Autokinesis is a visual illusion. It can occur under certain conditions, especially on dark nights in areas with few visual cues (such as lights or other illuminated objects or landmarks). When a small, dim, and fixed light source remains within visual range for an extended period of time, this phenomenon can occur, making it appear as if the light source were moving. This visual illusion can be of particular danger to pilots at night. In addition, it is possible that this illusion may account for some supposed UFO sightings in which witnesses may see an isolated light, such as a bright star or planet, seeming to move erratically around. Therefore many UFOS are really IFOS (see Identified flying object) as the result of star or planet misidentifications due to autokinesis.