Talk:Gravitational constant/Archive 1

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Archive 1

Archive 2

precision of k

The precision of "k" is anomalous. The "units" of AU, solar mass, etc., are not well enough known! Of course, *theoretically*, we could just make them fundamental units, and then k would be known to arbitrary precision (it would be 2pi.) BUT: the orbit of the Earth is not circular, so a naive application of Kepler's law fails. Furthermore, because of various dissipations and three-body effects, the orbit of the Earth is changing slowly over time. I suppose this could be compensated by allowing the units to be dynamically fixed to the current orbital parameters.

If someone incredibly anal would like to work out what the true precision of k is using "solar" units, they have my utmost respect (and fear.)

Sdedeo 14:24, 11 August 2005 (UTC)

reversion of patrick

Patrick, i reverted the changes you made back to the version of Jumbuck. what you added really adds nothing of use, is inconsistent in precision and in style with the rest of the article and with other articles of physical constants. r b-j 18:31, 25 Nov 2004 (UTC)

typesetting of G

Hello. I see that instances of G in the text have been changed to $G\,$ . I agree that the Latex font is much nicer looking than the typical web browser font, and it is good to have the same font in the text as in the displayed equations. However, the bitmap image generated by Latex doesn't align well with ordinary text, and it doesn't resize when you zoom your browser display. I'm pretty certain the general convention in Wikipedia math articles (dunno about physics; different set of people involved) is to write ''G'' in text and <math>G\,</math> in displayed equations. Unless physics articles have a different convention, I'm inclined to revert to ''G''. Comments? Regards & happy editing, Wile E. Heresiarch 19:28, 24 Nov 2004 (UTC)

i was the person who changed it. i didn't know exactly what the wiki guidlines are but i find it very annoying when symbols such as

\hbar \,

or

\epsilon _{0}\,

are expressed differently in equations (full PNG rendering) than in the text where the exact same quantity or concept is referenced. it should be consistent. and for symbols such as the reduced Planck's constant, there is no other good way to put it in the text. r b-j 21:00, 24 Nov 2004 (UTC)

Not true. Planck's constant appears in Unicode, and so does h-bar; they are $210E (ℎ) and $210F (ℏ) respectively.

Urhixidur 21:32, 2004 Nov 24 (UTC)

but they don't look like the Tex rendering. and for some symbols, they look like crap. and in fact, your rendering of (ℎ) and (ℏ) shows on my browser only "?". it is not consistent and it doesn't always work. r b-j 22:08, 24 Nov 2004 (UTC)

Do you know what the convention is among people working on physics articles? If there is a convention, how consistently is it followed? Wile E. Heresiarch 21:58, 24 Nov 2004 (UTC)

nothing is particularly consistently followed. starting with Planck units, i have been trying to make related articles look consistent and be complete and concise. regarding this article, i think it would be best merged with Law of universal gravitation, but that is just my opinion for a discussion for another day. r b-j 22:08, 24 Nov 2004 (UTC)

Precision of G

Hello. I've changed the stated value back to 6.67e-11. It had been stated with greater precision. Given that supposedly very accurate measurements still disagree, I don't think additional decimals are justified. See the review by Gillies for more details. I agree that the recent experiment by Grundlach and Merkowitz is (to my untutored eye) very clever, but only time will tell if their result is replicated and adopted widely. Til then I think this article should emphasize the inherent uncertainty in all of the current values. Regards, Wile E. Heresiarch 17:39, 8 May 2004 (UTC)

Well, I've relented and put more decimal places back into the stated value, namely the CODATA recommended value. If it's good enough for them it's good enough for WP. The CODATA values is also stated in the physical constant article. Happy editing, Wile E. Heresiarch 00:21, 11 May 2004 (UTC)

Features of GR

From the article:

Two important features of General Relativity are the curvature of spacetime and the distribution of mass-energy which causes it. How are the two related? To get from an energy density to a curvature quantity multiply the energy density by G/c⁴. This is the reciprocal of the Planck force, which mediates between energy density and curvature.

I've never heard the term 'Planck force'. Googling for it finds refrences on planck.com, and various other sources of 'alternative physics' ideas, but not elsewhere...

See http://www.google.com/search?hl=en&q=%22planck+force%22

-- The Anome

Planck's force is just the unit of force in Planck units. It's not a force but rather a unit of measure of force which happens to be one in God's units. Restored the paragraph. Someone needs to copyedit for reciprocal.

Okay, I can accept that the system of Planck units defines a 'natural' unit of force. But I still can't Google a reference to "Planck force" or "Planck's force" on anything other than sites expressing 'alternative' opinions. Please cite some references from mainstream physics justifying your restoration of the paragraph, and I'll be happy. -- The Anome

Moved from talk:Alternative physics

Moved here since this is meta-discussion

Alternative physics is apparently a term that can easily get misapplied in ignorance to mainstream physics concepts as this recent (Feb. 10) Talk comment shows:

"I've never heard the term 'Planck force'. Googling for it finds refrences on planck.com, and various other sources of 'alternative physics' ideas, but not elsewhere..."

The Planck quantities (Planck mass, Planck time, etc.) are mainstream physics and the Planck force c⁴/G is simply the force belonging to that set. It is the force which gives unit acceleration to the Planck mass. Once quantities of mass, time and length are defined other types of quantity derive from them in a standard way: as the metric unit of force (newton) derives from the kilogram, second, and meter.

The commenter branded 'Planck force' as an 'alternative physics' idea after a Google search failed to turn up reference which the commenter considered satisfactory. There are academic sites, particularly those concerned with String Theory which refer to the force. I would imagine the Caltech one that Barry Madur manages has some references to Planck force as the basic tension in strings. His may simply describe it as "10⁴⁰ tons" which is the order of magnitude size and an informal handle some physicists use. The lesson seems to be not to apply epithets hastily based on one unsatisfactory Google search, or assume that because you personally haven't heard of something it must be 'alternative'.

The Talk comment was regarding an entry on the gravitational constant and was accompanied by a bold-face warning headline that essentially said "danger! alternative physics!" It looked like a case of trashing or defacing. Please consider whether Wiki etiquette discourages this.

I don't see a problem here. Googling works as an alarm system for detecting possibly dodgy material. It's remarkably effective. But it's not infallible - it just makes me aware that the material being discussed is either

not mainstream or
highly technical.

I don't deny that the Planck system of units defines a force, or that the name for it would be the "Planck force", just like the Planck energy, Planck time, or Planck distance.

Look, I can define a Planck pressure as the natural unit of pressure in Planck units, but it does not mean that it is a mainstream concept (although I just found that planck.com talks about it).

I'd just like some cites to convince me that the concepts you cite don't just appear in off-beat sources. Certainly, the earlier versions of this article contained some wacky stuff that has now been removed. Certainly, some of the ideas of mainstream physics are fairly wacky-looking. My physics training is some twenty years old, so I can no longer spot the good from the bad at a glance. Some of the other contributors here are up-to-date physicists and mathematicians, who may be able to help.

I can only find one legitimate-looking reference to "planck force" on Google: http://www.eps.org/aps/meet/APR00/baps/abs/S8440009.html , out of 48 matches on "planck force", most of which are from idiosyncratic alternative physics sites. Searching for "planck's force" produces even poorer results.

