Atmosphere of Earth (see the temperature section, below). Because the general pattern of the temperature/altitude profile is constant and measurable by means of instrumented balloon soundings, the temperature behavior provides a useful metric to distinguish atmospheric layers. In this way, Earth's atmosphere can be divided (called atmospheric stratification) into five main layers. Excluding the exosphere, the atmosphere has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. From highest to lowest, the five main layers are: The exosphere is the outermost layer of Earth's atmosphere (i.e. the upper limit of the atmosphere). It extends from the exobase, which is located at
A Planet Called Utopia same reason), and temporary personal relationships favored. Diseases are nonexistent, and cures have been found for all of them. Life involves pleasure and adventure (skiing, scuba diving, parachuting, automobile racing) all day long. The population nevertheless needs an occasional birth, so couples are allowed to have children according to a lottery system, such that the number of births is exactly equal to the number of accidental deaths in a year. The protagonist, Hardy Cronyn, is the first off-worlder to be allowed onto the planet in sixty years. A lot of diplomatic arm wrestling led to the planet's agreement to let