A better lunar yardstick

Since the mid‐1980s, scientists have measured the approximately 384,140 kilometers distance from the center of the Moon to the center of Earth to a margin of about 2 centimeters. But Tom Murphy, a University of Washington (UW) postdoctoral researcher in physics and astronomy wants an even more precise measurement. In acquiring the improved distance measure, Murphy and his UW team—astronomy professor Christopher Stubbs, physics professor Eric Adelberger, and physics graduate student Jana Strasburg—will perform one of the most sensitive tests ever done on several features of gravity. They will test Einstein's equivalence principal which concerns the acceleration of bodies of different composition and the variability of the strength of gravitational interaction. The team also will be undertaking a feasibility study for performing laser‐ranging experiments from space.