This is compared to

"planck energy" which yields 109,000 Google hits
"string theory" which yields 535,000 Google hits

You imagine that Barry Madur's Caltech site contains references to the Planck Force. I can't find a Barry Madur via Google. (Do you mean Professor Barry Mazur at Harvard, or Barry Simon at Caltech?, or maybe John Schwarz' caltech website at http://www.theory.caltech.edu/people/jhs/strings/ ?) Convince me - find a cite, quote the URL here. Again, my inability to find the site you quote worries me.

A quick search through the http://arxiv.org/ physics preprint archive fails to find the term in titles or abstracts of preprints.

Please help me, I'd love to believe that this term is in common use in mainstream physics, and that the details here are entirely correct. I guess I'll just have to do the research.

-- The Anome

I have removed the following from the article:

Within this system of units, the unit of force is Planck's force which in conventional units is c⁴ G^-1. In general relativity, this quantity is equal to the energy density of a region divided by the energy density curvature.

The first statement is certainly true. But it's only relevant here in the context of the second statement.

All the cites I have for Einstein's equation have some constant of proportionality. Try http://math.ucr.edu/home/baez/einstein/node3.html and http://www.theory.caltech.edu/people/patricia/test/Einstein35.html for cites. The ratio between curvature and energy density certaily have the units of force: in Planck units the ratio is a near-unity value. But the implication the second statement in the removed para does not appear to me to be strictly true. I think the mention of the 'Planck force' idea in this article is a red herring. Einstein's equation comes out neatly in Planck units, as does much of physics, and that's very interesting. But that does not mean that the Planck unit of force has any special significance in this context.

Again: I am not an expert, I could be wrong. But I think the presence of the para cited needs justifying.

-- The Anome

I know the value of G isn't known as well as, say, the speed of light or Planck's constant, but surely it's known to better than two places? Cite? (And if so, please clarify whether that means the first two after the decimal, or of the whole thing.) -- John Owens 10:38 Apr 6, 2003 (UTC) --

From the Institute of Physics 2002-2003 diary:

gravitational constant G: 6.673(10)x10^-11 m³kg^-1s^-2. ie, 6.673x10¹¹ plus or minus 0.010¹¹. The second decimal place is **probably** 7.

Also, searching on the Web of Science gives a hit for Planck scale physics and Newton's ultimate object conjecture by Winterberg F, printed in ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES 52 (1-2): 183-209 JAN-FEB 1997. This features the planck force and has been cited four times (admittedly, only by himself), including one being printed in PHYSICS TODAY.

Dragon Dave

Because the position of the planets are known far more accurately than the conversion factors to SI units, calculations in celestial mechanics are carried out using the units of solar mass, astronomical units, and years rather than the standard SI units.

It is not clear to me what is known accurately and what is not. Are masses accurately known in solar masses but not in kg? The various kinds of years seem to be accurately known in seconds, unlike suggested above. - Patrick 12:55 May 1, 2003 (UTC)

The point is that if you do it in astronomical units, you don't have to know the mass of the sun, since by definition, the mass of the sun is 1. If you do it in SI units, you have to give the mass of the sun in kg, which is known only to about 5 sig figs due to uncertainties in G. Put another way GM is known very accurately to eight or nine sig figs, but because G is not known accurately, then M is not known accurately. Roadrunner

Thanks. I edited the article accordingly. It would mean that also the mass of the sun can have an error of 1 to 700, which is 3, not 5 sign. digits. - Patrick 16:41 May 1, 2003 (UTC)

Controversy over Newton's Gravitational Constant

Readers: I just came across information regarding "The Controversy over Newton's Gravitational Constant", which I was unaware of. Read for yourself at http://www.npl.washington.edu/eotwash/gconst.html Then scroll down and click on the last reference in the list of "Relevant Literature", i.e. J.H. Gundlach and S.M. Merkowitz, Phys. Rev. Lett. 85 2869 (2000). The link will take you to their paper in which they present their refined finding: G = (6.674215 +/- 0.000092) x 10^-11 m^3 kg^-1 s^-2. Terry Sampson

Examining the reduced units of G: i.e. (m³/s²)/kg suggests a fascinating conclusion. Considering that m/s² is by definition linear acceleration (change in speed or direction), might we consider that m³/s² is a homologue of acceleration but in 3 dimensions (which we define as 'space')? In other words, 1 kilogram of matter accelerates (changes the direction or speed -- mind-bending concepts) of space by 6.67x10^-11 m³/s²? This idea is entirely consistent with Einstein's concept of gravitations as a curvature of space.

the link http://www.npl.washington.edu/eotwash/gconst.html appears to be broken — Preceding unsigned comment added by 98.100.253.42 (talk) 05:47, 24 June 2012 (UTC)

d vs. r

just something that bugged me: equation is an inverse square law in regards to distance. distance is commonly represented with a d. the only time i've ever seen the equation for gravitation used with an r, outside of the internet, is to help the slow physics students (who, unfortunately, seem to be the ones making web pages) remember that when trying to calculate acceleration due to gravity on a planet the distance is from the center of the spherical body (thus the replacement of d, distance, with r, radius). i changed this letter on the acceleration due to gravity page as well and added a d where the radius term is mentioned. i'm fine with it being changed back on the other page as long as what i mentioned above is noted somewhere. on this page, however, d should be used... we need to make the wikipedia look like a reliable source, d is the common letter usage for distance, let's not make everyone here look retarded. say in a calculation of speed you were using the distance of the circumference of a circle. you could use s=2πr/t for the equation in that instance, but would you then tell someone that the equation for speed is s=r/t?

Use of r in this sort of equation is very very common in physics. It is used at every level of physics. I strongly oppose an attempt to eradicate it from Wikipedia. --Strait 04:14, 3 January 2007 (UTC)

I also belong to the r faction and I oppose any attempt to make d the politically correct letter. Lucretius 08:41, 4 January 2007 (UTC)

Gravity is a central force, and using a polar or spherical coordinate system centered on the gravitating body often simplifies the math. A good reason to use r is that it suggests the use of one of these coordinate systems. I'm in favor of r. --Chetvorno^TALK 19:26, 9 September 2008 (UTC)

Gravity is a Universal Quantum Pressure

The Dimensions of the Gravitational Constant G is the inverse of Pressure, G= 1/P.

The value of this pressure is 1.44 Tera Newton/m². This is derived from G= 66.7 pico N-m²/(kg)² and replacing kg with 9.8N. This reduces the number of terms from three to two, N and m.

Gravity is rather than an attraction between bodies could be a pressure on all bodies in the Universe.

The value of the pressure is related to other Quantum Constants P= chR²R², where R is the wave rate of the Universe at the Origin or Source.

The wave rate can be computed from the above and is 1.638 Gigawaves/m.

This pressure is dervied from electromagnetic fields and the associated E field is E= 402Giga V/m.

