![]() | This article is rated C-class on Wikipedia's
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This article was the subject of a Wiki Education Foundation-supported course assignment, between 2 April 2019 and 28 June 2019. Further details are available
on the course page. Student editor(s):
Lmfifer.
Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT ( talk) 02:24, 18 January 2022 (UTC)
... and some of it, as it stands, I find odd, to say the least. But I do not intend to spend time trying to edit it. I leave that to the local author.
I now see that I have inadventently done some bad things which I should have left to an expert administrator. I am sorry for my mistake in this.
But I feel confident that the new title is the right one for this article. I hope a suitable administrative fix will be found. Chjoaygame ( talk) 04:28, 16 November 2012 (UTC)
I have constructed a more general set-up that seems to me appropriate for this article. The title does not pretend to be specific term of art, but is simply an encyclopaedia heading, in ordinary language, to encompass an area of interest, probably comprising several terms of art. I am not interested in trying to improve or edit or expand this article, but I am interested in protecting the structural coherence and consistency of Wikipedia article headings. I hope this is a reasonable compromise. Chjoaygame ( talk) 03:00, 18 November 2012 (UTC)
I am not happy with some of the internet sources cited for this article. In my opinion, they do not reach a suitable standard of reliability. The main problem is that internet sources are often very hard to check as to their actual sources. Sometimes citing the internet is a sign of lazy editorial activity. As reliable sources for Wikipedia articles, I much prefer established printed textbooks which themselves cite reliable literature sources. The question is not as to the correctness of the source, but as to its further checkability. A reliable source should be reliably checkable. Chjoaygame ( talk) 03:09, 18 November 2012 (UTC) Chjoaygame ( talk) 03:12, 18 November 2012 (UTC)
I prefer the previous more general version, but I am not interested in this topic, so I will not undo the new version.
This table was from time to time put into the article on thermal equilibrium, where it did not naturally fit. I have no idea of its possible value for the present article, but here it is, for your consideration. Those insertions were the cause of my concern with the present article.
Temperature comparisons |
Venus | Earth | Gliese 581 g | Mars |
Global equilibrium temperature |
307 K 34 °C 93 °F |
255 K −18 °C −0.4 °F |
209 K to 228 K −64 °C to −45 °C −83 °F to −49 °F |
206 K −67 °C −88.6 °F |
+ Venus' GHG effect |
737 K 464 °C 867 °F |
|||
+ Earth's GHG effect |
288 K 15 °C 59 °F |
236 K to 261 K −37 °C to −12 °C −35 °F to 10 °F |
||
+ Mars' GHG effect |
210 K −63 °C −81 °F | |||
Tidally locked |
Almost | No | Probably | No |
Global Bond Albedo |
0.9 | 0.29 | 0.5 to 0.3 | 0.25 |
Refs. [1] [2] [3] [4] [5] |
Vogt
was invoked but never defined (see the
help page).Stephens
was invoked but never defined (see the
help page).{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
Chjoaygame ( talk) 01:05, 27 November 2012 (UTC)
I agree that there is much to do on this article. It's very odd to put the equation in terms of the temperature and the radius of the star; that's not the usual way you see equilibrium temperature calculated. Temperature and radius are calculated, while the luminosity of the star is directly measured, so it's more common to see the equilibrium temperature in terms of the luminosity.
I added a section where the temperature is calculated as a function of the insolation, which is also a common calculation.
One quibble: if a planet has an albedo not equal to zero, it's not a "perfect blackbody"; it's emitting as a blackbody, but absorbing as a a grey body.
Geoffrey.landis ( talk) 20:48, 25 June 2014 (UTC)
Thanks a lot for your work. I originally started this article because I heard the term used when I was reading a journal article about one of the exoplanets discovered by the Kepler mission. There was no wikipedia article that addressed the topic so I created one. My original intention was to have a place to answer the question "How do they know what the temperature of an extrasolar planet is?"
