Lunar Laser Ranging Science: Gravitational Physics and Lunar Interior and Geodesy

TL;DR

Lunar Laser Ranging provides precise measurements that inform us about lunar interior, gravitational physics, and geodesy, confirming Einstein's theory and revealing details about the Moon's fluid core and tidal dissipation.

Contribution

This paper presents high-precision laser ranging data that constrains lunar interior models, tests fundamental physics, and improves geodetic measurements.

Findings

Lunar retroreflector positions are accurate within less than a meter.

Lunar tidal dissipation shows strong dissipation with Q=33 ± 4.

Tests confirm the equivalence principle to within 1.4 x 10^{-13}.

Abstract

Laser pulses fired at retroreflectors on the Moon provide very accurate ranges. Analysis yields information on Earth, Moon, and orbit. The highly accurate retroreflector positions have uncertainties less than a meter. Tides on the Moon show strong dissipation, with Q=33 \pm 4 at a month and a weak dependence on period. Lunar rotation depends on interior properties; a fluid core is indicated with radius ~20% that of the Moon. Tests of relativistic gravity verify the equivalence principle to \pm 1.4 x 10^{-13}, limit deviations from Einstein's general relativity, and show no rate for the gravitational constant $\dot{G}/G$ with uncertainty 9 x 10^{-13} 1/yr.