An Etymological Dictionary of Astronomy and Astrophysics

Based on chemical composition, the Earth atmosphere is divided into two broad layers: the homosphere and the → heterosphere. The homosphere extends from the surface of the Earth up to the height of about 90 km. It is characterized by an almost homogeneous composition of nitrogen (78%), oxygen (21%), argon (10%), carbon dioxide as well as traces of constituents like dust particles, → aerosols and cloud droplets.

See also: → homo-; → shere.