Brioude 1956, Aerial observation of a spherical object

Summary

On September 20, 1956, two pilots in flight observed a spherical, aluminum-colored object moving in the sky. Intrigued, they attempted to approach it but failed to catch up. The object remained at a great distance and moved very slowly. After giving up the pursuit, the pilots consulted the Puy-de-Dôme observatory, which confirmed the presence of a translucent, roughly spherical balloon visible throughout the day. This balloon, at 20 km altitude, moved slowly and disappeared from view at dusk. Although its origin was not identified, the GEIPAN classified it as an unidentified stratospheric balloon. The pilots, approaching at high altitude, could not significantly reduce the distance to the object, reinforcing the hypothesis of a perceptual illusion caused by the great distance.