There is no evidence of actual GHOSTS or "Spirits of the dead"---GHOSTS is a superstitious "explanation" to explain aspects of Nature that our Science has not gotten around to explaining yet. Certain glowing lights, Mists, and the appearance/disappearance of human and inanimate objects, that can't be explained at our current state of knowledge.---Its only "Human" to describe ANYTHING we cant explain yet, as being "Ghosts".
Just because an event or object is unknown for now, and REAL----does not mean it is a REAL GHOST. its just something we don't understand yet. Likely some obscure atmospheric effect , an electromagnetic effect or the result of something basic to higher order Physics like a time fold or distortion.---- One should be fascinated by unexplained phenomena--its by study of things not yet explained is hoe SCIENTIFIC discoveries are made.