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| − | The '''Variations in Gravity''' are the supposed variations to gravity due to either the gravity gradient of the earth or the presence of masses such as hills or celestial bodies. Numerous tests have been conducted in search of these variations. | + | The '''Variations in Gravity''' are the supposed variations to gravity due to either the variations in strength of the gravitational field of the earth or due to the presence of masses such as hills or celestial bodies. It is often stated that the strength of gravity decreases with altitude or that the gravity of the Sun and Moon pulls upon the earth's surface. However, the experiments either do not show variation or the few effects suggesting variations are questionable, contradicted, and may be attributed to other causes. |
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| − | It had been found that on Medium, Long, and Celestial ranges experimental evidence has shown that "gravity" deviates from the Universality of Free Fall and the Equivalence Principle at all. Gravity behaves as if the earth is accelerating upwards and there are no other gravitating sources around us. On shorter ranges, such as with the [[Cavendish Experiment]], it has been seen that the attraction is not consistent or accurate The detection of gravity was inconsistent, suggesting that there are other effects at that range creating those results.
| + | ==Celestial Tests== |
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| − | ==Celestial Variations in G==
| + | It is alleged that the Sun and Moon exerts a gravitational pull upon the earth. Very sensitive torsion balance experiments have been conducted over a period of 24 hours, showing that experiments are not affected by external sources as to cause a violation of the equivalence principle. External gravity sources, such as from the Sun, are unable be felt. |
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| − | The Equivalence Principle Torsion Balance tests are incredibly reliable precision machines which are used to measure the Equivalence Principal to increasing sensitivity. Experimenters have redesigned the Equivalence Principle's Torsion Balance tests to try and detect the gravity variations caused by the sun, moon, and the tidal forces. It was found that the gravitational influence of the sun, moon, or the tidal forces could not be measured as manifest of the attraction of the bodies in the experiments. Variations to "gravity" did not appear.
| + | *'''[https://wiki.tfes.org/Torsion_Balance_Tests#Celestial_Variations_in_G Torsion Balance Tests - Celestial Variations in G]''' - The gravitational effects from the Sun are unable to be detected in laboratory experiments |
| − | Contents
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| − | ===Princeton Experiment===
| + | See Also: |
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| − | From 'The Pendulum Paradigm: Variations on a Theme and the Measure of Heaven and Earth', by Professor Martin Beech, [https://books.google.com/books?id=qumVBAAAQBAJ&lpg=PA176&ots=7zlmtFg8WI&pg=PA176#v=onepage&q&f=false we read the following] on p.176:
| + | *'''[[Tides]]''' - The workings of the tides appear unrelated to the the Moon |
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| − | [[File:Torsion-equivelence.png|800]]
| + | ==Altitude Tests== |
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| − | Essentially, the experiment is summarized as follows:
| + | It has been found in experiments on various ranges that "gravity" does not deviate from the Universality of Free Fall or the Equivalence Principle. The Equivalence Principle is a principle of nature which says that 'gravity' behaves as if the experiment were conducted on an Earth or in a container which was accelerating upwards. Supposedly only a 'local' concept, experimenters have tested this concept at various scales without violation of this principle. |
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| − | {{cite|In the Princeton experiment the balance arm was oriented in a North-South direction (figure 4.13), and '''the idea was to see if a difference in the Sun's gravitational influence on the suspended masses could be detected'''. Specifically, as the Earth spins on its axis and difference between '''the Sun's gravitational interaction with the two masses will result in a 24 hour modulation''' or oscillation, in the orientation of the balance arm as seen in the laboratory. '''The Princeton group found no modulation''' of the torsion balance, and concluded that the Sun's gravitational acceleration on identical aluminum and gold masses was the same to one part in one hundred billion.}}
| + | *'''[[Gravitational Time Dilation]]''' - Time dilates in accordance with the uniform prediction of the Equivalence Principal to various heights |
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| − | The masses were not attracted to the sun in the experiment, to an accuracy of one part in one hundred billion.
