PONT-SAINT-ESPRIT (30) 12.12.2017

On 12 December 2017 at about 21:00, a witness walking his dog along a small road beside a railway noticed a silent luminous object crossing the clear sky. It was round, matte white and seemed lit from within. It moved toward an old bridge, then changed course. Its brightness gradually decreased until it disappeared. The observation lasted about 30 seconds. A telephone interview on 15 March 2018 added information (see the investigation note). Only one account was collected. Analysis of the account: - Appearance: a luminous matte-white sphere 'like a ping-pong ball', apparently illuminated from inside. - Sound: silent. - Appearance location: above the overhead railway wire, at about 30° (see the plan in the investigation note). - Size: described as considerably smaller than the Moon, but also as 23 mm on a ruler held at arm's length; both descriptions are retained from the source. It was largest when first seen above the wire, then shrank as it receded. - Brightness: contrary to one statement in the account, it did not fade instantaneously but dimmed with distance. Finally it flickered and disappeared. The witness thought the flickering might have been caused by trees passing in front of it. - Movement: constant altitude and speed. - Path: his drawing indicates northwest to southeast, contradicting the questionnaire's southwest disappearance direction. Movement toward the bridge would indeed be southeast. - Disappearance: behind the crane at about 15°. He did not know whether it went out or passed behind the skyline of houses and trees. - Duration: about 30 seconds, less than a minute. The dog did not react. The witness said he was color-blind; the source considers that the white appearance removed any risk of confusion with another color. He probably saw a white LED balloon. Its matte-white, ping-pong-ball appearance matches such balloons, and an internal LED would explain the apparent illumination from within. Its silence and northwest-to-southeast movement also fit the wind. The final turn probably reflected a wind change, which can occur near the ground around terrain or obstacles such as trees and houses. The continuously decreasing size fits a balloon passing near him and receding. Flickering before disappearance probably resulted from trees on the skyline. A windborne balloon traveling about 100 meters during the observation would have a speed consistent with the wind recorded that evening (see investigation note). The remaining uncertainty is the Tuesday date and winter season, less favorable to balloon releases or festivities, although a private party remains possible. GEIPAN classifies the case B: probable observation of a white LED balloon.