Talk:Gliese 581g

Referencing media articles for this article is serious folly.

I noticed that the very first reference for this article is a media article, which is a big mistake considering the history of the Gliese 581 c article that originally said that planet was habitable because the discovery team got their incorrect figures sensationalized by these media types, and it turned out when two other teams of scientists consisting of planetologist and geologists not just astronomers looked at it, both teams concluded that it was not in the habitable zone, not even close:
"...surface temperatures ranging from 700 K to 1000 K (430 to 730 °C)."
I will remove the media references if I find out they are incorrect as well.
24.78.166.69 (talk) 01:03, 30 September 2010 (UTC)

Relax a bit! Removing any references in an early article is unfriendly, but if there's errors or conflicting information in them (or here on the talk), that can be noted in the reference line. Otherwise someone else might just re-add the same wrong information! Tom Ruen (talk) 01:36, 30 September 2010 (UTC)

• Comparison for editors not article

Star Radius:	0.29		Temperature:	3480						Irradiance	%
Companion	Mass	±	M⊕	Semimajor axis	(AU) A±	Orbital period	(days) P±	Eccentricity	Ecc.±	W/m2	of Earth's
b	15.65	to	30.4	0.04		5.36874	± 0.00019	0		9448.40	691.68%
c	5.36	to	10.4	0.07		12.9292	± 0.0047	0.17	± 0.07	3085.19	225.86%
g	≥		3.1	0.14601	± 0.00014	36.562	± 0.052	0		709.11	61%
d	7.09	to	13.8	0.22		66.8	± 0.14	0.38	± 0.09	312.34	22.87%
f	≥		7.0	0.758	± 0.015	433	± 13	0		26.31	1.93%
Earth	-		1	1	-	365.26	-	0.0167		1366.0	100%

After all the debate about C & D being or not being habitable (turns out C is hotter than Venus not "habitable" oops, sorry, and D is colder than Mars not "Habitable" oops, sorry.), how convenient that another is found that receives 61% of the heat that the Earth does and they can play this game some more.
That is barely warmer than Mars; This new algorithm interpretation is born out of the fantasy scenario question "if Venus was at the orbit of Mars would it be habitable?" because of the GHG effect is so much stronger with Venus to make up for the distance.
Hopefully they will do the math and it can be clearly expessed the way it is now with the Gliese 581 c mention of Venus' GHG effect, +430 °C (770 °F). 24.78.166.69 (talk) 02:26, 30 September 2010 (UTC)

Good sleuthing. We'll see! Yes, hopefully there'll be some "contrary opinion" sourcing references to update the young article. It's hard to tell who's doing the real hyping, media taking the most hopeful quotes or researchers real opinions. Tom Ruen (talk) 04:18, 30 September 2010 (UTC)

This is from the main scientific source paper and I would like to turn the number data into a chart:
"Nevertheless, we estimate the equilibrium temperature given L⋆ = 0.0135L⊙ for the host star. We assume a Bond albedo for the planet of A=0.3, a typical value for objects in the inner Solar System (Earth’s Bond albedo is 0.29). For the 36.6-day planet candidate, its semi-major axis of 0.146 AU leads to an equilibrium temperature of 228 K (-45 °C). If instead the Bond albedo is assumed to be 0.5, the equilibrium temperature becomes 209 K (-64 °C). This planet candidate would thus appear to also satisfy another necessary condition for habitability, that Teq < 270 K (-3°C). An equally important consideration is the actual surface temperature Ts. The equilibrium temperature of the Earth is 255 K (-18°C), well-below the freezing point of water, but because of its atmosphere, the greenhouse effect warms the surface to a globally-averaged mean value of Ts = 288 K (15°C). If, for simplicity, we assume a greenhouse effect for GJ 581g that is as effective as that on Earth, the surface temperatures should be a factor 288/255 times higher than the equilibrium temperature. With this assumption, in the absence of tidal heating sources, the average surface temperatures on GJ 581g would be 236 – 258 K (-37°C to -15°C). Alternatively, if we assume that an Earth-like greenhouse effect would simply raise the equilibrium temperature by 33 K (33°C), similar to Earth’s greenhouse, the surface temperature would still be about the same, 242 – 261 K (-31°C to -12°C). Since it is more massive than Earth, any putative atmosphere would likely be both denser and more massive. It would be denser because of the larger surface gravity, which would tend to hold more of the atmosphere closer to the surface. And the atmosphere may be significantly more massive if we simply assume that the planet went through a formation process similar to that of the Earth and that all the bodies that went into forming GJ 581g had the same relative amount of gasses as in the bodies that went into making up the Earth. Some of these gases would subsequently be outgassed to make the atmosphere. Note however, that the amount of outgassing can depend critically on the (evolving) internal structure of the planet. More simply, the rocks that hold the gases in GJ 581g will have experienced different pressures and temperatures than those in the Earth. In turn, this determines how easily the gases would be released."

• Steven S. Vogt et al 2010, page 31.
  

24.78.166.69 (talk) 06:06, 30 September 2010 (UTC)

Although I find it highly suspicious that they have a 3.1 Earth mass planet but didn't bother to do the same calculations for the GHG effect of Venus, only for our 1 Earth mass planet Earth. I say used the same reasoning precident that exist in the Gliese 581 c article simply stating the GHG of Venus in the same article paragraph. 24.78.166.69 (talk) 06:19, 30 September 2010 (UTC)

	Venus	Earth	GJ 581 g
Equilibrium Temperature		255 K (-18°C)	228 K (-45 °C)
Surface Temperature		288 K (15°C)	209 K (-64 °C)
add Earth's GHG effect			242 – 261 K (-31°C to -12°C)
add Venus' GHG effect

-still working on it. I'll get this yet. 24.78.166.69 (talk) 06:43, 30 September 2010 (UTC)

The temperature of the planet is strongly dependant on the albedo, and it doesn't seem like the chart above includes this information. Constant insolation of ~700 W/m2 is greater than the average insolation of any place on the earth, including the poles during the 6 months of summer, so with a suitably low albedo (~.15 would lead to average surface insolation of something like 300 W/m2, but this is very dark and would have to be due to something like biological processes) it could well be nearly as warm as Earth (once albedo and rotation effects are taken into account, average insolation of the earth's surface is on the order of 450-500 W/m2, while Mars is somewhere around 200 W/m2). It's also entirely plausible that there are large areas of the planet on which liquid water could exist. It seemed like the paper referencing earthlike temperatures assumes that, as the planet is tidally locked, it may be possible for there to be warmer areas on the subsolar portion of the planet - It may be 200k on the antisunward side, but 300k on the sunward facing portions of the surface. This depends a lot on the existance of an atmosphere and its properties. I'm looking forward to future studies regarding this planet so that we can get some solid information. Isn't the James Webb telescope supposed to be able to directly detect IR emissions of planets like this one? Should make for some good science. Standard original research warnings apply. shaggy (talk) 06:45, 30 September 2010 (UTC)

The chart actually does include albedo, Steven S. Vogt et al used a 0.50 Albedo to come up with their "Surface temperature."
Your not reading the published paper the article is based on yet still comment here is starting to get annoying.
Your comparing direct Irradiance with modified Isolation is wrong, you don't have surface or atmosphere features to make those modifications.

