Talk:Faint young Sun paradox

message: 1: The article does not seem to mention Theia at all, nor accretion (incidentally, it seems fairly inconsistent with some other WP articles on Earth prehistory, which are somewhat mutually incoherent, but never mind that for now). Such a collision, plus possibly collisions extending into the Hadean, surely would have caused significant heating. I have seen speculations of extensive crustal melting resulting from such impacts, with little or no non-gaseous water on the planet for extended periods. Now, I have no fish to fry, but the mass of our current oceans exceeds our total atmospheric mass by orders of magnitude, not even counting even larger volumes of deep mantle moisture. If a lot of that water constituted the atmosphere of the day, it surely would have dwarfed the greenhouse effect of the CO2, either then or now, CO2 being a weaker greenhouse gas anyway? Not to mention CH4 and other organics of the day? Even after most of the steam had settled out as a warm liquid, the atmosphere could have remained humid for a long time, maybe even during the period of initial abiogenesis. Even after the surface had frozen, it would take some 4km deep water a long time to freeze all the way down.  The transition pre-life, pre-cellular period, even if it was followed by a snowball, might well have produced biochemical forms that would not have been harmed by indefinite freezing, and in evolutionary terms, might have hit the ground running in originating true life forms during the eventual thaw. The frozen crust might conceivably even have played a vital protective role at certain stages. Yes?
2: Even in a snowball Earth, there would have been a permanent phase at all times of molten water between hot rock and ice (in many local regions at least). There must have been far more vulcanism, and many more smokers than now. There also must have been a lot more radioactive heating 4GY ago than now. Snowball or not, complete or not, there never can have been a time when there was not a lot of molten water near the planetary surface. No?
3: So: I am no planetologist, though I would be willing to contribute some time to such an initiative by qualified editors, but is it not time to do some work, not necessarily to resolve such issues between the articles, but at least to put them into a healthy state of mutual perspective and possibly to resolve some questions not yet addressed? JonRichfield (talk) 15:10, 5 September 2022 (UTC)
thread_title: Questions and doubts. Comments please

message: The VAH portion of the article is very poorly written.  In fact, significant research on my part yielded no such consistent hypothesis. Although Volcanic Activity plays into many theories, this particular one seems somewhat invented on the author's part. Especially considering the original copy (before I edited it) read, "We think this accurately solves the Faint Young Sun Paradox", I think we can deduce the author of said section had a more subjective attitude than Origin Science and Wikipedia should tolerate. I am deleting this section. --Mastodizzle176 (talk) 02:08, 19 July 2012 (UTC)
thread_title: Volcanic Activity Hypothesis

message: Interesting, but this article is in dire need of some references. :) --Bookandcoffee 22:57, 28 September 2005 (UTC)
replies: text: So fix it.  ;-)  Dragons flight 23:04, 28 September 2005 (UTC)
thread_title: References

message: ... between this article and Sun#Faint young sun problem. Well, was it 70 or 75%? Is it normally called problem or paradox? Earth has always had constant temperature or the oceans have frozen? We should search for references... --euyyn 21:32, 28 June 2006 (UTC)
thread_title:  Incoherences 

message: This article states that the sun's output was less in the past, and thus the earth's surface temperature may have been cooler.  Some offsetting effects with green gases are mentioned, which may have negated this.  But I do not see a discussion of another effect -- maybe it's not important.  I have posted the below comment in the Sun article, as well as here:  
Neither this article nor the faint young sun subsection of the Sun article addresses the fact that the Sun was probably significantly more massive at the time (due to the blowoff by the solar wind in the intervening period, as mentioned in the Sun article -- though in connection with the future decrease in the solar mass). This would result in an earth orbit closer to the Sun, thus offsetting the lower intrinsic solar brightness. The radius of the orbit is roughly inversely proportional to the Sun's mass, while the solar flux intercepted at earth's orbit is inversely proportional to the square of the orbit radius. So, if the solar mass was roughly 20% bigger than today, that would have completely compensated for the lower, 70% luminosity. Even if the mass difference was smaller, it seems this effect could still have been a significant contributor to the liquid water, in addition to possible greenhouse gases mentioned here. Are there any references as to how much mass has been blown off from the Sun since it was formed, or references discussing this potential effect?24.58.175.197 (talk) 21:25, 31 October 2008 (UTC)
replies: text: Yes, mass loss could solve the Faint Young Sun Paradox. Wood et al. (2002) suggested, based on Hubble observations of nearby Sun like stars, that the solar wind was 1000 times more massive when the Sun was young. Increasing the presant day Solar mass loss rate given in Noerdlinger (2008) 100-200 fold, the Sun could have lost 5 to 10% of its mass. --Diamonddavej (talk) 02:39, 26 November 2008 (UTC)
thread_title:  energy balances 

