Other layers The volume fraction of the main gases in Earth's atmosphere according to height. The boundary between the homosphere (left) and heterosphere (right) is at about 100 km. The outermost layer of the exosphere (off the chart) is dominated by hydrogen. [32] Air pressure actually decreases exponentially with altitude, dropping by half every 5.6km (18,000ft) or by a factor of 1/ e (0.368) every 7.64km (25,100ft), (this is called the scale height) -- for altitudes out to around 70km (43mi; 230,000ft). However, the atmosphere is more accurately modeled with a customized equation for each layer that takes gradients of temperature, molecular composition, solar radiation and gravity into account. At heights over 100km, an atmosphere may no longer be well mixed. Then each chemical species has its own scale height. Even above the Kármán line, significant atmospheric effects such as auroras still occur. Meteors begin to glow in this region, though the larger ones may not burn up until they penetrate more deeply. The various layers of Earth's ionosphere, important to HF radio propagation, begin below 100km and extend beyond 500km. By comparison, the International Space Station and Space Shuttle typically orbit at 350–400km, within the F-layer of the ionosphere where they encounter enough atmospheric drag to require reboosts every few months, otherwise, orbital decay will occur resulting in a return to Earth. Depending on solar activity, satellites can experience noticeable atmospheric drag at altitudes as high as 700–800km. Main article: Absorption (electromagnetic radiation) Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light. Tyson, P.D.; Preston-Whyte, R.A. (2013). The Weather and Climate of Southern Africa (2nded.). Oxford: Oxford University Press. p.4.

Detlev Möller: Luft: Chemie, Physik, Biologie, Reinhaltung, Recht. Walter de Gruyter, 2003, ISBN 3-11-016431-0, S. 173. (View in Google Books).The exosphere is the outermost layer of Earth's atmosphere (though it is so tenuous that some scientists consider it to be part of interplanetary space rather than part of the atmosphere). It extends from the thermopause (also known as the "exobase") at the top of the thermosphere to a poorly defined boundary with the solar wind and interplanetary medium. The altitude of the exobase varies from about 500 kilometres (310mi; 1,600,000ft) to about 1,000 kilometres (620mi) in times of higher incoming solar radiation. [22]

Earth’s physical environment is often described in terms of spheres: the magnetosphere, the atmosphere, the hydrosphere, and the lithosphere. Parts of these spheres make up the biosphere, the area of Earth where life exists. The Moon may have dramatically affected the development of life by moderating the planet's climate. Paleontological evidence and computer simulations show that Earth's axial tilt is stabilized by tidal interactions with the Moon. [178] Some theorists think that without this stabilization against the torques applied by the Sun and planets to Earth's equatorial bulge, the rotational axis might be chaotically unstable, exhibiting large changes over millions of years, as is the case for Mars, though this is disputed. [179] [180] Land can be covered by surface water, snow, ice, artificial structures or vegetation. Most of Earth's land hosts vegetation, [106] but ice sheets (10%, [107] not including the equally large land under permafrost) [108] or cold as well as hot deserts (33%) [109] occupy also considerable amounts of it. Marshak, Alexander; Várnai, Tamás; Kostinski, Alexander (15 May 2017). "Terrestrial glint seen from deep space: oriented ice crystals detected from the Lagrangian point". Geophysical Research Letters. 44 (10): 5197. Bibcode: 2017GeoRL..44.5197M. doi: 10.1002/2017GL073248. S2CID 109930589.The crust is covered by a series of constantly moving tectonic plates. New crust is created along mid-ocean ridges and rift valleys, where plates pull apart from each other in a process called rifting. Plates slide above and below each other in a process called subduction. They crash against each other in a process called faulting.

Main article: Internal structure of Earth Geologic layers of Earth [125] Illustration of Earth's cutaway, not to scaleAncient sediments in the Gabon dating from between about 2.15 and 2.08 billion years ago provide a record of Earth's dynamic oxygenation evolution. These fluctuations in oxygenation were likely driven by the Lomagundi carbon isotope excursion. [53] Third atmosphere Oxygen content of the atmosphere over the last billion years [54] [55] The hydrosphere helps regulate Earth’s temperature and climate. The ocean absorbs heat from the sun and interacts with the atmosphere to move it around Earth in air currents.

All living or once-living materials contain carbon. These materials are organic. Plants and other autotrophs depend on carbon dioxide to create nutrients in a process called photosynthesis. These nutrients contain carbon. Animals and other organisms that consume autotrophs obtain carbon. Fossil fuels, the remains of ancient plants and animals, contain very high amounts of carbon. Due to the water cycle, the amount of water in the air is constantly changing. The lower troposphere can contain up to 4% water vapor (H 2O) in areas near the tropics, while the poles contain only trace amounts of water vapor. The concentration of water vapor decreases drastically with altitude. The upper troposphere has less water vapor than air near the surface, the stratosphere and mesosphere have almost no water vapor, and the thermosphere contains none at all. Aerosols Earth’s rotation causes the periods of light and darkness we call day and night. The part of Earth facing the sun is in daylight; the part facing away from the sun is in darkness. If Earth did not rotate, one-half of Earth would always be too hot to support life, and the other half would be frozen. Earth rotates from west to east, so the sun appears to rise in the east and set in the west.

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Barry, R.G.; Chorley, R.J. (1971). Atmosphere, Weather and Climate. London: Menthuen & Co Ltd. p. 65. ISBN 9780416079401. At the same time that it revolves around the sun, Earth rotates on its own axis. Rotation is when an object, such as a planet, turns around an invisible line running down its center. Earth’s axis is vertical, running from the North Pole to the South Pole. Earth makes one complete rotation about every 24 hours. Earth rotates unevenly, spinning faster at the Equator than at the poles. At the Equator, Earth rotates at about 1,670 kilometers per hour (1,040 miles per hour), while at 45° north, for example, (the approximate latitude of Green Bay, Wisconsin, United States) Earth rotates at 1,180 kilometers per hour (733 miles per hour). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.