Planetary and Lunar Ephemerides: testing alternate gravitational theories

Abstract

The planetary and lunar ephemerides have been improved over the past century by many orders of magnitude. It is expected that they will improve again into the fairly near future. The improvements come from more accurate observational data, from increased modelling of the gravitational equations of motion, and from the ability to numerically integrate the equations of motion. Present‐day ephemerides have the accuracy to be able to test a number of proposed possible modifications to the presently accepted laws of gravitation. In the future, with further improved accuracies, the ephemerides will be able to test even more subtle modifications.Experiments show that the Voyager range residuals at Uranus and Neptune, reported by Anderson et al. (1995) [1], are fully consistent with other observational data and with present‐day ephemerides.The modification to the laws of gravitation which is usually quoted to explain the Pioneer Anomaly, that of a constant acceleration of 8.74×10−10 m/sec2 directed toward the sun...