An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 2 Search : exosphere
exosphere
  برون‌سپهر   
borun-sepehr

Fr.: exosphère   

1) The outermost portion of the Earth's → atmosphere. Extremely tenuous, it lies above the → ionosphere from a height of about 500 km, to the edge of → interplanetary space.
2) An extremely tenuous kind of atmosphere surrounding a → solar system body. Since the → mean free path is much greater than the atmospheric scale height. The → atoms or → molecules never collide with each other. → lunar exosphere.

exo- + → sphere.

lunar exosphere
  برون‌سپهر ِ ماه   
borun-sepehr-e mâh

Fr.: exosphère lunaire   

An extremely thin gathering of gas surrounding the → Moon. It is made up of → atoms and → ions generated at the Moon's surface by interaction with → solar radiation, → plasma in the Earth's → magnetosphere, or → micrometeorites.

lunar; → exosphere.