Tucker, Libby. “Good Spirits: Orbs and Avatars” New York Folklore, vol. 36: 1-2, 2010. p. 29.
Summary
Since “seeing is believing” in our culture, visual evidence of a supernatural presence seems especially compelling. Ghosts in photographs and on videos get more attention than ghosts that whisper in the night. It should not surprise us, then, that orbs—bright spheres of light in photographs—...Some people believe that orbs represent ghosts; others believe that orbs come from glitches in the photographic process.