While the other comments have maybe correctly pointed out that this article lacks generality, I found Choyagame's comments belligerent and just too much to deal with. I was also a bit offended that his comments were twice the length of the original article. I looked up information on the internet, after a question I had about a journal article, and couldn't find what I was looking for - and decided to create a wikipedia article. I think that if someone has a "What's that?" question, there should be an answer somewhere in Wikipedia. So while the article may lack generality, it does answer "How do scientists know what the temperature of an exoplanet is?" which is what I intended to write. The great thing about wikipedia is that generality and context can be added later, because there is always another editor who knows more than the author.
I'm fine with any edits except those that remove the answer to the question I came to this article with.
Drxenocide ( talk) 17:01, 8 July 2014 (UTC)
The equation under "Theoretical Model" give an equilibrium temperature for Venus of 186 K, but the article previous gave a temperature of 260 K. I have changed this value for the sake of consistency. — Preceding unsigned comment added by 192.91.60.10 ( talk) 12:18, 19 August 2014 (UTC)
I think Planetary equilibrium temperature and the "Planet" chapter of Effective temperature are actually the same topic. Also it seems that equilibrium temperature and effective temperature are (at least in this context) the same thing. In my opinion the two articles should either be merged, or at least visible cross referenced. What's currently not good is that "equilibrium" and "effective" temperature are misleadingly defined like they would be different, while actually they are defined by the same formulas (and planetary equilibrium temperature is the same as effective temperature... for planets); in the formulas, the luminosity and albedo are notated (slightly) differently but everything else is identical, like two different people worked independently on two different articles which actually are about the same subject:
http://en.wikipedia.org/wiki/Effective_temperature#Planet vs http://en.wikipedia.org/wiki/Planetary_equilibrium_temperature#Detailed_derivation_of_the_planetary_equilibrium_temperature
-Paul- ( talk) 10:44, 22 October 2014 (UTC)
Temperature comparisons |
Venus | Earth | Gliese 581 g | Mars |
Global equilibrium temperature |
307 K 34 °C 93 °F |
255 K −18 °C −0.4 °F |
209 K to 228 K −64 °C to −45 °C −83 °F to −49 °F |
206 K −67 °C −88.6 °F |
+ Venus' GHG effect |
737 K 464 °C 867 °F |
|||
+ Earth's GHG effect |
288 K 15 °C 59 °F |
236 K to 261 K −37 °C to −12 °C −35 °F to 10 °F |
||
+ Mars' GHG effect |
210 K −63 °C −81 °F | |||
Tidally locked |
Almost | No | Probably | No |
Global Bond Albedo |
0.9 | 0.29 | 0.5 to 0.3 | 0.25 |
Under the section titled "Theoretical model" an equation is given for the equilibrium temperature of a planet. In the paragraph below this equation, an equilibrium temperature of Venus of 260 K is given, however if one actually uses the equation given one finds the equilibrium temperature of Venus to be ~186K. The 260K figure only appears if one uses the diameter of the sun instead of the radius in the equation. It also doesn't make sense for Venus to have a higher equilibrium temperature than Earth for the simple reason that it absorbs less radiation from the sun; the solar constant at Venus is twice that at Earth, but Venus also reflects 90% of the light radiation that reaches it while Earth only reflects 30%. This means Earth absorbs 3.5 times as much radiation than Venus, and so in the absence of the greenhouse effect it would have a higher temperature.
I'm not sure if this qualifies as original research or not, but I think the 260 K figure should at least be removed as incorrect. — Preceding unsigned comment added by 131.111.185.47 ( talk) 12:47, 9 November 2014 (UTC)
I was redirected from "Blackbody Temperature" and found myself confronted with an Article that starts thusly:
"The planetary equilibrium temperature is a theoretical temperature that a planet would be at when considered simply as if it were a black body being heated only by its parent star. ...".
