Regolith

Image of regolith covering surface of asteroid Bennu taken during the  OSIRIS-REx mission 28 March 2019 from a distance of 3.6 kilometers. Largest boulder in the upper left corner is 14.5 m wide. Image Credit: NASA/Goddard/University of Arizona

Mixture of unconsolidated rocky fragments, soil, dust and other fine granular particles blanketing the surface of a body lacking an atmosphere. Regolith is the product of “gardening” by repeated meteorite impacts, and thermal processes (such as repeated heating and cooling cycles).