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
Solar tower (astronomy) Solar tower (astronomy) A solar tower, in the context of astronomy, is a structure used to support equipment for studying the sun, and is typically part of solar telescope designs. Generically, the term solar tower has many more uses especially for a type of power production using Earth's Sun. Solar tower observatories are also called vacuum tower telescopes. Solar towers are used to raise the observation equipment above the atmospheric disturbances caused by solar heating of the ground and the radiation of the heat into the atmosphere. Traditional observatories do not have to be placed high above ground level, as