Talk:Age of Earth/Archive 2

Nov 2005

 * This talk page section has become so messy and difficult to read. :\
 * RoyBoy:
 * "But there isn't creation bashing in this article... is there?"
 * Currently it says the scientific majority view is fact and that other views are non-scientific. IMO softening the language (but not adding creationism content to this article) would significantly improve the article.
 * "I don't consider political/religious controversy terribly relevant to the actual age of the earth; but perhaps its notable enough to mention."
 * The article isn't titled "The Actual Age of the Earth", though...Shouldn't all "Age of the Earth"-related content go here, unless something is significant enough to get a separate article?
 * William M. Connolley:
 * "I did take the rant out though."
 * Okay. I'd actually considered removing that myself. (I didn't add it, in case anyone thought I did.) Ergbert 03:53, 7 November 2005 (UTC)

It is messy, so I just created a sub-section.
 * Other views are unscientific because the scientific evidence points unambiguously in the direction the article expands upon.
 * Well unfortunately I'm sounding like a broken record; but its understood an article with the title "Age of the Earth" in an encyclopedia would focus on... the (actual) age of the earth.

More to the point, not all related content should go into an article, that is what links (sub-articles) are for. Could you imagine all the abortion related material going into abortion. It would be a very large and even more difficult article to manage. Since various religions speak to the age of the earth they are mentioned prominently in this article as alternatives to scientific inquiry. I will seriously consider your proposal to remove "non-scientific", and pose the question to other administrators. However, I doubt it will gain much traction, as it is firmly established (by the scientific community) that creation related science is pseudoscientific. But, within the specific context of a redirect message, it may be appropriate to remove it. - RoyBoy 800 21:29, 7 November 2005 (UTC)


 * I wrote "unless something is significant enough to get a separate article". This article would not become too large if we described religious and minority scientific views that could be described in, say, no more than a paragraph, and linked to the relevant articles on views that need more detail. If there are too many of the former, then we could create a new article, link to it in the disambiguation text, and make it clear this article is for the views of the majority (again, not the whole) of the scientific community. The majority may feel 'creation science' is pseudoscientific, but they are not Wikipedia.


 * There are two article in the disambig and Dating creation does give religious origin date estimates. Seems most do not distinguish the age of the Earth from their creation myths, no additional article or section here is needed. The majority bit. Name a few from your imagined minority (with refs please). Vsmith 23:43, 7 November 2005 (UTC)
 * Yes, one of them does. For the final sentence, please see No personal attacks. Ergbert 00:46, 9 November 2005 (UTC)


 * "Since various religions speak to the age of the earth they are mentioned prominently in this article as alternatives to scientific inquiry."
 * No, they aren't. The links at the top are for views on how the Earth was created, not when, which is what this article is about.


 * See above response - does dating creation ring a bell? Vsmith 23:43, 7 November 2005 (UTC)


 * Is it alright to change "The radiometric age dating evidence from the zircons further confirms that the Earth is at least 4.404 billion years old." to "[...]indicates[...]" and "Ca-Al-rich inclusions – the oldest known solid constituents within meteorites which are formed within the solar system – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of the Earth." to [...]have been estimated to be[...]"? These changes will not make people think "Creationism is right!", will reduce the POV, and the latter uses a more proper verb tense. Ergbert 22:46, 7 November 2005 (UTC)


 * No. You may want to make the science appear weak and more uncertain than it is - for you religious POV or whatever. I'd suggest the article needs to be made stronger with much more detail on the scientific evidence (and uncertainty ranges) behind the dates. Your indicates and have been estimated to be... won't cut it. We need, as I said, more detail about the certainty & reliability of the scientific evidence. More evidence reported with sufficient clarity for the ordinary reader to grasp. Vsmith 23:43, 7 November 2005 (UTC)


 * Nope, I don't want to do that. I want to bring this article into compliance with official Wikipedia policy and for you to read Assume good faith and NPOV_dispute. Also, when reverting my edits, please provide explanations. Ergbert 00:46, 9 November 2005 (UTC)


