Talk:Natural units/Archive 1

Archive 1

Euclidean natural units

Someone created an article that said:

“ In Euclidean geometry, natural units are derived using the mathematical parameters of an isosceles right triangle and the basic mathematics used to describe the characteristics of waves. The three base units of the natural units are a length, a time unit and a numeric value for the speed of light.

The Euclidean units can be derived by either using the length of a known physical science constant or using a mathematical constant, 2π when used in its angular frequency form. The mathematical process mutually defines all the base units in relationship to each other.

”

Should this content be merged into this page or is it original research? I am not familiar with the subject. I am redirecting "Euclidean natural units" to this page either way. — Reinyday, 16:19, 5 August 2006 (UTC)

• The material entered is original research, thus there should be no google reference to it.

then should it even be WP? r b-j 05:16, 6 August 2006 (UTC)

... It is a set of natural units but the method of derivation is different from any other method of developing a metrology system. Just as Planck units has its "named page", Euclidean Natural Units (ENU) should remain a "named page"...

i haven't heard of it before. where does it come from (besides your own research)? also, what physical constants is normalized or set to a specific number (and if the latter, what are those specific numbers and what is the rationale for using them).

... I am having difficulty with MathML thus have been unable to enter the mathematical process to illustrate how the ENU are derived. ...

we use LaTeX here. check it out.

... Mathematically it is simple, but trying to explain how it works without the equation sets is difficult.

• Once the page has been properly wikified and peer-wikied, it should be identified in the "Natural units" page.

perhaps, but you haven't said a thing about these and they're source. be prepared for an WP:AfD if it looks like original research.

• The essence of the material has been disseminated through a privately published book, a number of forums, and in one on-line publication, but not using the ENU name. One recent attempt to get it published, titled, "Defining The Basic Constants: A Mathematical Method", highlighted its advantages over System International (SI) units, and this apparently stepped on some sacred cow.
• A current rendition of the material, titled, "Euclidean Natural Units", is a five page paper that notes the differences in how ENU and SI base units are defined and the precision of the ENU base units, and it lets the reader decide whether they are or are not significantly better than SI units.
• I actually identified the basis of the mathematical process some five years ago, but I didn't fully understand all of its implications back then. I still suspect there is an elegant mathematical algorithm that will pull it all together, ala Euler. Currere 04:31, 6 August 2006 (UTC)

what are the physical constants that are normalized with this ENU system? can that be clearly and quickly stated here? r b-j 05:16, 6 August 2006 (UTC)

• • Yes, but I was not aware that original material could not be presented on WIKI.

no original research on this particular wiki.

... The units normalized by the ENU system are the time unit (its duration), the length unit (it is actually a real physical science constant), and the speed of light which uses the two aforementioned values for its units of measure, and it can be calculated to near unlimited precision (try multiplying 2Pi by the square root of 2). However, I am not the originator of the concept, I identified it from the following dimension set: 47.71345cm at an angle of 26.25400 degrees. You can recreate the basic algorithm using those dimensions. The precision is limited because the dimension is expressed in SI units. The base algorithm is when the angle is 45 degrees. Whenever I told people where I found the dimension set they refused to believe it, so I quit trying years ago. Currere 17:46, 6 August 2006 (UTC)

i'm skeptical. you need to say (other than the speed of light ) specifically what gets set to what in these units (and if it is 1 or 4π or similar, a rationale why). and you need to cite where this comes from to avoid transgressing WP:NOR. r b-j 02:26, 7 August 2006 (UTC)

• The basic form is that depicted in special right triangles, and the equation form c=a(csc(α)), which is the trigonometric expression for the Pythagorean solution. When a wavelength and a frequency angular frequency are substititued for the vertical leg of the triangle, the result given for each of the substitutions is another wavelength and another frequency, each expressed as the value of the hypotenuse.

this is crap.

When these two values are multiplied together they give a value for the speed of light, see wavelength or frequency. It gives a pure mathematical derivation for the speed of light, but the numeric value is not in SI units (the second and the meter).

pure bullshit.

