From Nuclear explosion In  there was some initial speculation among the scientists developing the first nuclear weapons that there might be a possibility of igniting the earths atmosphere with a large enough nuclear explosion This would concern a nuclear reaction of two nitrogen atoms forming a carbon and an oxygen atom with release of energy This energy would heat up the remaining nitrogen enough to keep the reaction going until all nitrogen were finished This was however quickly shown to be unlikely enough to be considered impossible  Nevertheless the notion has persisted as a rumor for many years