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It's exceedingly obvious to me how to measure big G precisely and incontrovertibly. Send two space ships of equal and known mass into space. One of them will be placed within the pull of earth, but lined up directly under the moon. The other will be at the opposite side of earth farthest from the moon. Instruments on board the ships will all be fastened down so that the momentum of an object banging around inside the ship cannot distort the readings. There should be nothing in the ships that is not bolted firmly to the ship. When the ships are both in place, they will both be equidistant from the center of earth (not the height above land or sea level, because those both vary). The ships will then have all motion stopped such that they stay exactly in-line with the line that would join the exact center of the earth and the exact center of the moon. They are now allowed to drop to earth in complete freefall while instruments on board the ships measure their exact locations above the center of earth, using GPS and other measuring systems, and they would also measure the precise time that the space ships are at every altitude. It should be noted that the best design of these space ships would be a perfect sphere to minimize variations and differences due to wind resistance and the center of gravity in the lower atmosphere. Measuring Instruments should be in the dead center of the space crafts. There should be no humidity or rain or anything else on the day of the experiment, that is in line with the space ships' descent paths that would exert undue air resistance. Since a sphere is unwieldy to control, a secondary craft would need to carry the spheres to space before dropping them. This would help with knowing exactly how much the measuring crafts weighed since burned fuel changes the payload weight. The spheres would be reweighed on earth after a water or other safe landing, for added weight accuracy redundancy. After the data from the spheres is harvested, extremely accurate calculations can be made because of all the known variables and the large size of the objects in the experiment (space craft, the earth, the moon). Wind resistance would be minimized while the crafts are in space. The experiment will also be free of local distortions due to the gravity exerted by nearby mountains, buildings, and other objects, especially at the highest altitudes away from the earth. The experiment should ideally be repeated a total of at least 3 times to ensure accuracy and to account for the minor difference in gravity formed by bulging oceans and really tall mountain ranges. Varying conditions could be checked. Having the two space craft at opposite ends from the moon will allow for calculations based on the distance and mass of the earth and the moon, giving even greater accuracy through redundancy and two separate calculations. No measurement of big G can be completely perfect, but this is as close as we can come. The quantum/atomic measurement system used by other researchers may or may not hold true for large objects obeying "normal" laws of gravity, so the experiment above would be incontrovertible in this regard. — Preceding unsigned comment added by 70.193.36.108 ( talk) 08:11, 19 May 2016 (UTC)
To the poster below: The two quantities are related by g=(GMe)÷(r^2e) what are you missing to do the calculation?
A highly precise estimate of the mass of the moon and every object in the solar system is possible by observing its size and chemical composition using astronomical spectrometry. Also, numerous spacecraft have used these masses in calculations that have helped them to fly to distant places without error. The precision of decimal places in the experiment above would far exceed the atom interferometry experiment because the mass of the objects can be measured more accurately and to a higher precision whereas atomic masses are inferred. Regardless, the atom interferometry would of course be subject to your same GM issue as the space experiment, since you would be measuring the gravity due to earth.
Nevertheless, the attraction between multiple bodies of known mass is the same concept that the Cavendish torsion balance uses, only the spacecraft idea above gets rid of most of the errors due to various frictional forces and local gravity phenomenons. — Preceding unsigned comment added by 70.199.243.40 ( talk) 13:25, 19 May 2016 (UTC)
Oh, and if the spacecraft experiment was performed it would give a massive improvement to the article (and the science community) since the gravitational constant could be univocally defined. That's the whole point of the article: defining the so-called constant. — Preceding unsigned comment added by 70.199.243.40 ( talk) 13:34, 19 May 2016 (UTC)
This was commented out in the article, I am moving it here for future reference:
-- dab (𒁳) 09:40, 9 June 2018 (UTC)
A useful interpretation was added. Just used mass of proton instead of mass of electron. Алры ( talk) 21:20, 4 April 2019 (UTC)
Please, show me mistake if you can. Алры ( talk) 23:38, 4 April 2019 (UTC)
I repeated addition of the same content because it was deleted without demonstrating where I was wrong as Mfb stated. It was not shown yet. Now Mfb made another wrong statement that my addition is a random coincidence. It is obvious for anyone who knows physics that 18th degree of fine structure constant does not allow such a speculation. Even more it explains the known difficulties with getting accuracy of G. Yet another wrong argument is about our completely arbitrary choice of units. Actually my addition was made to avoid such a problem. The attached mass of the proton is natural unit unlike G.
