A detection of non‐Newtonian gravity

Abstract

An experiment was performed to test Newton's inverse square law of gravitation. The test compared accurately measured gravity values along a 600‐m tower with upward continued gravity estimates calculated from ground measurements using algorithms based on Newtonian potential theory. Gravity measurements with an internal consistency of better than 20 μGal (1 μGal = 10−8 m/s2) were made on the tower at intervals of about 90 m using a single LaCoste‐Romberg model G gravimeter. Field measurements of gravity (using the same instrument) and corresponding geodetic positions were performed at 77 points within a radius of 5 km from the tower. These and other gravimetric data within a radius of about 220 km were used to perform the upward continuation using two independent computational techniques. One is least squares collocation, which is based on a statistical interpretation of the local gravity field, and the other determines a local harmonic expansion of the field from the given data. The upward continuation from both methods gave almost identical results and is estimated to have an uncertainty comparable to the in situ measurements. The results of the experiment show a substantial departure from the inverse square law, asymptotically approaching about 500 μGal at the top of the tower, with a standard deviation of better than 40 μGal. This indicates that there is a non‐Newtonian attractive force which falls off rapidly with elevation.

Application of internal gravitational field equations to geophysical measurement of G

“…Correcting for that, only one non-Newtonian force (instead of two as previously reported by Eckhardt et al [1988a]; see also Romaides et al [1989]) is required to fit the observed data in the tower experiment [Eckhardt et al, 1988b]. Correcting for that, only one non-Newtonian force (instead of two as previously reported by Eckhardt et al [1988a]; see also Romaides et al [1989]) is required to fit the observed data in the tower experiment [Eckhardt et al, 1988b].…”

Tower gravity experiment: No evidence for non-Newtonian gravity

“…63, 1902 (1989), who saw no deviation from Newtonian attraction within the noise of their tower experiment. 12 The density of the regional residual topography varies less than 10% from the nominal value of 2.67 g/cm 3 …”

“…This procedure resulted in a set of terrain-corrected Bouguer gravity anomalies 9 that were upward continued using least-squares collocation with a covariance function appropriate for Bouguer anomalies and using a direct numerical integration of the upward continuation integral referenced to a Fourier-Bessel expansion. 3 The final step in the upward continuation involved computing the effect of restoring the masses (positive and negative) that were removed, thus returning the geophysical setup of the experiment to reality.…”

Earth Sciences report, 1989--1990

“…Several borehole experiments have been conducted byStacey and his collaborators in the past 10 years (Stacey et al, 1981; Holding and Tuck, 1984;Holding et al, 1986 Eckhardt et al (1988) and Romaides et al (1989) claimed to observe a breakdown of Newtonian gravity that indicated nn additional attractive force.…”