This is a full Irradiance chart for those interested:

Adj Bol.	Luminosity		Irradiance		Planet	Percent	of Earth
Luminosity	(Watts)	Periastron	Semi-Major	Apastron	Name	Periastron %	Semi-Major %	Apastron %
0.013	4.99435E+24	19732.211	19732.21	19732.21	Gl 581 e	1444.44%	1444.44%	1444.44%
0.013	4.99435E+24	10564.539	10564.54	10564.54	Gl 581 b	773.35%	773.35%	773.35%
0.013	4.99435E+24	5260.972	3624.28	2647.59	Gl 581 c	385.11%	265.31%	193.81%
1	3.84181E+26	1313.030	1366.08	1422.40	Earth	96.12%	100.00%	104.12%
0.013	4.99435E+24	833.015	833.015	833.015	Gl 581 g	61%	61%	61%
1	3.84181E+26	760.79	588.95	467.18	Mars	55.69%	43.11%	34.20%
0.013	4.99435E+24	954.530	366.92	192.67	Gl 581 d	69.87%	26.86%	14.10%
0.013	4.99435E+24	30.909	30.909	30.909	Gl 581 f	2.26%	1.23%	1.23%

=(3.84181E+26/(4*PI()*(149597876600)^2)) / 1366 = 100%
I'll clean up the sig.difs. later thanks.
Point is you could do another chart with variying Emissivity and Albedo to be most accurate.
I can see where they got their

• 236 – 258 K (-37°C to -15°C) and
• 242 – 261 K (-31°C to -12°C) from.

24.78.166.69 (talk) 15:31, 30 September 2010 (UTC)

Comparison to Mars / Venus / Mercury

Mars has 0.107 Earth masses as opposed to 3.1 - 4.3 for Gliese 581 g; a day of about 24 h as opposed to an infinite day for tidally locked Gliese 581 g; a surface atmospheric pressure of 0.636 kPa compared to 101 for Earth and an expected higher value for Gliese 581 g. The tidally locked nature of Gliese 581 g means there will be a wide range of stable temperatures present at different locations on the planet at different distances from the subsolar point, including almost inevitably temperatures conducive to liquid water at ambient pressure (very unlike Mars). How is are the conditions on Mars relevant to those on Gliese 581 g? WolfmanSF (talk) 19:00, 30 September 2010 (UTC)

We don't have tidally locked habitable plants in our solar system, or even close, the comparison is born strictly from the teams own figures. No one has removed the tidally locked parts of the section, you don't have to squawk like they have been, and the comparisons are as fair as any others, including the GHG effect of Venus, which for a 3.1 Earth mass planet they were negligent in covering.
Θ - Read the actual Astrophysics Journal paper before you try to judge the comparisons.
Θ - Read the comparisons at Gliese 581 c before you judge any comparisons.
24.78.166.69 (talk) 19:13, 30 September 2010 (UTC)

If we have no comparable planets then what is the need for such a lengthy comparison? It seemed to me stating facts about Mars for the sake of it rather than elucidating the properties of the planet the article is about, Gliese 581 g. On a related point I have just seen comments added about Venus, despite the sources seeming to not be backing up the claims like [1]. What was this meant to support?

On another note I think both of you have broken the three-revert rule in this dispute, please lets keep this debate both civil and in the talk page until a consensus is agreed on the way forward. ChiZeroOne (talk) 19:55, 30 September 2010 (UTC)

I think you are showing a lack of civility in continuing this line of arguing without looking at the presidents, specifically at Gliese 581 c, where the comparisons are also made. I think you are sorely missing the relevence of the dicussions on the talkpage of Gliese 581 c, and this kind of ignorance is root cause of these arguments. 24.78.166.69 (talk) 20:03, 30 September 2010 (UTC)

Sorry, but I haven't stopped reverting because I'm persuaded that your additions are appropriate. From my perspective the lengthy comparison to Mars still doesn't make sense. No explanation for why it is believed to be relevant is provided in the article. Gliese 581 g gets significantly greater irradiance than Mars. It's atmosphere is surely much thicker than Mars's. The statement that "A low atmosphere is similar to a tidally locked atmosphere in that way" doesn't make sense. If there is a wide temperature variation on Mars, that temperature variation occurs at single locations. On a tidally locked planet, that variation is irrelevant to a given location, which should have a fairly stable temperature. As long as there is one zone on the planet with conditions appropriate for liquid water, it is a good candidate for a habitat for life.

There is no justification at all for the extended quote simply to describe the use of the assumption of a similar greenhouse effect on both Earth and Gliese 581 g. Spinning the quote as "less optimistic" without explanation makes no sense. And any explanation would presume that the editor knows better than the authors, which I think is highly unlikely. WolfmanSF (talk) 20:43, 30 September 2010 (UTC)

This planet is far more favorable then Mars, Venuses climate. I'd make a statement like 581G is the second most favorable planet to life known. —Preceding unsigned comment added by Matthurricane (talk • contribs) 22:59, 30 September 2010 (UTC)

Content removed below:

For comparison, Martian surface temperatures vary from lows of about -87 °C during the polar winters to highs of up to -5 °C in summers. The wide range in temperatures is due to the thin atmosphere which cannot store much solar heat, the low atmospheric pressure, and the low thermal inertia of Martian soil. A low atmosphere is similar to a tidally locked atmosphere in that way.

The idea that this planet is not at all like Mars is false. To say it is like Earth is even more false. The Earth is not tidally locked and the heat recieved by this planet as stated in the primary source is inargualby closer to Mars than it is to the Earth. Adding the GHG effect of the Earth to the Equlibrium temperature of the Earth yeilds 15°C according to the paper. But in the case of this planet, adding the GHG effect of Earth to Gliese 581 g at an equlibrium temperature of 209 K (-64 °C) that would then yield a temperature of 224 K (-49°C), and so it is ridiculous to suggest that the comparison is not relevant. Depending on the size of the actual atmosphere the planet could be even colder than Mars. Because of this I am persuaded that Mars temperature are very much relevant in the article, just as Venus temperature are relevant in the Gliese 581 c article. Counterpointing it as less optimistic is a whole separate issue. Other editors have voiced there opinions that the astronomer is not a biologist and has said some very nonsensical things in his paper, his enthusiasm is almost obsessively biased. But that doesn't change the temperature figures that they themselves have published. Whether it is more optimistic or less optimistic is nonsense when compared to the actual figures and calculations in the primary source. GabrielVelasquez (talk) 03:47, 1 October 2010 (UTC)

We don't have any information about this planet's atmosphere at this time, and the paper doesn't cover anything except a very pessimistic scenario that still shows liquid water might exist somewhere on the planet. Can you tell me what the greenhouse effect on this planet would be with a .1 bar atmosphere? how about 1 bar? 10? 100? what if it's a CO2 atmosphere? What if it's a Nitrogen-Helium atmosphere? What if it's got a 3 bar Oxygen-Helium-Nitrogen-Argon atmosphere? Have you considered the effect of oceans? Can you model this and say that it wouldn't have liquid water? We can speculate, but it's not going to do much good without solid data from an observation of the planet, or sophisticated modeling of the planet's evolution and atmosphere, and that's something that will have to be done by researchers, not Wikipedia editors. As editors, we can only put information in the article that is properly sourced, and any comparison to Mars done by an editor is original research and should not be included. If Anon wants to write a scientific paper comparing Gliese 581 g to Mars, submit it for peer review, and have it published, that is when that information should be included in the article. shaggy (talk) 07:54, 1 October 2010 (UTC)

Good grief, another one who reads only what they want to read. The sky is blue does not need a reference, neither does any fair relevant comparison to planets that we know right here in our own solar system, otherwise, the whole article would end up nothing more than series of block quote boxes in various colors from the sources and there would be no article. You do know that Mars is a planet in our solar system, right? - the figures published by the primary source author are similar to the same data for Mars, and Mars is right here in our own solar system. Just because they failed to make the comparison doesn't mean we can't, you completely missed the discussion at Gliese 581 c and the precedent to good article writing that is there, for your own stubborn bias. The comparison using the Earth's Green house gas effect is speculation by the discovery team since no one knows the atmosphere of Gliese 581 g, are you aware this is speculation?? We don't need to provide you with a reference that says the sky is above the ground, their calculations of temperature are directly comparable to the temperatures of Mars. That's just good writing. - GabrielVelasquez (talk) 18:11, 1 October 2010 (UTC)

