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There are several conflicting definitions for geosphere. The geosphere may be taken as the collective name for the lithosphere, the hydrosphere, the cryosphere, and the atmosphere.〔() U.S. Geological Survey "components of the Earth System"〕 In Aristotelian physics, the term was applied to four spherical ''natural places'', concentrically nested around the center of the Earth, as described in the lectures ''Physica'' and ''Meteorologica''. They were believed to explain the motions of the four ''terrestrial elements:'' ''Earth'', ''Water'', ''Air'' and ''Fire''. In modern texts and in Earth system science, geosphere refers to the solid parts of the Earth; it is used along with atmosphere, hydrosphere, and biosphere to describe the systems of the Earth (the interaction of these systems with the magnetosphere is sometimes listed). In that context, sometimes the term lithosphere is used instead of geosphere or solid Earth. The lithosphere, however, only refers to the uppermost layers of the solid Earth (oceanic and continental crustal rocks and uppermost mantle).〔Allaby,A. and Allaby, M. (eds). 2003. The Dictionary of Earth Sciences. Oxford University Press. Oxford University Press Inc., New York. 2nd edition. pg. 320.〕 Since space exploration began, it has been observed that the extent of the ionosphere or plasmasphere is highly variable, and often much larger than previously appreciated, at times extending to the boundaries of the Earth's magnetosphere or geomagnetosphere.〔Siscoe, G.: Aristotle on the Magnetosphere, Eos Transactions of Am. Geophys. Un., v.72, pp. 69-70, 1991.〕 This highly variable outer boundary of ''geogenic'' matter has been referred to as the "geopause,"〔Moore, T.E. and D.C. Delcourt, The Geopause, Revs. Geophys., v32(2), p.175, 1995.〕 to suggest the relative scarcity of such matter beyond it, where the solar wind dominates. == Notes == 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「geosphere」の詳細全文を読む スポンサード リンク
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