Chetvorno stated that my addition was inadequately sourced. It is not true. I gave primary source to show that this idea appeared on American soil just after 6 years after the fine structure constant was introduced. Now there are a lot of the contemporary secondary sources. Chetvorno also stated that I added a controversial content to the article. Please, be specific.
I don't see arguments against my addition. Алры ( talk) 14:55, 5 April 2019 (UTC)
There are the contemporary secondary sources in every Wikipedia. For example, let see article "Feinstrukturkonstante" in German Wikipedia in paragraph "Vergleich der Grundkräfte der Physik". There's formula
where is equal to according to idea of American physicist A. C. Lunn.
Yet another example there is in Russian Wikipedia in the same article "Постоянная тонкой структуры" in paragraph "Ранние попытки". There's formula of A. C. Lunn:
Unfortunately, Mfb continues to show the invisible arguments like "just severe misconceptions". It looks like very personal. Алры ( talk) 14:03, 6 April 2019 (UTC)
According to Chetvorno I was right from the beginning. There are no arguments against my addition yet. Please, restore it. Or, please, explain specifically why you don't want to see it. It would be interesting to know.
Maybe, you just don't know that the stars are made from hot hydrogen? — Preceding unsigned comment added by Алры ( talk • contribs) 17:00, 6 April 2019 (UTC)
Should the article assert the fundamentalism of the Gravitational constant or
discuss the constant as a combination which can be assembled as a puzzle from other physical and math constants?
For example:
where
- reduced Planck constant;
- speed of light;
- average mass of neutron and proton + electron pair;
Mikhail Vlasov
Korablino (
talk)
20:38, 19 February 2018 (UTC)
Hi Chetvorno. Yes, I agree with attributing this to numerology. My question was - should article discuss next topic: is Gravitational constant a "prime" or is it a formation of other constants.
Hi Mfb. Agree with you as well except one thing. Fine Structure constant reciprocal itself is a composition of 137 and .
Korablino (
talk)
23:52, 19 February 2018 (UTC)
Yes. Instead of it is possible to use . Korablino ( talk) 19:05, 20 February 2018 (UTC)
Well, in the spirit of
notability, not truth, such speculation should be reported if made by someone with a reputation to lose.
It may still be complete coincidence, but it's worth reporting
if Dirac does it.
Perhaps just getting it published in a reputable journal would be enough, you don't need Dirac-levels of credibility.
The above seems quite random (as was pointed out, alpha != 1/137), but I find this quite funny,
or this,
These are both preprints, idk if either was published, but I am sure this type of paper is out there, and if based on published sources, this page certainly has room for a "numerology" section. Sure, you can always come up with this type of stuff, so it needs to pass some minimal threshold of peer review before it can even be considered amusing, but sooner or later one of these may just turn out to be meaningful. -- dab (𒁳) 10:09, 9 June 2018 (UTC)
The general consensus is, for the following reason, that G is somehow derivative rather than fundamental, so that there is indeed some kind of composite formula (so that all candidate formulas have to be taken seriously, if they fit). The reason is this: in higher dimensional theories, including Kaluza-Klein, supergravity and string theory, the coupling coefficient will be that for the higher-dimensional version of Einstein's equations, while the 4-dimensional version of Einstein's equations will fall out of this (by a process of dimensional reduction) from the higher-dimensional field equations. The coupling coefficient for the lower-dimensional Einstein equations will be a composite formed ultimately of the higher dimensional coupling coefficient and possibly integral expressions involving the extra dimensions (e.g. the arclength of the circle in 5D Kaluza-Klein, if the extra dimension is wrapped in a circle). Note that the units don't even match. For the Einstein equations, the coupling coefficient in n-dimensions, √(Aⁿ⁻²)T/ML², where L denotes length, T time, M mass and A = [g_{μν} dx^μ dx^ν], the dimensions of the line element, which is normally taken as A = L². The coupling κ comes out of the Einstein-Hilbert action S = ∫ (1/2κ) R √|g| dⁿx, which has dimensions [S] = ML²/T. In n-dimensions [√|g| dⁿx] = √(Aⁿ), [R] = 1/A, which implies [κ] = √(Aⁿ⁻²)T/ML² = TLⁿ⁻⁴/M. For 4D, that's [κ₄] = T/M, while for (say) 5D it would be [κ₅] = TL/M. The Newton coefficient G comes out of κ₄/8π up to powers of light speed, c; but - on these dimensional grounds alone - cannot be extracted from κ₅ (nor from the coupling for any other higher-dimensional theory) directly in this way. Instead, it has to emerge as a composite of some kind. — Preceding unsigned comment added by 2603:6000:AA40:1EF2:222:69FF:FE4C:408B ( talk) 18:58, 12 August 2020 (UTC)
