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Measurements of the Newtonian Constant of Gravitation, G



Christian Rothleitner, Stephan Schlamminger


The Newtonian Constant of Gravitation G seems to be the fundamental constant that is most difficult to measure accurately. In the past three decades more than a dozen precision measurements were performed. Unfortunately the scatter of the data points is much larger than the uncertainties assigned to the individual measurement, yielding a Birge ratio of about five. Today, G is known with a relative standard uncertainty of 4.7 X 10-5 which is orders of magnitudes larger than the uncertainties of other fundamental constants. In this article various methods to measure G are discussed. A large array of different instruments, ranging from the simple torsion balance to the sophisticated atom interferometer can be used to determine G. Some instruments, e.g., the torsion balance, can be used in several different ways. In this article the advantages and disadvantages of the different instruments, but also the different methods are discussed. For the different methods a narrative arc from the historical beginnings to the modern implementation is given. Finally, the article ends with a brief overview of the current state of the art and an outlook.
Review of Scientific Instruments


gravitational constant, torsion balance, beam balance


Rothleitner, C. and Schlamminger, S. (2017), Measurements of the Newtonian Constant of Gravitation, G, Review of Scientific Instruments, [online],, (Accessed May 21, 2024)


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Created November 29, 2017, Updated October 12, 2021