Ghosts Vampires And Zombies Cinema Fiction vs Physics Reality.pdf

Ghosts, Vampires and Zombies

Cinema Fiction vs Physics Reality

Costas J. Efthimiou 1

and Sohang Gandhi 2

Abstract

We examine certain features of popular myths regarding ghosts, vampires and zombies as they

appear in lm and folklore. We use physics to illuminate inconsistencies associated with these

myths and to give practical explanation to certain aspects.

1 Introduction

Perhaps for many, ghosts, vampires, zombies and the like are no more than Hollywood fantasy. How-

ever, increasingly these movies have come to reect popularly held pseudoscientic beliefs. For in-

stance, the movie “White Noise,” starring Michael Keaton, is based on the new trend among paranor-

malists — Electronic Voice Phenomena (EVP). The occult underground in both America and Europe

is witnessing a trendy rise in vampirism and belief in voodoo zombiecation which is widespread in

many parts of South America and Africa. Further, paranormal depictions in the media, especially

television and Hollywood, have a denite inuence on the way people think about paranormal claims

( [Sparks 1998, Sparks 2006] and references therein).

In this article we point out inconsistencies associated with the ghost, vampire and zombie mytholo-

gies as portrayed in popular lms and folklore, and give practical explanations to some of their features.

We also use the occasion as an excuse to teach a little about physics and mathematics.

Of course the paranormalist or occultist could claim that the Hollywood portrayal is a rather

unsophisticated and inaccurate representation of their beliefs, and thus the discussion we give hear

is moot. However, if they are to change their denition each time we raise issue, then all that they

are really arguing is that there exists something out there which may be given the name ‘ghost’, for

instance. Surely, no skeptic could argue with this.

2 Ghosts

2.1 Sudden Colds

It has become almost a Hollywood cliche that the entrance of a ghostly presence be foreshadowed by

a sudden and overwhelming chill (see, for example, “The Sixth Sense”, starring Bruce Willis). In fact,

sharp temperature drops are very commonly reported in association with supposed real-life encounters

with ghosts or poltergeists. This feature of supposed ghost sightings lends itself naturally to physical

explanation.

The famous Haunted Gallery at Hampton Court Palace near London, UK, is reputedly stalked by

the spirit of Catherine Howard, who was executed on 13 February, 1542, by Henry VIII. Visitors to the

room have described hearing screams and seeing apparitions in the gallery. A team of ghost-busting

psychologists, led by Dr Richard Wiseman of Hertfordshire University, installed thermal cameras and

air movement detectors in the gallery. About 400 palace visitors were then quizzed on whether they

1 C.J. Efthimiou is a theoretical physicist at the University of Central Florida (UCF). He is the advisor of the local

Campus Freethought Alliance (CFA) chapter which he helped to establish at UCF. Address: Department of Physics,

UCF, 4000 Central Florida Blvd, Orlando, FL 32816. costas@physics.ucf.edu

2 S. Gandhi has just received his BS in physics with honors. Among his many awards, he has been a Goldwater scholar

and an NSF fellow and was selected for the 2006 all-USA third team. He has served as the president of the CFA chapter

at UCF. In fall 2006, he will be a graduate student in physics at Cornell University.

could feel a “presence” in the gallery. More than half reported sudden drops in temperature and some

said they sensed a ghostly presence. Several people claimed to have seen Elizabethan gures.

Before moving on to an explanation, we will need to outline the concept of heat. When a ‘warm’

object is placed next to a ‘cool’ object (see gure 1) energy will begin to ow from the warmer body,

causing it to cool, to the cooler body, causing it to warm. This energy, which is being transferred

between the two objects due to their dierence in temperature, is called heat. Note that an object is

never said to ‘possess’ any amount of heat. Heat is only dened through transfer. For instance, no

matter how high one turns their stove, it never possesses any degree of heat. In the instance where

someone suddenly touches the stove, however, there is there occurrence heat — it is the energy owing

from the stove to that person’s hand.

Figure 1: Heat always moves from a hotter object to a colder object. Picture is borrowed from

[ Kirkpatrick & Francis 2007] .

As heat continues to be transferred from the warmer body to the cooler one in gure 1, and

the warmer body’s temperature continues to drop while the cooler body’s temperature climbs, there

comes a point when the two bodies are at the same temperature. At this point heat ceases to ow

between the two object since neither is the hotter one and heat has no denite direction in which to

be transferred. This condition is called thermal equilibrium.

