Talk:Timeline of natural history

4592.1 Ma???
Never ever heard such a number before, every other source says Sun is about 4.6±0.5 Ga old, that oldest meteorite is about 4.56 and so on. Any source for 4592.1 Ga (please)? Or is it just an extrapolation back from 4567.17 Ma, assuming a certain contraction time and planetary formation time?? Rursus 23:09, 18 October 2006 (UTC)


 * OK, I'm going to explain a little myself. Now, the magical number 4567.17 Ma often cited (which is much too precize) refers to age of CAIs in meteorites. Isotopic Ages says 4567.2±0.6. Other numbers for CAI ages are 4566±2 (Allende chondrite), and 4564.7±0.6 (Acfer 059). So lot's'a solsys boulders were formed about 4565 Ma ago. (Question: is this the main value or like the oldest known?)


 * Rursus answers Rursus: that site explicitly searches the oldest known. Rursus 13:12, 19 October 2006 (UTC)


 * Now according to isotopicAges again, the CAIs where formed in a protoplanetary disk, which according to en.wikipedia itself never are older than 25 Ma. So: 4567+25=4592!! Voilá, kind of ... B-/ But I protest - this is an unjustified leap!! 25 is max age of proplyds. Let's assume proplyds slowly decay from the influence of Sun and planetesimal formation (this is kind of bold too), then the most CAIs must have been formed some time within the range of 0 Ma and 25 Ma after the formation of the proplyd. Let's boldly assume that the median of CAI ages are f.ex. 10 Ma after the proplyd formation. Then we get 4565+10=4575, but this figure is created by speculating twice. 4575 Ma is an ill grounded number to use - don't use it - 4592 Ma is far worse! Rursus 07:16, 19 October 2006 (UTC)

While nagging around and being generally inconvenient, I'll somewhat sadistically feel an urge to add another objection: the figure 4567.17 Ma, does it really refer to the age of Earth? It certainly refers to the measured age of Efremovka CAI, one of the boulders measured - but Efremovka is a carbochondrite meteorite, Earth is a planet that may or may not have been created as much as 50 Ma afterwards, if we adher to the modern theories of protoplanet "oligarchic growth" (a modern and good theory - but yet just a theory!). Let's be pessimistic, saying that 50 Ma was the delay before Earth was created, and we get 4517 Ma, which is in disaccord with the Wikipedia time for creation of Moon 4533 Ma, or the one I found on the net 4527 Ma. But either way: Earth was probably formed in the time interval 4567 to 4527, but when?? Rursus 08:06, 19 October 2006 (UTC)


 * Answering myself again: the isotopicAges site presumes that Sun is created about the same time as the earliest CAIs. The age of Earth isn't mentioned -- except implicitly as lesser by implication. Rursus 08:51, 19 October 2006 (UTC)


 * Could we put these assumptions into a reference note at the bottom of the article. It would be good to start referencing all dates in this way. I have just for the  in the reference to Late Heavy Bombardment and deleted the Fact tag.  John D. Croft 08:20, 22 January 2007 (UTC)


 * I have put in a note on Rursus' comments (above) in the article and deleted the debatable tag for the moment.John D. Croft 11:11, 5 February 2007 (UTC)

4566 ± 2 Ma !! Don't use darned 4592.1 Ma!
Sigh! At last I found a proper source making the Original Reseach of this faulty article unnecessary. See Harrison J. Schmitt's (Apollo 17) Lecture 7 from NEEP533 Course Notes (Spring 2004)! It tells us the following: This means that there is nothing such as 4592.1 is  Remove it, darn!! The SN Trigger sprinkled the solar nebula with radioactivity, foremost Al-26, believed to be responsible for some inner asteroid melting, so the SN Trigger cannot have been much earlier than say 4568 Ma. Instead of using the WP:OR timeline sketched here, use Schmitts and mark it as speculative. Said: Rursus ☻ 21:26, 28 October 2007 (UTC)
 * CAI:s in carbonaceous chondrites formed 4566±2 Ma,
 * the Supernova Trigger (SN Trigger), that made the solar globule collaps, occurred >~750 ka before, the diagram on page 30 of Lecture 7 indicates 1-2 Ma, making about 4567.5±2.5 Ma,