Yaw 19:51, 23 December 2005 (UTC)

again, Yaw, i thank you for putting that here rather than the article. this really has the appearance of original research which is not material for Wikipedia. r b-j 22:37, 23 December 2005 (UTC)

Relative strength of gravity

I replaced an analysis of gravity's relative strength, which was expressed in terms of cars, with an analysis of its relative strength in terms of the electron and proton. I did so because the original wasn't quite clear how gravity was relatively weak and because it finished by comparing the force of gravity with the weight of a grain of sand, which is a puzzling comparison. Lucretius 01:43, 11 January 2006 (UTC)

the comparison was to that of the human experience (anthropocentric). perhaps making the comparison to other forces between subatomic particles is better, but again begs the question: "why choose those particles (that happen to have such small mass but not so small of a charge)?" r b-j 04:48, 15 January 2006 (UTC)

Lucretius wrote this - I agree with you Rbj that Planck units don't belong on this page. Also I think you're right to mention natural units in the intro to the article page, but I think the changes you made look like an 'add-in'. I've rephrased things accordingly so that the argument is more streamlined.

I agree also with simplifying the maths and I've taken it further by knocking off the 2.

I don't agree that we need the phrase 'average human being' - slight differences in human weight are irrelevant when compared with mass of Solar System.

Cheers Lucretius 05:51, 12 January 2006 (UTC)

i think the issue with this "average human being" vs. "you" thing is one of writing a techinical or descriptive article (as opposed to a short story or a "how too" article or something similar) is the use of the "second person". it is often frowned on by the profs i had in college to put in personal pronouns into a techinical or descriptive article. it's a matter of style, i agree, but i also think that the use of personal pronouns can almost always be avoided. r b-j 04:48, 15 January 2006 (UTC)

The original article I edited used an informal approach, expressing gravity in terms of cars, and the tone also was informal. I found this refreshing and I decided to keep something of that tone. You're right when you say it's a matter of style and as far as I know there is no Wiki policy that the style has to be 'professorial'. You should remember that this encyclopaedia can be edited by anyone and it should aim to cater for a variety of reading preferences. I think also that Wiki is a learning experience for its contributors rather than a fount of knowledge where professorial pronouncements are delivered ex cathedra. An informal touch here and there might help alert the reader to the fact that we are not a 'primary source' of information - we're mostly amateurs and sometimes even professional work is vandalized here.

I notice that you commented on the edit page that SI units do not in themselves indicate the relative weakness of gravity. I agree, but the point I was trying to make was that natural units are more revealing in this respect, which is also the view expressed on the Planck units page. However, I'm happy to accept the change you made. Lucretius 17:23, 15 January 2006 (UTC)

but L, you miss the point. if we're talking about the graviational force between 2 SUVs (they have a mass that is somewhere in the ballpark of a kg whereas a subatomic particle does not) spaced apart by a distance of a meter (it does seem unlikely that the center of masses could be that close, but that's beside the point), you are talking about quantities in the ballpark of the SI units. then the small value of G (measured in SI units) has some meaning. the force (in SI units) will be very small. but you yanked that thought example and replaced it with another, and then the leading qualifier makes no sense. the fact that the graviational force between two subatomic particles is far less than the electrostatic force has nothing to do with SI units. but the fact that the gravitational force between two SUVs in space is very small compared to a Newton, does have something to do with SI units. r b-j 18:49, 15 January 2006 (UTC)

I accept this also. But if you are to compare gravity with other fundamental forces, for reasons of simplicity and clarity it has to be in a context where more than one force is operating - the electron and proton are in this context a better example than 2 cars because the cars are not subject to any fundamental force other than gravity. Yes, the matter could be explained better still, but in an intro to an article on G there is not the space for a full and proper explanation - otherwise we would hijack the article. It's a compromise. If you want to have a try at it, go ahead. I'll let you know what I think. Lucretius 02:33, 16 January 2006 (UTC)

Rephrasing, perhaps?

Both these forces are weak when compared with the forces we are able to experience directly, but the electromagnetic force in this example is some 39 orders of magnitude (i.e. 39 = 67-28) greater than the force of gravity - that's even bigger than the difference between your mass and the mass of the Solar System!

This sentence is definitely understandable and very nice to read, but the phrasing seems a little less serious than what I'd expect from an encyclopedia, and more like a cereal-box funfact. --Ramsobol 19:47, 10 February 2006 (UTC)

i totally agree with you, but i had a few other bones to pick with Lucretius and had to choose my battles. you're welcome to hit the edit tab and fix this, too. r b-j 23:03, 10 February 2006 (UTC)

'Cereal-box' Lucretius speaking here. What's wrong with a cereal box tone in a popular encyclopaedia? A little informality might help alert the reader to the fact that this encycopaedia is not and can never be an authoritative source of information - anybody can edit this encyclopaedia and there will always be errors in it. Secondly, the people who turn to Wikipedia for information in whatever discipline are likely to be young amateurs and they might relate better to a cereal box tone than to high-sounding ex cathedra pronouncements. But feel free to change what you like.[:}}

Gravitational costant as function of time.

I just somewhere and now i a, not able to find the sourcce. It said due to universe expamding G is also verying. Please verify.

Relating G with e

With the aim of combining gravity with electromagnetism, Robledo's relation states that, in cgs units,

the second partial derivative of Newton's gravitational "constant"

elevated to the -1/2 power, at a given space point, is proportional to the volumetric charge density at that point.

   \frac{d^2 G^{-\frac{1}{2}}}{d t^2} \approx \rho_{charge}

This proposed relation has not been proved, however it IS dimensionally correct, so it may deserve further atention. (vrobledo@itesm.mx)

¿What do you think? 81.38.90.149 15:03, 14 October 2006 (UTC)

Hi Victor. I've not heard of your relation till now but, if it is significant, I'm sure physicists already know something about it. You should tidy up your equation before asking people to comment on it, and even then I might have to put it in the 'too hard' basket (I'm no expert!). Just having a guess, I suspect your relation is already known to science in terms of Stoney units. Thus the elementary charge in esu, when divided by the square root of G in cgs, is numerically equal to the Stoney mass when measured in grams. This equation is not an approximation - it is exact and it is dimensionally correct (the precise value of the Stoney mass depends on the value you assign G). The Stoney scale is ideally suited to the unification of electromagnetism and gravity and that seems to be where your ideas are coming from. These days, Planck units are preferred to Stoney units because they seem better suited to quantum theory, uniting all 4 fundamental forces - in other words, the science community is unlikely to take any interest in your Robledo relation, even if it is shown to be a respectable relation to George Stoney.

Regarding the notion of a time-varying G - this was first proposed by Paul Dirac. There is a lot of scientific literature around that limits the extent to which G can vary. However, I'm not sure such literature is worth the paper it is written on. Dirac's theory has implications for quantum gravity and nobody knows how quantum gravity would operate either at a local or global level, so it is surely impossible to argue from astrophysical observations whether or not Dirac's theory is wrong. However, many would argue that Dirac's theory is wrong in principle on the grounds that any variation in a physical fundamental constant is meaningless.Cheers Lucretius 07:14, 15 October 2006 (UTC)

this might be interresting matter to read on the subject, it's a paper that proposes that the varying values of G are related to movement of our solar system + milky way, and that it is an oscillating motion of G vs Time, that repeats itself every 113 million years. 81.204.16.252 (talk) —Preceding comment was added at 15:20, 8 January 2008 (UTC)

Why so many units?

