Finding a better value for G

MAY 01, 1971

Surprisingly, we know the gravitational constant only to within about half a percent. With this elegant method, we hope for a precision of at least one part in ten thousand.

DOI: 10.1063/1.3022732

Jesse W. Beams

The gravitational proportionality constant G, although one of the first constants measured and perhaps the most fundamental and universal constant in Nature, is now the least accurately known. G, which relates the force F between two particles to their masses $m_{1}$ and $m_{2}$ and the distance d between them ${F = −Gm}_{1} m_{2} {/d}^{2}$ is now known only with an accuracy of about one half of one percent. Because many contemporary techniques, such as in geophysics, require a good knowledge of G, as well as for purely theoretical interests, a group of us at the University of Virginia, Charlottesville, have been developing the apparatus shown in figure 1 to measure the absolute value of G as well as its possible variation with time or other factors.

References

1. R. H. Dicke, The Theoretical Significance of Experimental Relativity, Gordon and Breach, New York (1964).
2. F. C. Champion, N. Davy, Properties of Matter, Blackie, Glasgow (1959);
R. von Eötvös, D. Pekar, E. Fekete, Ann. Physik 68, 11 (1922).https://doi.org/ANPYA2
3. C. V. Boys, in Dictionary of Applied Physics (R. Glazebrook, ed.) 1, 3 (1923).
4. H. Cavendish, Phil. Trans. Roy. Soc. 88, 469 (1798).
5. C. V. Boys, Phil. Trans. Roy. Soc. A, 1 (1895);
R. von Eötvös, Wied. Ann. 59, 392 (1896).
6. P. von Jolly, Wied. Ann. 14, 331, (1881);
J. H. Poynting, Phil. Trans. Roy Soc. A 182, 565 (1891);
J. H. Poynting in Encyclopedia Brittanica, 11th ed., Vol. 12, page 384, New York, 1910.
7. P. R. Heyl, J. Res. Natl. Bur. Std. (US) 5, 1243 (1930);
P. R. Heyl, P. Chrzanowski, J. Res. Natl. Bur. Std. (US) 29, 1 (1942).
8. A. H. Cook, Contemporary Physics 9, 227 (1968);
Proceedings of the Int. Conf. on Precision Meas. and Fund. Const., 3–7 Aug. 1970.
9. “Recommended Prefixes; Defined Values and Conversion Factors; General Physical Constants,” US Natl. Bur. Std. Misc. Pub. US Government Printing Office, Washington, D.C. (1963).
10. L. M. Stephenson, Proc. Phys. Soc. (London) 90, 601 (1967).https://doi.org/PPSOAU
11. J. W. Beams, A. R. Kuhlthau, R. A. Lowry, H. M. Parker, Bull. Am. Phys. Soc. 10, 249 (1965); https://doi.org/BAPSA6
R. D. Rose, H. M. Parker, R. A. Lowry, A. R. Kuhlthau, J. W. Beams, Phys. Rev. Lett. 23, 655 (1969); https://doi.org/PRLTAO
W. R. Towler, H. M. Parker, A. R. Kuhlthau, J. W. Beams, Proceedings of Int. Conf. Precision Meas. and Fund. Const., 3–7 Aug. 1970.
12. J. W. Beams, Bull. Am. Phys. Soc. Series 2, 11, 526 (1966).

More about the Authors

Jesse W. Beams. University of Virginia, Charlottesville.