Comments

 * a shockwave in the Orion arm, a spiral arm of the Milky Way galaxy.: The spiral arms are travelling waves of densification which have likely passed through where the Sun is, several or many times since the Sun formed. Anthony Appleyard 16:28, 27 June 2006 (UTC)

Date of the Theia impact
I took the date 4533 Ma from Giant impact hypothesis. Before that, Timetable of the Precambrian said 4537±10 Ma. Anthony Appleyard 06:15, 17 July 2006 (UTC)


 * Sad to say, Giant impact hypothesis doesn't source the date, and I can't find a date (other than early in the Earth's history) in the References and External links in the article. I'll look around some more when I get a chance. --  Donald Albury ( Talk )  12:02, 17 July 2006 (UTC)


 * Dalbury said: Giant impact hypothesis doesn't source the date. Rursus replied: fixed! This link! (Ananova). It says 4527 Ma. Rursus 13:58, 19 October 2006 (UTC)


 * This USGS site says the oldest rocks brought back from the Moon are 4.4 to 4.5x109 years ago, and the oldest dates for Zircons found in sedimentary rocks on Earth are 4.3x109 years ago. That's certainly consistent with 4.5x109 or more years ago for the age of the Earth, but doesn't support anything more precise. -- Donald Albury 23:30, 19 October 2006 (UTC)


 * Acknowledged -- but much better than that I believe we cannot get, until humankind travel to Mars or Mercury, and unambiguously succeed to associate a meteorite with the Giant Impact and date it properly. Qaþ: Rursus 12:11, 20 October 2006 (UTC)


 * I object to the precision of the date given (6 significant digits). For something like this, I don't think we can be confident in more than 2 or 3 significant digits. I think we would be better off saying that internal evidence (the zircons) places the age of the Earth at more than 4.3x109 years, and that rocks brought back from the moon give it an age of 4.4x109 to 4.5x109 years, which supports an age for the Earth of 4.5x109 to 4.6x109 years. -- Donald Albury 01:47, 21 October 2006 (UTC)


 * 100% agreed! More opinions on this? Otherwise User:Dalbury and me may go and cut away misleading decimals. 3 will IMHO be perfect. Rursus 15:08, 23 October 2006 (UTC)

Possible mnemonics
Possible mnemonics are:- For the initial letters of the names of the periods:-
 * Some really outsize snakes can easily swallow turtles: comes easy.

For the root meanings of the names of the periods:-
 * Iron flowed from the mountains to the stable, covered its extension by a narrow stretch at the cold eddy.

Anthony Appleyard 18:04, 4 August 2006 (UTC)

Arrangement of the Timetable of the Precambrian page
This is the first time I've looked specifically at a page on the Earth Sciences portal. I was a little confused at first to see this page arranged with the oldest event at the top of the page. Geological convention would have the youngest at the top and the oldest at the bottom, to reflect Charles Lyell's Principle of Superposition in stratigraphy. I hesitate to suggest we should invert the order, on the basis that I might open a can of worms on numerous other pages - but one only needs to look at a stratigraphic column (see diagram in Table of geologic time section on that page) to see that it is the way a geologist would present such information. (user - dyvroeth).


 * It's true that the strat column forms from bottom to top. But it seems to me there's an argument for keeping the order as it is.  At least in most Western languages, we write and read from the top to the bottom of the page, and this is the order that we expect the narrative to unfold from the past toward the present.  We could go from the present (or in this case the Cambrian-Precambrian boundary) back to the origin of Earth, but many would find that confusing.
 * Cephal-odd 04:41, 15 October 2006 (UTC)

Animal tracks from 2000 Ma?
This line of the article caught my eye: "2000 Ma: Animal tracks in west Texas; first evidence of multicellular life." This would be a remarkble discovery if true. There have been claims for the discovery of burrows from over 1000 Ma, but as far as I know they're contentious. Does anyone have a reference for the west Texas tracks? Cephal-odd 04:48, 15 October 2006 (UTC)

Good question, I looked at that and did a double take myself... Jcforge 15:59, 6 December 2006 (UTC) From what I've found life seems to have 'started' only a few hundred million (to a billion) years after the earth was formed... which would be close to 2000 mya.... as for 'tracks' it's probably meaning traces of fossils that indicate life... it does seem misleading...

