than can be justified based on Selsis. What if we just added a bit of specificity to the sentence under consideration: "...although this situation is expected to be unstable except for very high albedos greater than about 0.95: release of carbon dioxide by volcanic activity or of water vapor due to substellar heating would trigger a runaway greenhouse effect."

This avoids the absolute assertion of instability -- which I think is stronger than Selsis can justify -- while making explicit the conditions for which it is unstable. I'll go ahead and make this change; feel free to change it back if you disagree. J. Langton (talk) 18:39, 18 August 2008 (UTC)

Radius of a planet with unknown mass

The article seems to be assuming that the mass of the planet is close to the lower limit, without making this assumption clear. Dynamical simulations provide an upper bound of about 30 Earth masses [9], which is greater than the mass of Neptune. Granted, according to the probability distribution of inclinations, the mass is likely to be close to the lower limit, but as yet it is unknown. Including a nice tidy figure of 1.5 Earth radii in the infobox and having the size comparison image glosses over this whole issue and conveys the impression that our knowledge of this object is significantly better than it is. 86.171.72.213 (talk) 10:46, 20 August 2008 (UTC)

That's a fair point, and I'm inclined to agree: we should only provide radii for transiting planets where the radius has actually been determined. If I were going to play devil's advocate, I would point out that most of the literature seems to assume it's close to the lower mass limit -- as, indeed, you would expect from the probability distribution: expectation value is 1.3 times the minimum mass, or about 6.5 Earth masses. In fact, the radius speculation I believe is sourced to Udry et al.

I can see two possible options: deleting the radius from the info box, or replacing the R~1.5 R_e with R>~1.5 R_e, since the rocky composition for the minimum mass seems to be a lower bound on the radius. The first is probably more responsible. J. Langton (talk) 14:56, 20 August 2008 (UTC)

I agree that dropping the value from the infobox is the way to go here (if the planet is a super-Mercury or iron planet, which of course while being unlikely are not ruled out by the data, the radius could be below 1.5 R_E), and that the discussion of the radius needs to be expanded in the article to include cases where the mass is greater than the lower limit. The expectation value of the mass is getting into the domain where accretion of massive hydrogen atmospheres may begin, a situation which would have significant implications for the radius and habitability of the planet. 86.171.72.213 (talk) 22:26, 20 August 2008 (UTC)

I've put some warnings about the radius speculation in the article, hope it's okay. Icalanise (talk) 23:22, 28 August 2008 (UTC)

Temperature addition

I noticed that User:142.161.15.88 has added the following to the article: [10] - however I suspect that this is invalid: it doesn't really make physical sense to transfer the addition of temperatures in this way - the underlying principles are albedo, emissivity and various feedback loops, which makes this very dodgy. Personally I think this should be removed, but I've left tags on them for the moment. Icalanise (talk) 09:27, 18 September 2008 (UTC)

It's definately speculation, but so is the official estimate. Is it incorrect? Well, it makes a valid point. I think it would fall under WP:OR unless sourced to something.--Marhawkman (talk) 13:59, 18 September 2008 (UTC)

The thing is whether it makes sense to say that because Earth is 33°C warmer because of a greenhouse effect, a planet with an atmosphere similar to Earth's but receiving a different amount of radiation would also be 33°C warmer. I don't think this makes sense - if you're going to play these games with speculative atmospheres at least do it in terms of albedo and emissivity (which can be entered into the equations in a reasonable manner), which give different results to this simplistic addition. The difference is that one way is an approximation using basic physics, one is not. In a sense, what the addition is doing is equivalent to saying a*x = x+b therefore a*y = y+b, which is not in general true. Icalanise (talk) 15:27, 18 September 2008 (UTC)

It would still follow a similar temperature scale. It allows a quick approximation that's relatively easy fo a lay person to understand. Admittedly 'tisn't 100% accurate but the whole this is based on estimations anyways.--Marhawkman (talk) 11:11, 20 September 2008 (UTC)

I've reworded the paragraph to provide a concrete example of the difference between effective and surface temperatures. I've removed the temperature addition because if we are going to use estimations, they should be physically justifiable. Icalanise (talk) 16:14, 20 September 2008 (UTC)