Although studies have been carried out on apparitions since early 19th century and many theories have been put forth and explained, scientists, priests, psychologists and parapsychologists offer all explanation of their own but still know very little about apparitions.
Parapsychologists study ghosts as part of their living. A parapsychologist seeks to understand paranormal phenomena. Paranormal phenomena is described as any phenomenon or occurrence that exceeds the bounds of what is possible, according to the established principles and laws of science.
Skeptics on the other side charge the controversy with several rational explanations for suspected ghost sightings that involve some type of naturally-occurring electrical, magnetic, or electromagnetic condition.
For instance, Scientists Richard Lord and Richard Wiseman explain that sound waves having frequencies less than 20 hertz are normally inaudible, nonetheless, they may cause someone to feel a presence or shift their mood to anxiety or dread. Carbon monoxide poisoning was cited as a cause for haunted houses as early as 1921 because it can cause hallucinations, ill feelings, and a sensation of dread as well.