Talk:Metre

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[edit] Reason for 299,792,458

I was curious - is there a reason why it was decided to divide the distance light covers in a vacuum by 299,792,458 rather than a more.. obvious (?) number, such as 1,000,000 or 100,000,000 et cetera? It seems arbitrarily chosen. Thanks. --A Sunshade Lust 03:01, 4 June 2006 (UTC)

See the history section. The new definition is (as accurately as possible) the same length as the older metre but just defined in relation to the speed of light rather than the older definitions. - SimonLyall 03:12, 4 June 2006 (UTC)
Since this is the second time this question has been asked, any way we could simply add this information to the introduction without cluttering it or lengthening it considerably? -- Centrx 18:30, 4 June 2006 (UTC)
The introduction does say the original defn already and gives more details in the history. please suggest better wording if you don't think it is clear. Do you mean we should have something like "Note: While the metre has been redefined several times the new definitions are all (as accurately as possible) the same lengh as the previous definitions" ? - SimonLyall 22:31, 4 June 2006 (UTC)
No I don't think there should be anything so unwieldy and excessive. I do think that the introduction may be insufficient to convey the proper meaning for many readers, but I do not know what would work to add. -- Centrx 18:14, 5 June 2006 (UTC)

Thank you, I didn't think of that (but now it all seems a bit obvious, and I a bit silly), I do think that something such as Simon's note should be in, but maybe not with the "Note:". --A Sunshade Lust 19:20, 6 June 2006 (UTC)

Interesting experiment: if the meter were to be defined as a the distance light travels in a vacuum in a billionth of a second, we would wind up with a meter about 11.8 inches long. Might give us colonials a reason to switch to metric. -- Jason Jones 05:48, 17 June 2006 (UTC)

How about writing "defined as the distance travelled by light in absolute vacuum in 1/c of a second". --I hate to register 17:53, 7 August 2006 (UTC)

I really don't think that works at all. Putting the number back in gives it a real value. The 1/c doesn't really make a lot of sense especially at first reading. I think it should be changed back. - SimonLyall 22:50, 10 August 2006 (UTC)
"1/c of a second" is not a legitimate phrase, not to mention it would result in a unit of seconds^2/meter.

[edit] Pendulum length calculation

This does not account for air resistance; they could have used a real pendulum, on Earth, which I think would make the resulting distance longer. Even if it didn't, it would not be exactly 99.36 cm, it would be "about 100 cm", which is what we have already because it is for the metre. Is this correct? We could have a range, but this is getting a little further into retroactive descriptions, it would be better to have a source that says, "they wanted this method, and measured it to be about this distance, which is about 99.36 cm". —Centrxtalk • 04:47, 13 July 2006 (UTC)


[edit] Distance from Equator to North Pole

The article mentions the "distance from the equator to the North Pole". Should it be made clear that this distance is not measured in a straight line? Technically it's a great circle. That distance, in a truly straight line that passes hundreds of miles underground, would be about 10% shorter than the great circle. But it's not true to say that the distance is measured "along the earth's surface" either, because that would imply a slighter greater distance because of interfering mountain ranges etc., or maybe a lesser distance under certain tidal conditions. My guess is the definition needs to mention sea-level.

Technically, it's not a circle but an ellipse. The article says, "one ten-millionth of the length of the Earth's meridian along a quadrant". Meridians follow the curvature of the earth, by definition. What the article does not seem to say is that the metre was based upon the length of one, specific merdian, the Paris Meridian. This value was determined by surface measurement.[1] However, actual length of the entire meridian is 40,007.86 km, while the value used to define the metre was equivalent to 40,000 km, which is less than actual distance, no matter how you measure it. --Nike 01:54, 27 July 2006 (UTC)

[edit] Circular Reasoning

"Now, it is defined by the International Bureau of Weights and Measures as the distance travelled by light in absolute vacuum in 1/c of a second." sounds circular. --Shanedidona 22:46, 9 August 2006 (UTC)

It sounds circular, but actually isn't. The speed of light in absolute vacuum is a universal constant, given the exact label c, and is measured rather than calculated. As long as the definition of "second" doesn't rely on the definition of "meter", there is no circular logic involved. --Dachannien 13:22, 11 August 2006 (UTC)

I have changed it back to 299,792,458 as I think 1/c is too hard for most people to grasp easily. Putting 1/c requires people to know what "c" means, roughly how big it is and how it relates to a metre. I think this is a big jump for the intro paragraph of the articvle - SimonLyall 22:08, 12 August 2006 (UTC)