The current revision is an exercise in weasel wording, "There is a good approximate 'Theory of everything' relation", "The relation can be justified for example" -- oh really, it "can" be justified? This isn't acceptable, the only thing we are interested in here is: who has proposed this in what year and in what publication, and how has the suggestion been received since? It doesn't need to be part of the mainstream consensus, but the further away it is from the mainstream, the more the text needs to focus on qualifying exactly who came up with it, when and where, and how others have reacted to it. If no experts bothered reacting to it, i.e. not even dismissively, it has no business being in the article. -- dab (𒁳) 07:23, 16 April 2021 (UTC)
In
what is the "h" that is squared? — Quantling ( talk | contribs) 18:34, 27 March 2023 (UTC)
What is the gravitational constant (6.67408 * 10^-11) converted to imperial units (in ft and lb instead of m and kg)? 212.186.0.174 ( talk) 12:58, 19 May 2019 (UTC)
In a comment, @ TowardsTheLight: writes "the text defines F as the attractive force. No negative sign is needed for this case where the force is defined to be attractive". I agree that no negative sign is needed when the force is defined to be attractive. However, my experience (and maybe yours too?) is that Gmm/r^2 gravitational force is almost always written with a negative sign. I don't think that we are doing the reader any favors by going counter to this convention. I would rather go with convention by giving the minus sign in the equation, and adjust the text so that it works with the equation. Might something along those lines work? — Quantling ( talk | contribs) 21:46, 27 March 2023 (UTC)
<ref>...</ref>
markup, or would the change I am proposing meet with sufficient approval? —
Quantling (
talk |
contribs)
16:18, 29 March 2023 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 |
It's exceedingly obvious to me how to measure big G precisely and incontrovertibly. Send two space ships of equal and known mass into space. One of them will be placed within the pull of earth, but lined up directly under the moon. The other will be at the opposite side of earth farthest from the moon. Instruments on board the ships will all be fastened down so that the momentum of an object banging around inside the ship cannot distort the readings. There should be nothing in the ships that is not bolted firmly to the ship. When the ships are both in place, they will both be equidistant from the center of earth (not the height above land or sea level, because those both vary). The ships will then have all motion stopped such that they stay exactly in-line with the line that would join the exact center of the earth and the exact center of the moon. They are now allowed to drop to earth in complete freefall while instruments on board the ships measure their exact locations above the center of earth, using GPS and other measuring systems, and they would also measure the precise time that the space ships are at every altitude. It should be noted that the best design of these space ships would be a perfect sphere to minimize variations and differences due to wind resistance and the center of gravity in the lower atmosphere. Measuring Instruments should be in the dead center of the space crafts. There should be no humidity or rain or anything else on the day of the experiment, that is in line with the space ships' descent paths that would exert undue air resistance. Since a sphere is unwieldy to control, a secondary craft would need to carry the spheres to space before dropping them. This would help with knowing exactly how much the measuring crafts weighed since burned fuel changes the payload weight. The spheres would be reweighed on earth after a water or other safe landing, for added weight accuracy redundancy. After the data from the spheres is harvested, extremely accurate calculations can be made because of all the known variables and the large size of the objects in the experiment (space craft, the earth, the moon). Wind resistance would be minimized while the crafts are in space. The experiment will also be free of local distortions due to the gravity exerted by nearby mountains, buildings, and other objects, especially at the highest altitudes away from the earth. The experiment should ideally be repeated a total of at least 3 times to ensure accuracy and to account for the minor difference in gravity formed by bulging oceans and really tall mountain ranges. Varying conditions could be checked. Having the two space craft at opposite ends from the moon will allow for calculations based on the distance and mass of the earth and the moon, giving even greater accuracy through redundancy and two separate calculations. No measurement of big G can be completely perfect, but this is as close as we can come. The quantum/atomic measurement system used by other researchers may or may not hold true for large objects obeying "normal" laws of gravity, so the experiment above would be incontrovertible in this regard. — Preceding unsigned comment added by 70.193.36.108 ( talk) 08:11, 19 May 2016 (UTC)
To the poster below: The two quantities are related by g=(GMe)÷(r^2e) what are you missing to do the calculation?
