Talk:Earth/Archive 4

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This is Archive 4 covering August 8, 2006 - August, 23, 2006.

Known by Humans

Isn't it redundant to describe the earth as the only place known by humans to support life? Most readers assume that encyclopedia articles reflect human knowledge... Sceptre Seven 14:16, 8 August 2006 (UTC)

Earth#The_Moon

Te picture states that "Earth and Moon to scale." ,Distance included in the scale? if so ,it should be stated in the article...

After a quick ruler check, I've updated the caption to reflect that both the sizes and distances appear to be to scale. Specifically, on my display, an 8-mm Earth = 8,000 miles => 223 mm distance = 223,000 miles, which is about right for a rough check. A similarly rough check on sizes (8-mm Earth to 3-mm Moon) seems to have the Moon a bit bigger than it should be (0.273 Earth diameter, according to The Moon, instead of 0.38), but I'll assume the image creator was more accurate than my quick measurements for now. In any case, we should update the image description to confirm exactly what is to scale. ~ Jeff Q (talk) 15:52, 4 April 2006 (UTC)

The surface area of the Earth

Hey. Sorry, I'm not very good with editing page but I think this is what I'm suppposed to do when making a discussion...?

Anyhow, it says the surface area of the Earth is 510,065,284.702 km². How can this be measured to such a degree of accuracy? It is obviously not true because I could dig a hole in my back-garden and spread the soil evenly across my lawn. This would change the surface area...

Because the surface area = $4\pi r^{2}\,\!$ and the "surface area radius" is known as the authalic radius, which equals about 6371.005076123 km. Of course the precision/accuracy is theoretical——but since everything else is measured to .001 km, we might as well be consistent, especially as a reference source (in most cases the reader will probably round it to 510,000,000 km, but the theoretically-precise-to-the-meter value is given for the record). ~Kaimbridge~ 13:55, 8 April 2006 (UTC)

That's fantastically dumb. All of those numbers should be cropped down to something consistent with their uncertainty. Dragons flight 01:10, 9 April 2006 (UTC)

Well if that's the case, given the variation in terrain, why not just let a = 6380 and b = 6355? P=/

Because these specific values have been refined (via GPS and other means) to theoretically less than .001 km. If one is using a specific model (be it GRS-80/84, Hayford/International, Clarke or whatever) involving other data based on it (e.g., such as in dealing with the direct problem of geodesy), then that specific model should be used throughout. But this article is meant as a planetary overview——most planetary sources round a and b to only .01 km [1]: Given the extensive refinement over time made, I see no reason why the rounding shouldn't be extended to .005 km, which is real close to the most recent, established models, and provides the same general ellipticity of these established models (including IUGG's GRS-80/84):

               a,b          b/a
           (6380,6355 = 0.996081505)
           (6378,6357 = 0.996707432)
      6378.14,6356.75 = 0.996646358
  6378.2064,6356.5838 = 0.996609925
    6378.388,6356.912 = 0.996633005
     6378.16,6356.775 = 0.996647152
    6378.137,6356.752 = 0.996647140
    6378.136,6356.749 = 0.996646826
    6378.135,6356.750 = 0.996647139
    6378.134,6356.751 = 0.996647452

I have updated the physical characteristic section to reflect reference values and reasonable precision, which for the surface area came out to a few hundred km^2 rather than 0.001 km^2. Dragons flight 02:23, 9 April 2006 (UTC)

You seem to be arguing both ends: On one hand you're saying GRS-80/84 should be used since it is IUGG established (I think that is being too model specific, given the other models still in widespread use——.005 km is adequate for a general purpose, non-datum specific model for Earth, particularly since it is so close to the most recent established values), and on the other hand you are saying the subsequent values found (surface area, etc.) should be rounded to 100s of km²——let the READER round it! P=) I certainly have no problem, though, with a disclaimer pointing out uncertainties and precision practicality! P=) P=) P=) ~Kaimbridge~ 09:38, 10 April 2006 (UTC)

Kaimbridge, it is basic error propogation. If A = a*b (obviously not the Earth, but a simple example), then the uncertainty in A is dA = ((b*da)^2)+(a*db)^2)^(1/2) where da and db are the uncertainties on a and b respectively. With an uncertainty of order 5 m in the edge length, the uncertainty in the area is magnified by the length scale (e.g. 6400 km) to give dA of order 50 km^2. Now this is just an approximation, working it out correctly (and keeping things like factors of 4 pi) gives an uncertainty in the area of a few hundred km². Hence having more precision than that is simply false advertising. We shouldn't be feeding the reader meaningless digits. Dragons flight 15:55, 10 April 2006 (UTC)