The value of G is given in three different unit sets, differing only in the exponent. This is completely redundant. Why not just leave the value in SI units (the first) as is usual in Wikipedia? --212.81.220.70 10:18, 4 December 2006 (UTC) (Alvaro)

Actually the Newton version is quite popular in physics. It would be nice to leave at least that one. -- Talamus 21:58, 22 March 2007 (UTC)

Most of the Physics community uses the constant in CGS (Gauss) units instead of MKS. —Preceding unsigned comment added by 160.36.29.144 (talk) 21:32, 9 November 2007 (UTC)

Nonsense. In North America, SI is widely used. Certainly at the elementary - that is high school and undergrad - level in Canada, SI is used almost exclusively. Ronstew (talk) 02:12, 11 March 2008 (UTC)

Cavendish wasn't the first to measure G

I think there should be more of the history of this important constant in the History section. Cavendish wasn't the first to measure the gravitational constant. As detailed in Gravitation Constant and Mean Density of the Earth,1911 Encyclopedia Brittanica, both before and after Cavendish there were a number of experiments to measure the gravitational force from geographical features. Bouguer (1740), Maskelyne (1774) and Carlini (1824) measured plumb line deflection due to mountains. Hooke (1664) compared the weight of a test mass at the top and bottom of a mine. Airy (1854) measured the difference in pendulum rates at the top and bottom of a mine. These were perfectly serious experiments to measure the gravitational constant (although like Cavendish's their results were reported as values for the density of the Earth). They were just not very accurate because of the difficulty of estimating the mass of the geographical features. --Chetvorno 08:27, 9 August 2007 (UTC)

Recent measurement

This section appears to be giving undue prominence to a particular paper. The value they got is nether more accurate than the CODATA value, nor is it in disagreement with it. This should be removed or merged into the rest of the article somehow in a far less pronounced way along with mention of why it is given particular prominence. Deuar 10:13, 11 August 2007 (UTC)

I added the section because there have been repeated instances of vandalism where a vandal changed the value of the constant, sometimes just a little, sometimes by orders of magnitude, sometimes changing the units. This section has a link to an external site from which one can easily verify whether the numerical value given here is correct (or not). JRSpriggs 18:25, 11 August 2007 (UTC)

However, there's already an external link on the main number at the beginning of the article that links to a NIST site that does the same, and is a synthesis of available measurements. Deuar 09:39, 13 August 2007 (UTC)

Whoa - which in fact gives a different error value than is shown here at the moment. Fixing... Deuar 09:41, 13 August 2007 (UTC)

Should we include more of the history?

I think that their could be a more detailed explanation of the exprement used by the men that first measured G; however, I do not have the historical know-how to modify the page.

Just a thought Kevin.presley 02:13, 12 September 2007 (UTC)

I agree. There needs to be more history. There was a long history of gravity measurement even before Cavendish. I'm accumulating info to add to the section, but I don't have much spare time. --Chetvorno^TALK 15:09, 9 September 2008 (UTC)

Difficulty of Measuring G

I hope I am not duplicating a discussion above, but it is worth pointing out that no citation is needed for the difficulty of measuring G. In the Physics community (and History of Science community?), this is common knowledge passed down from everyone who has ever tried to measure it because of the "long-scale" nature of the gravitation force.

This is one of the few cases where asking for a citation shows an extreme lack of knowledge and hurts Wikipedia's credibility. If you absolutely need a reference, grab a copy of Fowles and Cassidy,Analytical Mechanics, and read the footnote on page 204. It might be a good idea to ask around on the talk page or pick up an undergrad mechanics book next time... —Preceding unsigned comment added by 160.36.29.144 (talk) 21:29, 9 November 2007 (UTC)

Dimensions

The article said it was citing CODATA value for G in SI, then followed with cgs and, more fancifully, Newtons x m^2/kg^2. I can see some good in retaining cgs, but the Newtons expression is eccentric and not at all CODATA. Anyhow, I deleted both and retained only the CODATA dimensions. Lucretius (talk) 22:47, 8 March 2008 (UTC)

The advantage of the expression which uses Newtons is that those dimensions are most obviously correct when one looks at the formula for gravitational force where G is used. One can then convert it to the regular SI units used by CODATA. JRSpriggs (talk) 06:54, 10 March 2008 (UTC)

Thanks for tackling the issue here rather than just reverting my edit. I don't agree that force is the dimension most obviously associated with G. What about gravitational potential energy, for example? In that case, we might as well define G in terms of Joules. It's simpler and less confusing to go with convention and to define G in the CODATA manner rather than in our own separate ways. Thanks. Lucretius (talk) 08:43, 10 March 2008 (UTC)

While repetition of the numerical value is not helpful, I think that showing various alternative sets of units (including both Newtons and Joules) might be useful to some people. JRSpriggs (talk) 09:00, 10 March 2008 (UTC)

Plenty of high school textbooks use Newtons x m^2/kg^2: Giancoli, Glencoe, Gore & Castle Rock among many others. A mention of equivalent units would be helpful to inexperienced readers. We introduce the gravitational constant in terms of force because it is a good entry point. Grade 11 physics students fall to pieces when you introduce energy, but they do have some grasp of force. Ronstew (talk) 02:24, 11 March 2008 (UTC)

OK it looks as if I was wrong. If that's the way it's taught then that's the way it is, though it looks strange. Rather than just undo my edit, I hope you take care with the phrasing, as the old version implied that those dimensions were CODATA. It would be nice if you can add some reason why those dimensions are used i.e. pedagogical reasons, though I don't know where you'll find them written. Thanks for correcting me.

Actually, why not put the 'student' dimensions in the next section, which is in fact all about dimensions? Lucretius (talk) 10:19, 11 March 2008 (UTC)

I was going to say that. Ronstew (talk) 18:23, 11 March 2008 (UTC)

The books you cited might be all the citation that is needed. In that case, just cut and paste the 'student' equation to the dimensions section, explain the reason and then add the citations. I think after 'natural' units (G=1) is the best place for it. But you might have some better ideas. Cheers. Lucretius (talk) 22:19, 11 March 2008 (UTC)

I've now edited the text to include 'student' dimensions. However, I don't have the necessary citations - if anyone has a school text with 'student' dimensions, could you please cite the text where indicated in the edit. Feel free to change anything else if you feel I have not done enough. Lucretius (talk) 23:17, 12 March 2008 (UTC)

G = 9.8 ?

In other articles, particularly Newton's law of universal gravitation it mentions that in Newton's equations that the G stands for the gravitational constant needed for the equations. I have always been taught in physics that the gravitational constant (G) is equal to 9.8 on Earth (or 10 if you don't want to be so accurate). I don't see in the article any mention of G on Earth being 9.8 which I think would be very useful information if this is correct. I am going to add this information to the page, feel free to talk bout it here if you disagree. --Atyndall93 ^{(talk | contribs)} 09:33, 8 April 2008 (UTC)

Please do not edit articles which you know nothing about. As the lead of this article says, "It should not be confused with "little g" (g), which is the local gravitational field (equivalent to the local acceleration due to gravity), especially that at the Earth's surface; see Earth's gravity and standard gravity.". The thing which you are talking about is little g, not big G. JRSpriggs (talk) 10:35, 8 April 2008 (UTC)

Thankyou for illuminating that for me, but I suggest that you refrain from saying to someone that you have just met "that they know nothing about a topic" (WP:BITE) as one day you might might meet someone who doesn't have such a mild attitude towards perceived insults. By the way, I thought by little g the article was referring to g-force. --Atyndall93 ^{(talk | contribs)} 11:30, 8 April 2008 (UTC)

