Does the gravitational constant vary over time? A new measurement of the number that influences the force of attraction between bodies has re-ignited the question, which is of great interest to physicists, particularly those who study the evolution of the Universe. The force of attraction between two bodies is proportional to the product of their masses and inversely proportional to the squared distance between them. The so-called universal gravitational constant (G) enters into the equation and determines the magnitude of this force. Its official value of 6,67384 ± 0,00080 x 10-11 m3 kg-1s-2 was calculated by the Committee on Data for Science and Technology from an average of the measurements made up to 2010. Now, the team led by Terry Quinn of the International Bureau of Weights and Measures in France has determined G with record accuracy. Using independent methods, he arrived at a value of 6,67545 ± 0,00018 x 10-11 m3 kg-1s-2 (PRL, September 5, 2013). This value is 240 millionths higher than the official value and matches the other measurement done in 2001 by Quinn’s group. The authors themselves suspect there was some type of error that they have not yet managed to find. Some theoretical physicists hope that G really is not a constant. An oscillating gravity might explain the mysterious dark matter that is accelerating the expansion of the Universe.
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