Merging luminous balls over Cesson-Sévigné

Summary

Between 10:35 and 11:15 PM on 17 May 2008, two people in Cesson-Sévigné watched three luminous balls merge and split against a low, cloudy sky. Similar phenomena had been reported in the area the previous night. GEIPAN concluded the display was most likely artificial lights projected onto the cloud layer, of the Sky Rose type or a similar commercial lighting show. The seemingly complex movements are explained by the interaction of the beams with the clouds.