Beyond any doubt, earthlights or similar phenomena account for many UFO sightings. I feel that these explain many of the legendary sightings near volcanos and other seismically active areas. Many examples of sightings and their interepretations are given. I don't feel that this or any other known phenomenon can explain away all credible UFO sightings. https://www.physicsforums.com/showthread.php?s=&postid=83705#post83705 Please note also the the father of the swamp gas explanation for UFOs was Dr. J. Allen Hynek - who later became the father of modern Ufology.