Determination of the Gravitational Constant<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>G</mml:mi></mml:math>

Rose, Robert; Parker, H. M.; Lowry, R. A.; Kuhlthau, A. R.; Beams, J. W.

doi:10.1103/physrevlett.23.655

Cited by 75 publications

(21 citation statements)

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“…1. The source masses are sintered tungsten spheres approximately four inches in diameter weighing 10.489 980 and 10.490 250 kg each, and have been used in previous experiments [10,11]. These spheres are situated upon a round table of Cervit glass held by a nonmagnetic aluminum air bearing.…”

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confidence: 99%

Preliminary Results of a Determination of the Newtonian Constant of Gravitation: A Test of the Kuroda Hypothesis

1997

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Two preliminary determinations of the Newtonian constant of gravitation have been performed at Los Alamos National Laboratory employing low-Q torsion pendulums and using the time-of-swing method.Recently, Kuroda has predicted that such determinations have an upward bias inversely proportional to the oscillation Q, and our results support this conjecture. If this conjecture is correct, our best value for the constant is ͑6.6740 6 0.0007͒ 3 10 211 m 3 kg 21 s 22 .Interest in the value of the Newtonian gravitational constant, G, has increased recently with the publication of several disparate results [1][2][3][4]. This discrepancy, as much as 50 standard deviations, is an error unheard of in the measurement of any other of the fundamental constants. A torsion pendulum instrument has been assembled at Los Alamos National Laboratory which determines G by the method of Heyl, also called the time-of-swing method, and preliminary results of this effort are reported herein. Kuroda has shown [5] that popular models of anelasticity predict a bias in these determinations where the damping of the pendulum is caused by losses in the suspension fiber, and this upward fractional bias should be 1͞pQ. Two determinations were carried out employing systems which differ in Q by a factor of 2, and the disagreement of their results is consistent with that predicted by Kuroda.In a time-of-swing, or Heyl-type, measurement, the oscillation frequency of a torsion pendulum is perturbed by the presence of source masses. In their absence, the free oscillation frequency, squared, is related to the moment of inertia, I, and fiber torsion constantThe interaction potential energy of the pendulum and source masses, U g ͑w͒, contributes a "gravitational torsion constant,"where w is the angle between the axis of the pendulum and that of the source masses. Therefore, the frequency of small oscillations of the pendulum isThe gravitational torsion constant is at a maximum when the pendulum is in line with the source masses (w 0, or "near" position), and at a minimum when it is perpendicular (w p͞2, or "far" position). It is proportional to G, and is calculable from the geometry and densities of the pendulum and masses, so the gravitational constant is given bywhere k g K g ͞G, and D͑v 2 ͒ is the difference of the square of the frequencies recorded at the two orientations.The above derivation assumes that k g remains the same at each orientation, but this assumption has been called into question recently. Interest in gravitational wave detectors has spurred research into the anelastic properties of suspension materials at low frequencies, and one model of anelasticity has been shown [6-8] to predict accurately the behavior of several different materials. This model treats a physical spring as a perfectly elastic spring in parallel with a continuous number of Maxwell units, characterized by a spectrum of relaxation times. The model predicts that the torsion constant is a function of oscillation frequency. Kuroda [5] has shown that, for a Heyl-type measu...

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confidence: 99%

Preliminary Results of a Determination of the Newtonian Constant of Gravitation: A Test of the Kuroda Hypothesis

1997

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“…an uncertainty of 210 ppm) by Luther et al [61]. Several interim results and technology development studies were also reported by Rose [62], Rose et al [63], Towler & McVey [64], Towler et al [65] and Lowry et al [66]. The same tungsten-sphere source masses were used throughout the entire series of measurements.…”

Section: Source Masses: a Specific Examplementioning

confidence: 81%

The attracting masses in measurements of G : an overview of physical characteristics and performance

Gillies

Unnikrishnan

2014

Phil. Trans. R. Soc. A.

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Simple spheres and cylinders have been the geometries employed most frequently, but not uniquely, for the attracting masses used historically in measurements of the Newtonian gravitational constant G . We present a brief overview of the range of sizes, materials and configurations of the attracting masses found in several representative experimental arrangements. As one particular case in point, we present details of the large tungsten spheres designed originally by Beams, which have been incorporated into several different apparatuses for measuring G over the past 50 years. We also consider the question of possible systematic dependence of the results and their precision on the size of the large masses/mass systems that have been employed to date. We close with some considerations for possible future work.

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“…Another dynamic method is the angular acceleration method. This method was first proposed by Beam et al in 1965 [39], and Rose et al had performed an experiment and determined G with an uncertainty of 1800 ppm in 1969 [40]. Gundlach and Merkowitz used the angular acceleration feedback method to measure G with an uncertainty of 14 ppm at the University of Washington in 2000 [22].…”

Section: Determining G With Torsion Pendulamentioning

confidence: 99%

Determination of the gravitational constant G

Liu

Luo

2006

Front. Phys. China

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A precise knowledge of the Newtonian gravitational constant G has an important role in physics and is of considerable meteorological interest. Although G was the first physical constant to be introduced and measured in the history of science, it is still the least precisely determined of all the fundamental constants of nature. The 2002 CODATA recommended value for G, G = (6.6742 ± 0.0010) × 10 −11 m 3 ⋅ kg −1 ⋅ s −2 , has an uncertainty of 150 parts per million (ppm), much larger than that of all other fundamental constants. Reviewed here is the status of our knowledge of the absolute value of G, methods for determining G, and recent high precision experiments for determining G.

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Determination of the Gravitational ConstantG

Cited by 75 publications

References 6 publications

Preliminary Results of a Determination of the Newtonian Constant of Gravitation: A Test of the Kuroda Hypothesis

Preliminary Results of a Determination of the Newtonian Constant of Gravitation: A Test of the Kuroda Hypothesis

The attracting masses in measurements of G : an overview of physical characteristics and performance

Determination of the gravitational constant G

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