In the 1960s, the US launched a group of satellites to monitor international compliance with a treaty prohibiting all tests of nuclear weapons except those conducted underground. In 1979, one of the satellites detected an unidentified double flash characteristic of an atmospheric nuclear explosion. The data were initially interpreted as evidence of a South African nuclear test, but experts later determined that the flash was likely not nuclear in origin and may have instead been caused by what? Discuss
Source: The Free Dictionary