Batch I
The article is wrong, and a very good example of when cited by a high school student, making him/her fail by citing erroneous sources. The article must be rewritten in its entirety: Now, I'll challenge the factual accuracy. Said: Rursus ☻ 21:45, 28 October 2007 (UTC)
 * why is Phanerozoic occuring in a timeline of Precambrian? Precambrian is what comes before Phanerozoic!
 * the time line should be backwards in time, not forward,
 * Earth isn't 4567 Ma old, the predecessor Proto-Earth was formed about 4560-4555 Ma ago, the number 4567 is the age of the entire solar system, that means the protosun and the solar nebula, practically it's the age of certain CAI intrusions within carbonaceous chondrite meteorites of a certain class, exemplified with the Allende meteorite,
 * Earth in modern meaning was formed about 4535-4525, with the collision of Theia and Proto-Earth,

Batch II
Worst errors fixed now, but new found: Sorry for being unconvenient (eh, actually a kind of sadistic pleasure, hehe!) Said: Rursus ☻ 22:02, 28 October 2007 (UTC)
 * Proto-earth and Earth aren't the same, Proto-earth is only about 75% of its current size, when colliding with Theia. Earth is Proto-earth plus Theia, minus most of the Proto-earth's crust, which became Moon,
 * one geological expert at stratigraphy.org, don't regard the formation of Proto-earth as the start of the Hadean, Hadean started when Moon and Earth were formed, and assuming the Theia theory, this means that there is an unnamed eon before the Hadean,


 * this "one expert at stratigraphy.org" refers to Dr. Wouter Bleeker (hereby elected to Ueber-guru de Precambrian – by me...) chairman of the Subcommission on Precambrian Stratigraphy. Said: Rursus ☻ 11:43, 29 October 2007 (UTC)

Batch III
And another error (?): Said: Rursus ☻ 22:09, 28 October 2007 (UTC)
 * the Snowball Earth scenario isn't proven, a viable alternative Slushball Earth says that there was a global glaciation, but the equatorial sea was ice free, mostly, to allow unicellular plankton. But ... both theories are put into doubt by the fact that they imply little continental glaciation deposits, while in reality continental glaciation deposits dominate the Cryogenian – the article should just refer to Cryogenian Glaciations, not presume that Snowball Earth is a proven fact.

++Linx
Now fixed also Hadean and Earth/Proto-earth issues. More to be done about the article: Said: Rursus ☻ 22:35, 28 October 2007 (UTC)
 * add the Lecture 7 sources above (Harrison Schmitt).
 * add Bleeker 2004 for discussions about eon division, actually he speaks about Hadean from 4510 and later and two (2!) eons, eon 2 from Earth-Moon system formation to 4510 Ma, and eon 1 before!!

Batch IV
One more error found: Neoproterozoic Subcommision of ICS, annual report of 2006, says that Cryogenian starts 750 Ma. Said: Rursus ☻ 22:49, 28 October 2007 (UTC)

General
The language contains lots of technical terms, it must be fixed to be comprehensible by Jim, Joe and Mary. Said: Rursus ☻ 06:49, 29 October 2007 (UTC)

The Moon took a few million years to form, and 1-100 years, according to this article and the Giant impact hypothesis article, respectively
This article says:


 * This impact vaporized a huge portion of the crust, and sent many quadrillions of tons of material out into outer space, which hung around in the form of rings for a few million years, until these rings condensed into the body we now call the Moon.

The Giant impact hypothesis article says:


 * Current estimates based on computer simulations of such an event suggest that some two percent of the original mass of Theia ended up as an orbiting ring of debris, about half of which coalesced into the Moon between one and 100 years after the impact.

So which is it?

