Definition
Atmospheric escape refers to the loss of a planet’s atmosphere to space. Broadly speaking, escape may be energy limited or diffusion limited. For the energy-limited case, permanently removing a molecule from a planet’s atmosphere can be compared to sending a rocket from Earth to space: one must impart enough velocity to the object, and in the right direction, to allow the object to overcome the potential energy at the bottom of the gravitational well and still have enough kinetic energy left over to allow the object to continue moving away. The study of atmospheric escape in this case thus amounts to the study of the various ways in which the necessary energy can be imparted to molecules to reach the escape velocity, which is the minimum velocity an object needs in order to escape to infinity, provided no drag forces intervene.
Overview
The thermal escape velocity is obtained by equating initial kinetic energy to the gravitational potential energy:
References and Further Reading
Pierrehumbert RT (2010) Principles of planetary climate. Cambridge University Press, Cambridge
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© 2014 Springer-Verlag Berlin Heidelberg
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Pierrehumbert, R. (2014). Atmosphere Escape. In: Amils, R., et al. Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27833-4_128-2
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DOI: https://doi.org/10.1007/978-3-642-27833-4_128-2
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Publisher Name: Springer, Berlin, Heidelberg
Online ISBN: 978-3-642-27833-4
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Chapter history
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Latest
Atmospheric Processes, Escape- Published:
- 02 December 2020
DOI: https://doi.org/10.1007/978-3-642-27833-4_128-3
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Original
Atmosphere Escape- Published:
- 30 April 2015
DOI: https://doi.org/10.1007/978-3-642-27833-4_128-2