The astronomers then conducted an analysis called a Bouger correction in order to subtract the gravitational effect of topological features, such as valleys and mountains, from the total gravity field. What is then left is the gravity field hidden beneath the lunar surface, existing within its crust.
Beneath The Icy Crust Of Enceladus. The research paper written by scientists with the Cassini mission, published in the journal Science, suggests the presence of hydrogen gas. Hydrogen gas, that could potentially provide a chemical energy source for life, is pouring into the subsurface ocean of Enceladus from hydrothermal activity on the seafloor of this bewitching, distant moon-world.
The astronomers observed this effect in the upper layer of the lunar crust, termed the megaregolith. This layer is heavily pockmarked by relatively small craters, measuring only 30 kilometers or less in diameter. In contrast, the deeper layers of lunar crust, that are scarred by larger craters, appear not to have been as badly battered, and are, therefore, less porous and fractured.