What UFOs turn out to be

Optical phenomena mistaken for UFOs

Ice crystals in the air produce halos around the Sun or Moon, sun dogs ("mock suns" on either side of the Sun) and light pillars above ground lights. Temperature inversions create mirages that make distant lights appear or distort them.

These effects stay fixed relative to the light source that creates them: an "object" that accompanies the Sun or a light on the ground is almost always optical.

SkyUnknown lists 23 UFO sightings explained as an atmospheric optical phenomenon (halo, sun dog…), from 1977 to 2023, drawn from official records: GEIPAN (CNES) for 22 cases and Aeronautica Militare (Italie) for 1. The busiest year was 2013, with 4 cases.