 * Looking at the issue of the redirect (having just come from the note in village pump) I find I have some sympathy with the idea of softening it a little. I think some readers would read the phrase "non-scientific views" as having a slightly derogatory overtone, whereas I am sure what is intended is just that the other views are the views without the backing of the scientific evidence. Could a form of words like "This article describes the historical development of the scientific estimation of the "age of the Earth", including modern dating methods. For other views..." be a compromise that would upset less readers but still not make the "science appear weak"? IanBailey 01:19, 9 November 2005 (UTC)


 * Simply marvelous. Bravo to everyone, especially me!') - RoyBoy 800 03:10, 9 November 2005 (UTC)
 * For other views ... Wow! Ain't this fun :-) Vsmith 04:32, 9 November 2005 (UTC)
 * Well, the article starts out with non-scientific history and that is still judging creationism (and any other non-creationism alternate views). What's the problem with saying the majority of scientists disagree with creationism? IMO it's clear that's what official policy supports...Is it just my particular choice of words? Ergbert 05:42, 10 November 2005 (UTC)


 * I don't think so. This isn't just a matter of scientists disagreeing; but of creation(ism) simply not relying/requiring and adhering to scientific methodology. Modern attempts to do so are in dispute as to their validity; and do not change the non-scientific historical context of creationism. - RoyBoy 800 18:08, 10 November 2005 (UTC)


 * Oops...Did what I wrote sound like "the article starts out with non-scientific history, which is judging creationism"? I meant the suggested new wording isn't perfect because it's still judging creationism and the article isn't completely about scientific estimation. Ergbert 21:17, 10 November 2005 (UTC)


 * I'm a little tired right now, but I'll, or someone more awake than I can get back to you on that. - RoyBoy 800 08:22, 12 November 2005 (UTC)


 * About to head up north so might be a while till I get back. The article indeed isn't just about scientific estimation; but the non-science is put in a historical context.
 * As to the intro "judging creationism"; I think it neutrally points out that creationism is not in line with "modern scientific dating methods"; and as such it is an "other view". I think that's entirely accurate. - RoyBoy 800 04:01, 14 November 2005 (UTC)
 * What Vsmith changed it to is fine with me from an NPOV standpoint, although after looking at Dating Creation more carefully, it appears to be about the Age of the universe.
 * Vsmith objected to my other proposed changes. Does anyone have suggestions for how to better fix those NPOV problems? IIRC one of the policy/guidelines pages says to improve edits, not revert them, if possible...Ergbert 00:30, 27 November 2005 (UTC)


 * I just read the article and it looks perfectly NPOV to me. For reference here is the NPOV policy on "undue weight":


 * * If a viewpoint is held by a significant minority, then it should be easy to name prominent adherents;
 * * If a viewpoint is held by an extremely small (or vastly limited) minority, it doesn't belong in Wikipedia (except perhaps in some ancillary article)


 * If you want YEC to get more than a single link (e.g. flat earth in the earth article) then it seems that you need to cit your prominent adherents. Funkyj 07:05, 21 December 2005 (UTC)
 * I don't particularly want the article to mention YEC any more than it currently does. What I want is for the article to not flat-out state that the current majority scientific (Declaring other views unscientific would be biased and inappropriate for Wikipedia, no matter how true.) viewpoints are true. An example: "The radiometric age dating evidence from the zircons further confirms that the Earth is at least 4.404 billion years old." Yes, it supports that, but to say outright that it confirms it violates NPOV policy. Ergbert 02:27, 28 December 2005 (UTC)

