The Vela Incident of 1979
In 1979 an American satellite recorded an unusual light flash near the coast of South Africa.
The event quickly attracted the attention of scientists and government officials because the flash pattern resembled that of an atmospheric nuclear test.
Although no official confirmation was initially given, the observation triggered a vigorous debate over whether a secret test had occurred.
Investigations focused on analysing the satellite data and considering alternative explanations such as meteoroid impacts.
To this day it remains unresolved whether the flash was caused by a nuclear test or had a different natural origin.