Earth is one of the eight planets of the solar system, and the study of its rocks, minerals, internal and external geological processes, and related aspects is studied under the subject of geology. It deals with geodomains such as geodesy, astrology, tectonics, sedimentology, chronology, topography, and natural resources, which cover almost all aspects related to Earth sciences, including celestial bodies, hydrosphere, and atmosphere. There are further divisions of these domains as pure, historical, and applied geology branches, important of them are astrogeology, geodesy, physical geology, geomorphology, petrology, mineralogy, crystallography, structural geology, palaeontology, stratigraphy, economic geology, mining geology, environmental geology, hydrogeology, engineering geology, geochemistry, and remote sensing. Geomorphology mainly deals with studying landforms created by endogenic and exogenic Earth processes. Structural geology deals with the study of different primary and secondary structures, such as folds, faults, fractures, joints, foliations, lineations, and lineaments, formed in igneous, metamorphic, and sedimentary rocks due to various geological activities. Several fundamental geological principles are adopted to establish the sequence of rock formations in terms of geologic rock units, geologic time units, and geologic time rock units studied under stratigraphy. Fossils and their remains are studied under palaeontology, which plays a very important role in stratigraphy. The chemistry of minerals and rocks, which are the constituents in different layers of the Earth, and cycles of the elements such as carbon, phosphorus, nitrogen, oxygen, sulphur, water, and rocks are studied under geochemistry. The water cycle, including the surface and groundwater, and its management are studied under hydrogeology. Economic geology is the branch that studies economically important mineral deposits, their exploration, mine planning, exploitation, beneficiation, etc., while environmental geology studies the aspects and impacts due to these activities and their measures. Geological and geotechnical aspects related mainly to mega infrastructural projects, such as dams, bridges, rail and roadways, high rises, and settlements, are studied under engineering geology. Studies about the Earth sciences, done using aerial photographs and satellite imageries, are covered under remote sensing and photogeology.