In our stove example, heat was transferred via conduction — the exchange of heat through direct

contact. There are two other modes by which heat may be transferred. These two modes involve

the exchange of heat by two objects which are separated by some distance. If these two objects are

emersed in a uid (Earth’s atmosphere for example), then the warmer body may provide heat to the

uid in its immediate vicinity. This warmer uid will then tend to rise thus coming in contact with

a cooler body above. There may also be a lateral current in the uid, thus allowing the heated uid

to aect a cooler body to the side. This type of heat transfer, by an intermediary uid, is called

convection.

Figure 2: Convection currents in a uid. Picture is borrowed from [ Bolemon] .

In gure 2( a) we give an example of what is known as convection currents. Suppose that the right

wall is kept warm and the left wall is kept cool. Then air in contact with the right wall will tend to

gain heat and then rise while air in contact with the left wall will tend to loose heat and then sink.

The circular ow that then forms is called a convection current. Air cycles around a loop picking

up some heat at the right wall, dropping it o at the left wall, and then coming back around again.

Actually, the air current pattern will be somewhat more complicated then what we just described.

There will be all kinds of smaller cycles and eddies embedded in some complex pattern as in gure

2( b). The overall ow, however, will be as in gure 2( a).

The third mode of heat transfer allows for exchange between two separated objects even if they

are in a total vacuum. How can two objects exchange heat if there is no mater in between them? The

answer is radiation. The thermal energy of a body is expressed in the ‘jiggling’ of its various constituent

particles. As electrically charged particles within a body jiggle about, they produce electromagnetic

waves. When these waves hit another body, they cause the particles in that body to jiggle even more

than they were before and thus the body heats up. Since hotter bodies produce more of this radiation,

there will be more radiation from the hotter body falling upon the cooler body than radiation from

the cooler body falling upon the hotter body. Thus, overall, the hotter body will be loosing heat while

the cooler body will be gaining heat. We will not be too concerned with this particular mechanism

for heat exchange here.

Returning to the Haunted Gallery at Hampton Court Palace, Dr Wiseman’s team reported [BBC 2001]

that the experiences could be simply explained by the gallery’s numerous concealed doors. These el-

derly exits are far from draught-proof and the combination of air currents which they let in cause

sudden changes in the room’s temperature. In two particular spots, the temperature of the gallery

plummeted by up to 2 ◦ C (3.6 ◦ F). “You do, literally, walk into a column of cold air sometimes,” said

Dr Wiseman. “It’s possible that people are misattributing normal phenomena... If you suddenly feel

cold, and you’re in a haunted place, that might bring on a sense of fear and a more scary experience.”

The rumor that ‘cold spots’ are associated with ghosts seems to be a myth created by the construction

of old building and the vivid imagination of people.

But how could a few degrees drop in temperature explain the dramatic chills described so many

in ghostly accounts? First o, what we sense as cold is not correlated to temperature so much as

to the rate at which heat is being transferred from our body to the environment. For instance, even

in a temperate pool, one feel a very sharp chill when one rst enters. A moderate draft containing

condensed moisture could cause a very sharp sensation of cold. Secondly, we are all aware of the

‘tall-tale’ eect. Memories tend to become distorted and exaggerated. It is exactly this reason why

scientists tend not to rely on unchecked eyewitness accounts.

2.2 The Inconsistency of the Notion of Material-lessness

Popular myth holds that ghosts are material-less. For instance in the movie “Ghost” (starring Patrick

Swaze, Demi Moore, Whoopi Goldberg), the recently deceased main character tries desperately to

save his former lover from a violent intruder. His attempts grant him no avail, as at each lunge he

passes right through the perpetrator. It is interesting, however, that he was able to walk up the stairs

just previous to this. In fact, this is a common feature of the ghost myth. Ghosts are held to be able to

walk about as they please, but they pass through walls and any attempt to pick up an object or aect

their environment in any other way leads to material-less ine cacy — unless they are poltergeists, of

course!

Let us examine the process of walking in detail. Now walking requires an interaction with the

oor and such interactions are explained by Newton’s Laws of Motion. Newton’s rst law is the law

of inertia. It states that a body at rest will remain at rest until acted upon by an external force.