PS. I'm not wedded to any particular set of reference values, but I used what I had at hand when updated. I am however committed to cropping measurements down to a level consistent with what is known rather than offering as many digits as a calculator will display. For the record, if f(a,b,c) is a function of independent variables a, b, and c with normally distributed uncorrelated errors da, db, and dc respectively, then the error in f is given by $df={\sqrt {({\partial f \over \partial a}da)^{2}+({\partial f \over \partial b}db)^{2}+({\partial f \over \partial c}dc)^{2}}}$. Dragons flight 17:39, 10 April 2006 (UTC)

The poor quality animated GIF image

Look you all I'm not vandalizing the article....I'm just removeing an eyesore from it to improve its quality. How about this if I find a better one would that work? 138.163.0.37 00:36, 9 April 2006 (UTC)

• Yes. Danny Lilithborne 00:40, 9 April 2006 (UTC)
• User 138.163.0.37 I have put a silghtly better image on the Earth page. DO NOT DELETE IT without discussing it here.....it is only fair Aeon 00:41, 9 April 2006 (UTC)
• The old image definitely was sub-par, and I agree with its removal, 138. Aeon's image is better, but I still think the article would look better without it. Also, with an unknown copyright status, the image will likely be deleted soon anyway. — Knowledge Seeker দ 01:25, 9 April 2006 (UTC)

Adding a caption to the rotating earth image

New satellite.

Hey how do I add a caption to that image? any help would be great Aeon 00:45, 9 April 2006 (UTC)

Use something like [[Image:IAstronaut-EVA.jpg|thumb|right|200px|New satellite.]], which I used to display the image at right. Aeon, where did you get the animation of the rotating Earth? — Knowledge Seeker দ 01:28, 9 April 2006 (UTC)

I did a google search....I will find the site and get the copyright status of it....Aeon 02:24, 9 April 2006 (UTC)

I change the image found one that was not copyrighted and added a caption. Aeon 02:32, 9 April 2006 (UTC)

Where did you get this image? Could you supply the URL? — Knowledge Seeker দ 02:35, 9 April 2006 (UTC)

Need help correcting factual error re age of Earth

Article states: "Scientific evidence indicates that the Earth and the moon were formed around 7,000-10,000 years ago." Obviously, this is not true.

In fact, all scientific evidence points to an earth that is about 4.6 billion years old, along with the rest of the solar system. An earth younger than 10,000 years exists only in the belief system of certain religions, and is not based on scientific analysis. If someone experienced with Wikipedia could correct this, we would all appreciate it. Thanks.66.243.43.98 21:13, 11 April 2006 (UTC)

You're correct; an anonymous user changed it and I didn't notice it until fifteen minutes later. It should be correct now. Thanks for pointing it out! — Knowledge Seeker দ 21:31, 11 April 2006 (UTC)

two hemispheres

(near the winter and summer solstices, which are on about December 21 and June 21, respectively).

With respect the Earth had two hemispheres last time I check and that this statement referrs only to the northern hemisphere, for the southern Hemisphere this is factually incorrect as summer solstice occurs about December 21 and the winter solstice occurs about June 21. Gnangarra 14:40, 28 April 2006 (UTC)

Earth's future

In the chapter named "Earth's future" it says both "billion years" and "Gyr". I believe it should be corrected. Only one term should be used. --Idan Yelin 04:42, 18 May 2006 (UTC)

I tried to clarify the use of the term in the text. Repeatedly saying a "thousand million" seems excessively wordy. Thanks. — RJH 17:44, 21 May 2006 (UTC)

the use of "GYR" should be explained better. I followed the link to the page it refers me to and yet I cannot find any reference to the abbreviation used. I can only find "gaussian year" and "great year". the one that is in use is not specified. this seems a very strange measurement of time anyway. why not simply use the standard units of time? and add trillions or billions or whatever you need to. if this article is supposed to be for everyone it should use terms that normal people can understand. it should be standard. 17:08, 27 July 2006 (UTC)

