Explained mysteries, but still unsolved
Ghosts
Ghost, nonmaterial embodiment or essence of an organism, especially of a human being. The term is sometimes used virtually as a synonym for soul or spirit, and in the Christian religion, in the form Holy Ghost (now, more often, Holy Spirit), it has a specialized meaning. More frequently, however, the term ghost is applied to an apparition, usually of a dead person, that varies in apparent solidity from a mere foglike mass to a perfect replica of the person. A wraith, in contrast, is the visible spirit of someone still alive. A doppelgänger is a special form of wraith that makes its appearance at a time when the physical body of the subject is observed at some distant place.
In many religions, and particularly in primitive faiths, the belief exists that the spirit wanders away from the body during periods of unconsciousness such as sleep. Such religions also teach that after death the spirit lingers near the body of the dead person. A common practice of groups holding such beliefs is to propitiate the ghosts of the dead by offerings of food, clothing, and other objects that the ghosts may find useful in the spirit world. In many primitive civilizations the personal possessions of a dead man, including his weapons, his pets, and sometimes even his wife, are buried or burned with his body. The practice of ancestor worship, as well as the mourning rites of many modern civilizations, probably originated in the belief in ghosts.
Poltergeist
Poltergeist, German for 'noisy ghost,' unexplained phenomenon that invisibly moves objects or hurls them about, starts fires, or causes other mischief. Identical phenomena attributed to poltergeists have been reported from all parts of the world and throughout all ages. Poltergeist disturbances include noises of every description, especially bell-ringing. Serious physical injury is rare, although on occasions great force is displayed. The manifestation is usually confined to a house, and it may cease as suddenly as it began and for no apparent reason.