Yes - further confirms means just that, the new evidence (read the references) add solid data that confirms the previous estimates at least back to the ages of those rocks. You obviously don't understand scientific evidence - it is not some inviolate truth - it is factual evidence based on the most recent and reliable techniques. As researchers press forward new evidence will no doubt push that 4.404 Byr even further back, that is to be seen. At present the available evidence does confirm that age to be accurate, within limits of experimental error. The further confirms is not POV, it is a statement of fact based on current research and is backed up by valid published, peer-reviewd research. The objective is to report what is the current state of our understanding from a scientific basis. And not to water the facts down to accomodate the anti-science bias of certain groups. The religious and mythical viewpoints are covered in the disamb articles listed - that is quite enough. - Vsmith 04:37, 10 January 2006 (UTC)
 * "You obviously don't understand scientific evidence" No personal attacks
 * As for the rest...The article currently states that this evidence is fact. It does not matter if this is so, because it violates Wikipedia policy. Wikipedia policy says "The task before us is not to describe disputes as though, for example, pseudoscience were on a par with science; rather, the task is to represent the majority (scientific) view as the majority view and the minority (sometimes pseudoscientific) view as the minority view; and, moreover, to explain how scientists have received pseudoscientific theories. This is all in the purview of the task of describing a dispute fairly.". (Neutral point of view) We have to change the article so it does not say one view is correct or incorrect and so it says which view is held to be true by whom and why. Ergbert 04:58, 13 January 2006 (UTC) "and so it says which view is held to be true by whom and why." I don't mean we need all age of the Earth-related content in one article, BTW -- topics that could have an article of their own only need a brief mention here. Ergbert 00:29, 14 January 2006 (UTC)
 * I just got here, but im siding with Ergbert, if we're trying to reach consensus or something. I hardly think evidence that can only produce an estimate can really be called a fact, and besides, this is an encyclopedia, not a majority scientific belief forum. Homestarmy 03:48, 31 January 2006 (UTC)

Mathematical Calcuation: Deletion?
This is my first post and do not want to step on any toes or use inappropriate "wiki-manners", but it would appear that the mathematical calculation at the bottom of this article is flawed and needs to be removed for the following reasons.


 * 1) The present day 235U/238U is ~0.007, not 0.07 as suggested in the article.  This can be verified by consulting any table of isotopic abundances, googling "isotopic abundances of uranium", or consulting Isotopes of uranium.
 * 2) 235U/238U cannot be measured, as suggested in the article.  One cannot measure an isotopic ratio in the past, one can only calculate it from a present day ratio.  Neither can one "assume" a value of unity at accretion for nucleosynthetic reasons, in fact relative isotopic abundances (as produced via nucleosynthesis) are commonly very different.  For verification, consult any table of stable isotopes.  I calculate that, in fact, at 4.5 Ga (Ga = 109 years), 235U/238U = 0.303.
 * 3) Even using the incorrect value of the present day 235U/238U, and the incorrect assumption of "accretion" 235U/238U = 1, the calculation listed in the article appears to give an age of 3.2 Ga and not 4.6 Ga.

Anyways, thanks to the person that posted it for injecting a quantitative flavour to the article, the effort is very much appreciated. I apologize for suggesting that it be taken out, but it appears to me to be fatally flawed. The appropriate substituion, perhaps, is what is known to isotope geochemists as the "geochron", or a age calculation based on the 207Pb/204Pb and 206Pb/204Pb values of meteorites and the earth (which, by the way, should really be mentioned in the article as this is the method by which the "scientific" age of the earth was first determined). The calculation, however, is both numerically (the equation is transcendental) and conceptually (why use the Pb isotopic composition of meteorites and ocean sediment?) complex and probably unsuitable for a general-knowledge encyclopedia.

If someone could check to make sure that I don't misunderstand the calculation and then delete it, that would be great. As this is my first post I am hesitant to eliminate something that clearly took someone a great deal of effort to produce. Rickert 21:19, 31 January 2006 (UTC)

Yes, you misunderstood the method. I made a typo, putting in 0.07 instead of 0.007, this is all. ati3414

And no, the equations don't have to be transcendental, they are linear, I just showed it. So plug in your favorite isotopes of Pb and you should get the same result. ati3414

If those numbers you've got are correct, then couldn't what you've got here just go inside the article in place of the old information? Homestarmy 23:39, 31 January 2006 (UTC)

Yes, it could except some idiot keeps editing it out. What I am giving here is a METHOD. After correcting my typo everything is copathetic. The short article shows that, contrary to what another guy keeps posting, it is PERFECTLY REASONABLE TO ASSUME EQUAL DISTRIBUTION OF ISOTOPES for U235/U238. I got sick of all this bs and I did my own page, don't dare to erase it. You can keep this one for yourselves.