| + | ==Latitude Tests== |
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| − | ===Moscow State University Experiment===
| + | It is alleged that gravity varies by latitude due to a combination of the effects of the rotation of the earth and the bulging mass at the equator. Experiments performed with scales exposed to the atmosphere have shown that weight increases by a fraction of one percent near the polar areas, as compared to areas near the warmer equator. However, ''weight'' is also affected by factors outside of 'gravity'. It is also related to a buoyancy related to pressure, humidity, air viscosity, temperature, etc, which exist differently in different locations, and which may contribute in complex ways to the readings of the scale. |
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| − | The experiment was repeated and improved by researchers at Moscow State University. The title of the paper states the conclusion:
| + | *'''[[Weight Variation by Latitude]]''' - Variations in weight by latitude appear in an uncontrolled scale experiment |
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| − | '''Verification of the Equivalence of Inertial and Gravitational Mass'''<br>
| + | In contradiction to this, experiments conducted with sensitive clocks at different latitudes show that the expected time dilation due to velocity does not occur in response to the different latitudinal velocities of the earth. |
| − | V. B. Branginsky and V. I. Panov<br>
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| − | [http://www.jetp.ac.ru/cgi-bin/dn/e_034_03_0463.pdf Full Text Link] ([https://web.archive.org/web/20190115061724/http://www.jetp.ac.ru/cgi-bin/dn/e_034_03_0463.pdf Archive])
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| − | {{cite|During the period 1959-1964 the principle of equivalence was again tested by Dicke, Krotkov, and Roll. [2] A hypothetical difference between the accelerations of two bodies, made of gold and aluminum, respectively, in the gravitational field of the sun was measured. From measurements conducted during many months it was concluded that the ratio of the inertial and gravitational masses for these two bodies does not differ by more than 3 x 10<sup>-11</sup> with 95% confidence.[2] An analysis of the experimental work in [2] shows that it is possible, in principle, to considerably improve the resolution by using a mechanical oscillatory system having a long relaxation time.[3] We shall here describe an experiment intended as a new test of the principle of equivalence.
| + | *'''[[Time Dilation by Latitude]]''' - The predicted time dilation caused by Earth's rotation does not occur |
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| − | 1. MEASUREMENT TECHNIQUE
| + | ==Landmass Tests== |
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| − | We retained the experimental scheme of Dicke, Krotkov, and Roll. [2] A torsion balance falling together with the earth in the gravitational field of the sun should be acted upon by a torsional mechanical moment that is proportional to a hypothetical difference between the accelerations of the materials comprising the balance (if the principle of equivalence is not fulfilled). Because of the earth's rotation this moment should vary sinusoidally with a 24-hour period (Fig. 1).}}
| + | The theory of the universal gravitation of mass leads to the expectation that the mountain ranges should produce a larger gravitational pull than the plains, owing to the greater bulk mass in the area. However, gravity measurements show that the mountains are associated with ''negative'' gravity anomalies. |
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| − | ===Repetitions===
| + | *'''[[Isostasy]]''' - The mass attraction of mountains and continents does not behave in accordance with 'gravity' |
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| − | Additional experiments of this class [http://202.38.64.11/~jmy/documents/publications/equivalence%20principle.htm are described] ([http://archive.fo/RI0ld Archive]). The two experiments experiment in this list is the Princeton and Moscow State experiments above:
| + | ===Gravimeters=== |
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| − | {| class="wikitable"
| + | Mainstream materials on the gravimeter device used to study the Earth's gravity show that it is not studying gravity directly. The device is described as studying density variations in the subseismic band assumed to be caused to gravity, where phenomena such as the tides are observed. Gravimeters can be double purposed as seismometers, seismometers can be double purposed as gravimeters, and the gravity anomalies are associated with the seismic zones. |
| − | ! Authors
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| − | ! Year
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| − | ! Description
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| − | ! Accuracy
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| − | |-
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| − | | Roll, Krotkov and Dicke
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| − | | 1964
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| − | | Torsion balance experiment, dropping aluminum and gold test masses
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| − | | difference is less than one part in one hundred billion
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| − | |-
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| − | | Branginsky and Panov
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| − | | 1971
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| − | | Torsion balance, aluminum and platinum test masses, measuring acceleration towards the sun
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| − | | difference is less than 1 part in a trillion (most accurate to date)
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| − | |-
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| − | | Eöt-Wash
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| − | | 1987–