Little g is the force of gravity (g-force) per unit mass, i.e. an acceleration, at the Earth's surface. And its value is about 9.8. If you do not know the difference between big G and little g, then you really do know nothing about the topic of this article. If your ignorance insults you, then so be it. JRSpriggs (talk) 12:53, 8 April 2008 (UTC)

then you really do know nothing about the topic of this article. If your ignorance insults you, then so be it. - Someone woke up on the wrong side of the bed today :-D No need to be rude, in fact, please stop :-D (WP:CIVIL) --Atyndall93 ^{(talk | contribs)} 09:09, 10 April 2008 (UTC)

Of course you're right about the physics JR, but gotta back Atyndall up here: some extra care considering how you make other users feel wouldn't go amiss. Politeness is as important to the wiki community as intelligence is to the content (you've obviously got the second one right). The whole point of Wiki is to allow people to develop their intelligence, making someone feel stupid is absolutely counter to that. If you're contributing to wiki then you must be interested in helping people out (you've made some great contributions), so when you're rude to someone, you're really working against your own goals. Just thought I'd point that out. Hope I haven't offended you in turn : ). Tleave2000 (talk) 10:51, 28 February 2009 (UTC)

There is a mistake in "GM prodcut"

Hi,

the line "If instead of mean solar day we use the sidereal year as our time unit, the value is very close to 2π." should probably have 1/2pi instead (just look at the number, which is very unlike 6.28, but not quite afar from 1/6). Unfrotunately, i have no idea, how to deal with mathematical expressions in wiki language, so I suggest someone who does fixes the stuff.

nice day, Jan —Preceding unsigned comment added by 213.195.202.6 (talk) 16:52, 19 August 2008 (UTC)

'Mathematical approximations' section is numerology not physics

The numerical coincidence detailed in the 'Mathematical approximations' section is unsourced, not notable, and may be original research. It is only tenuously connected with the topic of the article. I think it should either be merged into numerology or deleted. --Chetvorno^TALK 10:34, 8 September 2008 (UTC)

Yes you're right and I have removed the bogus section. Keep an eye out as this sort of stuff often has a way of coming back. Lucretius (talk) 01:10, 9 September 2008 (UTC)

Pi was once a physical constant, you know. I say physical because its value could only be determined empirically, ie. by making a measurement. Mathematicians worked out how to calculate pi to any desired accuracy without making any measurements. That is how it became a mathematical constant. It wasn't always.

The obvious question is, can all physical constants (or rather, dimensionless combinations of them) be determined to any degree of accuracy purely by mathematical procedures? The answer to this question is unknown. Though there are theories in this regard that have gained popularity (mainly those against), nothing yet has been proved.

With that point in mind, clearly the fact presented is an interesting one.

The content of the section 'Mathematical Approximations' can be verified with a pocket calculator in five minutes. There is nothing to dispute. It was stated clearly and prominently that the mathematical coincidence noted has no theoretical explanation, ie. there is no attempt to make a physical assertion, only the noting of a mathematical coincidence.

But though the fact is easy to verify, it is difficult to stumble upon. For that reason it is a potentially valuable piece of information. It was also stated concisely. There doesn't seem to be a strong reason for removing it.

I understand the crusade against mumbo jumbo, but I think this time you have erred. It's as if you have assumed that you know for sure that dimensionless combinations of physical constants will never be determined by mathematical procedures alone. Nobody knows that.

I have explained my reasons for providing the content in question and leave it in your hands to decide whether it belongs in this encyclopedia.

--Vibritannia (talk) 09:04, 9 September 2008 (UTC)

To Vibritannia: Numerology is not notable (in the context of gravitational physics). It is not useful to anyone who is trying to understand or work with Newtonian gravity or Einsteinian gravity. Mathematical coincidences are a dime-a-dozen. Please do not add any more. JRSpriggs (talk) 13:03, 9 September 2008 (UTC)

I wouldn't know where to find them. :) --Vibritannia (talk) 11:18, 10 September 2008 (UTC)

Measurement of the Gravitation Constant

Has anybody ever set up an apparatus to measure G and then repeated the experiment using different isotopes of the materials involved. One would assume that the results obtained would be the same, but has anybody actually ever verified it?

Did you know that the gravitational acceleration experienced by photons is twice that experienced by non-relativistic particles? (The Comprehensible Cosmos - Victor J. Stenger)

--Vibritannia (talk) 10:35, 9 September 2008 (UTC)

See Eötvös experiment; versions of this have been done with materials which have different ratios of neutrons to protons with no significant variation in G noted.

Yes, I am aware that in general relativity the motion of the gravitating objects changes the force between them. This does not indicate any variation in the value of G. JRSpriggs (talk) 13:10, 9 September 2008 (UTC)

Thanks. Interesting article. --Vibritannia (talk) 11:19, 10 September 2008 (UTC)

History of measurement section

Reading this article I see that the History of measurement section is misleading. After reading this section the writer concluded that

The gravitational constant appears in Newton's law of universal gravitation, but it was not measured until 1798 — 71 years after Newton's death — by Henry Cavendish. For more reading on this check out Wikipedia.

We know that Cavendish did not measure G because G was defined about a century after Cavendish died. History of the measurement section implies this by saying that "Cavendish measured G implicitly." I don't know what that means. It still implies that Cavendish knew about G. Cavendish did not know G and he did not measure G implicitly or explicitly. His measurements were later interpreted by physicists as such. There is a big different. I suggest that the section be linked to Did Cavendish determine G on the Cavendish Experiment page. Zeyn1 (talk) 04:22, 2 November 2008 (UTC)

Suggestion

Perhaps we should post a direct text instead of alt text. Tailsfan2 (talk) 15:58, 6 January 2009 (UTC)

G=\left(6.67428\pm 0.00067\right)\times 10^{-11}\ {\mbox{m}}^{3}\ {\mbox{kg}}^{-1}\ {\mbox{s}}^{-2}.

Tailsfan2 (talk) 16:00, 6 January 2009 (UTC)

Was this number 6.67428 etc the CODATA number in 2006? Later corrected to 6.67408? --Richardson mcphillips (talk) 03:53, 5 March 2017 (UTC)

Astrophysical conversion is wrong, should be 10 to the minus 2 power. —Preceding unsigned comment added by 129.21.116.158 (talk) 17:08, 13 April 2009 (UTC)

Geophysical determinations

In the 1980s, a lot of effort was expended in measuring G in geophysical settings. I was involved in one such experiment, to measure G using a precise gravimeter in a borehole in the exceptionally pure ice of the Greenland Ice Cap (Zumberge, M. A., M. E. Ander, et al. (1990). The Greenland gravitational constant experiment. Journal of Geophysical Research. 95: 15483-15501). The driver was that geophysical evidence tended to suggest the G was NOT constant, but varied with distance and possibly with the material involved. This line of research has petered out because the evidence, although positive in several experiments, was not strong, and fell by the "extraordinary claims require extraordinary proof" standard. For example, the result from the experiment cited was significantly different from the results from lab based measurements, but a hypothetical and extremely unlikely geology beneath the ice cap could theoretically have produced the same results. --APRCooper (talk) 12:37, 22 June 2009 (UTC)