Sorry, I am not being clear. In addition to the problems that the section faces based on it's two incorrect 235U/238U values, it has a more fundamental flaw: You cannot derive the age of the earth from 235U/238U systematics.

The premise of the calculation, that one can calculate an age of the earth using only uranium isotopic ratios is incorrect. With the corrected values I presented above, all one can do is calculate the 235U/238U of the earth at any time in it's history (or, I suppose, in the future). Although potentially useful, it has no place in an article on the age of the earth. Thank you for pointing out the lack of clarity in the previous post.Rickert 23:50, 31 January 2006 (UTC)


 * Why not? take the statement: "If we assume that at the formation of the Earth the isotopes U235 and U238 could be found in equal amounts then the time t represents the time elapsed from the beginning of the Earth. Solving (5) for t we obtain....". What is wrong with it? If we assume that the two isotopes could be found initially in equal amounts and today they are in a much different amount, fully knowing their half lives we should be able to find out at what time in the past they were to be found in equal amounts. ati3414

Thanks for responding quickly, Ati. Please do not take this as an attack on you. You have hit the nail on the head by drawing attention to the statement you have placed in quotation marks. The simple answer is that the assumption is invalid: There is no reason to assume that the isotopes had an equal abundance during the accretion of the earth or at any other time. Nucleosynthetic processes (i.e. stellar processes by which most of the heavy elements in our solar system were created) have no "reason" to create isotopic symmetry by balancing the amounts of one isotope with another. In fact, many processes operate to favour one isotope over another. An example is oxygen (although it is created by a slightly different nucleosynthetic process than uranium) for which 16O is present in excess of 400 times that of 18O. Since both isotopes are stable they represent a "primary" (that is, reflecting relative abundances at the accretion of the earth) isotopic signature, and suggest that the assumption of an isotopic "symmetry" is invalid. Similar arguments can be made for stable heavy elements (see some of the lanthanides, for example).

Additionally, with the correct present day 235U/238U (listed in my first post) the "time" that is calculated using the (completly valid!) equations in the article (the time at which the two isotopes had equal abundances) is approximately 5.9 Ga: older than the currently accepted age of the solar system (either 4.6 Ga or 4000a, depending on your POV). :)  Rickert 01:07, 1 February 2006 (UTC)

That's bs, the number comes out 4.4 and this seems to CONFIRM the equiprobable hypothesis as an interesting side effect of the simple methos that I put forward. I wish you took your first post elswhere because it is dead wrong.


 * The user who added the calculation was Ati3414. I have left a message on ver talk page in reference to your suggestion. Perhaps displaying any calculation creates the false impression that the calculations that led to the established age of the Earth are easy to explain. -- Ec5618 00:02, 1 February 2006 (UTC)

Ah, I understand then. Well then, we should at least see if Ati knows about this, if he knows how those numbers work, maybe he has something to say on this. Homestarmy 00:12, 1 February 2006 (UTC)

I've removed the section here for discussion. It appears to be original research.
 * '''==Mathematical Calculation==


 * We can determine the Earth age by observing the following:


 * 1.	the amount of Uranium isotopes U235 and U238 that can be found nowadays is in the ratio N235/N238=0.007


 * 2.	the two isotopes of Uranium have a half life of 4.5 billion years for U238 and 0.7 billion years for U235


 * 3.     at the formation of Earth the two isotopes were to be found in a proportion of 1:1


 * A radioactive element decays with time according to the law:


 * N(t)=N0exp(-a*t)			                              (1)


 * From (1) we can can calculate the coefficient a if we know the half life.
 * For example, in the case of U235:


 * N(0.7)=N0/2 				                                  (2)


 * Therefore :


 * a235=ln2/0.7				(3)


 * In the case of U238 we obtain:


 * a238=ln2/4.5				(4)


 * Because today’s ratio of U235 to U238 is 0.007 we have:


 * 0.007=exp(-a235*t)/ exp(-a238*t)=exp(a238 - a235)t	(5)


 * If we assume that at the formation of the Earth the isotopes U235 and U238 could be found in equal amounts then the time t represents the time elapsed from the beginning of the Earth. Solving (5) for t we obtain:


 * 1/t=(1/0.7-1/4.5)*ln2/(ln1000-ln7) or approximately t=4.4 billion years

We can verify both the above method and the correctness of the equiprobable distribution by replacing in the above calculations U235 with U234.

U234 has a half life of 2.45x10^5 and N234/N238=0.000055. Therefore:

a234=ln2/0.000245                  (6)

and


 * 0.000055=exp(-a234*t)/ exp(-a238*t)=exp(a238 - a234)t	(7)

Solving (7) we obtain :


 * 1/t=(1/0.000245-1/4.5)*ln2/(ln1000000-ln55) or approximately t=4.8 billion years

IF YOU DO NOT LIKE THE RESULT, AT LEAST ACKNOWLEDGE THAT THE METHOD IS GOOD. I GAVE YOU A MATHEMATICAL WAY OF CALCULATING. THERE IS EVERY REASON TO CONSIDER AN EQUIPROBABLE DISTRIBUTION OF ISOTOPES AT THE TIME EARTH WAS FORMED. IF YOU DON"T LIKE IT, PLUG IN YOUR FAVORITE NUMBER. Have at it! ati3414

Discuss below please. Vsmith 00:40, 1 February 2006 (UTC)


 * Discuss what? I gave you a reasonable straightforward algorithm, just plug in your favorite numbers and you can get the approximate age of the Earth ASSUMING that there was an equiprobable distribution of isotopes when the earth was created. ati3414

Well, there are two arguments. One is that the calculation has nothing to do with the age of the earth (the assumption is demonstrably wrong). The other is the one that Vsmith just pointed out. If this is a new formulation (correct or not) it is inappropriate for a Wikipedia article. Rickert 01:09, 1 February 2006 (UTC)

It looks like ati got the ratio between U isotopes right, and it also says 2.3 billion years not 3.2, im afraid im lost again :/. Though I do understand the part about not knowing what the original ratio was when the earth was supposedly created via big bang theory and stuff, how can we assume that it was equiprobable distribution, or that there were such heavy elements at all?Homestarmy 01:12, 1 February 2006 (UTC)

It is 4.4 after replacing the 0.07 with the correct value of 0.007. I wish you could read more carefully.

I still can't think of any reason why both uranium isotopes would of come into existance on earth at the same exact time the earth supposedly pullled together or something. Homestarmy 14:20, 1 February 2006 (UTC)

Hi Homestarmy. You are correct. Isotopes of heavy elements like U are produced during supernovae events, and it is common for isotopes of the same element to have markedly different abundances. The following link has a list of the abundances abundances of stable isotopes of each element. With a few very minor caveats, these represent the original abundances of of the isotopes on the earth when it was accreted because they are neither produced nor do they decay. Note the differences in isotopic abundances for each element. Rickert 14:33, 1 February 2006 (UTC)


 * ati3414, please stop re-adding the section to the article. There is no evidence for the following:
 * 3. at the formation of Earth the two isotopes were to be found in a proportion of 1:1


 * Couldn't you read the fact that I used a different isotope (U234) and i got the SAME RESULT?


