Sighting in Challes-les-Eaux (73) 11.10.2017 T2, October 11, 2017

At around 2:30 p.m., a witness lying on a deck chair was looking at the sky to the south. They suddenly noticed a white, fairly round object, about the apparent size of a handball, moving quickly eastward. After about a minute, the object seemed to move off "backwards". The witness went to fetch their mobile phone to take a picture. On returning, they had trouble finding the object again, but eventually photographed it: the image showed a bright white blotch. Searching the sky again with the phone, they spotted a smaller object, which soon vanished from view.

The witness then sat back down and saw filaments floating in the sky. Their daughter, who was present, saw these threads too. The witness took several photos and later found a few of the threads caught in their cherry tree.

Only one account was collected. It was consistent and precise, and the photos were very valuable for the analysis. The investigation identified two separate phenomena. The first was two airliners crossing at the same apparent spot and time, which gave the illusion of a single object moving backwards. The second was that the photographed threads were "gossamer" (known in French as "fils de la Vierge"), silk strands on which tiny young spiders let the wind carry them, a phenomenon called ballooning. GEIPAN classified this case as A (observation of ballooning); the mistaken identification of the airliners is covered in a separate file, also classified A.