An American satellite orbiting above known as Vela Hotel 6911 detected a bright double flash of light below that seemed to be indicative of a nuclear explosion.
However, after going through the data, this panel curiously came to the conclusion that the Vela incident as was getting to be known was most likely caused by a natural event.
But in a way that's kind of what makes the Vela incident and other mysteries so interesting, the fact that you don't know all of the answers and the possibility that one day you might.