Gakrivas (talk) 20:37, 21 October 2008 (UTC)
 * You will have to decide. One of the characteristics of understanding is that the knower knows the limitations of knowledge. At any given time in the state of our knowledge is that some things are known to high precision; other things are undefined; other things are partially known. --24.106.44.158 (talk) 21:53, 30 December 2008 (UTC)

Proposed split
About the proposed split: I have no objection to the creation of separate more detailed articles as suggested. However, I think this consolidated list gives a useful combined overview of all these topics, and should be kept, with links to other more detailed timelines as appropriate.--Kotniski (talk) 10:23, 28 May 2008 (UTC)

4 million years ago: start of last ice age
This does not agree with the Vostok Ice Core nor do the links suppport it. Where does this come form? Tks Veteran0101 (talk) 00:24, 25 December 2009 (UTC)
 * yes, some editors have problems in vocabulary and dating f.e. glacial vs. ice age 2.588 Ma ago (end of pliocene) would be more correct, i guess. 80.186.209.39 (talk) 06:15, 29 August 2010 (UTC)
 * revised.  Serendi pod ous  06:27, 29 August 2010 (UTC)

Reversal of Order
Why in blazes did someone undertake to start with the most recent dates on top, going further and further back to the bottom. This makes no sense at all.66.108.94.216 (talk) 20:07, 22 June 2010 (UTC)Disappointed in Wiki editorship Allen Roth
 * The Big Bang is not an event usually tied to the word "prehistory"; yes, technically it is prehistoric, but the term prehistoric is almost always used in reference to Homo sapiens. The Big Bang has more to do with cosmology and physics than prehistory, and so to see it at the top of the timeline is somewhat jarring, at least for me.  Serendi pod ous  20:27, 22 June 2010 (UTC)
 * Arguably a "backwards" order makes as much sense. It is how we unravel the story: it reflects archaeological and geological stratigraphy and the fact that the resolution of our knowledge diminishes as the distance from the present increases. It may not seem 'intuitive' at first but this actually ought to help people engage with the material PatHadley (talk) 11:36, 18 March 2011 (UTC)

The principal issues I had with reversing the order (use of the word "prehistory" and the inclusion of the stone age) have been resolved. So I reversed the order to earliest to latest.  Serendi pod ous  17:17, 9 July 2011 (UTC)

Oldest writing 7000 years old vs Jiahu
It says in the article that protowriting evolved 7000 years ago but the Jiahu culture had a script 9000 years ago http://en.wikipedia.org/wiki/Jiahu —Preceding unsigned comment added by 188.27.206.7 (talk) 11:02, 16 April 2011 (UTC)
 * There seems to be some controversy as to whether these symbols are systematic or merely random pictograms.  Serendi pod ous  11:13, 16 April 2011 (UTC)

stone age timeline (part of prehistory)
Edit : http://en.wikipedia.org/w/index.php?title=Timeline_of_prehistory&diff=436536951&oldid=436500714

Serendipodous, why did you remove the stone age timeline (part of prehistory) from the timeline article!?! This really belongs here. This timeline isn't that complex. --J. D. Redding 02:06, 28 June 2011 (UTC)
 * Because it didn't add any new information to the timeline, and made it harder to read.  Serendi pod ous  05:41, 28 June 2011 (UTC)
 * If you want simple, go to . It should be here. And it added contextual information to the article. I'm going to readd it as a ... to the side. It should be here. J. D. Redding 10:57, 28 June 2011 (UTC)
 * For what it's worth, I tend to agree with Serendipodous - this page is most useful if the layout is kept simple. Detailed timelines for particular periods can go in the articles on those periods.--Kotniski (talk) 09:27, 28 June 2011 (UTC)
 * This is the timeline article. Timelins should not be in the timeline article? --J. D. Redding 10:57, 28 June 2011 (UTC)
 * Well no. This article is a timeline (of a sort; not a graphical one, but it is a "timeline"). That doesn't mean it has to contain lots of more detailed timelines within it.--Kotniski (talk) 11:28, 28 June 2011 (UTC)
 * There is no reason why the timeline should not be in the timeline article.
 * And ... Why do you want to remove the details? --J. D. Redding 11:36, 28 June 2011 (UTC)
 * The timeline is in the timeline article (the article is the timeline). That doesn't mean we have to put other more specific timelines into it as well. This page is intended as an overview, so cluttering it up with excessive detail about a particular period is going to make it less convenient to use for its intended purpose.--Kotniski (talk) 11:42, 28 June 2011 (UTC)