Seriously? We can say "this planet has an equilibrium temperature similar to the surface temperature of Mars" and give those figures, but that is misleading without a discussion of equilibrium temperatures, and a comparison to Mar's equilibrium temperature (which is something like 218k, -55C, with an albedo of .25) You would also need to discuss the albedo, potential atmosphere, effects of tidal locking, tidal heating, and every other detail that makes this planet almost nothing like Mars. It is fair to compare the equilibrium temperature of this planet and the Earth as was done in the paper because it illustrates why this planet is potentially habitable. If I recall correctly, the paper referenced in the article regarding the habitability of planets in red dwarf systems even makes a point to say that the habitable zone may be further away from the star if the planet is tidally locked. It seems you are pushing a direct comparison with Mars because you personally disagree with the finding that this planet might be habitable, but references are given in the paper for sources that the team used when making the conclusion that this world is possibly habitable, and there is no reason to reject their findings at this time simply because you disagree with them. This is not the same team responsible for the issues over planet c, so your bias against them seems unreasonable. Every time there is an important discovery, (Another good example is Eris), the Wikipedia article generally becomes a focus for speculation and it is important to keep a clear head and only include things that are verifiable. shaggy (talk) 22:41, 1 October 2010 (UTC)

Scary. You think 224 K (-49°C) is not comparable to 218 K (-55°C), hmmm.
You make the point for the comparison without realizing it.
If I disagreed with the primary source authors I wouldn't be quoting them.
Face it, the planet is in the habitable zone, but not ready for colonization.
GabrielVelasquez (talk) 07:44, 2 October 2010 (UTC)

Making a sweeping comparison between Mars and a planet still under study is not at all like saying the sky is blue. First of all, assuming that gliese 581 g is tidally locked, that could mean that temperatures vary greatly depending on how far the location is from the terminator. Even if the terminator is too cold, you could travel toward the sunlit side until you found an ideal temperature. However, we don't know what the atmosphere is like exactly, and how this will affect the surface... as the article describes in greater detail. These questions are very important, so it's reasonable to speculate on them, although we must not jump to conclusions until more facts are known. Bigdan201 (talk) 13:07, 2 October 2010 (UTC)

A tidal locked planet with a day/night cycle

The wiki entry sites a source in claiming that Gliese 581g has day-night cycle the same length as its orbital period, due to it being tidally locked to its star. However, if it's tidally locked to its star, it shouldn't have a day-night cycle at all. I'm talking about the sciencemag.org article. —Preceding unsigned comment added by 207.38.213.229 (talk) 02:21, 30 September 2010 (UTC)

Yes, you are correct this is weird. The moon has a day night cycle because it is tidally locked to the Earth and changes it's facing to the Sun during its orbit around the Earth. If this planet is tidally locked to its star there is no day/night cycle with respect to the star but it does change its facing as it orbits the star with respect to anything else. It is how some people define tidally locked, the orbit period being the same as the revolution period, that causes the confusion. 24.78.166.69 (talk) 02:32, 30 September 2010 (UTC)

If the eccentricity is non-zero, there will be a "day-night" cycle on part of the planet as the day-night terminator will shift due to orbital libration. It looks like the data shows a circular orbit, but this is probably an artifact due to the limited number of observations. Of course, this is original research (even if it is a known behavior of tidally locked objects in eccentric orbits, like the Earth's moon) so it shouldn't go anywhere near the article until properly sourced. I just think it's neat. shaggy (talk) 05:26, 30 September 2010 (UTC)

• "Gliese 581g is likely to have evolved to a spin-synchronous configuration, leading to one hemisphere of the planet lying in perpetual darkness. Joshi et al. (1997)" Pg.31 - Steven S. Vogt et al.
  HELLO, this is from the main reference; Original Research? What article are you reading? 24.78.166.69 (talk) 06:11, 30 September 2010 (UTC)

My OR warning only applies to my speculation that there is a day-night cycle on limited areas of the planet due to orbital libration. Sorry if that wasn't clear. shaggy (talk) 06:47, 30 September 2010 (UTC)

How can Joshi et al. 1997 talk about Gliese 581 g in 1997, while "the discovery of Gliese 581 g was announced in late September 2010" ?122.117.35.27 (talk) 15:46, 1 October 2010 (UTC)

They're not writing about Gliese 581 g in 1997, they're writing about spin-synchronous (tidal lock) orbits, a topic in planetary physics. Gwen Gale (talk) 15:56, 1 October 2010 (UTC)

The article referenced investigates the habitability of planets in red dwarf systems in general, particularly the difficulties faced by tidally locked planets such as Gliese 581 g is theorized to be. The conclusions of that paper are broadly applicable to any planet found in the habitable zone of a red dwarf. shaggy (talk) 15:58, 1 October 2010 (UTC)

We say Gliese 581 g is expected to be tidally locked to its star, just as our moon is to the Earth - should we point out why (when Earth, for example, isn't)? I'm assuming its because since this is a red dwarf the goldilocks zone is much nearer the star, so the 1/r^3 stuff makes it more likely to be locked William M. Connolley (talk) 14:17, 30 September 2010 (UTC)

Yes, I had an alikened thought. Meanhile, is the orbit believed to intersect the elleptical orbit of d, as the SVG shows? Gwen Gale (talk) 14:32, 30 September 2010 (UTC)

I think the SVG is out of date, as the planets are all said to have circular orbits in the paper. I'll have to look into this.shaggy (talk) 14:56, 30 September 2010 (UTC)

Thanks. It threw me for a loop. (pun alert) Gwen Gale (talk) 15:17, 30 September 2010 (UTC)

Tidal locking would mean the planet would have no axial tilt and therefore no seasonality in any normal sense of the word. Huh? The moon is tidally locked and has an axial tilt of about 6 1/2°. Am I missing something? --ἀνυπόδητος (talk) 13:43, 1 October 2010 (UTC)

different system, different orbital properties. The moon's orbit is complicated by its position as a satellite. Check this out: Orbit of the Moon. shaggy (talk) 14:33, 1 October 2010 (UTC)

Ah, thanks --ἀνυπόδητος (talk) 15:58, 1 October 2010 (UTC)

Orbit and template rendering

I looked at the SVG source, easy and well-documented, so I added a circular orbit for g, crossing elliptical orbit of larger planet d. I wouldn't expect cross-orbits this to make for long term stability! Tom Ruen (talk) 05:19, 30 September 2010 (UTC)

Interesting, in the paper they didn't show 'd' was elliptical (in Fig. 6 in the paper).Tallerjp (talk) 13:57, 30 September 2010 (UTC)

• So, has it been settled whether the orbits cross each other or not? And whether d has an elliptical orbit or not? I'm a bit confused by the changing diagrams. Bigdan201 (talk) 08:44, 1 October 2010 (UTC)

The elliptic orbits might have been an artifact of the other undetected planets in the system. This is one of the limitations of the radial velocity method. The 6-planet solution in the paper supposes that the orbits are all circular, so for now this diagram is correct. shaggy (talk) 11:26, 1 October 2010 (UTC)

Only four stars are shown in the template graphic but there are six in the list that follows. Can someone update the graphic/template please? Philg88 (talk) 12:12, 30 September 2010 (UTC)

The two newest planets were announced very recently, the article is still being edited to update it with this information. I am sure it will get done. shaggy (talk) 12:32, 30 September 2010 (UTC)

I've updated the diagram to use the circular-orbits 6-planet solution in Vogt et al. (2010), available here. An updated version of this diagram incorporating the orbit of the outer planet f is on my to-do list. Icalanise (talk) 23:52, 30 September 2010 (UTC)

I decided to have some fun, updated the template image and mapping. Feel free to change. I just tried to give very approximate positioned new images, with larger worlds for higher masses, and vague symbolically rescaled spacings. The new image is Image:Gliese581_2010.png, and the same old template was used, with new mappings. Tom Ruen (talk) 04:08, 1 October 2010 (UTC)

It looks good. shaggy (talk) 07:58, 1 October 2010 (UTC)

Discovery Date?