So by definition of this Article a Extrasolar Planet, Sub-brown Dwarf or even a Rogue Planet doesn't have a "Planetary Equilibrium Temperature" or an Effective Temperature because it is a Blackbody without a "Parent Star".
All things (objects) hotter than Absolute Zero and with an Emissivity greater than zero emit radiation and thus have a temperature (or Black-body Radiation), objects with an emissivity less than zero are reflective and reflect heat, they are called a Whitebody.
Even a Black Hole (a perfect Blackbody) is thought to emit Hawking Radiation and thus have a temperature.
I'm not trying to split hairs, just looking for the Link I clicked on before this redirect - I wonder if Planet Effective Temperature duplicates some of this Info.
70.71.206.161 ( talk) 06:21, 20 March 2017 (UTC)
How the Moon can have higher equilibrium temperatre than Venus, given it is further from the Sun?-- Reciprocist ( talk) 23:12, 23 December 2018 (UTC)
I am going to make a few changes, mostly to clarify aspects of the article that are vague or misleading. One part that could use work is a clearer separation between equilibrium temperature and effective temperature. Equilibrium temperature is the temperature a planet would have to radiate at (like a blackbody) to produce a flux equal to the incoming flux it receives from the sun. Effective temperature is the temperature a planet would radiate at to produce a flux equal to the incoming solar flux PLUS any additional sources of energy, such as internal energy on giant planets. Lmfifer ( talk) 22:10, 11 June 2019 (UTC)
References
The mentions of emissivity during the complete derivation seem unnecessary, given that the definition of equilibrium temperature rests on a blackbody flux equaling incident solar flux, not a graybody (which is the only time emissivity should come into play).
Also in the derivation, a lot of attention is paid to the size (radius) of the star, while the equilibrium temperature could be defined more simply in terms of insolation (which the article uses earlier). Maybe the stellar properties (and orbital distance of the planet) could be introduced at the end of the derivation, as an aside? Lmfifer ( talk) 02:29, 12 June 2019 (UTC)
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
This article was the subject of a Wiki Education Foundation-supported course assignment, between 2 April 2019 and 28 June 2019. Further details are available
on the course page. Student editor(s):
Lmfifer.
Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT ( talk) 02:24, 18 January 2022 (UTC)
... and some of it, as it stands, I find odd, to say the least. But I do not intend to spend time trying to edit it. I leave that to the local author.
I now see that I have inadventently done some bad things which I should have left to an expert administrator. I am sorry for my mistake in this.
But I feel confident that the new title is the right one for this article. I hope a suitable administrative fix will be found. Chjoaygame ( talk) 04:28, 16 November 2012 (UTC)
I have constructed a more general set-up that seems to me appropriate for this article. The title does not pretend to be specific term of art, but is simply an encyclopaedia heading, in ordinary language, to encompass an area of interest, probably comprising several terms of art. I am not interested in trying to improve or edit or expand this article, but I am interested in protecting the structural coherence and consistency of Wikipedia article headings. I hope this is a reasonable compromise. Chjoaygame ( talk) 03:00, 18 November 2012 (UTC)
I am not happy with some of the internet sources cited for this article. In my opinion, they do not reach a suitable standard of reliability. The main problem is that internet sources are often very hard to check as to their actual sources. Sometimes citing the internet is a sign of lazy editorial activity. As reliable sources for Wikipedia articles, I much prefer established printed textbooks which themselves cite reliable literature sources. The question is not as to the correctness of the source, but as to its further checkability. A reliable source should be reliably checkable. Chjoaygame ( talk) 03:09, 18 November 2012 (UTC) Chjoaygame ( talk) 03:12, 18 November 2012 (UTC)
I prefer the previous more general version, but I am not interested in this topic, so I will not undo the new version.
This table was from time to time put into the article on thermal equilibrium, where it did not naturally fit. I have no idea of its possible value for the present article, but here it is, for your consideration. Those insertions were the cause of my concern with the present article.
