]> An sphere of influence of a planet [Wiktionary] The term Geosphere is often used to refer to the densest (solid) parts of Earth, which consist mostly of rock and regolith [Wikipedia] A hydrosphere in physical geography describes the combined mass of water found on, under, and over the surface of a planet. [Wikipedia] The part of the Earth surface that is not covered by water [Wikipedia] An ocean is a major body of saline water, and a principal component of the hydrosphere. [Wikipedia] An atmosphere is a layer of gases that may surround a material body of sufficient mass,[1] by the gravity of the body, and are retained for a longer duration if gravity is high and the atmosphere's temperature is low. [Wikipedia] The cryosphere, is the term which collectively describes the portions of the Earth’s surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets, and frozen ground (which includes permafrost). [Wikipedia] A surface that acts as a divider between components A qusai-horizontal surface spanning all or part of a planet that corresponds to a constant value of some parameter The surface of the planet defined by solid and/or liquid layers Planetary phenomena are the movements of planets and the sun, including for example orbits, alignments, eclipses day and night cycles, and the change of seasons.