 * Plus the section is original research, such as it is. I have my students do a quite similar calculation, not to do anything with the age of Earth - but to gain familiarity with the concepts, equations and calculations. The section is not encyclopedaic. Also, please don't create other fork articles with the content as you have already tried. I would also caution you to be civil in your comments here and elswhere. Vsmith 14:31, 1 February 2006 (UTC)

Why should I be civil when you are uncivil in erasing my contribution?

Hi. A couple of new comments on the new calculation, just to clear things up and make sure no one is confused.
 * 1) The arithmatic given last line appears to give a time of 0.0035 Ga (3.5 Ma), not 4.8 Ga.  I do have a bad habit, however of making errors in my own arithmetic, so if anyone else wants to check it that would be great.

Most likely you made an error. The point is that the distributions of isotopes are not exact and the method is used as a means to show the order of magnitude, not the exact age. No wonder the creationists are having a party with this page ....


 * 1) The calculation of  234U/238U is different, and much more complex than the calculation of 235U/238U because 234U is an intermediate decay product in the 238U-decay series (i.e., it is produced by decay of 238U)).  A good online resource for these concepts (and related mathematics) can be found at Bill White's Cornell website.  A link to the relevant chapter in his free, online textbook follows.

Why don't you read my text carefully, I used an apples to apples replacement of U235 with U234, same type of data.


 * 1) As a note to ati regarding the "transcendental" vs. "linear" nature of the equations.  You are correct in that the equations you presented have exact solutions are are not transcendental.  The equation that I was referring to is the one in which a Pb-Pb age is determined and has little to do with your calcuation.  I apologize for the confusion.

Yeah, I got it. Your remark on stable Pb has nothing to do with what I was trying to show you which is based on radioactive decay. Thank you.

Thanks everyone. Rickert 14:33, 1 February 2006 (UTC)
 * 1) The problems with the premise (and the mathematics) notwithstanding, the "No original reseach" issue that was kindly brought up by Vsmith has not been resovled. I agree that if an appropriate reference cannot be produced suggesting that this calculation has been used in this way before, it should be removed from the article.

Try "Instant Physics-from Aristotle to Einstein, and Beyond" bu Tony Rothman,page 147. The bit with using two different isotopes and the exact math are mine. OK? ati3414


 * Firstly, your behavious seems odd and combative. There is no need to yell, for example.
 * Since the calculation is original research, it will have to removed, I'm afraid. Wikipedia is not about shaping knowledge, it is about cataloguing it. On top of that, it appears your calculation is flawed, which is another reason it should be removed. Thank you, but Wikipedia policy is quite clear on this matter. -- Ec5618 16:34, 1 February 2006 (UTC)

"Instant Physics-from Aristotle to Einstein, and Beyond" page 147, by Tony Rothman

Try reading. I simply put the text into mathematical formulas. I also used two different methods to arrive to the same result.


 * I have the book and just re-read that demo bit. Rothman is simply using it as a demo to help students understand - much as I have with my students. He states assume the Earth was formed with equal amounts of these isotopes and then sets out with some simple calculations.
 * The book and exerpt is for a dummied down intro to physics. The demo as such is not encyclopedaic. Your math playing with the info from the book is original research. The stated assumption is not valid. End of case. Vsmith 17:15, 1 February 2006 (UTC)

Thank you. How do you explain that you get a very similar result by replacing U235 with U234? A coincidence? Why are you so hung up agains the equiprobable distribution at the initial point? Seems to work perfectly fine. And if you don't like my approach, why don't you or any of the other critics produce a calculation that would shut down the creationists? There must be one. Adios.

See Articles for deletion/How to calculate Earth's Age. Seems our friend ati3414 is forking the content elsewhere. Vsmith 17:42, 1 February 2006 (UTC)

I was just trying to build my own page, I was fed up with the bs on this page.
 * I'm afraid it isn't this page that you're in conflict with, it's Wikipedia's policy. Please see Wikipedia is not, Civility and Verifiability. I'm afraid we simply cannot allow original research on Wikipedia. -- Ec5618 18:45, 1 February 2006 (UTC)