Pangaea

The section of Pangaea, while well written, doesn't really belong in this article, in my opinion. It seems out of place and a bit arbitrary—why a section on Pangaea and none of the other continents or supercontinents? Perhaps a section on continental movements could be included instead, or perhaps relevant information discussed briefly in the Earth#History section. — Knowledge Seeker দ 08:36, 22 May 2006 (UTC)

I agree. The subject is already covered at a higher level in the History section. I think the Pangaea section should be merged into the Pangaea page. — RJH 19:02, 22 May 2006 (UTC)

As it appears to be the introduction of that article, I removed the section. — Knowledge Seeker দ 21:40, 22 May 2006 (UTC)

Moon and the Earth's Axial tilt

Perhaps somebody knows the answer to this question: If the Moon continues to recede from the Earth, at what point (time or distance) will it no longer exert a significant influence in stabilizing the axial tilt of our planet? Thank you. — RJH 03:01, 23 May 2006 (UTC)

~2 Gyr. [2]. Dragons flight 04:39, 23 May 2006 (UTC)

Mostly Harmless.

Pressure

Isn't the pressure 101.325 kPa? 203.218.86.162 11:31, 2 June 2006 (UTC)

How about removing the adverbs?

Is anybody but me struck by how silly it is to write Precipitation patterns vary widely ... or The Earth's terrain can vary greatly ...? Precipitation varies widely compared to what? Precipitation on Mars? Jupiter? My back yard? I could be wrong here but I bet Jupiter has a lot more variation in precipitation, just becuase it probably has a lot more precipitation overall. Things can only vary widely or greatly in comparison to something else. When you're talking about the whole Earth itself there really isn't much to compare against. Just making the sentences longer to make them look good buys us nothing.

I tried removing an adverb once, writing just Precipitation patterns vary ... but somebody put it back. Rather than start an edit war I figured I'd point out the sillyness here. --kop 05:57, 9 June 2006 (UTC)

I see what you're trying to say here. I agree with you that it's absolute rubbish to compare something with... absolutely nothing. People should rather stop writing BS on all the articles in order to express their ideologies. We want a Wikipedia with factuous information that can be and has already been proven. People should also be more careful when edititing articles because they never know what simple-minded person they might influence with this BS of them. --Scotteh 17:58, 15 June 2006 (UTC)

Ideology

"The Earth was formed around 4.57 billion (4.57×109)[1] years ago (see Age of the Earth) and its largest natural satellite, the Moon, was orbiting it shortly thereafter, around 4.533 billion years ago."
This part is nonsense and cannot be proven. Therefore I have removed it. --Scotteh 17:49, 15 June 2006 (UTC)

Do not remove well sourced valid content. -- Kim van der Linde ^{at venus} 17:51, 15 June 2006 (UTC)

Are you saying that because some fool wrote a book about how old the planets are that is enough reason to believe this nonsense? I believe you are ignorant, therefore you are ignorant. What's the logic within that? Stating the Earth is how many ever billion years old, is foolish because the author of this hypothesis has not beared in mind the factors of thermodynamics, to say the least. Also, stating that the Earth is so many billions of years old, is in contrast with the beliefs of Christians, and is therefore discriminating that specific group. Until someone climbed into a time machine and visited the time when the Earth began existing, and confirmed it's age, the "billions of years"-statement is bogus. Therefore such utter nonsense must be removed off this Wikipedia. I will not go on an immature edit war, so I'll leave ignorant Wikipedia articles to the ignorant Wikipedia community. Also, I do not understand who tagged that citing as well sourced and valid. Must be the author himself. --Scotteh 18:05, 15 June 2006 (UTC)

I would say, if you want to challange the scientific evidence, provide alternative scientific evidence that shows the page is incorrect. Just your assertion will not do. -- Kim van der Linde ^{at venus} 18:24, 15 June 2006 (UTC)

And who suddenly gave science so much authority? This planet is not inhabited solely by scientists. It seems Europeans always want to do away with what God says, nevermind their own contrasting so called evidence. Why, you know I'm just a kid and I don't have much knowledge about these stuff, but if you go ask other people who don't lurk around Wikipedia for their whole lives, you'd be surprised about what you'd found. Hereby I settle this. Wikipedia has proven itself unworthy of providing sourceful information, and it's only reason for existense is to be a message board for atheists to agree on nonsense. Unless this would change in any way, Wikipedia would remain a foolish resource, or dumpsite, for any reasarch done. --Scotteh 18:36, 15 June 2006 (UTC)