PS! The geology required to "explain" the results of the Ander and Zumberge study were so extreme that I'd like a share of the mineral rights if it's true! The densities required could only be explained by the presence of large quantities of very high grade heavy metal ores! —Preceding unsigned comment added by APRCooper (talk • contribs) 16:44, 22 June 2009 (UTC)

Just a thought but should this be merged with the Fifth Force article? The Fifth force manifests itself as variations in the measured value of the gravitational constant, if it exists. --APRCooper (talk) 16:45, 24 June 2009 (UTC)

I think such a merger would just confuse most readers of this article. The gravitational constant has to do with the force of gravity which is one of the well-known four forces, not the fifth force. A link to fifth force in the "see also" section should be sufficient. JRSpriggs (talk) 20:35, 24 June 2009 (UTC)

Should A. N. Whitehead's work be referenced here in variable G discussion? http://en.wikipedia.org/wiki/Alfred_North_Whitehead —Preceding unsigned comment added by 128.221.197.58 (talk) 18:33, 15 June 2010 (UTC)

The article doesn't currently have any discussion of variable G at all. Whitehead's theory was disproved by experiment decades ago, so it's probably not very important to discuss here.--207.233.88.212 (talk) 22:09, 19 October 2010 (UTC)

Error in formula?

"Failed to parse (unknown function\cm): G = 6.67428 \times 10^{-31} \ \mbox{m}^6 \ \mbox{kg}^{-1} \ \mbox{s}^{-2} = 6.674118 \times 10^{-16} \ {\cm N}\, {\rm (m/kg)^2}." --87.168.140.238 (talk) 18:59, 14 March 2010 (UTC)

In the first formula "F=Gm1m2/r2" ... surely it's "F=-Gm1m2/r2"! — Preceding unsigned comment added by Rogers kp (talk • contribs) 11:30, 23 April 2011 (UTC)

Deleted out of date value

The lead had two SI values for G, which were statistically inconsistent with one another. The first value was referenced to CODATA 2006. The second value had only a reference to "Standish, p. 5." Looking back at old versions of the article, I found that the Standish reference had originally been given in full, and only later somehow became shortened to the useless "Standish, p. 5," so I made an edit and put the full reference back in. But the thing is, that reference was to an IAU report from 1994. It's really, really silly for the article to list two values for G, one that is the best and most recent one, and one that is 16 years old. Therefore I've made a second edit to get rid of the out of date one. For anyone who wants to see the actual Standish reference, here is the url: http://ssd.jpl.nasa.gov/iau-comm4/iausgnsrpt.ps .--75.83.69.196 (talk) 00:46, 19 October 2010 (UTC)

Confused by concise notation

I think good notation is one that is intuitive. I had never before seen the concise notation that is used in the current lead-in since June. It says:

G=6.67384(80)\times 10^{-11}\ {\rm {N}}\,{\rm {(m/kg)^{2}}}

I had to look up on CODATA to understand this "concise" notation:

“

Use of concise notation

If, for example, y = 1 234.567 89 U and u(y) = 0.000 11 U, where U is the unit of y, then Y = (1 234.567 89 ± 0.000 11) U. A more concise form of this expression, and one that is in common use, is Y = 1 234.567 89(11) U, where it understood that the number in parentheses is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.

”

— http://physics.nist.gov/cgi-bin/cuu/Info/Constants/definitions.html

As far as I can see, there is no way to know that in 1 234.567 89(11), (11) actually means ± 0.000 11, and more precisely the amount of leading zeroes to 11 is not expressed. Unless someone can explain to me the logic behind this concise notation in layman mathematical terms, I will convert the value in lead-in to ± notation. (6.67384 ± 0.00080) --hydrox (talk) 22:36, 24 September 2011 (UTC)

The digits of the uncertainty value in parentheses, however many there are, are applied to the rightmost (least significant) digits of the result. So, the number of decimal places (leading zeros) to the left of the uncertainty value is equal to the number of places to the left of an equal number of the rightmost digits of the result (is that confusing enough?) So:

5.394801(7) = 5.394801 ± .000007

5.394801(29) = 5.394801 ± .000029

5.394801(614) = 5.394801 ± .000614

I agree that this specialized terminology for uncertainty doesn't need to be used in a general-purpose encyclopedia article, and I support changing it back to the more familiar plus-or-minus form. --Chetvorno^TALK 20:28, 25 September 2011 (UTC)

Thanks, I think I understand it now. I tried to cram in the ± notation to the lede, but I can't make it fit in the layout reasonably (which quite empirically shows why the concise form is used.) It would fit if we expressed G either in terms of SI base units only (m³kg^-1s^-2) or only in the "N form" (N(m/kg)²), that most people are more accustomed to. But neither is a good solution. Instead, I just added more examples to the uncertainty article to explain the "concise notation", that now redirects there.--hydrox (talk) 20:41, 26 September 2011 (UTC)

Why we need the proportionality-constant G

Since we measure masses in our arbitrarily-chosen units of kilograms, and measure distances in our arbitrarily-chosen units of meters, we need the proportionality-constant G. According to a paper published recently, [October 16, 2011, On-line-first] in Astrophysics and Space Science, by Hasmukh K. Tank, if we measure masses in Nature's own unit of total-mass of the universe, and measure distances in radius-of-the-universe, then the proportionality-constant G becomes unity; that is we do not need any proportionality-constant.219.91.130.29 (talk) 08:34, 23 October 2011 (UTC)

The units are wildly impractical. You could use something like c=10⁹, giving a light nanosecond or foot of 299.792458, and by setting G to 10^-9, you get a pound of 405 grams. The density of 1 g/cc comes out as Ge12, eg 66.7+ lb/cu ft. You can write G as 1/c, then and get rid of this while using practical size units. Wendy.krieger (talk) 08:36, 3 November 2011 (UTC)

Is Gravitational Constant a combination of other physical constants?

Is Gravitational Constant fundamental?
Most likely it is not because its units of measurement are contained in other physical constants.
For example: Gravitational Constant G can be expressed as follows

G={\frac {\hbar \cdot c}{m^{2}}}\cdot {\frac {{\alpha }^{7}}{{\mu }^{7}}}\cdot {\frac {1}{log_{2}(2\pi )}}=6.67430606(67)\cdot 10^{-11}\ m^{3}\cdot kg^{-1}\cdot s^{-2}

where
$\hbar$ - reduced Planck constant;
$c$ - speed of light;
$m$ - mass of proton;
$\alpha$ - Fine structure constant;
$\mu$ - proton-to-electron mass ratio.

Mikhail Vlasov
Korablino (talk) 02:54, 9 November 2011 (UTC)

Response to Korablino:

The current value of G gives 1.309136, while this value gives 1.3092278, when measured in the scale of

G=1.309136{{\frac {{c}^{3}}{\hbar }}{\frac {\alpha ^{25}}{(4\pi R_{\inf })^{2}}}}

It just then is a matter of plugging in values of various numbers to see what one gets accordingly. The value i give, is pretty much the value when the base units are taken as L=1/4πR_∞, M=m_e/α², V=α³c, Q=e/α, θ makes k=1. It's on the edge of what you would expect with two values. Wendy.krieger (talk) 08:55, 19 November 2011 (UTC)

Your expression also confirms that Gravitational constant is not fundamental physical constant.
Korablino (talk) 01:28, 22 November 2011 (UTC)

The discussion in the article its relation to Planck-* would seem ti imply that it is. --Belg4mit (talk) 22:13, 11 January 2012 (UTC)

Incorrect value?