To be valid at 45 degrees, the duration of the time unit has to equal one, but that duration is not that of the second. The current SI definition for the speed of light is just that, a definition, which provides a reference numeric value for everyone to use. The Euclidean definition provides a numeric value with near unlimited precision. The dimension set that was identified in an old document was 47.713 cm at 26.25400 degrees (there was a scaling factor). The old document did not express this in centimeters, but I use centimeters so others will not have to convert the value. Once I recognized that the dimension represented a wavelength, it was then finding the mathematical form that represented the general case. I was astounded by how much technical and mathematical information was expressed by that simple dimension. I was also astounded that somebody over a century ago knew how to express that technical information in that form, let alone knowing the 21 cm wavelength. The author that recorded the information did not have a clue as to what it meant. The only thing original in "Euclidean Natural Units" is substituting wavelengths and frequencies as values in a right triangle. Wavelengths, frequencies and triangles are already defined, it was just a matter of implementing these relationships in a mathematical form. There is no process to describe this form of substition, and it seemed logical to assign the name that fits the geometric form.

because it's original research. it might also be crap. WP does have standards, even though it is still heavily criticized for being unreliable.

In practice, the only thing original is substituting wavelengths and frequencies for the elements of a right triangle. Currere 15:39, 7 August 2006 (UTC)

i asked 3 times, other than an allusion to the speed of light, you mentioned nothing about what physical constants get normalized or set to a known quantity with these so-called "natural units". i don't think that you understand the topic matter and are unable to make a real contribution because you just show no evidence that you understand what this is. r b-j 17:51, 7 August 2006 (UTC)

I stated that the three physical constants are "length", "time" and the "speed of light". Have you analyzed the mathematics and the meaning of the values that are described by the dimension set of 47.713 cm at 26.25400 degrees? Currere 21:33, 7 August 2006 (UTC)

you have succeeded in demonstrating that you really don't know what you're talking about nor what the functional basis of what natural physical units are. c is a physical constant. "length" and "time" are not. they are dimension of physical quantity of which some natural units can be defined. to define a natural unit of length, mass, and time, you need to constrain 3 universal physical constants to be some given natural values (usually 1) in terms of the natural units you are creating. that is 3 equations (for the 3 constrained physical constants) and 3 unknowns, the unit length, unit mass, and unit time. you have 1 (that is c). you need 2 more. r b-j 01:23, 8 August 2006 (UTC)

Conversions

I would like to see another column in each table, with approximate conversions to the metric system. I see a few of the conversions in the main articles (e.g., Planck units). What say you? --DevastatorIIC 20:38, 26 August 2006 (UTC)

i think it's a good idea. go fer it. it was something i thought should be done but am too lazy to crank it out. if you have a good math program (like MATLAB or Octave, the latter is free) where you can put numerical values to symbols and then crank out the expression and value, that would be safe. or do it with a calculator. whatever works. BTW, i think eventually Natural units should become the "main article" and Planck units can be sucking on the teat of Natural units. but i am not invested in it. i know that once some real physicists notice the page, this article will grow and refine. r b-j 01:18, 27 August 2006 (UTC)

BTW, use the "m" or minor edit flag only for fixing a spelling mistake or similarly something merely cosmetic. that way, you're telling other editors not to bother to check over your edit (even though some will anyway). adding a new idea to a talk page is, IMO, not really minor. you want people to look it over. r b-j 01:22, 27 August 2006 (UTC)

I've been adding in the SI conversions periodically. I just got around to doing it for the Stoney Units table. I'll get to the others eventually if no one beats me to it.--Tibbets74 18:55, 12 November 2008 (UTC)

DevastatorIIC

In humble obedience to your request, I have faithfully calculated EXACT conversions between the natural units featured in this article, and the metric system using the “Conventional” values of the von Klitzing and Josephson constants. I hope these are suitable for your needs and viewing enjoyment. —Preceding unsigned comment added by Unitfreak (talk • contribs) 06:16, 23 April 2008 (UTC)

See the section below entitled “The SI section is not about SI units”. —Preceding unsigned comment added by Unitfreak (talk • contribs) 06:18, 23 April 2008 (UTC)

Greater emphasis on problem-dependent choices?

Somehow, the emphasis of the present article on listing "common" choices of natural units, with particular names for each choice, seems wrong.

I do theoretical physics myself, and I virtually never see someone say "let's use Schrödinger units" etcetera. Rather, the choice is almost always driven in a problem-dependent fashion: "in this problem, it is convenient to such-and-such quantities to 1." (For example, in classical electromagnetism, it is common to start with SI-like Maxwell's equations and then set $\epsilon _{0}=\mu _{0}=1$, so that there are neither constants nor 4π factors flying around.)

—Steven G. Johnson 15:30, 9 August 2007 (UTC)

The conventional electrical units section is not about SI units.

