[D137] DE SAINTE-GEMME-LA-PLAINE (85) VERS MOREILLES (85) 26.08.2021

On the night of August 25-26, 2021, a motorist travelling on the D137 southward reported having observed, at the exit of the municipality of SAINTE-GEMME-LA-PLAINE (Vendée), an unusual luminous phenomenon. He described an intense flash, comparable to lightning at altitude, although the sky was clear and the Moon clearly visible. This flash illuminated a large portion of the sky in front of him, immediately followed by the appearance of a bright, blue-coloured ball, stationary, located near the horizon. This light remained visible between one and five seconds. The witness estimated that the apparent size of this ball was slightly lower than that of the Moon that night, with slightly blurred contours. The driver of the vehicle before him also perceived a flash and a blue colour, without distinguishing the ball. This second witness did not wish to testify officially. The evidential quality* of this case is considered medium: two witnesses, but only one testimony, lack of a photo or video of the UAP. *according to the GEIPAN criteria, evidential quality is the amount of information collected for an account that is considered reliable and objectively established. The investigation led to closer examination of lightning and fireball hypotheses. The description of the UAP, including the brevity of the observation, is consistent with the hypothesis of the observation of a bright meteor, the flash possibly corresponding to a meteoroid’s atmospheric entry (see investigation report). It cannot be lightning, even distant, since no stormy activity was detected at the time of observation. The fact that the UAP was observed on the horizon suggests that it was probably above the Gulf of Lion. Furthermore, a fireball was detected from Rome (Italy) at a time compatible with that of observation, by a sensor of the FRIPON network. However, the absence of path data does not allow GEIPAN to determine the precise direction of its displacement. The strangeness perceived by the witness is due to two elements: - a flash like lightning high in the sky in a non-stormy sky -a blue ball. The flash can be explained by the hypothesis chosen. The appearance of a blue ball could be a retinal afterimage. GEIPAN classifies the case B, likely observation of a fireball.