Talk:Late Heavy Bombardment

message: I notice this section has been re-added. I had originally removed this because the later data suggests that the "single impact" theory does not hold water. Given that some of these meteors are assumed to have come from the dark side, the "lower bound" at the same figure is extremely strong evidence that the Apollo rocks are genuine and not derived from Imbrium. The same argument is strong evidence against the second claim as well. Further progress in geochronology has pretty much ruled it out anyway, something that is covered (in passing) in one of the other refs I posted. I'm all for leaving these comments in, but the way the are presented leaves much to be desired. I believe the "back and forth" of history presents a valuable insight into thr workings of real-world science, and that separating the arguments breaks this chronology. For instance, the single impact concern now appears later than the evidence that is used to counter it. To the reader this suggests that the evidence in question does not have an answer (an astute reader might notice this, but that's not the point), and further it seems confusing because that line of argument predates the meteor information. I'm also a little worried about the wording of this section, because it seems to suggest something is "amiss" in the fact that the meteors date to a spread of times, but this is precisely what one would expect, it's the "lower bound" that is so interesting, for exactly the same reason that the "lower bound" is so interesting here on Earth. Maury 12:47, 7 March 2007 (UTC)
replies: text: Many respectable scientists do not believe the cataclysm hypothesis, and that is why I added an up to date reference by Bill Hartmann (he is one of the founders of the "crater chronology" method). I thought that the way it was written in the previous version misleadingly would lead someone to believe that the scientific community now believes that the case is nearly closed, which, as a lunar scientist myself, I can say it is not. Recently, even some of the dynamicists are beginning to question whether the data actually require a cataclysm. Perhaps we could have a "history of the cataclysm hypothesis" section, but I think that such a controversial topic also needs an "evidence for" and "against" section as well. When I get some more time, I will add more references. I am somewhat busy in real life right now preparing for the upcoming lunar and planetary science conference. Lunokhod 13:33, 7 March 2007 (UTC)
replies: text: Well I'm sure that "respectable scientists do not believe", but that's a hopeful sign. My concern is really about the presentation. Perhaps we could return to the historical overview layout, and then add another section called "ongoing debate" or something similar? Maury 16:57, 7 March 2007 (UTC)

text:  This is not meant as a challenge, Lunokhod, merely a request for information: can you give a pointer in the technical literature to doubts among the dynamicists? I recently heard a talk by one pushing the cataclysm idea. BSVulturis 22:19, 19 October 2007 (UTC)
replies: text:  I think we should keep this in prospective; You will always find orders of magnitude of greater information supporting a new idea than information trying to debunk it. I don't think we should compare "believers" vs. "non-believers", or talk about *who* believes or does not, as that should hold some importance in a logical argument over what is true.  I think we should describe the hypothesis, and describe logical reasoning as to why it may be wrong, like everywhere else on Wikipedia.  Science is not a faith.  The reader can form their own conclusions, but only if we provide them with the actual thinking out there on the subject.  I think which great mind thinks it is right or wrong is trivia.  An article describing a hypothesis should just describe how it may be right and how it may be wrong, and list evidence, not a celebrity list. Onexdata (talk) 16:30, 25 July 2012 (UTC)
thread_title:  Re-adding of the critisims section 

message: Does "Mya" stand for "million years ago"?  If so, we should explain that somewhere, and remove the "a" in contexts where the "ago" is not appropriate.  If not, what does it stand for?  --Doradus 18:00, 9 July 2007 (UTC)
replies: text: Point taken, fixing... Maury 20:52, 9 July 2007 (UTC)
thread_title:  Mya 

message: University of Arizona News and University today on Strom et al.:'s scenario:
:Jupiter migrated inwards and disrupted the asteroid belt to throw boulders around.
This they base on careful asteroid counting, but on the other hand they cathegorically dismiss most earlier time lines based on crater counting in the outer solar system ... Said: Rursus ☻ 17:32, 4 August 2008 (UTC)
replies: text: Eahgmgrrlmbl... compatible with the gas giant migration scenario, but nothing else. Said: Rursus ☻ 17:57, 4 August 2008 (UTC)
thread_title:  Yet another scenario 

message: isn't a proof – just an important argument – this site argues that the current overabundance of noble gases is best explained if earth was bombarded by circa 0.5% of KBO:s alongside the asteroid material. Said: Rursus ☻ 19:57, 4 August 2008 (UTC)
thread_title: Noble gas proof

