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The layers are to scale. From the Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius. The exosphere is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is so low that the molecules are essentially collision ...
As a lower boundary for the exosphere this boundary is also called the exobase. [ 1 ] The exact altitude varies by the energy inputs of location, time of day, solar flux, season, etc. and can be between 500 and 1,000 kilometres (310 and 620 mi) high at a given place and time because of these.
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.
The NASA astronauts who became the first people to land on the moon's surface in the 1960s and 1970s also discovered a previously unknown lunar characteristic - it has an atmosphere, though quite ...
Total atmospheric mass is 5.1480 × 10 18 kg (1.13494 × 10 19 lb), [36] about 2.5% less than would be inferred from the average sea-level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the ...
Exosphere: The outermost layer of Earth's atmosphere extends from the exobase upward, mainly composed of hydrogen and helium. Thermosphere: The top of the thermosphere is the bottom of the exosphere, called the exobase. Its height varies with solar activity and ranges from about 350–800 km (220–500 mi; 1,150,000–2,620,000 ft).
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. [1] [a] Flames, the most visible portion of the fire, are produced in the combustion reaction when the fuel reaches its ignition point.
Haines Index (also known as the Lower Atmosphere Severity Index) is a weather index developed by meteorologist Donald Haines in 1988 that measures the potential for dry, unstable air to contribute to the development of large or erratic wildland fires. [1]