Preface
“A man should look for what is, and not for what he thinks should be.”
-Albert Einstein-
What is a ghost anyway? If you ask this question in paranormal circles, chances are you will get a lot of different answers. A quick internet search alone turns up hundreds of references from hundreds of resources. But no matter what answer you get, or what definition you choose, the common theme is a ghost is believed to be the physical manifestation of a dead person.
Unfortunately, the reality of the idea of the existence of a “ghost” is for the most part unproven scientifically. Since our beliefs and perceptions of ghosts are based loosely around folklore and not corroborative scientific research, many naturally explainable phenomena have been mistakenly labeled a “ghost”. In fact, when we take the time to look deeper into the phenomenon of a haunting from a scientific perspective, a plethora of very real scientific possibilities emerge. While the following speculations may seem rather deep to some, they are based on sound scientific principles of physics. I will try to explain the concepts as simple as possible, but some technical jargon is required.
Possible scientific explanations of a “ghost” include:
Time anomalies – It is very possible that some “haunting” are anomalies that have occurred in the fabric of space-time in such a fashion that when we enter the area of effect, we “witness” an event that has occurred at a previous time in history. This is a result of time being a landscape, not a flowing entity, and based on where you are physically located on that landscape determines the period of time you experience. Some theories, (most notably special and general relativity), point out that certain geometries of space-time, or specific types of motion in space, may possibly allow time travel into the past and future if this landscape is a reality. Generally speaking, in white papers physicists avoid using the terms "moving" or "traveling" through time as movement refers only to a change in spatial position as the time coordinate is varied, and instead discuss the concept of closed time-like curves, which are considered to be world lines that form closed loops in the space-time stew, allowing objects to return to their own past. Interestingly, there are solutions to the equations of general relativity that define space-times which contain closed time-like curves, but the physical plausibility of these solutions has yet to be proven. On the other hand, it may be that certain conditions may occur naturally that cause a spatial flux to occur creating a space-time “nodule” or bubble if you will, which would allow a witness, if contained within the area of effect, to experience events from another time. This would not necessarily break any rules of physics and may be a more plausible explanation for “ghosts”.
Physicists assume that if one were to move away from the Earth at relativistic (near light) velocities and return, more time would have passed on Earth than for the traveler. It is therefore accepted that relativity allows "travel into the future". But, many in the scientific community believe that traveling back in time is highly unlikely. Any theory which would allow time travel would require that issues of causality (cause and effect and the resultant time-line alteration) be resolved. The classic example of a problem involving causality is the "grandfather paradox", in which if one were to go back in time and kill one's own grandfather before one's father was conceived, he would have never existed to kill his grandfather in the first place.
WARNING! Thinking about things like this can make your head ache. Not so fast though; some scientists believe that paradoxes can be avoided, either by appealing to the Novikov self-consistency principle (the Novikov consistency principle states that if an event exists that would give rise to a paradox, or to any "change" to the past whatsoever, then the probability of that event is zero) or to the notion of branching parallel universes (the casualty simply causes the creating of a new alternate universe in which the new series of events unfold). However, there is another possibility. What if instead of a corporeal body traveling back in time, we experience a glimpse back in time, which may encompass the environment as well as the witness’ perception? Perhaps this has something to do with how psychics see things from the past or the future. Maybe they “glimpse” a notion in time.
Simply put, we may be witnessing an event unfold over and over again because of a condition which alters our perception when standing in a specific sphere of influence relating to an event that has occurred in the past. The big question is what the specific sphere of influence is, and what causes it?
Parallel dimensions, universes and worlds – This idea is getting a lot of juice now because of new developments in mathematical research at Oxford by Dr. David Deutsch who has demonstrated the mathematical reality of parallel universes, and researchers at other institutions such as Don Page, who is investigating the philosophical implications of quantum mechanical mathematics involved. Don has determined that quantum mechanics' equations imply that there are an infinite number of universes that are as real as the universe revealed by human perception. The universe, it appears, may not be alone.
So now we don’t have to feel bad. TRYING to understand what lies behind the bizarre mathematics of quantum mechanics gives even physicists a splitting headache. I don’t know about you but I certainly harbor some comfort from that!
A parallel universe or alternative reality per se is a self-contained separate reality that co-exists with our own. This concept is as old as man himself and is reflected in the practices of ancient cultures via shamanism and endures to this day. A related or connected grouping of parallel universes is called a multiverse, although this term has also been used to define the potential parallel universes that comprise physical reality. While the terms "parallel universe" and "alternative reality" are for the most part synonymous with one another and can be used interchangeably in most cases, the term "alternative reality" can also mean that the reality is a variation of our own. The term "parallel universe" on the other hand is more general, lacking any implications of a relationship or lack thereof with our own universe. For example, a universe where the very laws of nature are different, such as it has no relativistic limitations by our definition and the speed of light can be exceeded at will, without consequence, would qualify as a parallel universe but not an alternative reality.
Hugh Everett was an American physicist who first proposed the many-worlds interpretation (MWI) of quantum physics in his doctoral thesis back in 1957, as his "relative state" formulation. He left the field of research physics shortly after completing his Ph. D., discouraged at the lack of response to his theories from other physicists. He went on to pioneer the use of generalized Lagrange multipliers in operations research and applied this commercially as a defense analyst and a consultant, becoming a multi-millionaire. So while he was a success, he never fully covered from the ridicule he experienced as a doctoral student.
Proponents argue that MWI reconciles how we can perceive non-deterministic events (such as the random decay of a radioactive atom) with the deterministic equations of quantum physics. Prior to the postulation of many worlds our reality had been viewed from the perspective of a single "world-line". Many-worlds introduced it as a many-branched tree where every possible branch of history is realized.