Lunar observation mistaken for a UFO on Groix island

Summary

On the night of 13–14 April 1982 three people on the island of Groix perceived a luminous object in the sky that seemed to follow them as they drove across the island. A fourth witness confirmed seeing a bright, stationary object they could not recognise. The gendarmerie investigated but found no other witnesses or physical evidence.

Although the witnesses were deemed credible, their accounts contained contradictions, particularly regarding the date and the object's movement. GEIPAN concluded it was the Moon in its last-quarter phase. The impression that the object was following them is explained by the relative-motion illusion a distant celestial body creates when the observer is moving. One witness saw something similar the following night, reinforcing the lunar hypothesis. The case was classified A.