Atmosphere of Earth years ago. About 3.4 billion years ago, nitrogen formed the major part of the then stable "second atmosphere". The influence of life has to be taken into account rather soon in the history of the atmosphere, because hints of early life-forms appear as early as 3.5 billion years ago. How Earth at that time maintained a climate warm enough for liquid water and life, if the early Sun put out 30% lower solar radiance than today, is a puzzle known as the "faint young Sun paradox". The geological record however shows a continuous relatively warm surface during the complete early
Gas-s-s-s military gas leak involving an experimental agent that kills everyone on Earth over the age of 25. (A cartoon title sequence shows a John Wayne-esque Army General announcing — and denouncing — the "accident"; the story picks up after the victims have died.) The lead characters, Coel and Cilla, are played by Robert Corff and Elaine Giftos, and the cast features Ben Vereen, Cindy Williams, Bud Cort and Talia Shire (credited as "Tally Coppola") in early roles. Country Joe McDonald makes an appearance, as spokesman "AM Radio". In Dallas, at the Southern Methodist University, news comes in about a gas