Well, if that is your view of wikipedia, so be it. Because if we would base the entries in religeon, we will need a long discussion about which religeon, because mine gives a very different picture than yours for example. -- Kim van der Linde ^{at venus} 18:51, 15 June 2006 (UTC)

Fair enough. --Scotteh 18:54, 15 June 2006 (UTC)

So, until that is settled in this world, I suggest to leave religeon out of the equation for articles like this. :-) -- Kim van der Linde ^{at venus} 19:00, 15 June 2006 (UTC)

Ok, you win. For now. --Scotteh 19:15, 15 June 2006 (UTC)

It is not about winning as far as I am concerned. -- Kim van der Linde ^{at venus} 20:15, 15 June 2006 (UTC)

And as far as I am concerned, it is. So then it is all about winning. Oh please, you know what I mean. --Scotteh 20:41, 15 June 2006 (UTC)

Ok, if that is the way you want to see it. In my view, winning is with a loser, and I do not view you as the loser of our discussion. In this context, you might be interested in Age of the Earth page, especially under prescientific concepts. -- Kim van der Linde ^{at venus} 21:01, 15 June 2006 (UTC)

Actually I was the loser. But thanks anyway. And thanks for the articles. --Scotteh 21:17, 15 June 2006 (UTC)

My troll detection unit is blinking. Should I be concerned? :-) — RJH (talk) 22:22, 26 June 2006 (UTC)

Names for the planet Earth?

The Lexicography section gives cognates to "earth" which is interesting in its own right (although it might show the need for an article on earth - although this might be too similar to soil) but what I'd be interested in names other cultures use for "Earth". I assume most Indo-European languages also use their equivalent to "earth" but what about elsewhere? Some of it is touched on in the first paragraph of the Descriptions of Earth section but are there more? It may be that it is all as mundane as our own naming system but there may also be interesting information that could be drawn together. So would some kind of new section ("Names for the planet Earth" perhaps?) be worth considering? (Emperor 17:52, 17 July 2006 (UTC))

RV problem

For some reason, whenever I try to RV some edits, I get redirected to an edit conflict with Simon Harcourt, peculiar... 惑乱 分からん 10:00, 21 July 2006 (UTC)

Me too - anybody have any idea what's causing this? Bob 11:01, 21 July 2006 (UTC)

Right now, I even have trouble to view the page, if I don't check out the history. But it doesn't seem to be a user-related problem. (I think I even saw one user RV that religious edit, on one occasion, can't get back to that now, however...)

Might be some software conflict, where two pages have the same ID or something... (Uhhh, what am I saying?) 惑乱 分からん 11:36, 21 July 2006 (UTC)

Same problem on Age of the Earth - can't get edit to revert, methinks someone is playing Vsmith 12:17, 21 July 2006 (UTC)

comment in opening paragraph

"distance from the Sun, and the fifth in order of size. We are mostly harmless." what is that comment about? --Dan 20:42, 22 July 2006 (UTC)

It's a reference to the Earth's entry in the fictional book Hitchhiker's Guide to the Galaxy, although it's very out of place.

MASS

can we have some different measurements for mass? I spent AGES trying to figure out how many teratons the earth was..... I now know it to be roughly 5 billion teratons, but it took me a LOT of searching and a LOT of (what I consider) complex maths...

Should we add units in English/Imperial?

It's a great article, however it contains units of measure that are virtually meaningless to roughly 5% or so of the world's population. I propose to add English/Imperial measurements to all the figures given, using google calculator. Any objections? Supercam 21:25, 25 July 2006 (UTC)

Given the number of units in the article, it will make it longer (particularly the infobox) and possibly harder to read. Who are the 5% who would find them meaningless? Perhaps a link to a page about the units would be better. I'm sure there's one here somewhere. Kevin 21:54, 25 July 2006 (UTC)

As an American who has difficulty with with metric/SI units, I still strongly support their use in scientific (and other) contexts. In my opinion, providing conversions for all the units would make the article needlessly bloated; readers who are unfamiliar with SI units may use Google Calculator or their method of choice to convert to their desired measurement system. — Knowledge Seeker দ 03:23, 26 July 2006 (UTC)

