Sighting in Plouarzel, March 14, 1983

On the evening of 14 March 1983, between 8 and 10 pm, several witnesses gathered in the same hamlet saw a yellowish light that seemed stationary above the tip of a megalithic monument, then appeared to move. Intrigued, they decided to drive closer and were surprised to find that the object seemed to follow the road and the vehicles. A fifth witness reported an observation the next day, around 9 pm, while driving toward Saint-Renan.

The first witness, very excited by what they had seen while driving, had come to alert three other witnesses: a parent and two of their children. All three first thought it was a big star. One described it as 3 to 4 times larger than a star, bright and yellowish. After car trips with the first witness, the parent became convinced that the light was moving, while the other two, who had stayed in the yard, first judged it motionless. On the second outing, they came to believe they saw it move. One saw it descend in the sky, the other saw it leave toward Ouessant.

The investigation established that the object seen above the menhir, to the northwest, was Venus (azimuth 272°, elevation 10°). The apparent movement came from the "following ball" illusion: a star's direction stays fixed relative to a car holding its course, but rotates relative to the road when the car turns. This illusion, combined with strong emotion, spread to the other witnesses through suggestion. The witnesses' own movements in the yard, as they tried to follow the car with their eyes, also played a part. The changes in color and brightness, and the disappearance, match Venus low on the horizon and setting. The fifth witness's account is poorly documented; they had probably seen Arcturus, noticed because the press had reported a UFO. GEIPAN classified the case as A, astronomical misidentifications.