In the article's body, Gliese 581G is reported to have been discovered in September 2010. However, in the "Discovery information" in the little box on the right hand side, the date is given as 21 April 2009. I can't seem to find anything with an actual discovery date to be able to rectify the problem... —Preceding unsigned comment added by 71.182.244.39 (talk) 05:42, 30 September 2010 (UTC)

"We have had GJ 581 under survey at Keck Observatory for over a decade now. In this paper, we bring 11 years of HIRES precision RV data to bear on this nearby exoplanet system. Our new data set of 122 velocities, when combined with the previously published 119 HARPS velocities, effectively doubles the amount of RVs available for this star, and almost triples the time base of those velocities from 4.3 years to 11 years." - pg.6, Steven S. Vogt et al.
Thats because what they did was merge observation measurements from over eleven years into one set and redid the cancellation algorithm to have only 20 extra things that might be interferometry errors for the best cancellation and say it must be six planets. The publish date of the astronomy article will have to do. 24.78.166.69 (talk) 06:24, 30 September 2010 (UTC)

Well done! Now its actual date of discovery is perfectly wrong in the box on the right as well as in the article itself. Otherweise I wonder, why the given references all date "back" to September 2010. If it was discovered all the way back in April 2009: Prove it! I need a reference. And what on Earth is this going to mean:

In an interview, co-discover Steven Vogt claimed "that chances for life on this planet are 100 percent."

Ah, the chances are 100% -- this could only mean utter certainty; besides being also utter nonsense: Go spread the word! There's alien life on Gliese 581g! If anyone doesn't buy it, don't bother, there still is Wikipedia! And this is what Wikipedia says. Hilarious. Zero Thrust (talk) 06:29, 30 September 2010 (UTC)

I can't disagree with you, the hype is going to be ridiculous, it can't remain in the article or again Wikipedia will be negligently responsible for false hype like Gliese 581 c. 24.78.166.69 (talk) 15:35, 30 September 2010 (UTC)

The chances of life in a habitable zone are high. We know that to be true on Earth. Life finds a way in extreme environments. Wherever conditions are right for liquid water, we find life. It does not mean that there is a 100% chance of life being found. Viriditas (talk) 21:05, 30 September 2010 (UTC)

I agree that much of this astronomer's claims are nonsense, as he ignores the fact that very little of the planet is of habitable temperature, and we should give opinions from biologists. Sopher99 (talk) 02:08, 1 October 2010 (UTC)

Astrobiologists actually, and I agree some of what he says is nonsensical.GabrielVelasquez (talk) 05:29, 1 October 2010 (UTC)

You can agree all you want, but what he says is accurate. In other words, it is likely that the chances for life in a habitable zone where liquid water can exist are very good. Please stop reading things into it that aren't there. There's nothing "nonsensical" about it. Viriditas (talk) 07:51, 2 October 2010 (UTC)

"Chances of life are 100%"

Vogt's claim that chances of life on the planet are 100% is nonscientific and somewhat ridiculous in an article like this that is otherwise so scientific. I'd suggest we should either 1) remove this claim, 2) tone it down (saying simply that he is optimistic about the prospects of life should be enough) and/or 3) supplement it with opinions of other researchers. Offliner (talk) 15:05, 30 September 2010 (UTC)

I think it's helpful to let readers know about one of the co-discoverer's eager outlook on this, which he himself says is not scientific: Sourced opinion is ok and this opinion has indeed gotten coverage. Sourced reaction to the opinion is also ok. Gwen Gale (talk) 15:16, 30 September 2010 (UTC)

I think many editors are misinterpreting what is being said here. Vogt is saying the chances of life in a habitable environment are 100%, not that there is a 100% chance of life being found. Even I was confused when I first heard it. Viriditas (talk) 21:04, 30 September 2010 (UTC)

He said "“the chances of life on this planet are almost 100 percent.” I don't think he or any of us know what we're talking about and moreover, I think he hinted at that too, in his own way. Gwen Gale (talk) 21:40, 30 September 2010 (UTC)

The quote was taken from the full NSF interview (it is in the external links section). Out of context of the interview as a whole, it doesn't make much sense, however, when you put the quote into context of what Vogt is talking about, the "chances" he is referring to are the chances of life finding a way to survive. Remember, he prefaced this statement with, "given the ubiquity and propensity of life to flourish wherever it can". In other words, given what we know about extreme environments (see extremophile), what Vogt was saying is that the chance of life in such an environment is very high. This is the foundation of the assumptions behind astrobiology. Viriditas (talk) 21:48, 30 September 2010 (UTC)

He said, after being nudged, "the chances of life on this planet are almost 100 percent."[2] By "this planet" he straightforwardly meant Gliese 581 g. Life has a somewhat wide meaning in biology, if that's what you mean. Either way, it's utter, eager speculation. Gwen Gale (talk) 21:56, 30 September 2010 (UTC)

As I explained previously, the NYT article you quote was taken from the full NSF video interview linked at the bottom of this article. The NYT took that quote out of the context of the original interview. Viriditas (talk) 22:00, 30 September 2010 (UTC)

I think it highly unlikely that his English is that weak. Gwen Gale (talk) 22:05, 30 September 2010 (UTC)

His English is very good. The problem isn't with his language, but with the media culture of sound bites. Viriditas (talk) 23:53, 30 September 2010 (UTC)

I am in favor of doing option #3, as he is not even a biologist, and he is ignoring the temperature factor Sopher99 (talk) 02:06, 1 October 2010 (UTC)

As you can see and hear from this brief excerpt, Vogt is clearly not saying life exists on the planet. This was a soundbite dug up out of context in the full interview by various news organizations. Vogt is only talking about the chance of life existing in a habitable zone. In other words, Gilese 581 g may be hospitable to life. That's it. There is no reason to take option 3, because that would mean supplementing a misinterpretation, which is beyond silly. There are ways to further explain this in the context of the original interview, but the link I just gave you shows he is not saying there is life on the planet. So, really, nothing to "supplement". Viriditas (talk) 02:34, 1 October 2010 (UTC)

Ok then, change the article to fit your reasoning then, I agree with your statement. Sopher99 (talk) 02:35, 1 October 2010 (UTC)

Well, I also agree it is confusing people, and it had me confused until I watched the video. I know how to make it clear, but it's going to take me at least a day or so to fix it. Viriditas (talk) 02:37, 1 October 2010 (UTC)

Thats ok as long as it is changed to your statement. Sopher99 (talk) 02:38, 1 October 2010 (UTC)

My local TV newscast just today stated that this planet is "habitable for people." This is truly ridiculous also, and I hope you continue to qualify the statements in the article so the are not as ridiculous as that. The layman that reads this article is not going to look at "Habitable" in the same way an astrobiologist is going to, so you also definitely need to qualify habitability in the article with reference to extremophile life. There is an Associated press article that does that very well quoting the primary source author and then talking about bacteria and mold. I will find it and post a quote here. GabrielVelasquez (talk) 05:25, 1 October 2010 (UTC)

• "Life on other planets doesn't mean E.T. Even a simple single-cell bacteria or the equivalent of shower mold would shake perceptions about the uniqueness of life on Earth." - Associated Press. - GabrielVelasquez (talk) 05:53, 1 October 2010 (UTC)
  • Nice work! : ) Viriditas (talk) 07:12, 1 October 2010 (UTC)

That same AP article quotes Vogt as saying "chances for life on this planet are 100 percent." Viriditas, if you've been saying that this "soundbite" would mislead most readers into thinking he meant human life, I don't think that's much of a worry (although some folks always do misunderstand anything they hear in the news about astronomy, given much of what they don't know, they "learned" from Star Trek and so on). Gwen Gale (talk) 08:47, 1 October 2010 (UTC)

