regoliitti

Regolith is a layer of loose, unconsolidated material that blankets solid bedrock on the surfaces of many planetary bodies, including the Moon, Mars, Mercury, and most asteroids. It comprises dust, soil-like material, broken rock, and other fragmented debris produced by weathering and impact processes. On airless bodies, its formation is dominated by micrometeoroid bombardment and thermal cycling rather than rainfall or biological activity.

The regolith varies widely in thickness and composition. It can range from a few meters to tens of meters thick depending on location and body. Its materials span fine dust and glassy particles to larger rock fragments. In the Moon, regolith contains agglutinates—glass-rich grains created by micrometeorite impacts—and is often referred to as lunar soil in a broad sense.

Regolith is central to understanding surface geology and planning space missions. Its properties influence lander stability, rover mobility, and sampling strategies, and it may host volatiles or resources near the surface. It is distinct from bedrock beneath and from Earth-like soil, which forms under hydrological and biological processes; regolith forms under the more extreme, largely nonbiological conditions present on other planetary bodies.