Temperature comparisons |
Venus | Earth | Gliese 581 g | Mars |
Global equilibrium temperature |
307 K 34 °C 93 °F |
255 K −18 °C −0.4 °F |
209 K to 228 K −64 °C to −45 °C −83 °F to −49 °F |
206 K −67 °C −88.6 °F |
+ Venus' GHG effect |
737 K 464 °C 867 °F |
|||
+ Earth's GHG effect |
288 K 15 °C 59 °F |
236 K to 261 K −37 °C to −12 °C −35 °F to 10 °F |
||
+ Mars' GHG effect |
210 K −63 °C −81 °F | |||
Tidally locked |
Almost | No | Probably | No |
Global Bond Albedo |
0.9 | 0.29 | 0.5 to 0.3 | 0.25 |
Refs. [1] [2] [3] [4] [5] |
Vogt
was invoked but never defined (see the
help page).Stephens
was invoked but never defined (see the
help page).{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
Chjoaygame ( talk) 01:05, 27 November 2012 (UTC)
I agree that there is much to do on this article. It's very odd to put the equation in terms of the temperature and the radius of the star; that's not the usual way you see equilibrium temperature calculated. Temperature and radius are calculated, while the luminosity of the star is directly measured, so it's more common to see the equilibrium temperature in terms of the luminosity.
I added a section where the temperature is calculated as a function of the insolation, which is also a common calculation.
One quibble: if a planet has an albedo not equal to zero, it's not a "perfect blackbody"; it's emitting as a blackbody, but absorbing as a a grey body.
Geoffrey.landis ( talk) 20:48, 25 June 2014 (UTC)
Thanks a lot for your work. I originally started this article because I heard the term used when I was reading a journal article about one of the exoplanets discovered by the Kepler mission. There was no wikipedia article that addressed the topic so I created one. My original intention was to have a place to answer the question "How do they know what the temperature of an extrasolar planet is?"
While the other comments have maybe correctly pointed out that this article lacks generality, I found Choyagame's comments belligerent and just too much to deal with. I was also a bit offended that his comments were twice the length of the original article. I looked up information on the internet, after a question I had about a journal article, and couldn't find what I was looking for - and decided to create a wikipedia article. I think that if someone has a "What's that?" question, there should be an answer somewhere in Wikipedia. So while the article may lack generality, it does answer "How do scientists know what the temperature of an exoplanet is?" which is what I intended to write. The great thing about wikipedia is that generality and context can be added later, because there is always another editor who knows more than the author.
I'm fine with any edits except those that remove the answer to the question I came to this article with.
Drxenocide ( talk) 17:01, 8 July 2014 (UTC)
The equation under "Theoretical Model" give an equilibrium temperature for Venus of 186 K, but the article previous gave a temperature of 260 K. I have changed this value for the sake of consistency. — Preceding unsigned comment added by 192.91.60.10 ( talk) 12:18, 19 August 2014 (UTC)
I think Planetary equilibrium temperature and the "Planet" chapter of Effective temperature are actually the same topic. Also it seems that equilibrium temperature and effective temperature are (at least in this context) the same thing. In my opinion the two articles should either be merged, or at least visible cross referenced. What's currently not good is that "equilibrium" and "effective" temperature are misleadingly defined like they would be different, while actually they are defined by the same formulas (and planetary equilibrium temperature is the same as effective temperature... for planets); in the formulas, the luminosity and albedo are notated (slightly) differently but everything else is identical, like two different people worked independently on two different articles which actually are about the same subject:
http://en.wikipedia.org/wiki/Effective_temperature#Planet vs http://en.wikipedia.org/wiki/Planetary_equilibrium_temperature#Detailed_derivation_of_the_planetary_equilibrium_temperature
