How to Build a Big,
Swirly Wormhole
“I must warn you, we’re going to pass through,
well, a sort of gateway thing. It may disturb you.
It scares the willies out of me.”
—Slartibarfast, THE HITCHIKER’S GUIDE
TO THE GALAXY
In “She” (A-1), a comely female demon named Jhiera arrives in Los Angeles by means of a mystical portal from her home dimension of Oden-Tao. In her world, the women are enslaved. Jhiera has escaped and is essentially running an interdimensional underground railroad to help other females from her world do likewise, with a posse of the males of the species in hot pursuit. Thanks to the portal mechanism, Oden-Tao’s war between the sexes spills into an entirely new dimension.
Cordelia is understandably dismayed to learn that dimensional portals exist. The members of Team Angel have enough trouble fighting the demons in their own dimension, never mind the occasional imported creatures from another. Her dismay would be shared by many scientists, since they have yet to uncover any direct evidence that portal-like tears in the fabric of space-time can even occur, much less be used to transport large living objects from one world to another (assuming other worlds exist). The skeptics would include adherents to Many Worlds, since that theory insists on separate universes being “causally isolated” from each other. They cannot interact with other universes, and must be entirely self-contained.
The notion of a multiverse is essentially a reworking of Many Worlds, with one critical difference. In the multiverse, the dictum against interactions isn’t absolute. Travel between worlds is technically within the laws of physics, but statistically highly unlikely. One might be inclined to think that baby universes should be self-contained and noninteracting. However, once one postulates the existence of wormholes, it raises the possibility of using those hypothetical structures to travel between linked worlds, although the practical difficulties associated with making such structures traversable are pretty intractable. Just the probabilities of a wormhole spontaneously opening in our immediate vicinity are so minuscule that we would have to wait a very long time—longer than the entire lifetime of our universe—before such an event occurred.
That probability is much greater in the Buffyverse. In fact, the phenomenon happens quite frequently, even though we are told explicitly in “Spiral” (B-5) that the various dimensions are meant to be kept separate from one another. Portals nonetheless exist between them—Sunnydale’s Hellmouth is one example—just like the wormholes that may link baby universes. Characters will insist now and then on opening a portal, even though the end result of doing so is almost never positive.
A BRIDGE TOO FAR
On an otherwise typical night at Caritas, the demon karaoke bar owned by Lorne, a mysterious, big swirly hole opens up onstage and spits out a hell-beast (“Belonging,” A-2). The vortex is a portal connecting Los Angeles with Lorne’s home dimension of Pylea, and the hell-beast is called a drokken. Lorne enlists Team Angel’s help to track and kill the drokken before it feeds on too many local residents. So begins an adventure so big that it spans the next three episodes. Angel and his cohorts discover more than Cordelia ever wanted to know about dimensional portals, even traveling to Pylea themselves.
One of the Pyleancentric episodes is called, aptly enough, “Through the Looking Glass” (A-2), a reference to Lewis Carroll’s nineteenth-century sequel to Alice in Wonderland. Carroll’s looking glass resembles a wormhole that connects Alice’s world with a strange new land, and wormholes are the closest concept in real-world physics to the mystical portals found in the Buffyverse. Technically, a wormhole is defined as any structure that connects two otherwise distant or unrelated points in space-time. The notion is an outgrowth of black hole physics. We’ve seen that a black hole has at its center a point of infinite density and infinite gravity, known as a singularity, as well as a theoretical point of no return called the event horizon beyond which nothing escapes—not even light.
Einstein thought that black holes were merely theoretical objects, but mathematically, he showed that there might be a wormhole at the heart of one. According to the equations of general relativity, wormholes can arise when black holes bend space-time far enough to poke a hole through to another point in space-time. Picture a bedsheet stretched taut. That sheet is Einstein’s flat, geometric space-time. Place a large bowling ball in the center of the sheet, and the sheet will bend inward in response, creating a gravitational pull. Now imagine that the bowling ball is being squeezed, so that the same amount of mass must fit into a smaller and smaller space. The ball will become denser and denser as it becomes smaller and smaller, causing the sheet to dip lower and lower, until finally the ball has been squeezed down to the size of a (very heavy) pinhead. At that point, its density becomes so great, and the resulting gravitational force so strong, that it pokes a small hole in the center of the sheet.
That’s exactly what would happen if a wormhole formed at the center of a black hole: For a brief moment, there is a tear in the fabric of space-time. But what lies on the other side? Always a stickler for symmetry in his equations, Einstein hypothesized that a “mirror universe” must exist on the other side. A black hole can be visualized geometrically as a large funnel with a long throat. If one “cuts” the throat and merges it with a second black hole that has been flipped over (a “white hole”), the resulting configuration resembles an hourglass, with the two ends connected by a thin filament. This so-called Einstein-Rosen bridge (named for Einstein and his collaborator, Nathan Rosen) is an early theoretical incarnation of a wormhole, serving as a back door leading from the interior of one black hole into another.
