MONTMARAULT (03) 29.09.2012

On Saturday 29 September 2012, 2 witnesses watched 30–40 luminous red-orange spheres pass silently through the night sky. They appeared at regular intervals and followed the same straight north-to-south axis, seemingly grouping above the forest of Château Charles in Montmarault. The witnesses decided to go there but found that the spheres had disappeared. GEIPAN identifies the characteristic orange glow, silent movement and windborne path of sky lanterns. A candle lights each envelope and heats the air, lifting it like a hot-air balloon. The envelope appears as an orange sphere. With stable internal temperature and no gusts, it can maintain a steady altitude without sound. Météociel recorded north-to-south winds of 10–15 km/h, cloud cover of 6/8, temperature 12°C and pressure 1,020 hPa. These conditions match the path described by the witness and Gendarmerie report. The witness’s 50 km/h estimate is substantially too high in GEIPAN’s assessment: overestimating distance to an unrecognised object also overestimates speed for the same observed angular motion. A Saturday evening suits a family or friends’ celebration; the Gendarmerie report mentions a wedding. Successive lighting explains lanterns following the wind 20–25 seconds apart. Their apparent grouping above the distant forest and the impression that the first spheres waited for the others are perspective effects, like railway tracks converging towards the horizon. Their disappearance corresponds to the candles burning out, after which the unlit lanterns lose lift and fall. GEIPAN classifies the case A: sky-lantern observation.