My intention in writing this section was not to discuss the SI system. My intention was to discuss a trend in the SI community towards using natural definitions for SI units. Keep in mind that the “conventional” values for the von Klitzing and Josephson constants are technically not part of the SI. The NIST website currently maintains both “SI” and “conventional” values for these constants:

SI – Josephson constant – http://physics.nist.gov/cgi-bin/cuu/Value?kjos

SI – von Klitzing constant – http://physics.nist.gov/cgi-bin/cuu/Value?rk

Conventional – Josephson constant – http://physics.nist.gov/cgi-bin/cuu/Value?kj90

Conventional – von Klitzing constant – http://physics.nist.gov/cgi-bin/cuu/Value?rk90

So if the conventional values are not part of the SI then what are they? My point is that the conventional values represent a “quasi-natural” system of units - units that can be directly calculated from other natural unit systems.

I do understand your concern. Perhaps this material would be better suited in a different article. But I can’t think of a topic that is more directly related to this discussion than the one I have chosen. Does anyone have any suggestions? —Preceding unsigned comment added by Unitfreak (talk • contribs) 05:37, 23 April 2008 (UTC)

---

When I first read this section, I got the imression that the Josephson constant and the von Klitzing constant did have exact values. In other words, this section can be misunderstood.

NB.

---

—Preceding unsigned comment added by 84.55.114.217 (talk) 12:47, 21 June 2008 (UTC)

I was thinking of exactly that when clicking the "discussion" tab. The values cited for Josephson's and von Klitzing constants are "conventional" values (whatever that means), much like 4 kcal/g is the conventional food energy value of proteins. They did not redefine the ohm or the volt by declaring that values to be exact. In fact, the "conventional" value of the von Klitzing constant is more than thirty standard deviations less than the 2006 CODATA (measured) value. And they couldn't possibly fix the von Klitzing constant, because it equals μ₀c/2α, where the magnetic constant μ₀ and the speed of light c are already fixed to 4π ×10⁻⁷ H/m and 299,792,458 m/s respectively by the definitions of ampere and metre, and the fine-structure constant α is a dimensionless number, indipendent of any system of units. So, I'm removing that section from the article. -- Army1987 (t — c) 22:51, 5 December 2008 (UTC)

You should have read the Wikipedia article on conventional electrical units. And you should spend some time reading the literature in this field before jumping to conclusions. Your post is just flat wrong.

“the magnetic constant μ₀ and the speed of light c are already fixed” --Wrong-- these values are fixed for SI units, not for conventional electrical units. — Preceding unsigned comment added by 199.46.245.231 (talk) 20:30, 5 December 2009 (UTC)

It appears that the magnetic constant is squishily defined in conventional electrical units, but not the speed of light, no? I think, even in these conventional electrical units that c is still fixed 299792458 m/s. We need to be careful about what the 18^th CGPM conference said in 1990. They did not redefine the ampere (and hence the definition of the unit charge). Those ohms and volts used when they express "fixing the conventional Josephson constant at exactly 483,597.9 ×10⁹ Hz/"V", and the conventional von Klitzing constant at exactly 25 812.807 "Ω"" cannot possibly be the same ohms and volts of the SI definition (they are defined completely differently and happen to have magnitude of about the same as SI). In that manner, I completely understand what Army1987 is unhappy about. 96.252.13.17 (talk) 00:41, 6 December 2009 (UTC)

Conventional electrical units are a fine set of units, but what are they doing here? This is the article on natural units. Conventional electrical units are not "natural units", they're just "units". This article doesn't cover SI units, it doesn't cover Gaussian units, it shouldn't cover conventional electrical units either. It's great content, though, and should certainly be in the conventional electrical units article. --Steve (talk) 07:42, 6 December 2009 (UTC)

I think you're right, Steve. At first I thought that they were the same as Electronic units except for the scaling factors used (which are arbitrary constants, but they're constant). But that thought was wrong. These Conventional electrical units continue to define the second the same way that SI does, and unless someone comes up with a nice closed form equations that expresses the period of ₁₃₃Cs radiation (in terms of fundamental constants and masses of particles), there is no way to relate these to any set of natural units. In addition, no one else sets permittivity to anything other than ε₀=(4π)^-1. 96.252.13.17 (talk) 22:05, 7 December 2009 (UTC)

Actually, on second examination, a scaled version of conventional electrical units could be compared to the other natural units. It would be described as

$c=e=\hbar =1\$

with consequence:

$\epsilon _{0}={\frac {1}{4\pi \alpha }}\$

The difference between this and conventional electrical units is only one of scaling by well defined (but arbitrary) constants. So, with conventional electrical units, any observed variation over space or time in the value of α is attributed to variation in the vacuum permittivity. Certainly, one important property of natural units are that some fundamental constants get set to unity, but that's not such a big deal. The more important property of a choice of natural units is the choice of which fundamental constants are fixed and which are subject to measure. And since we only truly measure dimensionless values (like α), then the choice of natural units is one of which fundamental constant you want to blame a variation of α (or something else) on. 96.252.13.17 (talk) 22:37, 7 December 2009 (UTC)

