Talk:Physical constant/Archive 1

Stupid question
It is impossible to access the link to "Planck's constant" & "Dirac's constant"

unclear superscripts on planks units
the 1/2 (square root) on plank mass, length, time are unclear

singular vs plural on the table
Usually article titles are singular, but since this page is a list, I moved it to the plural. (It was already listed in the plural in the list of physics topics, and the plural page redirected to the singular). Michael Hardy 16:10, 5 Jan 2004 (UTC)

The list is getting rather long. Would it benefit from being sorted alphabetically or does it work better sorted by category? --Xwu 19:58, 9 Mar 2004 (UTC)


 * Lets not have categories inside a table. Sort alphabetically.Jay 04:30, 10 Mar 2004 (UTC)
 * Personaly, i prefer it catogarised, at least it helps in finding out what a constant is used for, oh, and the fact that lists are one of my pet hates ;-) tooto 13:54, 2 Oct 2004 (UTC)

What is reference
What does the 4th column "Ref." in the table mean ? Jay 04:30, 10 Mar 2004 (UTC)

Please, I meet Jay in the 4th column question. gl:user:Agremon

It refers to the references section: a is for the first reference (and they could be more later.

But they all come from the same reference, which is the BEST one. I propose dropping the Reference column, because in all cases the column is constant. 64.165.202.231 04:20, 31 Jan 2005 (UTC) This will also make the formating better.


 * Amen. Gene Nygaard 05:19, 31 Jan 2005 (UTC)


 * The reference column is, as it stands, entirely useless, so i'm going to remove it. When it serves a purpose (and the article explains that purpose) then it can be reinserted Fresheneesz 01:34, 3 December 2005 (UTC)

Edit by Azhyd
Ok since I received a question about the detail of my edit:

I agree that I should have splitted the updates... I'll know better next time. Here are my changes beside layout and grouping changes: Azhyd 22:29, Jul 10, 2004 (UTC)
 * add Plank temperature
 * add conductance quantum and resistance quantun
 * add Josephson constant and magnetic flux quantum
 * add von Klitzing constant
 * add equation for Bohr radius
 * add equation for electron g factor and use new value
 * rename magnetic moment of protons in H20 and use new value
 * rename proton resonance frequency per field in H20 and use new value
 * add equation for Rydberg constant
 * add equation for Boltzmann constant and Faraday constant
 * add equation for first radiation constant and second radiation constant
 * add equation for Stefan-Boltzmann constant


 * Hi Azhyd, thanks for the information. What are the new names of magnetic moment of protons in H20 and proton resonance frequency per field in H20 ? Also, what is the source of the new values for those two and electron g factor ? Thanks for your help. Wile E. Heresiarch 01:43, 11 Jul 2004 (UTC)


 * All my values and constants come from the NIST site. The new names are respectively "proton magnetic moment to Bohr magneton ratio" (which I later removed since I think all those ratio would be clutter) and "proton gyromagnetic constant" divided by 2pi. Azhyd 04:49, Jul 11, 2004 (UTC)


 * Great. Thanks for the info, and thanks for all your work on the article. Regards, Wile E. Heresiarch 16:22, 11 Jul 2004 (UTC)

Comparing to CODATA values
Hello. I was comparing the table in the article to the 2002 CODATA values at NIST. I can't identify a couple of the table items. (1) IS "magnetic moment of protons in H20" in the article the same thing as "shielded proton magn. moment to Bohr magneton ratio" in the NIST CODATA list? (2) Is "proton resonance frequency per field in H20" the same thing as "shielded proton gyromagn. ratio over 2 pi" in the NIST CODATA list? Thanks for any light you can shed on this. Happy editing, Wile E. Heresiarch 03:12, 10 May 2004 (UTC)

The value for Planck's constant h doesn't fit with the CODATA value. I'm quite sure it's wrong so I changed it to the CODATA value (which is then in accordance with h bar). Best Regards, P. —Preceding unsigned comment added by 88.217.30.23 (talk) 10:42, 1 September 2008 (UTC)