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| − | | Torsion balance, measuring acceleration of different masses towards the earth, sun and galactic center, using several different kinds of masses
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| − | | difference is less than a few parts in a trillion
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| − | |}
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| − | The Eöt-Wash experiments were repeated by others:
| + | *'''[[Gravimetry]]''' - Gravimeters are described to be seismometers by mainstream sources<br><br> |
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| − | https://plato.stanford.edu/entries/physics-experiment/app4.html ([http://archive.fo/gjFJS Archive])
| + | [[Category:General Physics]] |
| − | | + | [[Category:Gravity]] |
| − | {{cite|The torsion-balance experiments of Eöt-Wash were repeated by others including (Cowsik et al. 1988; Fitch, Isaila and Palmer 1988; Adelberger 1989; Bennett 1989; Newman, Graham and Nelson 1989; Stubbs et al. 1989; Cowsik et al. 1990; Nelson, Graham and Newman 1990). '''These repetitions, in different locations and using different substances, gave consistently negative results.'''}}
| + | [[Category:Universal Acceleration]] |
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| − | ==Long Range Variations in G==
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| − | ===Universality of Free Fall===
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| − | '''The Newtonian gravitational constant: recent measurements and related studies'''<br>
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| − | By George T Gillies
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| − | https://iopscience.iop.org/article/10.1088/0034-4885/60/2/001/pdf
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| − | p.200
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| − | '''5. Searches for variations in G<br>
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| − | 5.1. Spatial dependence of G'''
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| − | {{cite|Searches for a change in G with intermass spacing have constituted a compelling quest in laboratory gravitation, especially during the past 25 years. The motivations for carrying out this kind of study were originally empirical, with the results of various benchtop experiments being interpreted in terms of either a value for or limit on some distance-dependent form of the gravitational constant (i.e. a G(r) effect), or in terms of a breakdown in the inverse square law (i.e. a modification to it of the form 1/r<sup>2+δ</sup>, where δ is the departure parameter). Then, in the 1980s, observations that seemingly revealed evidence for non-Newtonian gravity at larger distance scales (Stacey et al 1987) fuelled much additional interest in this line of work. The contemporaneous suggestion by Fischbach et al (1986) that there may be previously undiscovered, weak, long-range forces in nature provided further impetus for investigating the composition- and distance-dependence of gravity, since the presence of any such effect might reveal the existence of a new force. During this time, a theoretical framework for admitting non-Newtonian effects into discussions of the experimental results was emerging. It led to the practice of using the laboratory data to set limits on the size of the strength-range parameters in a Yukawa term added onto the Newtonian potential, and this has become a standard method for intercomparing the results of this class of experiments. '''Even though convincing evidence in favour of such new weak forces was never found, the many resulting experiments, when viewed as tests of the universality of free-fall, did much to improve the experimental underpinnings of the weak equivalence principle (WEP) of general relativity. In fact, searches for departures from the inverse square behaviour of Newtonian gravity have now come to be interpreted as attempts to uncover violations of the WEP.'''}}
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| − | p.202
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| − | {{cite|Other recent experimental searches for a breakdown in Newtonian gravity at large distances include a second set of tower gravity measurements made by Romaides et al (1994). '''Their data, taken at five points over a nearly 500m vertical rise, reconfirmed the exactness of the inverse square law.''' A similar result over a vertical distance of approximately 320 m was obtained at a meteorological tower in China by Liu et al (1992).}}
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| − | ==Medium Range Variations in G==
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| − | ===Eöt-Wash Hill Experiments===
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| − | From [https://books.google.com/books?id=_RN-v31rXuIC&lpg=PA70&ots=eEYQg9MqLO&dq=eot%20wash%20hill%20experiment&pg=PA70#v=onepage&q&f=false No Easy Answers: Science and the Pursuit of Knowledge] by Allan Franklin, on p.70 we read a summary of the Eöt-Wash hillside experiments with the rotating torsion balance:
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| − | {{cite|The Eöt-Wash experiment used a torsion pendulum located on the side of a hill on the University of Washington campus. If the hill attracted the copper and beryllium test bodies that were used in the apparatus differently, then the torsion balance would experience a net torque. '''None was observed'''.}}
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| − | [https://books.google.com/books?id=Ke32COxghksC&lpg=PA446&ots=dYem2HX5qf&dq=eot%20wash%20hill%20experiment&pg=PA445#v=onepage&q&f=false Study Link]
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| − | An [https://www.npl.washington.edu/eotwash/sites/sand.npl.washington.edu.eotwash/files/documents/publications/schlamminger_AAPT07.pdf Eöt-Wash presentation explains] ([https://web.archive.org/web/20190114182230/https://www.npl.washington.edu/eotwash/sites/sand.npl.washington.edu.eotwash/files/documents/publications/schlamminger_AAPT07.pdf Archive]) that the influence of an external source mass on these type of experiments would be a violation of the Equivalence Principle (EP).
