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
The World We Live In (Life magazine) by "The Epic of Man", focusing on the development and history of human civilization, and "The Wonders of Life on Earth", a series of articles tracing Darwin and evolution. Both of these were written by Barnett as well, and featured many of the same artists. "Life"'s series on the International Geological Year was hailed as a spiritual "update" to "The World We Live In". The World We Live In (Life magazine) The World We Live In appeared in the pages of LIFE magazine from December 8, 1952, to December 20, 1954. A science series, it comprised 13 chapters published on