Table format
Can someone who knows about this stuff make the tables work better? With the math in column 2, my browser makes that far too wide, and the stuff in column 3 is a jumbled mess, split numbers and split units of measure, etc. Gene Nygaard 22:22, 1 Jan 2005 (UTC)


 * how does it work now? I wiki-ized all the tables. Maybe it works better..? Fresheneesz 22:40, 3 December 2005 (UTC)

Scientific American Article
The article here [http://www.sciam.com/article.cfm?chanID=sa006&articleID=0005BFE6-2965-128A-A96583414B7F0000&pageNumber=1&catID=2 Inconstant Constants in the June 2005 Scientific American has interesting information about the changing of physical constants.

Constants that really aren't
Avogadro's number and acceleration due to gravity on earth aren't physical constants, are they? Avogadro's number is a conversion factor between atomic mass units and grams, and acceleration due to gravity on earth is only constant on earth.


 * I agree, the accelleration due to gravity is only an approximate constant, and avogrado's number is based purely on the definition of a kilogram and is slightly arbitrary anyway. They probably should still be included, but perhaps in a different section? Fresheneesz 01:34, 3 December 2005 (UTC)


 * Also, how can a *constant* require specific conditions?? Look at "Loschmidt constant", "molar volume of an ideal gas", and "Sackur-Tetrode constant". It seems to me they're not constants if they change depending on certain conditions... Fresheneesz 22:42, 3 December 2005 (UTC)


 * All these questions can be answered by considering the history of chemistry and physics. For instance, the atomic hypothesis (in its present form -- Democritus just had an idea, and no way to test it) is not as old as the metric system. When chemists first started talking about Avogadro's number, they were trying to estimate how many atoms of hydrogen are in one gram of hydrogen. In that sense Avogadro's number is just as "constant" as the speed of light -- it's a dimensionless number relating two "different" units of measurement that are fundamentally the same, from the point of view of physics and chemistry. (In other words, a "meter" and a "second" are essentially the same thing, in the Minkowski metric.)


 * The main reason for defining the value of one standard gravity is for making comparisons that correspond to our everyday experience. When we say that the astronauts were subjected to an acceleration of 7 ""gees" we can immediately figure that this made them 7 times "heavier" than they would have been in everyday circumstances. Oh, yeah -- gn is not "approximate" -- the physicists have actually defined it to be 9.80665 Newtons. Probably the best way to think of this is to say that the acceleration of gravity at any particular point on the Earth's surface is approximately one gee, in the direction of the earth's center (recognizing that this depends not only on one's latitude, longitude, and altitude, but also on the position of the moon and the sun (and to a lesser extent of other heavenly bodies) at the moment the acceleration is measured).


 * From a mathematical point of view Fresheneesz is certainly right about the "Loschmidt constant", the "molar volume of an ideal gas", and the "Sackur-Tetrode constant". But from the point of view of statistical mechanics, these are indeed useful "constants". For example, the "Loschmidt constant" and the "molar volume of an ideal gas" are simply alternative versions of Avogadro's number, useful for making calculations when operating in the laboratory under standard atmospheric conditions (273.15° Kelvin and 1 atmosphere pressure). And the "Sackur-Tetrode constant" can be thought of as the constant term that must be added in when a certain definite integral is evaluated, to compensate for a range of temperatures (from absolute zero to 1° Kelvin) over which the integrand fails to converge. DavidCBryant 16:50, 27 November 2006 (UTC)

Extensive edits by user:fresheneesz
-  I've made some extensive edits to the tables on this site, so I thought i'd better explain them. First of all, I wiki-ized a couple tables so far. Wiki formated tables are easier to edit, and shorter - all around better - I don't expect anyone should have a problem with that.

-  However, I also CUT lots of things I deemed inappropriate for this page. This inluded the properties of some particles like a muon, electron, etc. I firmly believe that properties of particles belong on an entirely different page. This page is about physical constants not particle properties. Particle properties are unique to the particle they describe, and are not universal constants.

