Searches for Non-Newtonians Variations in the Earth's Gravity

A series of experiments is underway to search for non-Newtonian behavior in the earth's gravity field. The objective is to measure the variation of gravity with depth in settings where the density of the surrounding material is known accurately. Gravity values were obtained to a depth of 1.7 km in the Greenland ice sheet during the summer of 1987, and measurements to a depth of 5 km in the Pacific Ocean were initiated in the summer of 1988. Descriptions of these experiments, their hoped-for accuracies, progress on analysis, and conclusions to date will be presented.