Ghost lights are lights in the air that are not well understood by scientists. There are few reports of ghost light sightings. Ghost lights can be close to ground or in the sky. Ghost lights close to ground are commonly called "will o' the wisp" while ghost lights in the sky are often called UFOs. There are very different kinds of ghost lights: some resemble balls of light, others look like flame, and some look like a bright cloud. Many ghost lights move.