In my detailed answer, I shall go steps by steps.
What is your story referring to :
-Hauntings (phenomena often attributed to ghosts and encountered in places a deceased individual is thought to have frequented, or in association with the person's former belongings).
-Possession, belief in the control of the behavior of a living thing or natural object by a spiritual being
The science which study these two phenomena is called Parapsychology, a study of ostensibly paranormal events including survival of consciousness after death. The first step is always to collect “facts”, to understand what are we talking about.
Haunted locations or haunted places are sites of reported ghost activity. The reports of these hauntings are often referred to as ghostlore. Ghostlore is fueled by history and legends and is a part of folklore. These accounts can be subjective in nature and there is no commonly accepted objective evidence that ghosts or similar phenomena exist. See as an example :
List of alleged haunted locations in USAApproaching paranormal phenomena from a research perspective is often difficult because even when the phenomena are seen as real they may be difficult to explain using existing rules or theory. By definition, paranormal phenomena exist outside of conventional norms. Skeptics contend that they don't exist at all. Despite this challenge, studies on the paranormal are periodically conducted by researchers from various disciplines. Some researchers study just the beliefs in paranormal phenomena regardless of whether the phenomena actually exist.
Parapsychology only studies those anomalies that fall into one of three general categories: ESP, mind-matter interaction and phenomena suggestive of survival after bodily death, including near-death experiences, apparitions, and reincarnation. Most parapsychologists today expect that further research will eventually explain these anomalies in scientific terms, although it is not clear whether they can be fully understood without significant (some might say revolutionary) expansions of the current state of scientific knowledge. Other researchers take the stance that existing scientific models of perception and memory are adequate to explain some or all parapsychological phenomena.
Such experiences seem to challenge contemporary conceptions of human nature and of the physical world. They appear to involve the transfer of information and the influence of physical systems independently of time and space, via mechanisms we cannot currently explain. The existence of these phenomena suggest that the strict subjective/objective dichotomy proposed by the old paradigm (see below) may not be quite so clear-cut as once thought. Instead, these phenomena may be part of a spectrum of what is possible, with some events and experiences occasionally falling between purely subjective and purely objective. We call such phenomena "anomalous" because they are difficult to explain within current scientific models.
When one speaks about a topic which is controversial to many, such as parapsychology, it is crucial to understand the concept of a paradigm. A paradigm is an underlying worldview. It can be thought of as a framework of beliefs which are so taken for granted that most folks are not even aware they have made any assumptions. A paradigm helps us to make sense of the world around us. But perhaps more importantly, in terms of science, it not only determines what is true, but how truth itself can be determined. There is an obvious catch to this. If one does not recognize the underlying assumptions one makes with a paradigm, it has the potential to limit our perception of the world, what we can discover, and how we can determine that knowledge.
The old paradigm, which many have held since the days of Descartes, states that the subjective and objective worlds are completely distinct, with no overlap. Subjective is "here, in the head," and objective is "there, out in the world." The Cartesian paradigm presupposes that there are objective ways to define and measure the fixed external world--which the proponents of this paradigm would say is the only world that matters. The classical paradigm favors experimental research design, which presumes to measure the world in an objective way.
Quantum theory triggered a fundamental shift in how we understand the world. Physicists suddenly realized that there is always some indeterminacy in our measurements. This is because the act of measurement itself can define and change that which is being measured. Because of this, the experimenter may always part of the experiment, and all our "objective" facts are, in fact, potentially flawed (with ESP making it impossible to ever have a truly "blind" experiment). This insight led to the idea of a paradigm based on nonlocality. And while not all physicists agree, the new paradigm that is emerging is one in which the universe is a single whole, within which every part is connected on some level to every other part. This new paradigm does not "prove" psi exists. However, it is compatible with the possible existence of psi, and may lead to a better understanding the phenomena.
It should be noted that the conflict between these two paradigms is ongoing. Because these belief systems are both widespread and deeply ingrained, topics that touch on these fundamentally different worldviews may give rise to bitter and violent debate, with little or no room for compromise. The lack of common ground between paradigms means that the question cannot be solved by discussion. Ultimately, the answer will have to be determined by which paradigm does the best job of answering the questions raised by research.
You see, when I begin talking about parapsychology, I can’t stop ! It’s one of my favorite hobbies. But it’s enough for now.
Summarising my opinion,
Are the related haunting experiences reported by so many people real ? Yes.
Is it possible to explain them inside the old paradigm ? No.
Will future researches bring an explanation to these phenomena ? Perhaps.
Could the present researches about the beginning and the future of the universe (Big Bang theories) bring a contribution to the researches in parapsychology (Parallel universes) ? Why not.
Old bob