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
What We Live For on the future. "Go Big or Go Home", which would ultimately appear as the seventh track on the final album, was released in May 2015 as a single, after the band's last single promoting "Oh, What a Life", "Luck", was released a year previously. "Pride" also appeared on a single in December 2015, and was also solicited as a promotional single to United States adult contemporary radio thereafter. "What We Live For" was officially unveiled by the band and Island Records on March 2, 2016, with pre-orders for both a digital download and compact disc version of the album being