It still sounds circular to me. c=299,792,458 m/s, and m=1/cs, it seems circular: the definition of meter depends on itself. Maybe someone with more scientific background could explain it to me. -- R'son-W (speak to me/breathe) 22:13, 26 August 2006 (UTC)

The distance that light travels in one second is not dependent on the definition of the metre. We describe it in terms of the metre, but we could just as well describe it as a distance between certain stars or in the same way you might describe the length of your arm. The current definition of the metre, with number the number 299,792,458, is based on using the old definition of the metre, such as with a bar, to describe the speed of light, but in terms of the pure, ideal definition, it is not circular. —Centrxtalk • 01:24, 29 August 2006 (UTC)

I understand your confusion about the circular reference, but there is no need to be confused. The metre is a length chosen out of thin air so it needs to be defined by something. Light in a vacuum travels at the same speed in any vacuum and you can see this speed; it doesn't need a definition. Also, I don't think there is anything wrong with expecting people to know what c is. The typical person who would read about the definition of the metre would probably be interested enough in science to know what c is. Even if you don't have a scientific background, you should really know what c is. Owen214 23:53, 13 October 2006 (UTC)

It's got a be "1/299 792 458" (as it is in the article presenly), not "1/c". Note that "c" is "299 792 458 m/s", not just "299 792 458", so "1/c" is "1/299 792 458 s/m". So with "1/c" then sentence would be equivalent to "as the distance travelled by light in absolute vacuum in 1/299 792 458 s/m of a second", which is nonsense.--Niels Ø 11:44, 16 October 2006 (UTC)

[edit] Multiples

Please don't remove multiples, for consistency they are in all seven base SI units. —The preceding unsigned comment was added by 83.5.62.208 (talkcontribs) 15:22, 6 September 2006 (UTC)

[edit] Spelling in introduction

Originally, this article had "metre" as the only spelling given in the first sentence, and then at the end of the paragraph had a statement like "In American English, this is spelled "meter". Then at some point in 2005 it was changed to put "metre or meter" in the introduction, and then later changed again to have parenthetical comments like "metre (Commonwealth) or metre (American)". The reason for having both in the first sentence is that either is a reasonable, commonly used spelling. Neither should be deprecated to an endnote. The reason for having the parenthetical notes was to explain the which was most commonly used where, but this is clearly unwieldy and also not strictly necessary for an encyclopedia article. So it was changed back to having no parenthetical comments. The problem with the new change is that it suggests that "metre" is the 'correct' spelling with "meter" being a peculiar aberration, when instead there is no reason to especially value either and when "metre" would be an acceptable spelling for someone to use in the United States and "meter" is the spelling that is used chiefly in the United States, but not exclusively. These are words, they don't fit in regional lead boxes. —Centrxtalk • 00:40, 10 September 2006 (UTC)


The US is the only country in the world that uses the spelling "Meter" so the CORRECT spelling is Metre. I have know idea why America (like everything else) damages perfectly good words and spelling.
Well, for one thing, sign your posts, and check your own spelling. Anyway, here in Denmark, we also write "meter". It's not English, but Denmark is a "country in the World". Of course, the article must give both those spellings that are correct in English, and of course it should, a bit further down, state the facts about their usage.--Niels Ø 13:18, 8 October 2006 (UTC)
This word was an invented word, it didn't exist before this. The spelling was in French and it was metre. English speaking countries adopted this spelling then the US changed it. Therefore, there is a correct spelling and it is metre. It is ridiculous that the US changed it anyway. The US has typically changed the spelling of words to make them more logical. It is not logical to change the spelling of this word to meter because the word meter was already taken, so you create disambiguity by having two words with the same spelling and different meanings. Therefore it is not logical and doesn't even fit the typical US system. Another thing is that the US is not justified to change the spelling, especially since they still use imperial measurements. Changing the spelling is just telling foreign countries that they're getting their own spelling wrong and should do it differently. This is incredibly arrogant and unjustified. The US should revert to the original spelling and maybe consider changing to the SI system of measurements instead of using the stone age, imperial system. Owen214 23:46, 13 October 2006 (UTC)
American spelling has used the -er instead of -re ending since the days of Daniel Webster (center instead of centre, theater instead of theatre, etc). I do not believe this was a conspiracy to offend the French, Owen.  :-) Also, it is not an invented word, it has a well-known meaning in the English langauge (as in volt meter, gas meter, etc). DonPMitchell 20:43, 15 October 2006 (UTC)
True, it's not invented, but merging two historically different words is equally artificial. - Рэдхот(tce) 21:01, 5 December 2006 (UTC)

[edit] Table formatting

What was wrong with the formatting of the old table? The problem with this one is it using a lot of formatting rather than the easily editable wikitable, and the black heading is not pretty. —Centrxtalk • 01:08, 13 September 2006 (UTC)