-  I also cut the inverse of the "fine-structure constant" - If you want the inverse, just do it on a calculator - this page is not meant to do simple math for people. Fresheneesz 03:06, 3 December 2005 (UTC)


 * By the way, if all the values are now taken from single reference, can you please put that reference front and center, and please state explicitly that all values in all tables are taken from that reference. Thanks. Wile E. Heresiarch 03:04, 4 December 2005 (UTC)

- I came here for the particle stuff... maybe there should be a disambiguation page for blundering (and unpedantic :p) first-year undergraduates like myself. It could be under 'physical constants' but have an introduction explaining how it's a disambiguation for people looking for things commonly, yet wrongly, considered physical constants. This is the sort of accessability physics needs to not completely alienate everyone ever. Telling people curtly that particle properties are not constant without doing something to help future makers of this mistake makes people feel stupid when in fact they're just ignorant or not pedantic enough. That's my two cents anyway, I didn't mean to go on a rant there. --130.88.182.233 04:19, 13 December 2005 (UTC)

Assessment comment
Substituted at 21:54, 3 May 2016 (UTC)

Move Boltzmann constant to Universal constants
Since statistical transcends any domain, it is best to shift it to the table of Universal constants. It is not restricted to physico-chemical systems. — Preceding unsigned comment added by 103.246.106.10 (talk) 14:07, 5 February 2012 (UTC)
 * You might be right. kB is just an expression of what units you are using for temperature and that is not restricted to physico-chemical systems.  But the same can be said for c, G, ħ, ε0.  These constants only have meaning in regard to the units one is measuring and describing physical quantity with.  If you use Planck units, they all go away, including Boltzmann.  So why not move it? 70.109.179.87 (talk) 04:34, 7 February 2012 (UTC)
 * No, there is a fundamental difference between this constants. kb is not like the others because its units are energy per temperature and temperature is a statistical distribution of a specific quantity of kinetic energy, i.e. it is unitless, i.e. dimensionless. Also, c is unitless because meters and seconds have a strict relativistic relationship, i.e. meters=i*c*seconds (see Einstein's "Relativity" appendix 2) so the "unit" of c is 1/i which is not a unit or normal physical dimension, but a mathematical dimension. We can measure other units like G, h, charge, etc, but we define the value of c by either defining seconds or meters in terms of the other. kb is not arbitrarily defined, but it doesn't have units either. I mean, this should be readily apparent from S=kb*ln(states).  By replacing all instances of seconds in units with meters/(i*c) the units are more valid. We can't even measure meters, seconds, or mass unless we also specify the frame of reference. We can make units valid for all frames of reference by making meters=i*c*seconds which results in E= -1*mc^2 so we should replace all instances of energy or mass with the negative of the other. This will show F=-1*ma i.e. F+ma=0 which shows this methodology enforces conservation principles (E+mc^2=0 is the cosmological observation that gravitational energy plus mass energy of the Universe is zero). It also directly shows the relationship between energy and momentum: E-i*p=0.  You could say "wiki is not a place for original research" but it's all obvious enough that this is not original and should have been published long ago.  Ywaz (talk) 12:12, 1 August 2015 (UTC)

Anthropic Principle?
I am not sure that information about the "anthropic principle" concept belongs here. Leaving aside the implicit assumption that the physical constants that define certain aspects of the universe we inhabit could ever have had other values in the first place, the term has a page of its own, to which material relating to that concept should be moved. In my opinion. — Preceding unsigned comment added by 69.41.40.24 (talk) 16:53, 9 February 2012 (UTC)

Yes, I agree with that. This topics make me very uncomfortable, actually. Please move it131.193.192.155 (talk) 21:06, 12 August 2014 (UTC)

Are physical constants truly constant?
Somehow, this article smacks of linear thinking. Many physical constants, when in attempts to measure them, have some variability, like speed of light +/- (whatever variability). Under such circumstances, can they be proven to be truly constant? I'm no expert, but it seems to me that most constants should be derived from some more provevable constants, like the value of PI. Given the quantum variability of the universe, as well as our current knowledge of physics, can any physical constant be really be proven to be constant? Is there no possible way to modify the "constant"? Is this just a mathematical model that is declared to be a "fixed" value or "close enough"? Experts - please elaborate! --97.95.34.149 (talk) 01:48, 1 August 2013 (UTC)