 * This is about contextual information.
 * Cluttering it up with excessive detail? How are the below 'timeline in question' doing that?
 * When was the discussion that this should be "intended as an overview"?
 * A list of date is no very helpful. a visual representation allow the reader to see the time-spans easier ... I'm not sure if you have messed with alot of dates in history, but they are not very useful to understand the scope and quantity of subjects ...
 * The article only has few parts: stone age, complex life, and earth formation. Each should have a easy graphic timeline in-addition to the textual date listings ...
 * BTW, didn't see anything Timeline that exclude the inclusion of such information. --J. D. Redding 11:53, 28 June 2011 (UTC)

The point is, that the graphic timelines overwhelm the article and make the information less accessible. They're all already in Stone Age, to which this article now links, so they're not necessary.  Serendi pod ous  13:31, 28 June 2011 (UTC)


 * No. Please read Abundance and redundancy.
 * And, you have not stated _how_ does the graphic timelines "overwhelm" the artilce?
 * Anyways, I'll be putting a graphjical timeline in, I'll try to rework it into a verticle [if it can be small [verts are bigger than horizontals]] ... Or maybe just make a complete section at the bottome of the article to put in graphic timelines [much like gallery section in several article). --J. D. Redding 22:34, 29 June 2011 (UTC) PS., Good job on the section Paleolithic, Mesolithic, Neolithic etc.,, was goin to do something similar ... just haven't had time ...
 * If you can't see why those graphs make the list impossible to read, then all I can say is we're going to have to take this dispute to a higher level of arbitration.  Serendi pod ous  23:14, 29 June 2011 (UTC)

OK. I have an idea I can live with.  Serendi pod ous  06:37, 30 June 2011 (UTC)

stone age - end?
Why does this stop at the stone age? Geologic history didn't stop just because some brainy critter started throwing rocks (using geological materials). It should extend right up to the present - geology is still active. Plus it seems more about paleontology than geology. And: 34 million years ago: cats begin to evolve ... hmm what did the pre 34 mya cats do? how long were they in stasis before some unknown kitty says let's evolve. Vsmith (talk) 01:53, 10 July 2011 (UTC)
 * The end of the stone age begins the shift from natural history to real history. I thought this timeline should focus on geology/paleontology rather than archaeology or cultural anthropology. So, anyway, I changed the title.  Serendi pod ous  02:26, 10 July 2011 (UTC)
 * Ah ... better - still thinking as I watch where it goes. Thanks for helping the kitty bit too. Vsmith (talk) 03:44, 10 July 2011 (UTC)

Merge with Timeline of evolution?
There is a LOT of overlap between these two articles; indeed I think much of this was copied from that one. A broader, geological as well as biological approach may help Timeline of evolution reach FL.  Serendi pod ous  19:18, 30 January 2012 (UTC)
 * The discussion of this merger took place at talk:Timeline of evolutionary history of life and is now closed with no consensus to merge. RockMagnetist (talk) 22:03, 2 April 2012 (UTC)

Ma? why can't it simply say million, or billion years ago?
a lot of people have never even heard the term Ma before. i propose to have all of the sayings of Ma changed to billion or million years ago if it is appropriate. Staindfan10 (talk) 04:36, 16 June 2013 (UTC)
 * I'm not sure exactly, but Manual of Style/Dates and numbers would be the key reference to research the answer at. The 2 sections under "Years" and "Abbreviations for long periods of time" appear to cover our recommended standards. –Quiddity (talk) 04:45, 16 June 2013 (UTC)

I just noticed a Ma is an actual unit of time measurement, which means 1 million years. My bad, i just wanted to know what a Ma was.Staindfan10 (talk) 05:17, 16 June 2013 (UTC)
 * No problem, we're all here to learn :) –Quiddity (talk) 05:43, 16 June 2013 (UTC)


 * Ma is cool, it is referring to the respective definition←, and it is a conventional unit. Lincoln J. (talk) 09:10, 23 October 2015 (UTC)

Gigantopithecus (major error in information?)
With reference to the statement that this animal evolved 0.3 MYA, I believe this is completely inaccurate and that the animal diverged from the orang-utan lineage around 9 MYA. If someone could check that I am not mistaken or have not misread the facts then it would be wholly appreciated. — Preceding unsigned comment added by Kingcrasher (talk • contribs) 22:40, 10 January 2014 (UTC)
 * Agreed, and so I've removed it entirely. If someone wants to add it back in the correct section, go ahead. (Ideally with a ref :) –Quiddity (talk) 07:23, 18 January 2014 (UTC)

Ordovician
It presently lists:

First jawless fish

First shark

First agnathan fish.