message: The Possible Causes section needs rework (the first two sections say the same thing), and will be linked in content-wise to the corresponding section in Nice model, which is under construction. Iridia (talk) 07:51, 22 March 2009 (UTC)
replies: text: Ok, now the sentences are closer to their refs, fixing the problem that was the original source of my thought that they said similar things. Iridia (talk) 08:17, 22 March 2009 (UTC)
thread_title:  Nice model 

message: The "second criticism" states that it is a problem that the oldest rocks at from 4.1 bya. However, this is only a problem if it is assumed that the Moon formed earlier than this, which is not mentioned (and needs to be). Someone got a ref for this argument? Maury Markowitz (talk) 20:44, 7 July 2009 (UTC)
thread_title:  Wait a minute... 

message: Isn't this a pretty early period of the earth? Or was there also an "Early Heavy Bombardment" at some prior time? Please explain why it is called "Late" at all. -- 92.229.181.16 (talk) 07:35, 16 June 2010 (UTC)
replies: text: As far as I understand this, it's called 'late', because the apparent sudden increase in the rate of bombardment by asteroids/comets does not fit with the expected gradual reduction in impacts following the formation of the planets/moons, see here . Mikenorton (talk) 09:00, 16 June 2010 (UTC)
thread_title:  What's so late about the "Late" Heavy Bombardment? 

message: I notice a conflict between two wikipedia articles and am guessing it is merely a mistake of one letter for another. 
In this article "Late Heavy Bombardment" - it is stated that this cataclysmic event occurred "4.1 to 3.8 billion years ago."
However, according to the article "Timeline of evolution" this event occurred 3.9 MILLION years ago.
Which is correct?  — Preceding unsigned comment added by Jacque083 (talk • contribs) 20:08, 5 July 2011 (UTC)
replies: text: As I see them, these two articles are in agreement - one saying 4.1 to 3.8 billion, the other one saying 3900 Ma (million years). Mikenorton (talk) 21:26, 5 July 2011 (UTC)
thread_title:  "million" or "billion" years ago 

message: The picture :File:Lunar cataclysm.jpg, described as an "artists's" impression of the moon during the Late Heavy Bombardment, is too artistic and has very little in common with reality. It was extremely improbable that there were two impacts on the Moon at the same time even in that time, in fact there were quite long periods beween individual impacts. The article says that on the Earth "serious environmental damage would occur about every 100 years". The Moon is even smaller, so the rate of impacts would be significantly lower too. Therefore I consider the picture very misleading, no matter how impressively drawn it is. Jan.Kamenicek (talk) 17:39, 9 January 2012 (UTC)
replies: text: Very good point but observing even a single impact is still highly unlikely using your "once every 100 years" measurement.  A drawing of a red moon would be silly and would convey nothing.  I think the artist used 2 impacts to show that the moon was bombarded, and not struck a single time.  This image is attempting to indicate a very large (chronologically speaking) event, I think the illustration is trying to describe it in a single image, not so much trying to depict a "snapshot" of what you might see at any particular time during the event. Onexdata (talk) 08:58, 22 July 2012 (UTC)
thread_title:  "Artist's" impression 

message: In this section, we blithely tell people that Jupiter lost angular momentum, and so went further from the Sun. This is bit like applying the brakes to go faster. An orbit with less angular momentum is closer to its parent, not further away. One must add energy to do lifting. Wayne Hardman (talk) 01:06, 9 September 2012 (UTC)
replies: text: Y'know how water is soft but it really hurts to jump from the high board? Well a planet the size of Jupiter or Saturn has so much pressure at the bottom of its atmosphere (space probes are squashed like a bug only a fraction of the way into the atmosphere) that solid surface (ice) or virtual surface (gas) is immaterial (Radar reflection surface due to density gradient). (Surface of the Sun is "soft" gas and plasma but still a collision if you jit it.) Since both planets have clouds of Ammonia, Methane, etc. we can assume perhaps a liquid surface, however He/H2 would probably be above critical point (temp and pressure) before that. All of these are made up of frozen what-we-call gases, they do fit the "gas giant" moniker. Interesting to note that Jupiter like Earth are the only planets that radiate more energy than they recieve from the Sun. Like the movie "2001", interesting to see if sending a nuclear weapon would ignite it. Shjacks45 (talk) 08:36, 11 October 2013 (UTC)
thread_title:  Fifth gas giant hypothesis Section 