I moved and incorporated the section into conventional electrical units. I think you're trying to make the point that a unit system can be ultimately based directly on physical constants, without setting those constants to 1. This is true, and I tried to describe that fact in the article. SI units themselves will probably be based on only physical constants in 20 years, but not yet. Conventional electrical units already are. Either way, that doesn't mean we should use the term "natural units" to describe them. (No one else does.) I just called it "prototype-less unit systems". Please check my edits to both articles that I didn't get anything wrong or leave anything out, I don't want to lose your good research and good writing! :-) --Steve (talk) 15:26, 26 December 2009 (UTC)

N-body units

If natural units are defined so as to normalise universal physical constants whilst N-body units are defined so as to normalise a given system's total mass and virial radius, then N-body units are not natural units and deserve their own article. JIMp _talk•cont 08:10, 18 December 2009 (UTC)

Sure, why not? It'd be a short article. 96.252.13.17 (talk) 17:09, 19 December 2009 (UTC)

Wouldn't be the shortest ... JIMp _talk•cont 09:09, 20 December 2009 (UTC) ... done. N-body units JIMp _talk•cont 09:27, 20 December 2009 (UTC)

Restoring second column for dimension and row for Coulomb constant

I have restored the additional column for dimension of various constants, as the fraction format is much easier for most readers to interpret than the use of negative exponents. I think this helps to make the article understandable to lay folk. I resisted replacing the existing column, as some may prefer the negative exponent format for reasons that are beyond me. Bcharles (talk) 07:28, 17 February 2010 (UTC)

I restored the row for coulomb constant in the summary table. I think that it is significant that most systems here set it equal to 1 and a couple set it equal to alpha. I also restored the previous adjustments to the row labels. Bcharles (talk) 07:28, 17 February 2010 (UTC)

I know you like to be WP:BOLD, but you have to first understand what helps.

First, your fourth column does not have a consistent typeface to it. Compare the rows for Electron charge, Electron mass, and Proton mass to the other rows. They look like crap. Your other rows requires using the LaTeX math format which looks different and which means we cannot hot link the first occurrence of "L" with length, the first occurrence of "T" with time, etc.

Second, if a layman cannot understand that L T^-1 is the same as L/T, they are too lay to be able to deal with any of the concepts in this article. We want the format and appearance of the article to be consistent with the other related articles like Planck units and such.

k_e and ε₀ are two ways to refer to the same physical quantity (that some unit systems assume is constant). Unlike the characteristic impedance of free space or Josephson constant or von Klitzing constant which are combinations of two or more of the candidate constants, k_e and ε₀ are the same thing, not two different things. ε₀ is overwelmingly used in the lit and modern textbooks (because of its appearance in Maxwell's equations and from the concept of flux and flux density) and is unambiguous. k_e or k_C or just k are all used, even just here in Wikipedia. There is no consistency in symbol use.

I am selectively reverting this again. Bcharles, be WP:BOLD, but if your idea doesn't fly, please get WP:CONSENSUS on changes you make before reverting the reverts. Otherwise bad things happen and the project quality suffers. 64.223.105.222 (talk) 17:12, 17 February 2010 (UTC)

error?

The value here given for the planck length is 1.61609735, yet is elsewhere 1.616252. Which is correct? —Preceding unsigned comment added by 68.13.169.244 (talk) 00:26, 14 March 2010 (UTC)

According to the NIST, the correct value is 1.616252×10^-35 m. The 1.61609735 value was added in May of 2007. That was likely taken from a reliable source at the time. Since the length depends on the values of other constants, and we are constantly refining our accuracy of measurements, the official value has probably since been refined to the value listed at the NIST site. I'll go ahead and change the article. Thank you for pointing this out. 152.16.16.75 (talk) 00:52, 14 March 2010 (UTC)

The other possibility is that someone started with rounded values of the other constants and put in too many significant figures...I've seen that happen in lots of articles. Regardless, thanks for correcting. --Steve (talk) 02:16, 14 March 2010 (UTC)

I'll bet you're right. That must be it. After reading your comment I checked and found that the entries for Planck Time and Planck Temperature were also subtly off from the NIST figures. I've now corrected those values, also. 152.16.59.102 (talk) 09:02, 14 March 2010 (UTC)