Figure 3: Two stills taken from the movie “Ghost”. I the left still the ghost goes through a door. In

the right still, the ghost — which follows a burglar in his girlfriend’s home — looses his balance as he

ascends the staircase and falls on the stairs.

Therefore, a person cannot start walking unless a force, applied by some body other than herself, is

acting upon her. But where is the force coming from? The only object in contact with the person

while walking is the oor. So, the force moving a person during walking is coming from the oor. But

how does the oor know to exert a force when the person wants to start walking and stop exerting it

when the person wants to stand? Actually, there is no magic here. The person actually tells the oor.

She tells the oor by using Newton’s third law.

Newton’s third law says that if one object exerts a force on another object, then the second object

exerts a force, that is equal but oppositely directed, on the rst object — hence “for each action there

is an equal but opposite reaction.” Thus when the skate-boarder in gure 4 pushes on the wall, the

wall pushes right back on her, causing her to accelerate o to the left.

Figure 4: An example of Newton’s third law known as action-reaction law. Picture is borrowed from

[ Bolemon] .

Thus walking goes like this (see gure 5) : The person wanting to do the walking must remain at

rest unless a force acts on her. She gets the oor to apply a force on her by applying a backward force

on the oor with her foot. She keeps repeating this action, alternating feet. The point is that for the

ghost to walk, it must be applying forces to the oor. Now the oor is part of the physical universe.

Thus the ghost has an aect on the physical universe. If this is so, then we can detect the ghost via

physical observation. That is, the depiction of ghosts walking, contradicts the precept that ghosts are

material-less.

So which is it? Are ghosts material or material-less? Maybe they are only material when it comes

Figure 5: Forces acting on the feet of a person while walking. Picture is borrowed from [ Bolemon] .

to walking. Well then we must assume that they can’t control this selective material-lessness, otherwise

Patrick Swayze would have saved his girlfriend in “Ghost.” In this case, we could place stress sensors

on the oor and detect a ghost’s presence. Maybe they walk by some other supernatural means. Well

why can’t they use this power to manipulate objects when they want to? Even more, it seems strange

to have a supernatural power that only allows you to get around by mimicking human ambulation.

This is a very slow and awkward way of moving about in the scheme of things. In any case, you’d

have to go to some lengths to make this whole thing consistent.

Incidentally, the reader may have noticed that we skipped a law in our discussion. We heard about

the rst law and the third law. Newton’s second law of motion is that the acceleration of an object —

the rate at which it speeds up — is proportional to the force applied, the constant of proportionality

being the mass. We didn’t need this law for our discussion but mention it for completeness.

3 Vampires

Anyone who has seen John Carpenter’s “Vampires” or the movie “Blade” or any of the host of other

vampire lms is already quite familiar with how the legend goes. The vampires need to feed on human

blood. After one has stuck his fangs into your neck and sucked you dry, you turn into a Vampire

yourself and carry on the blood sucking legacy. The fact of the matter is, if vampires truly feed with

even a tiny fraction of the frequency that they are depicted to in the movies and folklore, then the

human race would have been wiped out quite quickly after the rst vampire appeared.

Let us assume that a vampire need feed only once a month. This is certainly a highly conservative

assumption given any Hollywood vampire lm. Now two things happen when a vampire feeds. The

human population decreases by one and the vampire population increases by one. Let us suppose

that the rst vampire appeared in 1600 AD. It doesn’t really matter what date we choose for the

rst vampire to appear; it has little bearing on our argument. We list a government website in the

references [ US Census] which provides an estimate of the world population for given any date. For

January 1, 1600 we will accept that the global population was 536,870,911. 3 In our argument, we had

at the same time 1 vampire.

We will ignore the human mortality and birth rate for the time being and only concentrate on the

eects of vampire feeding. On February 1st, 1600 1 human will have died and a new vampire born.

This gives 2 vampires and (536, 870, 911 − 1) humans. The next month there are two vampires feeding

3 It may seem odd to the reader that we have specied the population with so much precision — we have a number

in the one-hundred millions and have specied it all the way down to the ‘one’s place’ (...911). We chose the particular

value for convenience. The actual estimated population in the 17th century is 562 ± 17 millions. Beyond mathematical

simplication, our choice has little impact on the argument to follow. If we were to report any number in the range of

possible values for the population in year 1600, the end result of our calculations below would be essentially the same.

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