Relative standard uncertainty wrong?
At, I've requested comments on a possible problem with some of the relative standard uncertainty values in tables in this article. Additionally, I've asked about merging it and the other table templates (that are only transcluded in this article) with the CODATA2010 (currently) template, to avoid maintaining values in two places. Please comment here —&#91;  Alan M 1  (talk) &#93;— 22:50, 22 June 2014 (UTC)

Proposal to delete section Physical constant
While the removal of content from the article was not backed up with an edit comment, I agree that this particular content does not belong in this article. A philosophical debate of this nature is very tangential and speculative, and there is a lot of content that has more direct relevance, for example how they are measured. I am inclined to remove it again, but would like to hear from others first. —Quondum 22:35, 12 August 2014 (UTC)


 * I would keep it, but move it down to the end of the article since it is merely speculation about why the constants have the values that they do. No more relevant than Eddington's speculation that the "constants" were powers of the age of the universe. JRSpriggs (talk) 00:22, 13 August 2014 (UTC)

Article should be updated with 2014 values
It looks like the article uses 2010 values, but there are newer values from 2014. Here is a NIST table of values:

http://physics.nist.gov/cuu/Constants/Table/allascii.txt

I would correct them but I don't know how to format citations properly and I don't want to put 2014 values with a 2010 source. — Preceding unsigned comment added by 72.92.239.148 (talk) 23:34, 5 January 2016‎
 * Thanks for pointing this out. I have added the appropriate citation and updated the table of universal constants. If you update the other tables, you can simply add and remove the 2010 citation. I would recommend starting at the bottom because the 2010 citation is defined in Physical_constant. RockMagnetist(talk) 00:58, 6 January 2016 (UTC)

Transcluded templates
A few of the tables were transclusions of templates that were intended for use in multiple articles but only used in this one. They all had the same citations, but the citations could not be bundled; adding an identifier like "concise" just triggered an error message. I have replaced all the transclusions by the tables themselves. RockMagnetist(talk) 00:42, 6 January 2016 (UTC)

Tests of immutability
I came here looking for the article about tests of the constancy/immutability of physical constants. It turns out we do not have such an article; instead, the material is scattered unsystematically over a number of pages.

Trying to assemble this material, I propose to first create a section-redirect to this page, and later, if convenient/necessary, branch it out as a standalone article. There is more than enough dedicated literature on the topic, but I do not have the time to write such an article from scratch.

The way I understand it, there are two approaches to the question of whether a given quantity is actually a "fundamental" constant:
 * is it an epiphenomenon that can be described as arising from more fundamental things? Examples would be the proton mass, all of chemistry, etc.
 * is it not an actual constant but an incidential configuration peculiar to our position in time and space -- An example would be the Gravity of Earth, which surely is an important "constant" for life on Earth,  but which (a) is incidential to being on the surface of the Earth (b) is not actually constant because Earth is not a perfect sphere.

The first possibility is investigated by looking into Physics beyond the Standard Model (i.e., maybe the particle masses are not 'fundamental' because the elementary particles are 'really' built out of more fundamental stuff)

The second possibility is investigated by looking at cosmology, i.e. are the constants simply due to the current configuration of the universe and change with the long-term evolution of the universe.

A kind of borderline case is the "anthropic" argument that the constants are incidential to our observable universe, i.e. they are actually constant in the sense that we will never be able to observe any different values, but they are still "incidential" in the sense that there might be any number of "other universes" where they take other values, but these can never be observed. This crosses into philosophy because, while it seems to be a sound argument, it isn't falsifiable and as such not really in the province of the natural sciences.

--dab (𒁳) 08:31, 12 May 2016 (UTC)
 * I see that you have already created the section and the article, so I'll just say thank you - it looks like an excellent addition to the encyclopedia. RockMagnetist(talk) 14:55, 12 May 2016 (UTC)