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In summary, the mass of Earth's atmosphere is distributed approximately as follows: [37] 50% is below 5.6 km (18,000 ft), 90% is below 16 km (52,000 ft), 99.99997% is below 100 km (62 mi; 330,000 ft), the Kármán line. By international convention, this marks the beginning of space where human travelers are considered astronauts.
The International Standard Atmosphere (ISA) is a static atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes or elevations. It has been established to provide a common reference for temperature and pressure and consists of tables of values at various altitudes ...
An atmosphere (from Ancient Greek ἀτμός (atmós) 'vapour, steam' and σφαῖρα (sphaîra) 'sphere') [1] is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low.
At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately 1.204 kg/m 3 (0.0752 lb/cu ft), according to the International Standard Atmosphere (ISA). At 101.325 kPa (abs) and 15 °C (59 °F), air has a density of approximately 1.225 kg/m 3 (0.0765 lb/cu ft ), which is about 1 ⁄ 800 that of water , according to the ...
Earth's atmosphere has no definite boundary, gradually becoming thinner and fading into outer space. [218] Three-quarters of the atmosphere's mass is contained within the first 11 km (6.8 mi) of the surface; this lowest layer is called the troposphere. [219] Energy from the Sun heats this layer, and the surface below, causing expansion of the air.
Thus the standard consists of a tabulation of values at various altitudes, plus some formulas by which those values were derived. To allow modeling conditions below mean sea level , the troposphere is actually extended to −2,000 feet (−610 m), where the temperature is 66.1 °F (18.9 °C), pressure is 15.79 pounds per square inch (108,900 Pa ...
Its thick and noxious atmosphere is dominated by carbon dioxide - 96.5% - with lesser amounts of nitrogen and trace gases. In fact, with Venus getting far less scientific attention than other ...
~0.25% by mass over full atmosphere, locally 0.001–5% by volume. [7] notes This page was last edited on 25 February ...