[edit] Table: Defining “Most Common”

If one states there are certain “most common versions" (SI prefixes), there must be a sound, scientific basis other than "Centrx thinks these are most common." Google is an excellent way to determine what "most common" is. It may not be in accordance with what some might think ought to be common. However, since Wikipedia is an Internet-based tool, Internet-based sources of determining what is common is a perfectly valid basis. It certainly beats no basis that personal opinion amounts to. If you know of a better way to define "most common" please quote your source. However, it is certainly not the Wikipedia way to assert that something is true just because one believes it to be so, then removes a valid citation, and then doesn't even cite their own references to buttress their belief. Both micrometer and nanometer are extremely common among technically literate users of the Internet.

For instance, you apparently feel for some reason that the centimeter is more commonly used than other prefixed forms. It is unwise to assume that because you feel you are technically literate, that you are a perfectly representative user of the Internet. In fact, "nanometer" is more common on the entire Wold Wide Web than is "centimeter."

Here are the Google hits on what is currently on the Web:

decimeter 451 k
centimeter 12.9 million
millimeter 21.5 million
micrometer 6.84 million
nanometer 16.9 million
picometer 79.7 k
femtometer 30.8 k
attometer 11.6 k
zeptometer 25.2 K
yoctometer 25.1 K

decameter 242 k
hectometer 45.8 k
kilometer 56.3 million
megameter 24 k
gigameter 9.93 k
terameter 873
petameter 965
exameter 864
zettameter 35.8 k
yottameter 24.2 k

Clearly, there is a rational basis to assert that the ones marked in bold are common variations of meter. There is a pronounced drop in the numbers below 6.84 million; the next lower population is one-fifteen as common. If you want to assert that only centimeter and millimeter are common, then cite a reference or rational that is supportable. Otherwise, I suggest we avoid any claims of knowledge regarding what is "common" and simply list them all in plain text. This is much preferred over making an incorrect assertion.

I've converted the black to something hopefully more to your liking. You can compare the before and after versions in the History section to see what I changed in order to alter the color yourself to something better. You can add any hex value you like. Greg L 00:18, 16 September 2006 (UTC)