message: I've just read as proposed on this webpage that the atmospheric density in the Mesozoic would have been hundreds of times higher than now thus make the atmosphere retain heat much better, and not only retain it better but spread heat more evenly across the globe.
Now, not to start some original research, but this current article states that it's paradoxic because of the known Solar output of back then and the known atmospheric composition, but it fails entirely to take into account the atmospheric density and its effects, which I believe shows how a thick atmosphere could conveniently solve the paradox. But instead all we see is "there were perhaps more greenhouse gases even though evidence points to the contrary" or that thing about solar winds.
Just saying, perhaps the article should say something along the lines of "It has also been suggested that the atmospheric density of back then would have been much higher". --89.127.179.216 (talk) 16:38, 3 June 2009 (UTC)
thread_title:  Thick atmosphere hypothesis 

message: Quote from the article:
The minimum around 2,4 billion years goes along with a cosmic ray flux modulation by a variable star formation rate in the Milky Way.
Minimum of what?
Besides, isotopic evidence from the geochemical record is able to trace either an of the cosmic ray flux[5](14C and 10Be) and climate change based on δ18 Oxygen measurements of sediments[11].
This sentence does not make sense and so does the following sentence. Either are in line with climatical variations till the most recent past[5]. Northfox (talk) 08:00, 21 July 2009 (UTC)
thread_title:  nonsense sentences 

message: The scientific method tells us that if a theory contradicts facts then we must discard it and not try to explain away the facts. Now, in the article it is stated that there is the "contradiction between observations of liquid water early in the Earth's history and the astrophysical expectation that the Sun's output would be only 70% as intense during that epoch as it is during the modern epoch".
Conclusion? The Sun's output was the same billions of years ago (given constant Earth's size and orbit)! This simple resolution to the paradox isn't even stated in the article! --Shee-un (talk) 20:48, 27 May 2010 (UTC)
replies: text: Unfortunately your theory also contradicts the facts about stellar evolution. Therefore it must be discarded.—RJH (talk) 21:07, 27 May 2010 (UTC)
replies: text:  Well, how can you say that in light of the article's name? Since when stellar evolution became as clear as day or since when extrapolation of data becomes a fact? Maybe the Sun gives constant output, but only to some point in time; maybe the Sun outputs exactly the right amount of energy that is needed for any given planet at any given time... I do not encourage physicists to drop the whole Sun's physics theory just because in the past the Sun wasn't that different then it is today. I only suggest to revisit some parts of it. --Shee-un (talk) 16:54, 28 May 2010 (UTC)
replies: text:  I have to correct myself. The Minton and Malhotra (2007) paper suggests the possibility that the paradox may be explained by a more massive early Sun. A greater mass would result in a higher luminosity. However, this hypothesis would require a much higher mass loss rate than is expected via the standard solar model (to arrive at the present day solar mass). So yes, this seems like one possibility, but some evidence of a much higher mass loss rate (orders of magnitude higher) would be needed to lend credence to this hypothesis. —RJH (talk) 20:51, 28 May 2010 (UTC)

text:  There are no "facts" about stellar evolution.  It is all theory, and contradicted by numerous observations.  This "paradox" is just one of many.Scowie (talk) 20:43, 31 August 2011 (UTC)
thread_title:  Common sense, anyone? 

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thread_title:  External links modified