A highly precise estimate of the mass of the moon and every object in the solar system is possible by observing its size and chemical composition using astronomical spectrometry. Also, numerous spacecraft have used these masses in calculations that have helped them to fly to distant places without error. The precision of decimal places in the experiment above would far exceed the atom interferometry experiment because the mass of the objects can be measured more accurately and to a higher precision whereas atomic masses are inferred. Regardless, the atom interferometry would of course be subject to your same GM issue as the space experiment, since you would be measuring the gravity due to earth.
Nevertheless, the attraction between multiple bodies of known mass is the same concept that the Cavendish torsion balance uses, only the spacecraft idea above gets rid of most of the errors due to various frictional forces and local gravity phenomenons. — Preceding unsigned comment added by 70.199.243.40 ( talk) 13:25, 19 May 2016 (UTC)
Oh, and if the spacecraft experiment was performed it would give a massive improvement to the article (and the science community) since the gravitational constant could be univocally defined. That's the whole point of the article: defining the so-called constant. — Preceding unsigned comment added by 70.199.243.40 ( talk) 13:34, 19 May 2016 (UTC)
This was commented out in the article, I am moving it here for future reference:
-- dab (𒁳) 09:40, 9 June 2018 (UTC)
A useful interpretation was added. Just used mass of proton instead of mass of electron. Алры ( talk) 21:20, 4 April 2019 (UTC)
Please, show me mistake if you can. Алры ( talk) 23:38, 4 April 2019 (UTC)
I repeated addition of the same content because it was deleted without demonstrating where I was wrong as Mfb stated. It was not shown yet. Now Mfb made another wrong statement that my addition is a random coincidence. It is obvious for anyone who knows physics that 18th degree of fine structure constant does not allow such a speculation. Even more it explains the known difficulties with getting accuracy of G. Yet another wrong argument is about our completely arbitrary choice of units. Actually my addition was made to avoid such a problem. The attached mass of the proton is natural unit unlike G.
Chetvorno stated that my addition was inadequately sourced. It is not true. I gave primary source to show that this idea appeared on American soil just after 6 years after the fine structure constant was introduced. Now there are a lot of the contemporary secondary sources. Chetvorno also stated that I added a controversial content to the article. Please, be specific.
I don't see arguments against my addition. Алры ( talk) 14:55, 5 April 2019 (UTC)
There are the contemporary secondary sources in every Wikipedia. For example, let see article "Feinstrukturkonstante" in German Wikipedia in paragraph "Vergleich der Grundkräfte der Physik". There's formula
where is equal to according to idea of American physicist A. C. Lunn.
Yet another example there is in Russian Wikipedia in the same article "Постоянная тонкой структуры" in paragraph "Ранние попытки". There's formula of A. C. Lunn:
Unfortunately, Mfb continues to show the invisible arguments like "just severe misconceptions". It looks like very personal. Алры ( talk) 14:03, 6 April 2019 (UTC)
According to Chetvorno I was right from the beginning. There are no arguments against my addition yet. Please, restore it. Or, please, explain specifically why you don't want to see it. It would be interesting to know.
Maybe, you just don't know that the stars are made from hot hydrogen? — Preceding unsigned comment added by Алры ( talk • contribs) 17:00, 6 April 2019 (UTC)
Should the article assert the fundamentalism of the Gravitational constant or
discuss the constant as a combination which can be assembled as a puzzle from other physical and math constants?
For example:
where
- reduced Planck constant;
- speed of light;
- average mass of neutron and proton + electron pair;
Mikhail Vlasov
Korablino (
talk)
20:38, 19 February 2018 (UTC)
Hi Chetvorno. Yes, I agree with attributing this to numerology. My question was - should article discuss next topic: is Gravitational constant a "prime" or is it a formation of other constants.
Hi Mfb. Agree with you as well except one thing. Fine Structure constant reciprocal itself is a composition of 137 and .