message: I think that there should be a section on the postulated importance of the LHB in supplying the earth's water, as referred to at . As I understand it, it is thought that very little water would have survived the conditions on the early earth, and comets during the LHB may have been crucial in providing the water to fill the oceans and make plate tectonics and advanced life possible. I could have a go at this, but it is probably better done by an editor more expert than me. Dudley Miles (talk) 23:00, 25 November 2012 (UTC)
replies: text: Elemental distribution of Earth is different than Solar System. Earth has a Iron-Nickel core based on indirect data and dearth of expected Iron and Nickel. In fact there is a underrepresentation of Ferrophilic and Carbide forming elements (elements that can alloy with Iron like Carbon, Hydrogen, Chromium, Thorium, et al). Carbon and Hydrogen dissolved in molten Iron will react exothermically with Iron Silicate (Mantle Olivine) generating more Iron and Water and Carbon Dioxide. Water and Carbon Dioxide at high pressure (above the critical point) liquify rock although Magma formation is supposed to be an upper mantle thing. Just a thought. Shjacks45 (talk) 10:10, 11 October 2013 (UTC)
replies: text: It is unsatisfactory that neither this article nor Origin of water on Earth discuss the possible role of the LHB, but the article you cite dates to 2010 and my impression is that opinion since then has moved towards a main origin with water in the rocks which formed the earth. Dudley Miles (talk) 09:57, 20 May 2019 (UTC)
thread_title:  Role of LHB in supplying earth with water 

message: See http://www.sciencedaily.com/releases/2011/09/110907132044.htm
Assuming ferrophilic heavy metals were lost to the core and redeposited in the crust via LHB. Explanation for differing elemental abundance for Earth versus the rest of the Solar System in Abundance of the chemical elements. Of course Earth and Jupiter are the only two planets that emit more energy than input by the Sun. Higher amount of radioactive elements on Earth (assume Jupiter is "cold fusion", don't laugh, its got a few million PSI) mean fission products add to rare metals and gases (consider He3/He4 is higher on Earth than System or Sun). Another source noted that concentration of Gold and Noble metals in rock samples is higher than rocks older than 3.8 Billon years old. Of course this suggests a Gold rush for Moon dust?
Shjacks45 (talk) 09:58, 11 October 2013 (UTC)
thread_title:  There's Gold in them thar LHB 

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thread_title:  External links modified 

message: He Geisler group call their 2008 publication into doubt here:  Latrissium (talk) 12:18, 2 January 2018 (UTC)
thread_title:  The carbon isotope evidence for early life seem to be in doubt 

message: During the Late Heavy Bombardment, the Moon would have been tidally locked to Earth. And, because of the radiance of the molten Earth, the nearside of the Moon would probably have still been molten. The lunar farside should have been solid with a crust from a few kilometers thick to a few tens of kilometers thick.
Michael McGinnis (talk) 23:16, 2 February 2020 (UTC)
thread_title:  Regarding the artist's rendering of the Moon & Earth during LHB 

message: This article argues against the Lunar Cataclysm and instead proposes a milder Late Heavy Bombardment: Cataclysm No More: New Views on the Timing and Delivery of Lunar Impactors. It defines Lunar Cataclysm as a very short period of bombardment around ~3.9 Ga, and LHB per se as just an increased late bombardment. 
Conclusion: perhaps Lunar Cataclysm should be moved from the lede to be put into a certain section of the article. Rursus dixit. (mbork3!) 04:56, 29 August 2022 (UTC)
replies: text: The article distinguishes between the LHB and cataclysm as different theories (LHB from 4.2 to 3.4 GA or cataslymic spike at 3.9 GA), whereas the Wiki article treats them as synonyms. It would be helpful if an editor with good access to scientific sources investigated which usage is more common. Dudley Miles (talk) 08:05, 29 August 2022 (UTC)
thread_title:  LHB vs. Lunar Cataclysm 

message: There is a Paper in Science Advance that states, that the Bombardment must have happend in the first 100 million Years of our solar system and that it was continuus. My englisch is to bad, to work on scientific Articles in En Wp, but maybe someone else wants to add the research.
Here is an Article of the University in Münster that sums up the study, though in german. LukeTriton (talk) 09:22, 25 October 2022 (UTC)
thread_title: New Paper