Not sure where you got that from. Vogt's commment about the chances for life did confuse people, because many thought he was talking about life existing there now, rather than the chances for life existing within a habitable zone. According to Vogt, it was 100% likely that life could exist within the habitable zone occupied by Gilese 581 g. He didn't make this clear initially, hence the confusion, but when you listen to the entire interview in the full context, this becomes obvious. In other words, based on what we know, it is likely that life could exist in this environment. That's all. Viriditas (talk) 09:54, 1 October 2010 (UTC)

Uses of term Habitability

• " Habitability is the conformance of a residence or abode to the implied warranty of habitability. A residence that complies is said to be "habitable". It is an implied warranty or contract, meaning it does not have to be an express contract, covenant, or provision of a contract. It is a common law right of a tenant or Legal doctrine." - I disagree with your point, this is an exception, this word is very much misapplied by the astronomers arrogantly assuming everyone knows they mean extromphile life and not the bedbugs in your room, as is normally meant by "habitability." GabrielVelasquez (talk) 09:12, 1 October 2010 (UTC)
  • I think you got confused by my use of the term habitable environment. The word is not misapplied as it has a specific and precise usage in astrobiology. Words are used differently by discipline, and we are not talking about law. The point is that liquid water can exist in this zone, and from that assumption, everything else follows. The confusion is understandable, but easily corrected once you look into it. Viriditas (talk) 09:56, 1 October 2010 (UTC)

Oh the arrogance: I'm not talking about your use, I'm talking about reader understanding, That link uses that word, you conveniently ignored that to keep defending your ego. "Habitable environment" is not used anywhere in the article currently and that's point you blindly miss, Habitability is the word, and there is no redirect from that word/link to anything you are talking about. GabrielVelasquez (talk) 18:36, 1 October 2010 (UTC)

Please refrain from any future personal attacks. We are not talking about the word as it is used in law, and the link is your own, which doesn't make much sense. Viriditas (talk) 19:36, 1 October 2010 (UTC)

Yes. Truth be told, since nobody knows anything about the atmosphere or even the surface of that planet, from an editorial outlook I would say any sourced talk about "habitability" or "life" of any kind is utterly rash, to put it mildly and moreover, ripe for wild misunderstandings. It's getting coverage so it should be carried in the text (and what I see there now looks ok so far to me), but I do think this thread is worthwhile. Gwen Gale (talk) 09:19, 1 October 2010 (UTC)

Vindicated, thank you. GabrielVelasquez (talk) 07:21, 2 October 2010 (UTC)

There appears to be confusion between planetary habitability and the concept of a habitable zone, which is the reason this finding is notable in the first place. It is the first "Goldilocks" exoplanet, neither too hot nor too cold, and it is the best example in this class, so far. Viriditas (talk) 09:54, 1 October 2010 (UTC)

"Ecosphere" is a more accurate and less confusing term than "Habitable zone" (??)

I'm convinced from the above discussion that the less commonly used but more accurate term Ecosphere is preferable to continuing to use the vague/confusable "habitable" word. Just bypass the disambigous page and link it directly to the habitable zone article, the benefit is that the words in this article are less confusing to the layman and to the sensationalizing media. Any thoughts?? GabrielVelasquez (talk) 17:37, 2 October 2010 (UTC)

• Oppose. As one of the editors who helped create and develop the dab page in 2004, I'm afraid you are mistaken. Ecosphere is no longer used as the chosen term in the literature, and fell out of favor several decades ago. Feel free to do a search through the relevant papers on the subject, as I have. There's a good reason our article is located at HZ and not ES. Viriditas (talk) 18:06, 2 October 2010 (UTC)
• Support. You can pretend the word doesn't exist, but the favorableness factor is still with Wikipedia not adding confusion to an already complex issue and creating hype debate. This isn't a pop journal, it's an Encyclopedia, so we should favor accuracy over stirring up hype debate. GabrielVelasquez (talk) 18:52, 2 October 2010 (UTC)
• Oppose. Policy WP:COMMONNAME is to use the most common term, and ecosphere is used much less frequently for this concept. In fact none of the results on the first page of a Google search for the term "ecosphere" are related to the use of the term for the habitable zone, except for mention on a Wikipedia disambiguation page. Icalanise (talk) 19:05, 2 October 2010 (UTC)

Parent Star

why is the temperature (252K), obviously the planet's temperature, under the information about the parent star?

also, why is the radius 1.2 - 1.4 solar radii? this would be the planet's radius, and in earth radii.

I have copied the parent star data from Gliese 581 c, because it has the same parent star. (sorry, forgot to post reason for change)Matt The Tuba Guy (talk) 05:51, 30 September 2010 (UTC)

Distance of Gliese 581

This article quotes Gliese 581 as being 20.5 ly from Sol whereas the main article for Gliese 581 lists a distance of 20.3 ly. Which is correct? --Yoda of Borg (talk) 15:24, 30 September 2010 (UTC) Is within the margin of error Quantanew (talk) 16:38, 30 September 2010 (UTC)

Image copyright

I've put this on the image description file but I haven't requested deletion of a media file before and don't want to mess it up! This image (File:Gliese_581g.jpg) appears to be copyvio. The image, [3], is credited on the NASA website to another party (Lynette Cook) which according to [4] means it is copyright and not public domain. As this is an artist's impression I cannot see why a similar one cannot be created that is free-use so this image doesn't appear to satisfy fair-use, unfortunately. ChiZeroOne (talk) 18:02, 30 September 2010 (UTC)

Given that all we know about the planet's appearance is that it is a sphere orbiting a reddish star, I think creating an image shouldn't be too difficult. However, I would argue that an artist's interpretation doesn't add much to an article such as this, when we have so little to go on. Is the image really necessary? Spiel496 (talk) 23:44, 30 September 2010 (UTC)

True, though to be fair this current image does imply chlorophyll-based vegetation around the terminator which is generally considered more amenable to life on these tidally-locked worlds. So it is actually trying to add something to the explanation of the characteristics of this world, but to be honest it has more potential to mislead about the planet's actual habitability than to increase understanding. Perhaps the issue of artists impressions is a point to bring up on the Astronomy or Astronomical Objects WikiProjects? ChiZeroOne (talk) 00:07, 1 October 2010 (UTC)

The artistic image is in the news, so if it survives the licensing, it is a visual reference to the discovery. I only dislike it because the planet ought to be in reddish lighting! Tom Ruen (talk) 23:54, 30 September 2010 (UTC)

Bleargh, the phase of the planet is completely inconsistent with the light source. Furthermore, the star Gliese 581 has roughly the same temperature as a typical incandescent light bulb, so the dark red colour is inaccurate. Icalanise (talk) 00:03, 1 October 2010 (UTC)

Science and art, tricky bedfellows! Probably it was a quick cut&paste mixture because media people want something to look at! I see Gliese 581 d has a wiki-artist. File:Gliese_581_d-v1.jpg. Tom Ruen (talk) 00:48, 1 October 2010 (UTC)

The image is VERY misleadings, as no water or mountains have been discovered, thus we should replace it with a banal almost single color planet, until further information of it's atmosphere is given. Sopher99 (talk) 02:12, 1 October 2010 (UTC)

Not to mention that the dark side of the planet looks much like the light side, which would certainly not be the case if it was tidally locked. Mrienstra (talk) 03:15, 1 October 2010 (UTC)

Here is an image address of one that i think would be better. [5] (from article [6]) Sopher99 (talk) 02:14, 1 October 2010 (UTC)

Another wrongly colored star, and wrongly-phased image. I wonder who is the artist there? Another copy of the image at [7]. Tom Ruen (talk) 02:30, 1 October 2010 (UTC)

The star is a red dwarf, so it is not wrongly colored in the image showed. Sopher99 (talk) 02:37, 1 October 2010 (UTC)

There seems to be differing opinions, but (in both images) either the star is wrongly tinted (too red), or the reflected light of the planet is wrong (not red).

