Search results
Results from the WOW.Com Content Network
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.
If there is a strong thermally driven atmospheric escape of light atoms, heavier atoms can achieve the escape velocity through viscous drag by those escaping lighter atoms. [2] This is another way of thermal escape, called hydrodynamic escape. The heaviest species of atom that can be removed in this manner is called the cross-over mass. [3]
A University of Colorado, Boulder team has discovered that Mars has an atmospheric "escape route" which may have helped hydrogen drift into space at much faster rates.
In most situations it is impractical to achieve escape velocity almost instantly, because of the acceleration implied, and also because if there is an atmosphere, the hypersonic speeds involved (on Earth a speed of 11.2 km/s, or 40,320 km/h) would cause most objects to burn up due to aerodynamic heating or be torn apart by atmospheric drag. For ...
XUV radiation-induced atmospheric escape has been observed on gas giants. [291] M dwarfs emit large amounts of XUV radiation; [290] TRAPPIST-1 and the Sun emit about the same amount of XUV radiation [az] and because TRAPPIST-1's planets are much closer to the star than the Sun's, they receive much more intense [ba] irradiation. [57]
In practice, the diameter of gas molecules is not well defined. In fact, the kinetic diameter of a molecule is defined in terms of the mean free path. Typically, gas molecules do not behave like hard spheres, but rather attract each other at larger distances and repel each other at shorter distances, as can be described with a Lennard-Jones ...
The escape of any atmospheric gas can be diffusion-limited, but only diffusion-limited escape of hydrogen has been observed in our solar system, on Earth, Mars, Venus and Titan. [1] Diffusion-limited hydrogen escape was likely important for the rise of oxygen in Earth's atmosphere ( the Great Oxidation Event ) and can be used to estimate the ...
Ganymede is composed of silicate rock and water in approximately equal proportions. It is a fully differentiated body with an iron-rich, liquid metallic core, giving it the lowest moment of inertia factor of any solid body in the Solar System. Its internal ocean potentially contains more water than all of Earth's oceans combined. [19] [20] [21 ...