Information in this page is contradicted on another page

The values and equations listed for the Stoney units under "Stoney Units" is different from the values and equations for Stoney units listed on the separate page "Stoney scale units". Specifically, the values and equations for the Stoney unit of mass, length, and time, are all different from their definitions on the page "Stoney scale units" under "Primary Stoney units" and "Secondary Stoney scale units". I can't correct it because I do not know what the correct definitions are. —Preceding unsigned comment added by 99.61.83.5 (talk) 18:38, 20 June 2010 (UTC)

I believe that the other article is a pet article or a bit of OR from a particular anonymous IP. By use of non-standard symbols and some obfuscation of simple concepts, it can be initially difficult to figure out what, exactly, that article is saying. I can say for sure that Stoney units presented in this article is what is commonly meant and is, simply, what Stoney proposed in the 19^th century (just before Planck). Rather than normalize c, G, and ħ, Stoney units normalize c, G, and e. It need not be more complicated than that. I find it also unfortunate that this article references Stoney scale units when that other article is not consistent in content or style with the other natural units, such as Planck units or Atomic units. 70.109.186.21 (talk) 04:28, 21 June 2010 (UTC)

Should the "Other non-prototype unit systems" section continue to exist in this article?

I am not sure when it was added, nor if this section should continue to exist. Certainly a practical unit system totally devoid of prototypes differs from some natural unit system only by fixed numerical constants (e.g. the second would be a fixed constant multiple of, say, t_e, etc). I don't know if that is the point of the article or not. If it is, there is no reason for both Planck units and Heaviside-Lorentz natural units to be in the article since (at least if G is fixed), they differ only by fixed scaling constants. If it's not the point of the article, I don't know if this section should be in there.

To User:Sbyrnes321: You're completely correct that "prototypes can change" (which is why we don't like them so much), but the remaining point is; change against what? By definition, the kilogram prototype kilogram does not change (which is why it's a horizontal line in File:Prototype_mass_drifts.jpg, because whatever it is, it is the kilogram. Of course, just defining it that way does not, in itself, determine reality. It could be, measured against some natural unit of mass, that the IPK has changed. Since it is not a dimensionless physical quantity, the only way we can understand if it has changed is by comparison to a like-dimensioned standard. 64.222.86.211 (talk) 18:02, 26 July 2010 (UTC)

See the conversation #The conventional electrical units section is not about SI units. above. Someone had a "conventional electrical units" section in this article on the belief that conventional electrical units were a type of "Natural units" because they were based solely on physical constants which are defined to be certain exact integers. I said that there's a difference between "Natural units" and units without prototypes, and threw out the conventional electrical units section and replaced it with the section to clarify that natural units and prototype-less units don't mean the same thing. Whether it should be in the article or not depends on whether that's a reasonable and common mistake/misunderstanding (so the article should clarify) or a weird and idiosyncratic mistake/misunderstanding (so the article should not discuss it). What's your opinion? That's the issue of whether the section should exist. There's a different issue, which is is the section successful in clarifying this... :-)

"Prototypes can change" means change in the physical world, the normal sense that people mean when they say "something changes". Like, go from more platinum atoms to fewer platinum atoms. If the bar goes from more platinum atoms to fewer platinum atoms, its mass decreases. Sure, its mass measured in kilograms stays at 1, but really, its mass decreases. :-) [For example, the conservation of energy law doesn't work if there is no unique way to compare the mass of something today with the mass of something tomorrow.] --Steve (talk) 19:35, 26 July 2010 (UTC)

Well, we think the IPK has decreased in mass, but only because many more of the copies have "increased", relative to the IPK, than the number of copies that have decreased in mass, relative to the IPK. But there is no reason (other than maybe their numbers, but reality doesn't really take a vote) to say that the copies are so much better than the original and that they are the cylinders that have remained more constant. And the whole point of this Natural unit (and Planck unit) concepts, as well as the physical constants vs. fundamental physical constants, is that you can't meaningfully say that some dimensionful physical quantity has changed unless you say relative to what. That's why I think it's best to leave that qualification in the text, if the section is kept. 64.222.86.211 (talk) 19:57, 26 July 2010 (UTC)

Please, let's not lose our heads and confuse measurements with reality! Here's a question: Is the mass of the IPK larger than last year, or smaller than last year, or the same as last year? This is a question that has a right and wrong answer. For example, if it lost 15 iridium atoms and gained 10 oxygen atoms, then its mass is smaller. Mass can't just change spontaneously, it would violate conservation of energy. I hope we can agree on this simple principle of physics.

