NASA's GRAIL Mission Solves Mystery of Moon's Surface Gravity
"NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission has uncovered the origin of massive invisible regions that make the moon's gravity uneven, a phenomenon that affects the operations of lunar-orbiting spacecraft."
Gravity anomaly map of the conterminous United States
"Measurements of the gravitational field vary slightly from place to place due to the composition and structure of Earth's crust. These digital grids describe the complete Bouguer and isostatic residual gravity anomalies for the conterminous US."
"Mascons were first identified by the observation of small anomalies in the orbits of Lunar Orbiter spacecraft launched in 1966-67."
"The gal, sometimes called galileo, (symbol Gal) is a unit of acceleration used extensively in the science of gravimetry."