Phases of moonEdit
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- Main article: Atmosphere of the Moon
The Moon has an atmosphere so thin as to be almost negligible, with a total atmospheric mass of less than 104 kg. The effective surface pressure of this small mass is around 3 × 10-15 atm . This pressure varies, of course, with the diurnal moon cycle. One source of its atmosphere is outgassing—the release of gases such as radon that originate by radioactive decay processes within the crust and mantle.
- See also: Error: Template must be given at least one article name Another important source is generated through the process of sputtering, which involves the bombardment of micrometeorites, solar wind ions, electrons, and sunlight. Gases that are released by sputtering can either reimplant into the regolith as a result of the Moon's gravity, or can be lost to space either by solar radiation pressure or by being swept away by the solar wind magnetic field if they are ionised. The elements sodium (Na) and potassium (K) have been detected using earth-based spectroscopic methods, whereas the element radon–222 (222Rn) and polonium-210 (210Po) have been inferred from data obtained from the Lunar Prospector alpha particle spectrometer. Argon–40 (40Ar), helium-4 (4He), oxygen (O2) and/or methane (CH4), nitrogen (N2) and/or carbon monoxide (CO), and carbon dioxide (CO2) were detected by in-situ detectors placed by the Apollo astronauts.
- ↑ Globus, Ruth (2002). "Impact Upon Lunar Atmosphere". Retrieved on 2007-08-29.
- ↑ "Moon." Encyclopædia Britannica. 2008. Encyclopædia Britannica Online. 10 Sep. 2008 <http://www.britannica.com/EBchecked/topic/391266/Moon>.
- ↑ Cite error: Invalid
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- ↑ Lawson, S.; Feldman, W.; Lawrence, D.; Moore, K.; Elphic, R.; Belian, R. (2005). "Recent outgassing from the lunar surface: the Lunar Prospector alpha particle spectrometer". J. Geophys. Res. 110: 1029. doi:10.1029/2005JE002433.
- ↑ Stern, S.A. (1999). "The Lunar atmosphere: History, status, current problems, and context". Rev. Geophys. 37: 453–491. doi:10.1029/1999RG900005.