[Again, if you believe in conservation of energy, then you know how to "meaningfully say that some dimensionful physical quantity has changed". Energy is dimensionful, and the statement of conservation of energy is a statement that energy has not changed between 2010 and 2009.]

You raise a different question, which is whether we can figure out the answer to the above question using modern experimental techniques (including making copies). This is a very different issue.

I submit that the first problem (the mass of IPK is different than last year) is the more basic and important problem than the second problem (we're not sure exactly how much the mass of IPK has changed from last year). The first problem means that the kilogram is not really a well-defined unit of mass: The mass of an electron in kilograms in 2010 is different than the mass of an electron in kilograms in 2009, even though the mass of an electron is the same in 2010 as 2009. If not for the first problem, there would be no second problem.

I suggest: "because the prototype may change over time (for example, it could gain or lose atoms)". I think a typical reader will read that and get the picture. :-)

Anyway, I'm still not sure whether the section should exist or not. Maybe it could be moved to the top and broadened to "Differences between natural units and other unit systems"? The differences would be (1) No prototypes. (2) No arbitrary random numerical factors in the definitions (like the SI meter is the distance light travels in 1/299792458 seconds). (3) Some reasonable closeness between the quantities defined and the fundamental laws of physics...for example the SI kelvin scale is defined by the triple-point of water, which is a "natural" system but a very complicated microscopic phenomenon, much more complicated than a hydrogen atom (for atomic units) or no system at all, just pure parameters from the laws of physics (for Planck units). I dunno, some approach like that? I'm just thinking offhand. :-) --Steve (talk) 04:34, 27 July 2010 (UTC)

Well, I'm easy. I can go either way or any which way. When you count atoms in the IPK, you have an absolute notion of whether it's gaining or losing mass. I guess this is how prototypes are different from other physical quantities. I really disagree with variable speed of light advocates, because they often don't say with what speed standard that c is varying against. Do what you want to the article, Steve. As an IP (whose IP gets changed regularly by the ISP), I don't have much authority here. 64.222.86.211 (talk) 16:15, 27 July 2010 (UTC)

Haha, you have as much authority as you want! Anyway, I'll keep thinking about it. It's certainly not quite right as it is somehow, and you're welcome to keep editing too, you did a good job so far. :-)

Saying that the speed of something changes is not usually problematic, it's definition of "acceleration". But saying that the speed of light changes is problematic, because the speed of light is a parameter in the fundamental laws of physics, so it can only change if the laws of physics are changing at the same time. I agree with I think most physicists that it's meaningless to say that a dimensionful parameter in the fundamental laws of physics is different between today and tomorrow. And in particular, I agree that "variable speed of light" is a bad and confusing way to think about things.

This is a different issue. The mass of the IPK is not a parameter in the fundamental laws of physics, so it's not problematic to talk about whether it's changing or not. :-) --Steve (talk) 20:24, 27 July 2010 (UTC)

Delete Schrodinger units?

Any objections to my deleting Schrodinger units? It seems they were invented in this 1994 paper [1]. M. Duff made up the unit system just to make a certain pedagogical point:

"To complete the trio we need units that take e and hbar into account but are independent of c. It seems appropriate, therefore, to call these Schrodinger length, mass, time and charge...".

There's no evidence that anyone ever has or ever will use the units except for this specific context. So, it's not notable, it should be deleted. OK? --Steve (talk) 07:33, 31 July 2010 (UTC)

I also propose deleting "Electronic system of units" section for the same reason.

Atomic units and geometrized units are clearly important and should stay in the article. Stoney units are OK, they're occasionally mentioned, especially for their historical interest. I'm not sure about the QCD units. The section cites a Frank Wilczek article that makes it sound very common. But I'm not sure it is. So far I can't find anyone but Frank Wilczek who uses or discusses these units. --Steve (talk) 08:03, 31 July 2010 (UTC)

I don't have a problem other than the fact that the eV is not a natural unit of energy because the volt is not. I think, for comparison, that the tables for all systems should portray the units in terms of the physical quantities of nature that they are based on. Really Heaviside-Lorentz just normalize ε₀ = μ₀ = Z₀ = c = 1 and say nothing of ℏ or e. If the commonly used units for Heaviside-Lorentz "natural units" simply add ℏ to the list of parameters to normalize, then it is still not fully defined. If they define the unit mass to be (1 eV)/c², then they are not (fully) a system of natural units. They don't have to define it to fix G or m_e, but it has to be some parameter of nature for it to qualify. I think we should treat these "natural units" in the same way as geometrized units and not give them a table at all (because it's not all defined). 70.109.182.155 (talk) 21:01, 31 July 2010 (UTC)

