Atmosphere of Earth the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around . Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. The study of Earth's atmosphere and its processes is called atmospheric science (aerology). Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. The three major constituents of Earth's atmosphere are nitrogen, oxygen, and argon. Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around
Gas-s-s-s ahead, write something, just keep the title."" "Gas-s-s-s" was an idea of Corman's, about a world where everybody over thirty had died. Corman later said "my first thought was to do a science fiction film with allegorical overtones." Armitage remembers the concept just being "a sentence, and that's what we went with ... He let you make it your own, and I did." Corman said that although "there was some good work in" Armitage's first draft, "the points I was trying to make in the script either did not come through or came through too obviously different parts, and it