Word for "Earth" in other languages

Added a brief paragraph on the word for "Earth" in other languages, since I was curious about this and couldn't find it in other articles, or via Wiktionary. The best that I could come up with is this, via Google search. The examples are therefore all transliterated into English. Anyone with more experience in these languages or with linguistics, please feel free to add or revise the paragraph. --Brasswatchman 22:23, 28 July 2006 (UTC)

Earth's Equator

Am I at all correct or am I simply mistaken to think that the approximate mileage around the equator of the earth is something short of like 8000 miles in distance in the circle round the equator. I think (although I am not sure) that the actual mileage is something possibly close to 7,480 miles. I try to relate and to comprehend this number in such a way as to think as to how and to break it all down. Well ( i think to myself) if I drove 1000 miles then I would need to drive about another 6 and half times that distance around the earth to complete a full circle. And that is of course assuming my automobile could travel over the water and not sink to the bottom of the ocean. Maybe the Wikipedians out there could help to illuminate the precise expanse of the mileage and distance around the equator of the earth. I tend to comprehend the concept of actual miles better than I do kilometers or any other system of measurement. Is there a precise and a confident consensus for the number of miles starting from point A and either going west or east until you finally reach point B when you travel around the globe in a nice straight line. www.geocities.com/berniethomas68 02:16, 2 August 2006 (UTC)

Not even close! P=)

The distance around the equator equals $2\pi \,\!$ times the equatorial radius, a, which——for Earth——equals about 6378.135 km/3963.19 mi, so the equatorial circumference equals about 40,075.0 km/24,901.5 mi (if you're looking for the north-south, meridional circumference, that's an ellipse requiring the elliptic integral of the second kind, but works out for Earth to be about 40,007.9 km/24,859.7 mi——and the average circumference, as a whole, is about 40,041.5 km/ 24,880.6 mi!).  ~Kaimbridge~ 14:23, 2 August 2006 (UTC)

Thank you Kaimbridge, therefore, is it correct to say of that the equator is 24,901.5 miles around ? www.geocities.com/berniethomas68 18:01, 2 August 2006 (UTC)

It depends whether you want the nominal distance around an imaginary flat surface around the equator at its average height (which is probably about what you said, but you gave it too many significant figures: I would write 24,900 miles), or the actual distance, which will be very difficult to measure accurately, because of going up and down hills. (Consider: it may be a mile in a straight line, but if you drive over a hill, even in a totally straight line on the ground, you will cover more than a mile on the road). Notinasnaid 18:14, 2 August 2006 (UTC)

Actually I did round it to reflect a radius of between 6378.135 - 6378.137, which appears to be the most advanced and "accurate" value known. Of course it doesn't take into account local terrain——it is based on a smooth, "sea level" ellipsoid. So distances found, likewise, reflect a mathematically defined "smooth, sea level surface" (as opposed to the geoidal) surface, which takes into account gravity based, regional sea level variations). If the reference radius is good to .001, then the "reference distance" is also good to at least .001. Of course, once you calculate the distance, you can then round it to whatever precision serves your needs. Informally, if you want to include local terrain (Terr), find the "sea level distance" (DxE) and apply the Pythagorean theorem (making sure DxE and Terr are worked in the same measuring unit——i.e., meters, feet, km or miles):

$DxE_{adj}={\sqrt {DxE^{2}+Terr^{2}}};\,\!$

Keep in mind, though, this equation is vertically loxodromical in nature, so it degrades as the length grows (but should be good enough for tens of miles P=).  ~Kaimbridge~ 15:07, 3 August 2006 (UTC)

Name Terra

Shouldn't this page be titled Terra? Its the scientifically and politically correct term for Earth,same for the moon being called Luna. While some think it's just Latin, its also the proper scientific term.

There's nothing scientific correctness in the name Terra, as our planet does not happen to have an "official" name. Terra it is the Latin name for Earth, however this is the English Wikipedia and we should use English names if possible.--JyriL ^talk 21:34, 11 August 2006 (UTC)

POV

This section has been returned to the main talk page[3]

Some changes

I change the whole layout, added hydrosphere, changed plate tectonics (which is theory) to facts about tectonic plates on Earth, added pedosphere and some other minor changes. To write article about Earth is quite though task. There's too much information taht should be included and many other articles on Wikipedia related. GeoW 16:55, 21 August 2006 (UTC)

Time for another archive soon

I beleive that most current discussions are resolved. HighInBC 19:38, 23 August 2006 (UTC)