This one is fun, comparing size of planet and earth. [8]. Tom Ruen (talk) 02:39, 1 October 2010 (UTC)

Unfortunately I fear that picture perhaps has the temperature wrong. It is not a good image unfortunately. Sopher99 (talk) 02:43, 1 October 2010 (UTC)

It looks like the second image you found is 'borrowed' from an old rendering for planet c: [9] "Artist's impression of the planetary system in Gliese 581 (Credit: European Southern Observatory)" Tom Ruen Also at [10] from 2007.

At ESO website: [11]: "Artist's impression of the planetary system around the red dwarf Gliese 581. Using the instrument HARPS on the ESO 3.6-m telescope, astronomers have uncovered 3 planets, all of relative low-mass: 5, 8 and 15 Earth masses. The five Earth-mass planet (seen in foreground - Gliese 581 c) makes a full orbit around the star in 13 days, the other two in 5 (the blue, Neptunian-like planet - Gliese 581 b) and 84 days (the most remote one, Gliese 581 d).".

Tom Ruen (talk) 03:06, 1 October 2010 (UTC)

Maybe Don Dixon would like to expand his art? Here's an older artistic images of c:[12], wow, a movie too, [13]. But whatever is picked, someone has to track down the source artists and get licensing permission. Tom Ruen (talk) 02:44, 1 October 2010 (UTC)

A symbolic rendering?

One idea, perhaps the Template:Gliese 581, with image Image:Gliese581.png, which has more "symbolic" colored images, when its updated, each individual article table can have a larger image of the same symbolic world, so used as more a navigation symbol than rendering? 75.146.178.58 (talk) 03:23, 1 October 2010 (UTC)

Mention of "Systematic errors" in calculations is notable

Finally, it is important to keep in mind that, though all 6 planets presented here are well-supported by the calculated reduced chi-squared statistics and also by several different variants of FAP statistics, and the entire 6-planet system is consistent with the combined data set from both teams, caution is warranted as most of the signals are small. And there may yet be unknown systematic errors in either or both data sets. For example, Pont et al. (2010) have recently concluded from a detailed analysis of HARPS CoRoT-7 data that ”On the whole, there is a mounting body of evidence that unexplained variations at the 5-10 ms−1 level may exist in HARPS RVs for targets in the brightness range of CoRoT-7.” GJ 581 is only about a magnitude brighter that CoRoT-7, so it may not be completely out of the question that HARPS data for GJ 581 might also be affected by such unexplained errors. And to be completely fair, the HIRES data set could also have undiscovered systematic errors lurking within. This is very difficult work and there is no shame or dishonor in uncovering residual systematic errors at these levels of precision. Collegial and unabashed – 37 – inter-team comparisons on stars like GJ 581 and GJ 876 will be crucial to quantifying the true precision limits of any team’s data sets. Finally, because of the very small amplitudes involved, allowing significant eccentricities into the Keplerian fitting tree may yield viable alternate solutions. Here, phase gaps in data sets become problematical as fitting routines generally allow eccentricity to utilize these gaps, driving up the eccentricity artificially to enhance the quality of the fit, and hiding much of the velocity swing from eccentricity in the phase gap. Such situations sometimes result in misleading solutions that can overlook or mask additional planets in the system.

- Steven S. Vogt et al. 2010, page 36

24.78.166.69 (talk) 19:04, 30 September 2010 (UTC)

the HIRES data set could also have undiscovered systematic errors lurking within only says that such errors are *possible*, it does not assert their existence, much less prove them William M. Connolley (talk) 08:44, 1 October 2010 (UTC)

Experts needed

I think we need experts for the several disputes discussed above, but also for the article style regarding this subject. Styath (talk) 19:47, 30 September 2010 (UTC)

I agree there seems to be too much arguing that stems from ignorace of the precidents in the article and talkpage of Gliese 581 c. I think they are showing a lack of civility in continuing this line of arguing without looking at the presidents, specifically at Gliese 581 c, where the comparisons are also made and already debated and are included. I think you are sorely missing the relevence of the dicussions on the talkpage of Gliese 581 c, and this kind of ignorance is root cause of these arguments. 24.78.166.69 (talk) 20:03, 30 September 2010 (UTC)

No, it looks like you are edit warring, and cherry picking quotes out of primary sources to say something they don't say. You need to stop. Viriditas (talk) 20:36, 30 September 2010 (UTC)

"Cherry picking quotes" - that's a little harsh from what I saw the quotes from the primary source were relevant to the section it was applied to. Temperature and Habitability are not related?? - I seriously believe you are editing on the wrong topic. The idea that this planet is not at all like Mars is false. To say it is like Earth is even more false. The Earth is not tidally locked and the heat recieved by this planet as stated in the primary source is inargualby closer to Mars than it is to the Earth. Adding the GHG effect of the Earth to the Equlibrium temperature of the Earth yeilds 15°C according to the paper. But in the case of this planet, adding the GHG effect of Earth to Gliese 581 g at an equlibrium temperature of 209 K (-64 °C) that would then yield a temperature of 224 K (-49°C), and so it is ridiculous to suggest that the comparison is not relevant. Depending on the size of the actual atmosphere the planet could be even colder than Mars. Because of this I am persuaded that Mars temperature are very much relevant in the article, just as Venus temperature are relevant in the Gliese 581 c article. Counterpointing it as less optimistic is a whole separate issue. Other editors have voiced there opinions that the astronomer is not a biologist and has said some very nonsensical things in his paper, his enthusiasm is almost obsessively biased. But that doesn't change the temperature figures that they themselves have published. Whether it is more optimistic or less optimistic is nonsense when compared to the actual figures and calculations in the primary source. GabrielVelasquez (talk) 03:47, 1 October 2010 (UTC)

I'm not sure what you are on about. What nonsensical things were said in the paper? Viriditas (talk) 09:55, 1 October 2010 (UTC)

Now who is cherry picking, Ignoring your own discussion above: "Chances of life are 100%" - GabrielVelasquez (talk) 18:28, 1 October 2010 (UTC)

Please try to follow this discussion more closely. You said that the author "said some very nonsensical things in his paper." Could you point me to the page number please? Viriditas (talk) 19:26, 1 October 2010 (UTC)

You try to follow the discussion more closely, you're ignoring the similar comments in that section just to badger me.
Is hypocrisy in your vocabulary?? - GabrielVelasquez (talk) 20:06, 1 October 2010 (UTC)

I'll take that as a retraction of your previous statement. Thank you for conceding. Viriditas (talk) 20:16, 1 October 2010 (UTC)

Petty, very petty. - GabrielVelasquez (talk) 07:32, 2 October 2010 (UTC)

You want petty? As User:ChiZeroOne originally observed, you started editing only after article protection was implemented, preventing User:24.78.166.69 from continuing to edit war. Strangely enough, your first edit after protection was to "warn" User talk:WolfmanSF about edit warring with 24.78.166.69. So, let me ask the question that ChiZeroOne asked of you earlier and that I didn't see you answer. Are you 24.78.166.69? Think carefully before you answer yes or no. Viriditas (talk) 07:48, 2 October 2010 (UTC)

io9's name

This may or may not be worthnoting but io9 has decided the appropriate name for the planet is "Gloaming".

