Lab Notes
The Great Onion of Fear

Something is badly wrong with the town of Silent Hill. Not only does it have a coal mine fire burning underneath it, filling the air with toxic fumes, but parts of it have apparently been knocked completely out of our world. In fact, the town seems to be three distinct places: There's the "reality" layer, full of cops and other rescue workers looking for lost people and enforcing the gates and padlocks of a safety quarantine. In this Silent Hill, sunlight shines and rain falls, and plants still manage to grow and even thrive. Human beings can walk around with filter masks on their faces, with nothing to fear except perhaps a bit of smog-induced dizziness. And yet the place exudes an uneasy sense of danger and mystery and unfinished business. There are strange noises, half-glimpsed figures, murky records and frightened eyewitnesses who won't or can't say what really happened here. The place is, in a word, haunted.

But somewhere, somehow, there's another town called Silent Hill that looks almost exactly the same. The buildings, the abandoned cars, the general decay are all very similar, but the weather is not. Steeped in perpetual twilight, this place—we'll call it the "ghost" layer—knows neither rain nor sunlight. The coal smog is a lot thicker, and ashes rain down from the sky without ever seeming to really pile up on the ground. The rescue workers are nowhere to be seen, and instead of a chain link fence covered in warning signs, the town is girdled by a chasm deeper than the eye can see. For the people trapped in this layer, the outside world is little more than memory and rumor. There is no escape. And yet, although people in the reality layer can vaguely sense the presence of the ghost layer and the unquiet things within it, the "ghost" people aren't really ghosts in any conventional sense. They aren't dead; like ants in a terrarium, they eke out pathetic, insular lives, but they can bleed and scream and die like anyone else. Which is a real problem, if you happen to be one of them.

Peeling back the onion still further, we find a third Silent Hill, which, for lack of a better term, we'll call the "inferno" layer. Here the only light is the red glow of burning coal rising up through cracks in the earth. There are no plants; there is no sky. The dominant life forms are carnivorous beetle-like creatures with perversely human faces. The other, larger inhabitants appear to be former human beings, modified through various forms of surgery or mutilation that's left them in a state of permanent, murderous rage. "Brimstone" is another name for the element called sulfur, and while you can't smell things in a movie, one imagines its reek permeating this place, along with the odors of rot and excrement. Interestingly, materials seem to behave differently in this layer, too. Only metal and stone are durable; wood and paper and linoleum quickly peel away into ashes, while flesh ... well, bad things happen to flesh.

Travel between these layers is possible; during the course of the movie, at least three people tumble from the reality layer into the ghost layer, which itself seems to rotate in and out of the inferno layer on a regular basis. For human beings, escape from the inferno layer is simply a matter of time; survive a few minutes of sick, mortal danger and the dark world will melt away again, allowing the ghost layer to reassert itself. The quasi-human creatures can also appear sometimes in the ghost layer, although they pop like hydrogen-filled balloons when injured. No one seems to get out of the ghost layer, though, and deep underground—in caverns and subcellars and burned-out mine shafts—the ghost and inferno layers seem to overlap permanently.

Hell hath plenty of fury

Now, I'm not suggesting that Silent Hill is in any way a science-fiction movie. The horrors are clearly supernatural, and no attempt is made to justify them on scientific grounds. But the story does suggest an obvious question: Could these effects be reproduced technologically? Could science really put people in this sort of earthly hell?

The answer is clearly yes, because the town is based on a real place—Centralia, Pa., where a 40-year coal fire really has driven out all the residents—and the movie is based on a video game, in which the ghost and inferno layers are simply different VRML code and texture files. A "reality" layer also exists, although if it's going to interact with the ghost layer in interesting ways, it also needs to reside within the computer. Thus we need a fourth layer—call it "actual reality"—for the computer and the player and the virtual realities to exist in. Admittedly, watching the horrors unfold on a laptop screen isn't nearly as terrifying as seeing and feeling and smelling them all around you, but that's merely an engineering problem.

A full-immersion VR helmet would make the illusion more convincing, although when the eye is seeing motion that the inner ear doesn't feel, people tend to succumb to "cyber sickness" in the same way that people on boats become seasick. One solution people have been toying with since the early '90s is direct stimulation of the human vestibular nerves. Using electrodes pressed against the skin by a special headset, it's possible to create the sensation of movement or rotation to match what's happening on the screen. A bit creepy, yes, but it creates a much more realistic VR experience. And why stop there? A motion-capture suit lets the player's own body movements control the game, and a powered exoskeleton allows the game to push back against the arms and legs with considerable force. This stuff exists right now, and could easily be integrated into a single (expensive) package. You think a movie is scary? Try this instead.

But it gets worse! With a transcranial magnetic stimulator (TMS) of sufficiently high resolution, we could create sensations of heat and cold and pain. We could even make detailed tactile illusions—bugs crawling all over you, the warm trickle of blood, the wrenching agony of a broken bone. ... If fact, if we can do that, we can dispense with the goggles and headsets altogether and simply pipe all the input directly into the brain, while the victim lies paralyzed on a table, or in a Matrix-style coccoon. 'Nuff said? With sufficiently advanced technology, we could make a virtual world indistinguishable from hell itself, and literally scare people to death. And if that's not awful enough, we can use "augmented reality" instead of VR. Imagine the victims running around in a real town, seeing and feeling things that aren't really there and ignoring a lot of things that are. Vernor Vinge's new book, Rainbows End, uses this trick for pleasant forms of both work and play, but in the right hands—or the wrong ones—it can be a tool of pure terror.

Terror from the fifth dimension

But that's too technological, right? Not supernatural at all. A slightly mushier possibility is mass hallucination or dream broadcasting. Sleepwalking is one of the pervasive themes of the Silent Hill series, and if we could induce that state on demand, and exert some control over what people were dreaming, we could create as many scary layers as we wanted, in and out of actual places.

But the shapes of some of the monsters suggest another possibility: hidden dimensions. Our universe consists of three spatial dimensions (up-down, left-right and front-back) and one time dimension (past-future), but according to cosmologists there are other dimensions as well, which we perceive only through their effect on the forces of nature. What if a town—an entire town!—could fall askew in one of these hidden dimensions? If we take a cross-section of our world, we find a two-dimensional universe of thinly sliced trees and houses and human beings moving around, like a planet-sized CAT scan. But if we slide the cross section up and down, the shapes seem to change: now cutting people at the knees, now seeing their shoulders and arms, now just their brains and skulls and eyeballs. In exactly the same way, we can envision our three-dimensional bodies as "cross-sections" of some very complex five-dimensional object.

Is that too complicated? If so, ignore it and just take my word for the following: a human being slightly displaced in the fifth dimension would look distorted to us. Maybe it would have no arms, no face, no skin. Maybe it couldn't talk, couldn't scream for help, couldn't make itself fully visible in the reality layer at all. It would be stuck half in and half out of our world, in a realm where the laws of physics and chemistry might be different as well. What a nightmare.

We can take some comfort in the fact that this sort of dimensional shifting would require enormous energy, of a sort we don't yet know how to generate. A mere coal fire wouldn't do it. Still, the next time you feel the word "damnation" rising up on your lips, keep in mind that it may not be an idle threat!

Sources:
Silent Hill, Konami, 1999
Silent Hill, Sony Pictures, 2006 www.sonypictures.com/movies/silenthill
The Encyclopedia Britannica, 2004 Edition: ("sulfur")
Wikipedia, en.wikipedia.org ("transcranial magnetic stimulation")
www.anthrotronix.com
www.brl.ntt.co.jp/people/parasite
www.springwalker.com