Sighting in Quiévy, September 3, 2024

At about 10:15 p.m., a witness was in the garden behind their house under a cloudy sky. They noticed a white light, which they described as "huge" and as a "round spot", and which they placed above the clouds. It moved quickly from the northwest toward the southeast, stopped for about three seconds, then carried on in the same direction. Holding a graduated ruler at arm's length, the witness estimated its apparent size at about 30 mm. The whole sighting lasted roughly 10 seconds. There was only one witness and no photo or video, so GEIPAN rated the consistency of the case as medium.

According to GEIPAN, the appearance described matches a searchlight aimed at the sky, a "sky-tracer", of the kind used at events and festivities. Such devices can sweep rapidly in every direction and hold still for long periods, which accounts for the movement and the pause that struck the witness. The witness had thought of a searchlight but dismissed it, because the source seemed to be above the clouds. This is a common optical illusion: because of the distance between the ground source and the cloud layer, and the thickness of the clouds, the spot looks diffuse with blurred edges. The beam itself stayed invisible, since the air held few suspended particles and horizontal visibility was excellent, so no link to the ground could be seen.

The investigation could not identify who used such a device that evening. It might, for example, have been tested briefly that night ahead of longer use the following weekend for a celebration. GEIPAN classified the case as B: probable sighting of a sky-tracer.