Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any celestial body (such as the geology of the Moon or Mars).
Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates. In modern times, geology is commercially important for mineral and hydrocarbon exploration and exploitation and for evaluating water resources. It is publicly important for the prediction and understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology plays a role in geotechnical engineering and is a major academic discipline.