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Hydrogen is present throughout the exosphere, with some helium, carbon dioxide, and atomic oxygen near its base. Because it can be hard to define the boundary between the exosphere and outer space, the exosphere may be considered a part of the interplanetary medium or outer space. Earth's exosphere produces Earth's geocorona.
Temperature profile of the Uranian troposphere and lower stratosphere. Cloud and haze layers are also indicated. The Uranian atmosphere can be divided into three main layers: the troposphere, between altitudes of −300 [a] and 50 km and pressures from 100 to 0.1 bar; the stratosphere, spanning altitudes between 50 and 4000 km and pressures between 0.1 and 10 −10 bar; and the thermosphere ...
Detection of methane in astronomical bodies is of interest to science and technology, as it may be evidence of extraterrestrial life (biosignature), [116] [117] it may help provide organic ingredients for life to form, [116] [118] [119] and also, methane could be used as a fuel or rocket propellant for future robotic and crewed missions in the ...
Mercury, being the closest to the Sun, with a weak magnetic field and the smallest mass of the recognized terrestrial planets, has a very tenuous and highly variable atmosphere (surface-bound exosphere) containing hydrogen, helium, oxygen, sodium, calcium, potassium and water vapor, with a combined pressure level of about 10 −14 bar (1 nPa). [2]
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.
The Outer Space Treaty provides the basic framework for international space law. It covers the legal use of outer space by nation states, and includes in its definition of outer space, the Moon, and other celestial bodies. The treaty states that outer space is free for all nation states to explore and is not subject to claims of national ...
One classical thermal escape mechanism is Jeans escape, [1] named after British astronomer Sir James Jeans, who first described this process of atmospheric loss. [2] In a quantity of gas, the average velocity of any one molecule is measured by the gas's temperature, but the velocities of individual molecules change as they collide with one another, gaining and losing kinetic energy.
Terrestrial aeronomy focuses on the Earth's upper atmosphere, which extends from the stratopause to the atmosphere's boundary with outer space and is defined as consisting of the mesosphere, thermosphere, and exosphere and their ionized component, the ionosphere. [5]