Before revision: Michael H. Hart, astrophysicist who proposed a narrow habitable zone based on climate studies, edited the influential 1982 book Extraterrestrials: Where are They and authored one of its chapters "Atmospheric Evolution, the Drake Equation and DNA: Sparse Life in an Infinite Universe".Extraterrestrials: Where are They?
After revision: anMichael H. Hart, astrophysicist who proposed a narrow habitable zone based on climate studies, edited the influential 1982 book Extraterrestrials: Where are They and authored one of its chapters "Atmospheric Evolution, the Drake Equation and DNA: Sparse Life in an Infinite Universe".Extraterrestrials: Where are They?