Yes, eV is not based on simple physical constants, and I did mention that fact. However, if there's something which tens of thousands of physicists unanimously call "natural units", then it's natural units, and it needs to be described in this article, whether or not you think it should qualify as natural units. It's not up to us to judge or decide the meaning of a technical physics term, we need to use the term as it is conventionally used by physicists, and define the term as it is conventionally defined by physicists. This is an encyclopedia, not an opportunity to re-invent terminology and re-define words to be more rational. :-P

The standard definition of Heaviside-Lorentz units doesn't even define c=1. It's just a different set of electromagnetism units and electromagnetism equations from SI, which can crudely and not-quite-correctly be summarized as ε₀ = μ₀ = 1. It's like Gaussian units. It's originally (and still usually) used as part of cgs (cm, gram, second). It's not a system of natural units. But it's often combined with the particle-physics natural units, ℏ=c=1, and people sometimes call the combined system "Heaviside-Lorentz natural units" or something like that. Of course you're right, this is still one unit short of a full unit system. The almost-unanimous choice for the final unit is eV, so I think it makes sense in this article to use eV as the only example, if not quite the definition.

Certainly the particle-physics "natural units" could be removed from that big table if you think it doesn't belong. The mini-table I think is useful but needs a somewhat different formatting than the other ones, because it is a bit different...I'll change it. :-) --Steve (talk) 21:45, 31 July 2010 (UTC)

I deleted Schrodinger and Electronic units as discussed above. :-) --Steve (talk) 22:49, 26 October 2010 (UTC)

Deleted section based on error in BIPM website

There was a section based on this webpage: [2]

I deleted it. BIPM says they're describing "the natural unit (n.u.) system used in high energy or particle physics", and that this system sets the electron mass to 1. But they're wrong. No one in high energy and particle physics sets the electron mass to 1. I guess the section was written by someone who doesn't do particle physics, and they made a mistake.

I replaced the section with one that describes the standard and common "natural units", used in particle physics today. (The unit of mass/energy/length/etc. is almost always eV.) I put in lots of citations to this common definition. If you want more evidence, you can find it in literally every quantum field theory or relativistic QM textbook. --Steve (talk) 08:17, 31 July 2010 (UTC)

What is meant by the term "base units"?

Hi Kehrli, I don't want to get into a content dispute with you or anyone else. I can read here that you have a history of changing content in such a way that you sincerely believe is more correct, but is sometimes disputed (and reverted) by others.

My understanding of the meaning and usage of the term "base units" is that these are the units defined first (chronologically or pedagogically) and get established first and then the derived units come later. I also can understand that different systems of units can have different sets of base units. And there is no real consistency. For example, in SI, the unit speed is not a identified as a base unit even though, essentially SI defines the unit speed first (as c/299792458) and then the unit length is defined from that and the definition of unit time. But SI identifies the unit length to be a base unit, not the unit speed. But on the other hand, SI defines the unit current to be "base" and from that (and the definition of unit time) the unit charge is derived. But most of us are convinced that electric charge is the more fundamental physical quantity and that electric current follows conceptually as charge per unit time.

And the (again) the problem is for different systems natural units, that different quantities (universal and non-dimensionless physical constants) are chosen to define each system, yet, for comparison, the same "base units" are defined in each system so that they can be directly compared.

Now, I am not sure what should be done with the semantics here, but I think we better stick with the convention of base units vs. derived units. Although I understand precisely what you are trying to say. So I plan to change (not just revert) some of what you wrote in Natural units. But I hope to illustrate the point you made. Stay tuned. 71.169.191.235 (talk) 17:53, 17 October 2010 (UTC)

I moved your comment here since it addresses the content of this entry. Kehrli (talk) 07:13, 18 October 2010 (UTC)

Now, reading your comment, I agree with almost everything you say except your sentence: " [...] yet, for comparison, the same "base units" are defined in each system [...]" This seems not to be true and I don't even understand what you try to say. In the system of Stoney units, the elementary charge e is a base unit. In the system of Plank units, e is not a base unit. Instead the Plank charge is a derived unit whose derived value you find in the article. So how can you claim "... the same base units are defined ..."? It is the very essence of different systems of natural units that they have slightly different sets of base units. I assume you are mixing up the term "base unit" with something else. Kehrli (talk) 07:31, 18 October 2010 (UTC)

Next issue: "A purely natural system of units is defined in such a way that some set of selected universal physical constants are normalized to unity; that is, their numerical values in terms of these units become exactly 1." I have two issues with this sentence:

• I would argue that a constant would have to be dimensionless in order to be "normalized to unity". For example: 1 m is not unity (1 m ≠ 1). On the other hand dimensionless constants cannot be normalized to unity, exactly because they are dimensionless. Hence I find your wording too complicated and too misleading for an encyclopedia.
• This is a really complicated and confusing way to say that "universal physical constants are used as base units". The fact that "... their numerical values in terms of these units become exactly 1." becomes then very trivial and should not even be mentioned in the first paragraph.

