EARTH SYSTEMS

A system is any set of interactions set apart from the rest of the universe for the purposes of study, observation, and measurement. Theoretically, a system is isolated from its environment, but this is an artificial construct, since nothing is ever fully isolated. Earth is largely a closed system, meaning that it exchanges very little matter with its external environment in space, but the same is not true of the systems within the planet—geosphere, hydrosphere, biosphere, and atmosphere—which interact to such a degree that they are virtually inseparable. Together these systems constitute an intricate balance, a complex series of interrelations in which events in one sector exert a profound impact on conditions in another.