Studies:

Studies by doctors, psychologists, social workers and public opinion researchers confirm that experiences of apparent contact with the dead are commonplace all over the world. For instance, over half the healthy, normal widows and almost as large a percentage of widowers in the United States sense the presence of their departed mates at least once afterwards. Such experiences are usually unexpected and spontaneous, not invited in any way. They are also direct—they do not involve mediums. Apparent contacts are most common in the first year after a partner passes on, but they may recur for years, even for decades. Most such seeming visits from "beyond the veil" are perceived as pleasant; a significant few bring guidance or information that it would seem could only come from a spirit source.

• Interviews with 66 widowers and 227 widows in an area of Wales— almost all of those healthy enough to be interviewed—revealed that half the widowers and 46% of the widows had sensed some kind of after-death communication [ADC] with their departed mate. (Vivid dreams that seemed like visits from a loved one were not counted.) According to W. D. Rees, the general practitioner who reported this research in 1971, ADCs were usually perceived as helpful and pleasant. Those who had them were not particularly depressed or socially isolated. Instead, they were more likely to have had longer marriages, happier marriages, and marriages with children. Though ADCs were most likely to occur within the first year after a loved one's passing, sometimes they recurred for years, even decades. Often they continued after the widowed spouse remarried. See: The Hallucinations of Widowhood
• A 1970's survey of residents of Los Angeles which drew samples from white, black, Japanese- and Mexican-American neighborhoods found that 44% of the 434 people interviewed thought they had had encounters with someone who was dead. Over a quarter of those who reported such an encounter said that the dead person actually visited or was seen at a séance.
• The ambitious Harvard Bereavement Study of widows and widowers from the Boston area followed scores of subjects for four years after they lost their mates. Three weeks after their loss, 44% of those who expressed a high degree of yearning for their dead spouse felt that "My husband/wife knows and sees everything I do." More surprising, almost a third of those in the "Low Yearning" category also agreed with this statement. Most of the widows sensed that their husband was with them some or all of the time. "One reported hearing her husband come to the door after work and put his key in the lock. Four others reported catching sight of their husband out of the corner of their eyes. In one case he was sitting in the living room ... in another he was standing by the door." The widows found this sense of presence comforting. Interviewed thirteen months after bereavement, almost half agreed with the statement that "I have a feeling that my husband watches over me." The researchers stressed that their subjects were not psychotic and, observed that since "bereaved people are often reluctant to reveal information ... that might be taken to indicate mental illness," these figures were probably an undercount.
• In 1982, an Arizona psychologist, David Balk, interviewed a sample of normal American teenagers who had lost a sister or brother. About half of them at times had thought they saw or heard their dead sibling. Several reported occurrences that they felt "involved actual contact with the sibling."
• In 1985, a team of Americans headed by P. Richard Olson, MD, studied 52 widowed people in a North Carolina nursing home, none of whom appeared to be mentally ill or confused. Over 60% of the 46 widows had sensed their husbands with them after death in some way. For almost all of them, the experience was a pleasant one. Two of the six widowers in the nursing home reported similar experiences.
• A 1993 study measured the feelings of 20 American university students, 18-27 years old, who had lost a parent at least two years before. The great majority of them agreed strongly with the statement, "I feel he/she is still with me at times."
• A 1993 Swedish study of 14 widowers and 36 widows in their seventies found that one month after bereavement, 89% of the women and 57% of the men reported some kind of after-death communication—this even though ADCs "are hardly recognized in Sweden. They are spoken about neither publicly nor among close friends." Only after these widows and widowers were told that such sensations were common did they "speak freely, expressing relief from thoughts that they 'might become or be considered insane.'" A year after bereavement, over half of them reported that they were still sensing contact with their lost mates.
• A 1995 study of Norwegian women, 44-79 years old, who had lost their husbands or live-in partners showed similar results. Soon after bereavement, almost three-quarters of them (29 out of 39) sometimes sensed their lost mate's presence. And a year later, two-thirds of them were still sensing ADCs. Source: When Spirits Come Calling. Preview First Chapter

Astral Body:

Another widespread belief concerning ghosts is that they were composed of a misty, airy, or subtle material. Anthropologists speculate that this may also stem from early beliefs that ghosts were the person within the person, most noticeable in ancient cultures as a person's breath, which upon exhaling in colder climates appears visibly as a white mist. This belief may have also fostered the metaphorical meaning of "breath" in certain languages, such as the Latin spiritus and the Greek pneuma, which by analogy became extended to mean the soul. In the Bible, God is depicted as animating Adam with a breath.

The astral body refers to the concept of a subtle body which exists alongside the physical body, as a vehicle of the soul or consciousness. It is usually understood as being of an emotional nature and, as such, it is equated to the desire body or emotional body. However, some philosophies conceive that the astral body is a body made of ether(the soul body),built by each individual during the current evolutionary stage(the Philosophers' Stone),which is said to give support to the desire(emotional) body during the astral projection.

Ghost: Spirit

A ghost is usually defined as the apparition of a deceased person, frequently similar in appearance to that person, and encountered in places he or she frequented, or in association with the person's former belongings. The word "ghost" may also refer to the spirit or soul of a deceased person, or to any spirit or demon. Ghosts are often associated with haunting, which is, according to the Parapsychological Association, "the more or less regular occurrence of paranormal phenomena associated with a particular locality(especially a building)and usually attributed to the activities of a discarnate entity; the phenomena may include apparitions, poltergeist disturbances, cold drafts, sounds of footsteps and voices, and various odors."

Ghosts are a controversial anomalous phenomenon. According to a poll conducted in 2005 by the Gallup Organization, about 32% of Americans believe in the existence of ghosts. The term ghost has been replaced by apparition in parapsychology, because the word ghost is deemed insufficiently precise.