Agnatha are jawless fish, so I'm not sure what's trying to be communicated. First gnathan fish, maybe? Though it could probably be argued that that's still redundant with 'shark.'

Uncited entries may be WP:Original Research?
FWIW - seems uncited entries in the article may not be easily verified - adding references from WP:Reliable Sources to the added entries may help determine if the entries are ok - or - if the entries are WP:Original Research instead - I would think atm - in any case - hope this helps in some way - Enjoy! :) Drbogdan (talk) 12:06, 28 May 2015 (UTC)

Wrong wikilinks?
For 4450 (Hadean), there's the pluvial period ← check it for yourself: I could hardly find either if it even has anything to do with the Hadean nor... Say, what's the deal with that the there??! Wiki doesn't seem to have any articles on any Hadean pluvial period nor periods, by the way. Does somebody know anything about that??? Lincoln J. (talk) 09:17, 23 October 2015 (UTC)

Lunar Eras
Well, I don't mind but I can't understand something. In this timeline, I read "Nectarian began", "Imbrian began", I go with the links - and there I see totally different dates: the Nectarian on the Moon took place when it was already Archean here, not Hadean - but the dates here are Hadean. Don't get me wrong - I know the difference between Kelvin and Fahrenheit, lol. The dates are less ambiguous, I can assure you - "ago" and in years (was it kinda different years on the Moon?). So I don't get it - maybe it's all right while I should've known something "special"?? Some "transition shift" when applying lunar eras? Or is it kinda relativistic (yikes!)? Real shift in TIME? (Wow!) Don't get me wrong, Lincoln J. (talk) 13:54, 26 October 2015 (UTC) :)


 * According to a NASA paper a clock on the Moon's surface would be 6.5E-10 s/s faster relative to one on Earth (I assume at Earth's equator, sea level).

That equates to less than 3 seconds over 4.5 billion years. As a qualification, the NASA paper used current static masses and diameters of the bodies. Over billions of years these parameters are NOT static.98.17.181.251 (talk) 03:52, 12 July 2024 (UTC)

Oldest rock
"4,030 Ma: Acasta Gneiss of Northwest Territories, Canada, first known oldest rock, or aggregate of minerals." But actually, it seems to me the article hasn't been really updated for a huge while: for quite a few years - even a movie shot - already it's known about amphibolites of 4.28Ga roughly from the same area. Were they lying??? Lincoln J. (talk) 06:47, 27 October 2015 (UTC)
 * Added something to "Oldest rock"'s talk page... Hudson Bay, LiveScience...
 * Lincoln J. (talk) 09:44, 27 October 2015 (UTC)

Proper time sequence structure?
There present certain processes that span such significant an amount of time to actually occupy often more than one period (while the subsection is dedicated to only one): "2,200–1800 Ma: Continental Red Beds found, produced by iron in weathered sandstone being exposed to oxygen. Eburnean Orogeny, series of tectonic, metamorphic and plutonic events establish Eglab Shield to the north of West African Craton and Man Shield to its south – Birimian domain of West Africa established and structured."This one spans all through the whole current and the whole next period - if not yet another next one. So, I suggest we could consider putting such items out of the main period sequence - say, rewrite the description to place it under the subsection when it starts, so that it could be seen as if in between, or more general. You can't comfortably place huge periods/processes in the same line with other, short events of which it mostly consists. In any case, in addition to that proposed paragraph the prolonged event's starting point - in short - might be placed within the general sequence anyway - for the reference anyway. The suggested paragraph might look like the following: "Starting blabla Ma, throughout this and the whole next period, blablabla experienced blabla, resulting in subsequent blabla of blablabla.":) Lincoln J. (talk) 12:31, 3 January 2016 (UTC)
 * Fine by me.  Serendi pod ous  13:03, 3 January 2016 (UTC)