Source: What a colony might look like on Gloaming, the newly-discovered "second Earth"--DrWho42 (talk) 19:59, 30 September 2010 (UTC)

What drek that is. Gwen Gale (talk) 20:00, 30 September 2010 (UTC)

Here's an article I just read. [14]. I came over to Wikipedia to see if there was already an article.Malke 2010 (talk) 22:11, 30 September 2010 (UTC)

Forgot to mention it's also on Twitter.Malke 2010 (talk) 22:12, 30 September 2010 (UTC)

Confusing illustration

The illustration (File:485014main orbit comparison full 946-710.jpg) for this article is quite confusing. First, it seems to be primarily illustrating Gliese 581 f from the way it is drawn and the fact that only Gliese 581 f's orbit is compared with the orbits in our solar system. Second it make it look like the name Gliese 581 is being applied only to the orbit of Gliese 581 f. Maybe we should remove it until a better illustration, specifically highlighting Gliese 581 g can be found (or made). 208.64.187.110 (talk) 03:46, 1 October 2010 (UTC)

Also, it [planetary diameters?] doesn't seem to be to scale at all. Ideally, that should be mentioned. The2crowrox (talk) 04:43, 1 October 2010 (UTC)

Yes, doesn't really belong here. The image is being challenged for deletion (just like the one it replaced), but if it succeeds in licensing, it stil seems to better belong under the star article Gliese 581. Tom Ruen (talk) 04:59, 1 October 2010 (UTC)

One replacement option might be to take the updated SVG orbital diagram (File:GJ581orbits.svg), and make multiple versions, each highlighting a different orbit and planet, and each of those could go into the planet stat boxes. (BUT perhaps that should wait a while in case there're better data available?) Tom Ruen (talk) 05:03, 1 October 2010 (UTC)

I think this illustration is actually misleading. The primary significance of this planet is potential habitability. Gliese is smaller than Sol, so comparing orbits directly makes no sense for that subject. K. the Surveyor (talk) 13:49, 1 October 2010 (UTC)

This particular illustration is not only misleading it is completely false. Gliese 581 f doesn't get anywhere as much heat as Venus. Gliese 581 c would be just on the inside of the orbit of Venus and Gliese 581 g would be closer to Mars. GabrielVelasquez (talk) 17:36, 1 October 2010 (UTC)

What are you talking about? The present illustration shows the planets of Gliese 581 based on their semi-major axis. For example Gliese 581 f with a semi-major axis of 0.758 AU is slightly larger than the Venusian 0.723 AU which is why it is depicted as being beyond Venus, because it would be. It never claims to describe equivalent temperatures and why on earth should it?

Not only this, but this comment and others made is highly reminiscent of the comments of another editor, 24.78.166.69, further up the page. For clarity, are you the same person? ChiZeroOne (talk) 18:14, 1 October 2010 (UTC)

"Gliese is smaller than Sol, so comparing orbits directly makes no sense for that subject." Hello? - putting Venus and Gliese 581 f adjacent is deceptive, PERIOD.
If you scaled them for star mass they would be no where near each other, Read all the comments not just cherry pick the parts of the ones you disagree with. GabrielVelasquez (talk) 19:47, 1 October 2010 (UTC)

And? In the image Gliese 581 is depicted as smaller than Sol by about the right size. Comparing the orbits on physical scale is entirely appropriate which the image says is what it is doing anyway so there is nothing false about it. Not only that but the difference in radii for this star and Sol corresponds to approximately 0.003 AU therefore even if the image was made comparing semi-major axis directly then it would still be very accurate. Why on earth are you talking about "scaling them for star mass"? That is misleading, certainly in the infobox which people will expect to be a fairly representative representation.

Secondly, given your tone again in common with 24.78.166.69, I ask again are you the same person? ChiZeroOne (talk) 20:19, 1 October 2010 (UTC)

I don't think an image of Pluto fits in there either because it would give a false sense of how the planet would look like. The image is the first thing people will see, thus giving a wrong impression. Styath (talk) 19:17, 1 October 2010 (UTC)

Yes. This comment and the first comment in this section makes enough sense the orbit comparison image could be removed but not to replace with an image of Pluto (or any real planet from our home system). Most of the rest of the comments aside from ChiZeroOne's reflect more confusion than the image. But in any case a generic image of a planet in orbit around a red dwarf could be used until, say, the ESO creates an image which they usually do.Bdell555 (talk) 19:19, 1 October 2010 (UTC)

Well that didn't last long...[15]. Unfortunately I think any image put up will be changed by someone with an axe to grind, the fact is as artists impressions they are all subjective. In fact I doubt it will last long with no image either. ChiZeroOne (talk) 19:46, 1 October 2010 (UTC)

Ok, if you actually read the edit, you would see it said the Pluto image was supposed be a temporary patch, not permanent. Until one appropriate was found.

Also, dismissing the Encyclopedia's requirement of accuracy is somewhat naive, there is no "grudge" in it.GabrielVelasquez (talk) 20:03, 1 October 2010 (UTC)

I like the image being used now (File:GJ581orbits.svg). It isn't incredibly exciting, but at least it isn't confusing. Kaldari (talk) 00:26, 2 October 2010 (UTC)

Greenhouse effect bit

I think that Two factors that could potentially give Gliese 581 g a greenhouse effect greater than Earth's are the fact that Gliese 581 radiates a greater fraction of its energy output than the Sun at infrared wavelengths, and the possibility that the more massive planet has a correspondingly more massive atmosphere is dodgy. Also, I don't think it is clearly sourced.

The GHE effect works because the atmos is transparent to the insolation and opaque to the emitted IR. The redder the insolation the *less* effective the GH would be on the planet. The thicker atmos is right, though.

I don't think we use it in the article but from the paper it is clear that they don't really have an atmospheric physicist onboard: they can 't decide if increasing the temp by 288/255, or adding 33, is the right way to do the calculation (without thought I don't know either, I hasten to add) William M. Connolley (talk) 08:53, 1 October 2010 (UTC)

Well, peak emission of the star is in the near IR, at 830 nanometers, while re-emitted IR from a body between 250-300k is on the micrometer scale. I'm not sure that the effect would be that different. Until we get a better paper about the possible atmosphere and temperature of Gliese 581 g, we can leave it for now. I'm thinking it won't take too terribly long for someone to run a few models and publish a paper. shaggy (talk) 11:51, 1 October 2010 (UTC)

circulation must be extremely important. i was thinking it would be Venus-like, but then i realized that a large part of Venus' heat originates from loss of water and oxygen due to UV photo-separation in the upper atmosphere. that would not likely occur, here. if the atmosphere were opaque to 830 nm, wouldn't that yield a hotter upper atmosphere, and much cooler, below? -- 99.233.186.4 (talk) 12:56, 1 October 2010 (UTC)

IIRC the models predict that the planetary albedo decreases for planets around red dwarfs because the Rayleigh scattering is less effective and more of the energy is radiated at the same wavelengths as the absorption features for gases like water and carbon dioxide. Without taking into account other effects, this results in an increased effective temperature for the planet. This isn't usually what is meant by the "greenhouse effect" though. Icalanise (talk) 16:19, 1 October 2010 (UTC)

I've just taken out the frequency bit. It doesn't seem to be true (if anything it is the wrong way, but from the above maybe only marginally so) and I don't see it in the ref anyway William M. Connolley (talk) 21:20, 1 October 2010 (UTC)

SETI and Drake equation

I think the drake equation should at least be cite once. Regards. Yug (talk) 15:39, 1 October 2010 (UTC)

Please find secondary sources finding it in relation to this topic. I removed it from this article because I could not. I'm also not comfortable with the SETI content given such prominence in the habitability section. Viriditas (talk) 20:17, 1 October 2010 (UTC)

No source, but Wikipedia rules also say us to use logic. When the article say "If the fraction of stars with potentially habitable planets (η⊕, "eta-Earth") is on the order of a few tens of percent" we are de facto talking about one part of the drake equation. Yug (talk) 10:42, 2 October 2010 (UTC)

Agree. Speaking as one professionally involved with the SETI project, the "Drake Equation" is not any fixed scientific equation or theory, but a convinence to describe possible scenarios: originally by conceived by Frank Drake to demonstrate that it is at least possible life exists around other suns. The terms of the equations are (intentionally) statistically loose, and have, over the years, been constantly experimentally altered to investigate alternative scenarios. There is no single equation that merits mention. The factors of the "equation" should be individually discussed, with supporting reference to their individual importance. Alpha Ralpha Boulevard (talk) 10:47, 2 October 2010 (UTC)

(@Alpha: Agree with who ?)

