These days, physicists are often looking at scientific inconsistencies associated with strange creatures appearing in the movies. As an example, in 'Physics proves horror movies get it wrong,' ABC Science Online reports that some researchers have searched if ghosts, vampires and zombies could be more than Hollywood fantasy. Their conclusion is pretty straightforward. The idea of ghosts and vampires is inconsistent and contradictory with simple maths and physics. And the idea of zombies, if it relies on real cases, is simply a misrepresentation of criminal acts. But read more...
One of the researchers, Costas Efthimiou, of the Department of Physics at the University of Central Florida (UCF), has already published other papers on the subject. You can read for example "Physics in Films - A Blockbuster Class at UCF" (Sae Schatz, UCF News, May 2004).
Here is one paragraph of the ABC Science Online article about ghosts.
For instance, the ability to walk through walls is a common talent of celluloid ghosts. But Newton's laws of physics suggest that if a ghost can walk it shouldn't be able to pass through walls, say Efthimiou and Cornell University postgraduate student Sohan Gandhi. Newton says a body at rest will remain at rest until it's acted on by an external force and for every action there is an equal but opposite reaction.
Below is an illustration showing an example of Newton's third law known as action-reaction law. (Credit: Picture borrowed from the book of Jay Bolemon, "A Window to Our World," Prentice-Hall, first published in 1995)
So a ghost can't pass through walls. But can he walk? The researchers say the answer is no.
In order to walk, we apply a backward force on the floor with our feet, propelling the feet up and us forwards. But if a ghost can walk through walls, it must be "material-less", the authors argue, and incapable of exerting force. By the same token, a ghost that can walk through walls should also sink through the floor, and a ghost that can walk should be bouncing off the walls it tries to pass through.
Below is an illustration describing the forces acting on our feet when we walk. (Credit: same as above)
OK, ghosts are pure fantasy. But what about vampires? In their paper (see below), the researchers write that the principle of geometric progression rules out the existence of vampires.
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 first 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 film. Now two things happen when a vampire feeds. The human population decreases by one and the vampire population increases by one.
After two months, there are a total of 4 living vampires and 4 humans have died. And of course, the geometrical progression continues, until there are only vampires and no humans.
We conclude that vampires cannot exist, since their existence contradicts the existence of human beings. Incidently, the logical proof that we just presented is of a type known as reductio ad absurdum, that is, reduction to the absurd.
For more information about zombies and 'zombiefication,' a crime in Haiti equivalent to murder, you should read this technical paper, "Ghosts, Vampires and Zombies: Cinema Fiction vs Physics Reality." Here are two links to the abstract and to the full paper (PDF format, 11 pages, 293 KB, August 5, 2006) from which the images above have been extracted.
Sources: Judy Skatssoon, ABC Science Online, August 29, 2006; and various web sites
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