You can get a sense of the problems with a Google search by looking at some of the first results, e.g. a lot of conversion tools and a few companies. It also has the clear problem of saying that nanometer is more common in everyday use than centimeter (when in fact it is only more common in computing and science, toward which the Google is heavily biased), and if you use the British spelling you come up with the peculiar result that "decimetre" is almost as common as "nanometre". Google searches are valid for finding out whether a person is currently famous, not whether a particular word is more common. Using a Google search for this is trying to justify what we already know to be true. Yes, we should find a better source, but that doesn't mean that what we have there is not verifiable or that coming up with a bad source is the solution.
Also, Wikipedia being on the Internet has nothing to do with it. This is irrelevant to creating a valid encyclopedia and the purpose here is not to find the most common words on the Internet, but the most common words in English. It has nothing to do with technical literacy, except to classify nanometre and micrometre separately. The fact remains that no one but the scientist working in a laboratory uses nanometres, while most everyone in the world outside of North America use kilometres and centimetres on a daily basis. Wikipedia is not an encyclopedia of the Internet. —Centrxtalk • 02:33, 16 September 2006 (UTC)
Nanometers are used regularly by most science students, not just scientists. Anybody who studies wavelengths of light, for example, is likely to use nanometers; it's only the fossils who learned ages ago and who are not involved in academia who keep angstroms alive on Wikipedia and elsewhere. They appear fairly commonly in newspaper and magazine stories about DNA or whatever that fits in this size range.
One problem with the search for micrometer is the fact that it is two different words, spelled the same but (at least should be) pronounced differently, one being a measuring instrument and the other a unit of measure. The other problem with them is the question of whether or not Google includes hits for their now-deprecated-but-still-far-too-common synonym , microns. Gene Nygaard 02:53, 16 September 2006 (UTC)
What Gene said about the nanometer. Plus, micrometer is extremely common in both engineering and manufacturing throughout the world. And I can't fathom the jump in logic you're using Centrx. Making the statement that “Google searches are valid for finding out whether a person is currently famous…” (indeed, a true statement) and then saying that in light of this fact, it follows that “[Google searches are] not [good for determining] whether a particular word is more common” is a non sequitur. I'm sure one can do a Google search on both the American and International spellings and the summed results will probably come out around the same (i.e. micrometer/micrometre and nanometer/nanometre are very common). And that was a nice try when you wrote above that “Wikipedia is not an encyclopedia of the Internet,” (but who are you trying to kid?) If you want to say that centimeter and millimeter are the only SI prefix submultiples commonly taught in American grade schools, have at it. I doubt that it would be a relevant point for use in this Wikipedia article but at least it would be a completely true statement. Greg L 03:42, 16 September 2006 (UTC)
P.S. I parsed your writings above and came up with this statement that is derived directly from your arguments: “The prefixes listed in bold are the most common factors used by most everyone but scientists in the world outside of North America on a daily basis.” OK… I'll buy that. Greg L 03:56, 16 September 2006 (UTC)
They are more common everywhere and in all respects outside of technical contexts. —Centrxtalk • 04:14, 16 September 2006 (UTC)
I wholeheartedly agree with your statement. And one could revise the table and introductory sentence accordingly. One could, for instance, winnow the bolded entries down to your originally proposed subset and introduce them as being the prefixed forms that are routinely used by lay-people worldwide. Of course, this would be pretty much stating the obvious to nearly all readers worldwide except for certain (predominately older) Americans. It seems to me that expanding the scope to include all uses (scientific, technical, and engineering fields included) better serves the point of bothering to mention “common” at all. For nontechnical readers, they can now read the Metre article, and can see that people worldwide (for all purposes) commonly uses a millionth of a meter (micrometer or micrometre or µm or micron) but haven’t well-embraced a million meters (megameter, megametre, Mm). They can see that four of the decimal submultiples of meter are in common use whereas only one of the decimal multiples is. It seems to me that this makes for truly informative and interesting reading for the typical American and international reader visiting this site. And isn't that the purpose of any encyclopedia, including Wikipedia?   Greg L 17:46, 16 September 2006 (UTC)
Google search hit numbers can indicate whether a currently famous person is not notable. A lack of Google hits cannot entail that a 14th-century inventor is not notable, but it would mean that a software developer or movie star is not notable, because their Google hits correspond well with their real-world notability. (Note that the sheer number of hits would not, however, indicate that the person is notable, because half those hits could be someone else (see, e.g., Google: lightyear); of course it is useful to find additional sources.) Google searches can tell you whether a particular word is more common on the Internet, but not whether it is more common in general. Micrometer and nanometer being common in scientific use means that they are over-represented in Google hits. I'm not sure what you mean by the rest of your comment, do you mean that nanometre is actually more common generally than centimetre? Also, while Wikipedia does have the unfortunate systematic bias toward verifiability on the Internet ("If it's not the Internet it doesn't exist"), that doesn't mean this is the goal. This remains a general-purpose encyclopedia and the tendency needs to be corrected, not gleefully advanced in a snide insulting comment. —Centrxtalk • 04:14, 16 September 2006 (UTC)
If I came across as insulting to your character, I appologize. I try to direct my efforts to pointing out the weaknesses or failings in a logical argument (someone's words) rather than to someone's character. It can be difficult when people oppose one's thoughts.   Greg L 17:46, 16 September 2006 (UTC)
The only strange thing really worth noting is that nanometers, and even picometers and some of the others are more common than megameters.
And, that centimeters remain far too common. It's too bad the CGPM didn't have enough sense to consign the rest of the prefixes which are not powers of 1000 to the same fate as "myria-, by not including them in the SI either. Gene Nygaard 05:07, 16 September 2006 (UTC)

[edit] Metre → Meter

en.wikipedia uses American English as it's prefered variant of English as Wikipedia's servers are held in the US. Therefore, shouldn't this article be moved to Meter and have all instances of metre replaced with meter. --lEoN2323 18:30, 10 October 2006 (UTC)

No. Wikipedia does not use American English only. In this article, why should the one country which doesn't use the meter decide the spelling? Jonathunder 19:22, 10 October 2006 (UTC)
"en.wikipedia uses American English as it's prefered variant of English" Where did you ever get that idea? Fan-1967 19:23, 10 October 2006 (UTC)
"In this article, why should the one country which doesn't use the meter decide the spelling?" hahaha nice. drumguy8800 C T 04:18, 30 November 2006 (UTC)
Please see the archived discussion page for previous discussions of this - SimonLyall 10:43, 30 November 2006 (UTC)

[edit] Move

No this isn't another move proposal, but rather, I want to know if anyone else thinks it might be a good idea to note somewhere near the top of the page that moves have been proposed, and why they were defeated. - Рэдхот(tce) 21:12, 5 December 2006 (UTC)

Sounds like a good idea. - SimonLyall 10:27, 8 December 2006 (UTC)
At the top of the talk page, sure, but don't clutter the article with it. —Centrxtalk • 10:07, 9 December 2006 (UTC)