We are with Gliese 581 g improving the understanding of Drake equation's ne factor, with ne = the average number of planets that can potentially support life per star that has planets

N = $R^{\ast }\times f_{p}\times n_{e}\!$ $\times f_{\ell }\times f_{i}\times f_{c}\times L\!$

See Drake_equation#Current_estimates_of_the_parameters Yug (talk) 10:51, 2 October 2010 (UTC)

I agreed with the comments made by you and Viriditas, as written. However, there is no "improved understanding", because the Drake Equation does not represent a universal, empirical scientific truth such as Force = Mass x Acceleration or E=MC2. It's a convenience to describe possibilities. Not a testable scientific theory. Each term of the equation is open to debate -- as well as the terms in combination. Drake never intended to create a universal theory. It was a strawman equation for discussion. Hence the need to discuss each assumption (each term of the equation) separately. Alpha Ralpha Boulevard (talk) 11:18, 2 October 2010 (UTC)

Forest for the trees, please. While this is all related to the Drake equation on a historical and conceptual basis, when we speak of eta-Earth in this specific context, we are talking about NASA's roadmap for investigating, finding, and targeting promising planetary systems.[16] We are years and years away from even talking about ETI, with 2020 considered a likely timetable for such a discussion. So, while Drake certainly makes use of this figure in its equation that's not what we are talking about in this article. Talking about ETI in this context, would be like asking an infant to run a marathon. We are in baby step mode until we have more information. Viriditas (talk) 11:16, 2 October 2010 (UTC)

Yes, Viriditas, in essence. We all of us are just guessing now, scientists alike. But to keep the discussion straight, NASA had little to do with the Drake Equation. The equation came from Drake in the 1960s as a tool for demonstation and communication. The NASA SETI project lasted only lasted briefly, in the 1990s. That project did not seek to amplify on existing versions of the equation. Alpha Ralpha Boulevard (talk) 11:46, 2 October 2010 (UTC)

Please read what I wrote again and visit the link I provided. Eta-Earth is used by NASA as part of the roadmap for searching for habitable planets as is its use by Vogt et al. See p.13, "Recommended Missions, Implementation Framework, and R&D Programs".[17] It "helps set mission strategies by determining the number of stellar systems that must be explored to have a reasonable chance of success" of finding potentially habitable planets. We're not talking about the Drake equation here. This is a rebuttal to what Yug is claiming in his reply at 10:42, 2 October 2010. It's the same idea as Drake, but we're using it in a different context. We're not talking about SETI at all here. I realize that a lot of people are confused because of what the MSM is reporting. And, it looks like I was wrong about 2020. Page 20 of the roadmap says we won't even have good data until 2035. Viriditas (talk) 12:36, 2 October 2010 (UTC)

---

Closed.

Woow, so much argumentations for a so small issue. My former proposal was just "maybe we may add this Drake equation link, curious people interested to know more will then have the possibility to look at it". And that become a deep debate about "does this recent discovery scientifically modify estimations of factors of the Drake equation or not ?" My proposal/this issue don't worth so much human time. Yes: the Drake is just a blur toy, but still interesting to hear about. So let's each of us go to drink a good chocolate or something similar. [If we were in real I would pay your cups and listen at your astronomic stories ;( (<-wishing a real-life wikipedia)]

Thanks for your interesting posts !

Yug (talk) 13:41, 2 October 2010 (UTC)

Edit request from Merkert17, 1 October 2010

{{edit semi-protected}}

The caption under the picture says this is a planet in our solar system. This is inaccurate - it's a planet in another star system, although it is in our galaxy (the Milky Way, of course)

Merkert17 (talk) 19:00, 1 October 2010 (UTC)

Ok, buddy look at the edits, Gliese 581 f is nothing like Venus, the images was replaced to get rid of this deception, and in the mean time a tidally locked planet image was placed there, it doesn't say that is THE planet, it says it is an image of a planet in our solar system that is also tidally locked. GabrielVelasquez (talk) 19:16, 1 October 2010 (UTC)

I can't find any picture that matches this description, so I've declined your request. Feel free to make it again if you're more specific. Nyttend (talk) 21:46, 1 October 2010 (UTC)

Pic

is a nice pic from Habitability of red dwarf systems. Perhaps we could get one with 581 on it William M. Connolley (talk) 20:03, 1 October 2010 (UTC)

The necessity of locking the article.

The articles contents have not been universally publisised under the title given to it by wikipedia, so, as vandals typically take the pth of least resistance to trashing an article, is this likely to be necessarily an article they can refer to once the media hype goes down, as it almost inevitably will, on this subject? I don't think the page should have an auto-confirmation lock for more than a couple of days.--Cymbelmineer (talk) 21:10, 1 October 2010 (UTC)

The article was protected by request because of unacceptable edit warring, not randoms vandalising. ChiZeroOne (talk) 21:33, 1 October 2010 (UTC)

i have a question

if this planet does not rotate does that have an effect on the gravity of the planet? i was just thinking that if the planet not rotating causes weaker gravity the estimated gravity might be wrong... sorry if its a dumb question —Preceding unsigned comment added by 76.120.39.39 (talk) 22:23, 1 October 2010 (UTC)

A planet in tidal lock rotates (as does the moon). If the planet were not rotating (highly, highly unlikely), gravity might be ever so slightly stronger, not weaker. Gwen Gale (talk) 22:38, 1 October 2010 (UTC)

oh ok thanks for the info —Preceding unsigned comment added by 76.120.39.39 (talk) 22:49, 1 October 2010 (UTC)

Speaking of which, does anyone have more info/sources on the surface gravity? the citation, while being good, does not make this clear to me. Gravity is very important for potential colonization. Bigdan201 (talk) 15:37, 2 October 2010 (UTC)

The reason it is not clear is because it is not currently possible to know. The radial velocity method of detection can only give the object's mass (even then as you can see only a range of possible values), not it's radius or mean density. Worlds with a mass of 3-4 times that of earth are expected to be of predominately rocky composition hence a range of mean densities similar to rock are assumed and from both that and the mass the likely value for the radius is calculated. The surface gravity is obviously very dependant upon where the surface is. This is why they state a range of possible values, but then even these are simply educated guesses. There will be no more authoritative values until the planets other characteristics are better defined, which in many cases may require new technologies/methods. ChiZeroOne (talk) 16:08, 2 October 2010 (UTC)

Ah ok, thanks. I will say that the current educated guess of 1.1 - 1.7g is promising. I'm sure that astronomers will conduct a thorough investigation with the tools available, given this planets unique nature. Then we may find out about gravity as well as other important conditions that haven't been confirmed yet. Looking forward to it! Bigdan201 (talk) 16:22, 2 October 2010 (UTC)

grammar correction

Since this is locked: The line "Such a wide range in temperatures is due to the rarefied atmosphere," needs to be corrected to this for plural-singular agreement "Such a wide range in temperature is due to the rarefied atmosphere," Not sure the first comma after atmosphere is needed either. Jascal (talk) 06:49, 2 October 2010 (UTC)

Corrected. None of the commas were actually needed. I just love, the tendency people have, to insert extra commas to better replicate the pauses, and cadence, of normal speech. shaggy (talk) 07:55, 2 October 2010 (UTC)

Charts

The order of planets shown on this article shows planets as - e b c g d f. The chart on Gleise 581e article shows order of inner planets as - d c b e. Some major mistake on one of these pages. Tiddy (talk) 14:41, 2 October 2010 (UTC)

Judging by the fact you posted a similar comment on Talk:Gliese 876 e, it appears you have got confused. There is no orbit diagram on the Gliese 581 e article. Gliese 876 and Gliese 581 are two different stars. Gliese 876 has four known planets, designated d,c,b,e in order of increasing distance from the star. Gliese 581 has six known planets, designated e,b,c,g,d,f in order of increasing distance. Icalanise (talk) 15:20, 2 October 2010 (UTC)