Talk:Hadean

message: Should this article include the image (Hadean.png) that is an artist's impression of the Earth during the Hadean (created by User:Triangulum)? This image was removed on 14 November 2018 by IP user 86.141.111.80, who justified the removal by claiming that the image is original research. The image was restored by User:Vsmith a day later. How realistic is this image? Currently, there is no evidence that this image is supported by scientific research similar to how NASA's artistic impressions of planetary bodies are supported. Can use of the image be justified e.g. on the basis that although it is only a guess, it may be no less wrong than any other artist's impression because nobody will ever know for sure what the Earth looked like in the Hadean? On the other hand it may be completely wrong. My opinion is that this image currently seems to represent original research and therefore I suggest that it should be removed from the article. GeoWriter (talk) 16:29, 21 December 2018 (UTC)
replies: text: I quite liked the image and think that having a depiction of what Earth might have looked like during the Hadean greatly improves the article. I think it would be great if we could have the same or a similar image backed up with good sources in the article. Schweinchen (talk) 22:02, 22 October 2023 (UTC)
replies: text: @Schweinchen Is the current image OK? CactiStaccingCrane (talk) 17:35, 11 November 2023 (UTC)
replies: text: I think the current image (:File:Hadean planet.jpg) is misleading, because the Earth's ocean formed early in the Hadean (as long ago as 4.4 Ga). The current image doesn't reflect this. The image here is more realistic, but not PD. — hike395 (talk) 17:54, 11 November 2023 (UTC)
replies: text:  Please take a look at the Oceans and Plate tectonics sections of the article, including the diagram and the references. The current thinking is that even at 4.4Ga, the Earth had a shallow ocean, under a hot atmosphere with 27 atmospheres of pressure. The "lava planet" idea is outdated. Since we cannot agree on the image, perhaps we should just remove it? — hike395 (talk) 08:26, 15 November 2023 (UTC)

text: The initial magma ocean is thought to solidify very rapidly: within 5 million years, and possibly within 100,000 years. I don't think it's representative of the entire eon. — hike395 (talk) 08:51, 15 November 2023 (UTC)
replies: text: Agree. CactiStaccingCrane (talk) 09:56, 15 November 2023 (UTC)
thread_title:  Artist's impression image 

message: Big chunk of the picture is missing here, with no mention of the geodynamics: the moon arrived early in the Hadean, and started out with a distance somewhere around 50km surface to surface (much discussion needed about this, as different theories yield different results extrapolating backward from current known increase in moon distance - the tidal effects which drive this depend on when how much water existed on earth how early, and how much an early liquid mantle contributed), but it is intimately linked to earth's day length - the rotation period increased as its energy was passed to raise the moon's orbit, but the day was likely to have started out around 6 hours long, which means, in combination with the close moon, that tides of the early ocean would have been perhaps 100 metres high every 1.5 hours!!! This is far too ambitious a project for me to contemplate, but if no one steps up, I may hack up a paragraph about this in a few months. Some discussion of the effect can be found here: https://en.wikipedia.org/wiki/Earth's_rotation#In_rotational_velocity And here's another discussion of the sort of implications this can lead to: https://www.centauri-dreams.org/2018/02/08/lunar-recession-implications-for-the-early-earth/
2001:56A:F0E9:9B00:2906:4B4E:36B1:125B (talk) 11:53, 2 January 2020 (UTC)
thread_title:  Geodynamics 

message: This website from the ICS suggests Hadean is pronounced with only two syllables, not three. It shows the syllabification is 'Hade-an'. That seems really odd to me but they are an official body regarding such matters. Any ideas? Jason Quinn (talk) 04:54, 25 February 2023 (UTC)
replies: text: I think the point the ICS is trying to make is that it's pronounced "HAY-de-an" (to rhyme with "Adian") not "hay-DEE-an" (to rhyme with "Ian"). Merriam-Webster  gives the IPA representation /ˈhā-ˌdē-ən/ - note the stress marks. Tevildo (talk) 11:37, 25 February 2023 (UTC)
replies: text: I would treat the pronunciation guide of stratigraphy.org as only a suggestion. The ICS is definitely not an official body for pronunciation of any words. The compiler of the guide (Bruno Granier) seems to not be a native speaker of English. The ICS pronunciation guide claims that Lopingian is syllabized as "Lopin-gi-an". I think many English speakers would syllabize Lopingian as Lo-ping-i-an (The name is derived from a place called Leping in China). Similarly, the guide also claims that Givetian is syllabized as Give-tian. I think many English speakers would syllabize Givetian as Gi-ve-tian or Giv-et-i-an (The name derives from a place in France called Givet). All of the many geologists I know syllabize Hadean as had-e-an. (Note that splitting a word into syllables does not necessarily dictate how the individual syllables are pronounced).    GeoWriter (talk) 17:31, 7 March 2023 (UTC)
thread_title:  Pronunciation  

message: I intend to rename the section "Subdivisions" to "Proposed subdivisions". There are no subdivisions. And the article on the "lunar geologic timescale" suggests these are not in widespread use. So the section name is kind of misleading and could falsely make a skimming reader "learn" that the Hadean has subdivisions. Jason Quinn (talk) 14:31, 4 March 2023 (UTC)
replies: text: * Support rename to "Proposed subdivisions". GeoWriter (talk) 15:12, 4 March 2023 (UTC)
replies: text: Should we just delete the section? It places undue weight on an unadopted proposal. — hike395 (talk) 17:23, 4 March 2023 (UTC)
replies: text: It was the sentence "Nevertheless, at least one notable scientific work has advocated using the lunar geological time scale to subdivide the Hadean eon of Earth's geologic time scale." in the Lunar geologic timescale article that ultimately provoked me to start this rename proposal. I was worried that WP:UNDUE might apply. Unfortunately, I'm not familiar enough with this subject matter and the current literature and state of the field to make the call there. I was also concerned about WP:CRYSTALBALL but the proposed rename makes that issue disappear so I figured that's the minimum first step to improve the article. Jason Quinn (talk) 02:15, 5 March 2023 (UTC)
replies: text: I'm very much in favor of renaming, but I thought it would be even better to just delete the section. AFAICT, this proposal is now 13 years old and has gotten very little traction. — hike395 (talk) 05:53, 5 March 2023 (UTC)
replies: text:  I think I favor delete. Compared to the number of adopted proposals (in any field, pretty much), failed proposals (or proposals not yet acted upon) are far more numerous. There has to be something very special about an unadopted proposal to make it worthy of inclusion. The U.S. Equal Rights Amendment is certainly one of the latter. Is this? I doubt it. Mathglot (talk) 12:15, 15 November 2023 (UTC)
thread_title:  Rename section "Subdivisions" to "Proposed subdivisions"