Atmosphere of Earth relatively warm air above a colder one), and in others by a zone which is isothermal with height. Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e. Earth's surface) is typically the warmest section of the troposphere. This promotes vertical mixing (hence, the origin of its name in the Greek word τρόπος, "tropos", meaning "turn"). The troposphere contains roughly 80% of the mass of Earth's atmosphere. The troposphere is denser than all its overlying atmospheric
Salt of the Earth (song) Jagger and Richards using a personal tape recorder, "Salt of the Earth" was recorded at London's Olympic Sound Studios in May 1968. Featuring on the song are the Los Angeles Watts Street Gospel Choir and a piano performance by Nicky Hopkins. These additions, and their prominence near the end of the song, are further developed on their next album "Let It Bleed"'s closing song, "You Can't Always Get What You Want". "Salt of the Earth" has a unique live history. It has only been played once to an instrumental playback and live five times. Salt of the Earth (song) "Salt