So the GC value in SI units is 6.674•10^-11. I decided to go challenge this by looking at planets of the solar system, looked at their mass, the radius, and the formula for gravity. When I was finished, there was a small difference between the answer and the Equatorial Gravity (I used equatorial radius values and mass). May someone give an explanation? Avengingbandit 07:20, 11 July 2012 (UTC)

Aside from the caveat that you do not give an indication of exactly how far off your answers were: You need to understand that, where-ever your specific values for planetary masses (M) came from, those mass values were (very likely) dependent on the measured value of G (at the time of computation) in the first place. In astronomy (and in situ, if possible), the only acquirable measurements you can get with reasonable accuracy would be radius (r) and gravitational acceleration (a), from which you directly get ar^2 = GM. In other words, you may be assuming a value of G which differs slightly from the (possibly out-of-date) G which was used to determine those masses (your input data) in the first place. DWIII (talk) 13:47, 31 October 2012 (UTC)

Variable?

Just been reading "The Science Delusion" (Sheldrake, 2012) where it's suggested that G might not be constant after all. Any further details or thoghts on this provocative suggestion? Paradox the Sneath (talk) 17:42, 10 November 2012 (UTC)

1. Its measurements may vary when done on the Earth. There is rotation of the planet and there are several stars nearby: http://arxiv.org/ftp/physics/papers/0202/0202058.pdf

2. There are measurements of G stability over long time intervals: `a5b (talk) 06:40, 17 October 2013 (UTC)

2.1. van Flandern, T. C., Is the Gravitational Constant Changing // Astrophysical Journal, Vol.248, P. 813, 1981, BCode 1981ApJ…248..813V, doi:10.1086/159205: results indicate that G'/G = (-6.4±2.2)x 10⁻¹¹ yr⁻¹

2.2. J. P. W. Verbiest et al., Precision Timing of PSR J0437-4715: An Accurate Pulsar Distance, a High Pulsar Mass, and a Limit on the Variation of Newton’s Gravitational Constant // The astrophysical journal, 2008, Volume 679 Number 1, doi:10.1086/529576: «limit on the variation of Newton’s gravitational constant, |Ġ/G| ≤ 23 × 10⁻¹² yr⁻¹.» `a5b (talk) 06:40, 17 October 2013 (UTC)

Actually, this is still a hotly debated issue, up to the point of being called an embarassing mistery. Recent measurements by different groups give different results for G, well beyond the stated precision. See one of the recent publications in Phys. Rev. Lett. --Fedor Babkin (talk) 08:53, 17 October 2013 (UTC)

Fedor, what exaclty is the debated issue? Exact value of G or its variability in 24-hour period or its long-term stability? `a5b (talk) 12:16, 18 October 2013 (UTC)

The issue debated is why measurements by different qualified groups yield values of G varying well beyond the stated margin of uncertainty. --Fedor Babkin (talk) 19:34, 18 October 2013 (UTC)

Gravitational constant- a factor of time It is noted by recent observation that the G-constant is decreasing with time.It would be preferable if the point is jotted in the page — Preceding unsigned comment added by 1.187.29.60 (talk) 10:07, 31 October 2013 (UTC)

Which observation? Do you have any sources for that observation? --Fedor Babkin (talk) 11:00, 1 November 2013 (UTC)

Denotion

I would like to point out that it is also often denoted as γ (gamma), and instead G is the denotion for weight. — Preceding unsigned comment added by 80.80.44.76 (talk) 01:40, 28 December 2012 (UTC)

Why a constant?

Could someone with an adequate understanding of the subject add a few words to the article explaining why G is known/thought to be a universal constant? This is what I was looking for when I consulted the article, and if it is mentioned, I did not find it. Thanks, • • • Peter (Southwood) ^(talk): 05:03, 17 December 2013 (UTC)

A formula for G?

(I made is an essentially identical comment at Talk:Dimensionless physical constant#A formula for G?, as this identically describes the edit history there as well, with appropriate substitutions):

The grandiose claim "Of all fundamental constants, only formulae for value of the Newtonian gravitational constant have been given" has been made, and now the IP is insisting on it (with the edit summary relative to the rest of the article (also not discussed in talk) this was the well made part). I don't even see the claim as being substantiated in the arXiv paper cited. Some others please take a look. The same is the case at Dimensionless physical constant with this revert. —Quondum 17:33, 15 March 2015 (UTC)

I don't think it's "grandiose" - because it came about in reaction to what the article was saying previously: "There are no known..." Inorout (talk) 19:10, 23 March 2015 (UTC)

I find no such statement (containing "There are no known") in the history of this article going all the way back to 2 October 2013. Also, articles are not debates: "in reaction to" is never a justification for inserting material. —Quondum 20:13, 23 March 2015 (UTC)

arxiv paper doesn't appear to be up for peer review nor is it sensible: mentions things like the "Hyperverse" and usual pseudoscience claims of making dark matter and dark energy 'redundant' or irrelevant while unifying something across all parts of physics.68.105.173.30 (talk) 04:00, 16 March 2015 (UTC)

Clearly a crackpot reference. The article is semi-protected, so I removed the section and the IP cannot add it again. Should be fine now. --mfb (talk) 10:56, 16 March 2015 (UTC)

Clearly to whom? Is it your OR, or can you state another reference that says so? Inorout (talk) 19:11, 23 March 2015 (UTC)

I've reverted yet another insertion of essentially the same text. Interestingly persistent. Notice the geolocation and coincidence with edits by Inorout. This is suggestive of deliberate sock behaviour. —Quondum 19:44, 22 March 2015 (UTC)

Yes, it's a big coincidence. Maybe a sockpuppet investigation is warranted.

User:37.208.33.85, what is your reason for your edits? You need to stop reverting without comment and discuss the issue with us here, so we can find a consensus. Repeatedly reverting other editors is called EDIT WARRING and is prohibited on Wikipedia. Your last 5 edits have violated the three revert rule and you can be blocked. Let's work this out.--Chetvorno^TALK 22:41, 22 March 2015 (UTC)

Interesting discussion. Some 2 numbers, both coming from valid references afawk, were compared. Then the comparison was abruptly removed without discussion required for substantial edits such as removal of good-faith text and new references. It would be great if some of you would keep your personal opinion about (any) science references to yourselves. Those opinions are irrelevant, not to mention they constitute OR. Inorout (talk) 19:08, 23 March 2015 (UTC)

From Wikipedia:Verifiability "Any material lacking a reliable source directly supporting it may be removed and should not be restored without an inline citation to a reliable source.... The burden to demonstrate verifiability lies with the editor who adds or restores material" Your material has been discussed here for a week, and numerous editors have tried to talk to you about it. You have declined to participate and have just reverted anyone who disagreed with you, until you were threatened with a block. Is that "good faith"? Wikipedia works on a basis of collegiality and WP:consensus. I'm afraid your "personal opinions" about the references are no more important than ours. --Chetvorno^TALK 19:34, 23 March 2015 (UTC)

