phisical geography: the study of the natural features of the earth, such as mountains and rivers

climatology: the scientific study of climate

astro: relating to space, the planets, stars, or other objects in space, or to a structure in the shape of a star

atmosphere: the mixture of gases around the earth

meteorology: the scientific study of the processes that cause particular weather conditions

geology: the study of the rocks and similar substances that make up the earth's surface

geosphere: the rigid outer layer of the earth, having an average thickness of about 75 km and comprising the earth's crust and the solid part of the mantle above the asthenosphere

paleontology: the scientific study of organisms that lived on earth before there were written records, esp. by examining fossils

biosphere: a part of a planet's environment where life exists

hydrology: the study of water on the earth, for example, where it is and how it is used

hydrosphere: all of the water, ice, and water vapor at or near the surface of a planet

vapor: gas or extremely small drops of liquid that result from the heating of a liquid or solid

oceanography: the scientific study of the sea