-Paul- ( talk) 10:44, 22 October 2014 (UTC)
Temperature comparisons |
Venus | Earth | Gliese 581 g | Mars |
Global equilibrium temperature |
307 K 34 °C 93 °F |
255 K −18 °C −0.4 °F |
209 K to 228 K −64 °C to −45 °C −83 °F to −49 °F |
206 K −67 °C −88.6 °F |
+ Venus' GHG effect |
737 K 464 °C 867 °F |
|||
+ Earth's GHG effect |
288 K 15 °C 59 °F |
236 K to 261 K −37 °C to −12 °C −35 °F to 10 °F |
||
+ Mars' GHG effect |
210 K −63 °C −81 °F | |||
Tidally locked |
Almost | No | Probably | No |
Global Bond Albedo |
0.9 | 0.29 | 0.5 to 0.3 | 0.25 |
Under the section titled "Theoretical model" an equation is given for the equilibrium temperature of a planet. In the paragraph below this equation, an equilibrium temperature of Venus of 260 K is given, however if one actually uses the equation given one finds the equilibrium temperature of Venus to be ~186K. The 260K figure only appears if one uses the diameter of the sun instead of the radius in the equation. It also doesn't make sense for Venus to have a higher equilibrium temperature than Earth for the simple reason that it absorbs less radiation from the sun; the solar constant at Venus is twice that at Earth, but Venus also reflects 90% of the light radiation that reaches it while Earth only reflects 30%. This means Earth absorbs 3.5 times as much radiation than Venus, and so in the absence of the greenhouse effect it would have a higher temperature.
I'm not sure if this qualifies as original research or not, but I think the 260 K figure should at least be removed as incorrect. — Preceding unsigned comment added by 131.111.185.47 ( talk) 12:47, 9 November 2014 (UTC)
I was redirected from "Blackbody Temperature" and found myself confronted with an Article that starts thusly:
"The planetary equilibrium temperature is a theoretical temperature that a planet would be at when considered simply as if it were a black body being heated only by its parent star. ...".
So by definition of this Article a Extrasolar Planet, Sub-brown Dwarf or even a Rogue Planet doesn't have a "Planetary Equilibrium Temperature" or an Effective Temperature because it is a Blackbody without a "Parent Star".
All things (objects) hotter than Absolute Zero and with an Emissivity greater than zero emit radiation and thus have a temperature (or Black-body Radiation), objects with an emissivity less than zero are reflective and reflect heat, they are called a Whitebody.
Even a Black Hole (a perfect Blackbody) is thought to emit Hawking Radiation and thus have a temperature.
I'm not trying to split hairs, just looking for the Link I clicked on before this redirect - I wonder if Planet Effective Temperature duplicates some of this Info.
70.71.206.161 ( talk) 06:21, 20 March 2017 (UTC)
How the Moon can have higher equilibrium temperatre than Venus, given it is further from the Sun?-- Reciprocist ( talk) 23:12, 23 December 2018 (UTC)
I am going to make a few changes, mostly to clarify aspects of the article that are vague or misleading. One part that could use work is a clearer separation between equilibrium temperature and effective temperature. Equilibrium temperature is the temperature a planet would have to radiate at (like a blackbody) to produce a flux equal to the incoming flux it receives from the sun. Effective temperature is the temperature a planet would radiate at to produce a flux equal to the incoming solar flux PLUS any additional sources of energy, such as internal energy on giant planets. Lmfifer ( talk) 22:10, 11 June 2019 (UTC)
References
The mentions of emissivity during the complete derivation seem unnecessary, given that the definition of equilibrium temperature rests on a blackbody flux equaling incident solar flux, not a graybody (which is the only time emissivity should come into play).
Also in the derivation, a lot of attention is paid to the size (radius) of the star, while the equilibrium temperature could be defined more simply in terms of insolation (which the article uses earlier). Maybe the stellar properties (and orbital distance of the planet) could be introduced at the end of the derivation, as an aside? Lmfifer ( talk) 02:29, 12 June 2019 (UTC)