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| − | [[File:Eot-wash-experiment.png|600px]] | |
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| − | ==Short Range Variations in G==
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| − | ==History of the Torsion Balance==
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| − | The history of the Torsion Balance experiments began in 1889, with Barron Rosland von Eötvös' attempt to detect the [https://wiki.tfes.org/The_Coriolis_Effect Coriolis force.]
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| − | '''Foundations of Modern Cosmology'''<br>
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| − | By [https://en.wikipedia.org/wiki/John_F._Hawley Professor John F. Hawley], and Katherine A. Holcomb
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| − | From [https://books.google.com/books?id=s5MUDAAAQBAJ&lpg=PA219&ots=W9HMFR84Lu&pg=PA219#v=onepage&q&f=false p.219 of the above text] we read:
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| − | {{cite|The first highly accurate experiment to test the equivalence principle was performed in 1889 by Barron Rosland von Eötvös. Eötvös constructed a device called a torsion balance. He suspended two bodies of nearly equal mass but different composition, from a beam which hung from a very fine wire precisely at its center. If the magnitudes of the Coriolis force (from the Earth's rotation) and the gravitational force had differed between the bodies due to their differing composition, Eötvös would have been able to detect a twisting of the wire. '''None was seen''', and Eötvös was able to conclude that inertial and gravitational mass was equal, to approximately one part in 10^9. In the 20th century, Robert Dicke and others pushed the limit of such an experiment to 10^11, but the Baron's results were sufficient to convince many, including Einstein, that inertial mass and gravitational mass are equivalent.}}
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The Variations in Gravity are the supposed variations to gravity due to either the variations in strength of the gravitational field of the earth or due to the presence of masses such as hills or celestial bodies. It is often stated that the strength of gravity decreases with altitude or that the gravity of the Sun and Moon pulls upon the earth's surface. However, the experiments either do not show variation or the few effects suggesting variations are questionable, contradicted, and may be attributed to other causes.
Celestial Tests
It is alleged that the Sun and Moon exerts a gravitational pull upon the earth. Very sensitive torsion balance experiments have been conducted over a period of 24 hours, showing that experiments are not affected by external sources as to cause a violation of the equivalence principle. External gravity sources, such as from the Sun, are unable be felt.
See Also:
- Tides - The workings of the tides appear unrelated to the the Moon
Altitude Tests
It has been found in experiments on various ranges that "gravity" does not deviate from the Universality of Free Fall or the Equivalence Principle. The Equivalence Principle is a principle of nature which says that 'gravity' behaves as if the experiment were conducted on an Earth or in a container which was accelerating upwards. Supposedly only a 'local' concept, experimenters have tested this concept at various scales without violation of this principle.
Latitude Tests
It is alleged that gravity varies by latitude due to a combination of the effects of the rotation of the earth and the bulging mass at the equator. Experiments performed with scales exposed to the atmosphere have shown that weight increases by a fraction of one percent near the polar areas, as compared to areas near the warmer equator. However, weight is also affected by factors outside of 'gravity'. It is also related to a buoyancy related to pressure, humidity, air viscosity, temperature, etc, which exist differently in different locations, and which may contribute in complex ways to the readings of the scale.
In contradiction to this, experiments conducted with sensitive clocks at different latitudes show that the expected time dilation due to velocity does not occur in response to the different latitudinal velocities of the earth.
Landmass Tests
The theory of the universal gravitation of mass leads to the expectation that the mountain ranges should produce a larger gravitational pull than the plains, owing to the greater bulk mass in the area. However, gravity measurements show that the mountains are associated with negative gravity anomalies.
- Isostasy - The mass attraction of mountains and continents does not behave in accordance with 'gravity'
Gravimeters
Mainstream materials on the gravimeter device used to study the Earth's gravity show that it is not studying gravity directly. The device is described as studying density variations in the subseismic band assumed to be caused to gravity, where phenomena such as the tides are observed. Gravimeters can be double purposed as seismometers, seismometers can be double purposed as gravimeters, and the gravity anomalies are associated with the seismic zones.
- Gravimetry - Gravimeters are described to be seismometers by mainstream sources