Here are the reasons your sourcing is inadequate: Arxiv citations appear on WP but should only be used to support other RS's and when the author is known and respected (WP:Reliable source examples). The Omerbashich being unpublished does not by itself constitute a WP:RS. But in addition, the Omerbashich paper is a WP:PRIMARY SOURCE. Primary sources must be backed up by reliable secondary sources such as survey papers and textbooks (WP:PSTS). The article certainly contradicts mainstream physics by maintaining that the gravitational and Planck constants are not constant. Wikipedia says exceptional claims require exceptional sources. Read WP:Righting Great Wrongs. Wikipedia is not the place to present the news of new untested breakthroughs. When Omerbashich's theory is discussed by other mainstream sources and appears in review papers and texts, it can be included in Wikipedia. On top of this, your assertion that Omerbashich's derivation of G is the only derivation of a fundamental constant needs an independent source. Editors are not allowed to include their own unsourced conclusions drawn from sources, this is called WP:SYNTHESIS. --Chetvorno^TALK 20:39, 23 March 2015 (UTC)

FYI, User:Inorout has been indefinitely blocked as a suspected sockpuppet of User:Bosnipedian, (Bosnipedian sockpuppet archive) who was also a promoter of the work of Mensur Omerbashich. The IPs which supported him were also socks. Apparently this guy pops up new socks every month which promote the works of Omerbashich. Heads up. --Chetvorno^TALK 21:15, 23 March 2015 (UTC)

Is G still valid after GR?

Newton's law of universal gravitation ignores the speed of gravity and the fact that light is affected by gravity.

G is used in Hubble's law and the Schwarzschild radius, so does that mean G is valid despite Newton's law not being valid?--195.194.89.243 (talk) 10:43, 30 March 2015 (UTC)

Although the formulae of GR are different from those of Newton's gravity, the same constant appears in both, and yes, it is thus a valid constant of GR. See Introduction to general relativity § Einstein's equations. This is mentioned in the lead, but it seems strange to me that this is omitted from the body of this article. —Quondum 14:33, 30 March 2015 (UTC)

One way to see the logic in this is that GR must, in the Newtonian limit, reduce to Newtonian gravitation. It's hard to see how this would come about without the respective G:s being the same (modulo units used). I don't know any details about this myself though. YohanN7 (talk) 10:23, 28 April 2015 (UTC)

Steps to calculate G?

what are the steps to calculate G? I know that first i would do 6.673×10⁻¹¹ but what then? What does (m/kg)² mean? And finally, N = Newton right? -SGA314 (talk) 17:57, 27 April 2015 (UTC)

The talk page of an article is not the place to ask questions about your understanding of details, in this case apparently about understanding how units of measurement are used. You could try at Wikipedia:Reference desk/Science or Wikipedia:Reference desk/Mathematics. —Quondum 14:06, 28 April 2015 (UTC)

Ok. I am posting at the Mathematics Desk. Good to know and thank you. -SGA314 (talk) 14:15, 28 April 2015 (UTC)

Standard gravitational parameter value

The value of the standard gravitational parameter (G times a given mass) for the sun appears to be 1.32712440018(9) × 10¹¹ km³ s⁻² as given on the Standard_gravitational_parameter page (and in the citation shown) but it is 1.32749351 × 10¹¹ km³ s⁻² on this page. Am I missing something, or should these be the same? Synecdodave (talk) 04:10, 24 May 2015 (UTC)

The value here was wrong. Fixed it. --mfb (talk) 12:10, 24 May 2015 (UTC)

Does the gravitational constant “G” which ensconced in both classical and modern physics subliminal?

According to the Newton's universal law of gravitation

F = GMm/d^2, where G is the proportional constant

Similarly, Force = F = mg where g = GM/d^2 and hence G = gd^2/M = 6.673×10−11 N·(m/kg)2

This means “G” depend upon “g” which is itself discordant , a stern veracity unbeknown to illuminati for many centuries, in the Newton’s universal law of gravitation therefore does the practice of “G” in both classical and modern physics well grounded cogently?

Do we regress and need to rework from the get-go instead of vacillating if “G” is unsubstantiated?162.157.210.127 (talk) 06:09, 14 July 2015 (UTC)Eclectic Eccentric Kamikaze

This page is for discussing the article; it is not for discussing the subject itself or a platform for your personal views, see WP:TALK. --Chetvorno^TALK 11:11, 14 July 2015 (UTC)

G is the fundamental constant, g is a handy derived "constant" useful on the surface of Earth only. G does not depend on g. In the same way the length of a meter does not depend on your body height, although you can express your body height in meters and vice versa. --mfb (talk) 15:35, 15 July 2015 (UTC)

As Gravity is a space-time curvature, and that curvature is caused by the presence of mass therefore isn’t gravity zero on the surface of earth in the absence of any force and curved space i.e. weight (w = mg) of an object of mass on the surface of the earth is zero as space can’t tell the said object how to move further. Similarly, unit of Force “Newton” is also appeared in the unit of “G” when there is no involvement of force at all. Wouldn't earth’s rotation around the sun affect the rest position of an object on the surface of earth. At small scale electrons of the said two bodies repel each other. Since this is not a platform for discussion therefore this is my last post. 162.157.210.127 (talk) 20:38, 15 July 2015 (UTC)Eclectic Eccentric Kamikaze

That doesn't make sense at all (no matter how I try to parse the grammar). Also, see above, this is not the right place. --mfb (talk) 16:08, 31 July 2015 (UTC)

You don’t have the right to advise again because you are the one who edited this section twice for “none sense” despite knowing that its not a platform for discussion. Saying something in the habit of commenting anyway that doesn’t make sense is better than saying nothing at all. You are not above the Wikipedia rule. Anyhow, is G fundamental? - As g = GM/r^2, therefore G = 0 when centre to centre distance r = 0, this means this point is uninfluenced by external gravitational source. Its quite lucid that it all goes wrong anyway no matter what you do. We respect therefore this is my 2nd Period! — Preceding unsigned comment added by 162.157.210.127 (talk) 16:45, 6 August 2015 (UTC)

mfb is not the only one who is unable to make sense of the above statements. Furthermore their advice is appropriate and to the point. • • • Peter (Southwood) ^(talk): 18:18, 6 August 2015 (UTC)

My original post is for educational motive not for imprudent give-and-take therefore my response was reasonable and proportional nonetheless I could rephrase upon request for clarity.

Not enough description.

For the equation:

G=6.674\ 08(31)\times 10^{-11}{\rm {\ m^{3}\ kg^{-1}\ s^{-2}}}=6.674\ 08(31)\times 10^{-11}{\rm {\ N\ m^{2}\ kg^{-2}}},

It would be great to see it all re-expressed in more typical arithmetic so I could understand it. What would I type on a calculator?

I'll show you how much I can follow from this description:

Its the number, times cubic metres, over mass in kg, over.... what? What's s^-2?

The equation it equals, it's the number, what's N? Where do the square metres come from? Is it the radius squared diamatre? The kg^-2 this time, that's the mass?

So, I don't know what s^-2 is and, in the equation it equals, I don't know what N stands for and I don't know where the metres come from?

Please make the entry a little bit more descript because I will now have to search elsewhere to try to understand it! Thanks.

139.222.127.168 (talk) 13:54, 25 October 2015 (UTC)

These are metric units. s is seconds, while N is newtons, the unit of force in the SI, the modern metric system. Newtons have units of kilogram meters per second squared: N = kg m / s² --Chetvorno^TALK 14:05, 25 October 2015 (UTC)