Korablino (
talk)
23:52, 19 February 2018 (UTC)
Yes. Instead of it is possible to use . Korablino ( talk) 19:05, 20 February 2018 (UTC)
Well, in the spirit of
notability, not truth, such speculation should be reported if made by someone with a reputation to lose.
It may still be complete coincidence, but it's worth reporting
if Dirac does it.
Perhaps just getting it published in a reputable journal would be enough, you don't need Dirac-levels of credibility.
The above seems quite random (as was pointed out, alpha != 1/137), but I find this quite funny,
or this,
These are both preprints, idk if either was published, but I am sure this type of paper is out there, and if based on published sources, this page certainly has room for a "numerology" section. Sure, you can always come up with this type of stuff, so it needs to pass some minimal threshold of peer review before it can even be considered amusing, but sooner or later one of these may just turn out to be meaningful. -- dab (𒁳) 10:09, 9 June 2018 (UTC)
The general consensus is, for the following reason, that G is somehow derivative rather than fundamental, so that there is indeed some kind of composite formula (so that all candidate formulas have to be taken seriously, if they fit). The reason is this: in higher dimensional theories, including Kaluza-Klein, supergravity and string theory, the coupling coefficient will be that for the higher-dimensional version of Einstein's equations, while the 4-dimensional version of Einstein's equations will fall out of this (by a process of dimensional reduction) from the higher-dimensional field equations. The coupling coefficient for the lower-dimensional Einstein equations will be a composite formed ultimately of the higher dimensional coupling coefficient and possibly integral expressions involving the extra dimensions (e.g. the arclength of the circle in 5D Kaluza-Klein, if the extra dimension is wrapped in a circle). Note that the units don't even match. For the Einstein equations, the coupling coefficient in n-dimensions, √(Aⁿ⁻²)T/ML², where L denotes length, T time, M mass and A = [g_{μν} dx^μ dx^ν], the dimensions of the line element, which is normally taken as A = L². The coupling κ comes out of the Einstein-Hilbert action S = ∫ (1/2κ) R √|g| dⁿx, which has dimensions [S] = ML²/T. In n-dimensions [√|g| dⁿx] = √(Aⁿ), [R] = 1/A, which implies [κ] = √(Aⁿ⁻²)T/ML² = TLⁿ⁻⁴/M. For 4D, that's [κ₄] = T/M, while for (say) 5D it would be [κ₅] = TL/M. The Newton coefficient G comes out of κ₄/8π up to powers of light speed, c; but - on these dimensional grounds alone - cannot be extracted from κ₅ (nor from the coupling for any other higher-dimensional theory) directly in this way. Instead, it has to emerge as a composite of some kind. — Preceding unsigned comment added by 2603:6000:AA40:1EF2:222:69FF:FE4C:408B ( talk) 18:58, 12 August 2020 (UTC)
The current revision is an exercise in weasel wording, "There is a good approximate 'Theory of everything' relation", "The relation can be justified for example" -- oh really, it "can" be justified? This isn't acceptable, the only thing we are interested in here is: who has proposed this in what year and in what publication, and how has the suggestion been received since? It doesn't need to be part of the mainstream consensus, but the further away it is from the mainstream, the more the text needs to focus on qualifying exactly who came up with it, when and where, and how others have reacted to it. If no experts bothered reacting to it, i.e. not even dismissively, it has no business being in the article. -- dab (𒁳) 07:23, 16 April 2021 (UTC)
In
what is the "h" that is squared? — Quantling ( talk | contribs) 18:34, 27 March 2023 (UTC)
What is the gravitational constant (6.67408 * 10^-11) converted to imperial units (in ft and lb instead of m and kg)? 212.186.0.174 ( talk) 12:58, 19 May 2019 (UTC)
In a comment, @ TowardsTheLight: writes "the text defines F as the attractive force. No negative sign is needed for this case where the force is defined to be attractive". I agree that no negative sign is needed when the force is defined to be attractive. However, my experience (and maybe yours too?) is that Gmm/r^2 gravitational force is almost always written with a negative sign. I don't think that we are doing the reader any favors by going counter to this convention. I would rather go with convention by giving the minus sign in the equation, and adjust the text so that it works with the equation. Might something along those lines work? — Quantling ( talk | contribs) 21:46, 27 March 2023 (UTC)
<ref>...</ref>
markup, or would the change I am proposing meet with sufficient approval? —
Quantling (
talk |
contribs)
16:18, 29 March 2023 (UTC)