If you agree I will reword this sentence. Kehrli (talk) 11:52, 18 October 2010 (UTC)

User: Just granpa, will you stop being tendentious and silly?

The purpose of the table in section Candidate physical constants used in natural unit systems is to identify the universal physical constants that one may desire to normalize (in terms of the units of the system of units they are defining). No one is saying "Let's define the meter as our unit length so that the length of a meter is 1." Likewise, no one is saying, "Let's define the system of units we call "Planck units" so that we can normalize the Planck length (whatever that is)." It is non-sensical and meaningless.

Will you please stop being a crackpot and contaminating the article with your misunderstanding? It's bad enough that you crap up the talk page of other articles, but please leave the Main namespace alone, unless you are actually improving the article. The formatting you did was nice, but you are transmitting your confusion to other people who come to this article to actually learn something. Please stop. 71.169.180.100 (talk) 19:16, 22 November 2010 (UTC)

The meter is an arbitrary unit of distance. The planck length isnt arbitrary and it is normalized in Planck units. It therefore clearly belongs in the table. You have offered no convincing reason why it shouldnt be included in the table. All you have done is make insulting remarks. See Wikipedia:No_personal_attacks Just granpa (talk) 07:41, 23 November 2010 (UTC)

The point is the meter is defined non-circularly. It was originally defined so that 10 million of them was 1/4 of the great circle from the North Pole to the equator through Paris. Here, the Planck length is not defined in such a way that the Planck length equals 1; that is a circular definition and it is meaningless.

Why should the Planck length be defined to be $l_{\text{P}}={\sqrt {\frac {\hbar G}{c^{3}}}}$ ? The answer is not so that we can set ${\sqrt {\frac {\hbar G}{c^{3}}}}=1$, that would be circular. The answer is so that c=1, ħ=1, and G=1. Those latter three dimensional quantities belong in the table and l_P does not.

Call it an ad hominem if you want, but the shoe fits. You are consistently trying to degrade the article because you do not understand what it is you are editing. Just because you don't understand (despite all efforts to transmit such understanding to you) does not mean that your misunderstanding should be propagated to readers who come here to learn something. 71.169.180.100 (talk) 21:08, 23 November 2010 (UTC)

So why not also include the Planck mass and Planck charge and Planck temperature in that table? Why not include the Stoney units in that table, too? With your reasoning, are they also not candidates for normalization? 71.169.180.100 (talk) 21:10, 23 November 2010 (UTC)

Unit of information or entropy

Should this article mention Nat (information)? That article claims the nat is the natural unit of information. --Bequw (talk) 17:17, 11 January 2011 (UTC)

The article already says kB=1, which amounts to the same thing. I think "natural unit" is being used in the colloquial sense, not the specific sense of this article. I don't think it needs to be discussed. --Steve (talk) 18:39, 11 January 2011 (UTC)

Small point

In the section ""Natural units" (particle physics)" there are two different shaped epsilons. The one under "Rationalized" is a different shape to the others in the article.

Too scared to change it! —Preceding unsigned comment added by Blitzer99 (talk • contribs) 05:33, 19 May 2011 (UTC)

Summary table

I think it is a good idea to add a column with "SI units equivalence".

Normalizing magnetic and electric constants in a Planck/Lorentz-Heaviside system

Looking at Planck units Lorentz–Heaviside units, it looks as if we should be able to come up with a system where (excuse the poor formatting)

c = G = h-bar = ε₀ = μ₀ = k_B = Z₀ = 1

The units for length, time, and mass would stay the same as in Planck units, while the unit of charge (and associated electrical units -- resistance, capacitance, etc) would change to the Heaviside units, which appears to simplify things a bit. Or am I missing something? — Preceding unsigned comment added by 68.186.116.6 (talk) 14:55, 5 October 2011 (UTC)

They talk about this as "different normalizations" in the Planck units article. Also, there used to be an older version of this that had such units except it was 4πG = 1 which is similar to ε₀ = 1. 71.161.199.133 (talk) 03:26, 8 October 2011 (UTC)

Archive 1