Mathematicians call such hypothetical formations “multiply connected spaces.” To get a sense of how they work, consider a simpler (mathematically speaking) model for a wormhole called Misner space, which is the brainchild of Charles Misner, a theoretical physicist at the University of Maryland, College Park. Imagine that Buffy’s bedroom comprises the entire universe, and the walls correspond to the mouths of a wormhole. For instance, every point on the wall in front of her is identical to the corresponding point on the wall behind her. The two bedroom walls are joined, like a piece of paper that is folded over so that its two ends meet, forming a cylinder. So if Buffy walks through the front wall, she will reappear from the back wall.
It’s a bit like how old video-game screens used to wrap the field of play around both the left and right edges of the computer monitor. In fact, if the bedroom is small enough—barely able to contain Buffy’s body—and she passes her hand through the wall in front of her, she could reach completely around her little universe to grab her own shoulder when her hand reemerges from the wall behind her. In much the same way, the mouths of a wormhole create a shortcut between two points in space. If each of those points is a separate universe, rather than different points in Buffy’s bedroom, the wormhole bridges two worlds.
Wolfram & Hart’s torturous prison dimension in “Underneath” (A-5)—where the senior partners confine renegade lawyer Lindsey McDonald—resembles a Misner space. On the surface, it appears to be a pleasant, middle-class suburban street with rows of identical houses stretching into the horizon. (The horrific rituals that go on in the basements of those houses are far from idyllic, however.) But if Lindsey tried to leave the dimension by walking down that street toward the horizon, eventually he would hit a “wall” and find himself right back at the other end of the street. In this case, the two “mouths” of the Misner “wormhole” connect opposite ends of the prison dimension, rather than leading to another world. The only way out is through a separate, interdimensional portal—a fiery opening in the dreaded basement, aptly called “the Wrath.”
As recently as 1990, most scientists agreed with Einstein that black holes were theoretical entities—an intriguing mathematical anomaly, to be sure, but largely the stuff of science fiction. However, several hundred such objects have since been identified, and as many as 300 million might exist in the visible universe. Astronomers now believe that most of the galaxies in our universe have black holes at their centers; a black hole was identified at the center of our own Milky Way. But the existence of wormholes is still open to debate. Scientists have yet to uncover any hard, physical evidence of one. That’s partly because we can’t see inside a black hole to observe directly what lies at the singularity, and partly because wormholes would be extremely difficult to make. Enormous amounts of mass and/or energy are required to achieve the extreme curvature of space-time that would give rise to a macroscopic wormhole—energies far beyond our present capabilities. And as Wesley says in “Over the Rainbow” (A-2), “There’s obviously not going to be any big, swirly hole-jumping without a big, swirly hole.”
Fortunately, staggering amounts of extra mystical energy are readily available in the Buffyverse, provided one knows how to harness it—and, in the case of dimensional portals, where to look. The gang learns that portals only open in certain “hot spots,” areas of concentrated psychic energy that serve as natural gateways to other worlds. Phrased in less mystical terms, one could say that the presence of this extra energy means that the fabric of space-time is more vulnerable to bending and tearing in those areas, so it can more easily rearrange itself to create the requisite portals when certain conditions are met.
The process is considerably easier in the Buffyverse than it is in our own universe. To open a portal to Pylea, one must read aloud from an ancient book written in a language comprised entirely of consonants. Mystical languages possess great power in the Buffyverse, and Fred discovers why this might be the case: The book in question doesn’t contain actual “words,” but consonant representations of mathematical formulae for transfiguring the fabric of space-time. Even without such a book, Fred’s physics training enables her to calculate the requisite math for opening portals. She just doesn’t know where the hot spots are located, and thus assumes that her equations are wrong. In fact, she unwittingly opens several portals while trapped in Pylea.
AS THE WORMHOLE TURNS
When Cordelia is accidentally sucked into Pylea, Angel decides to open another portal and go in after her. After all, how hard can it be to read aloud from a book, even if the text is all consonants? Alas, things are never that simple and straightforward in the Buffyverse. There is always a catch. For instance, in keeping with the laws of thermodynamics, psychic hot spots often “go cold” after use. The hot spot located in Caritas is drained of its energy when Cordelia is sucked through, but Angel can’t wait for it to recharge. He must find a second hot spot in order to open another portal.
Furthermore, whenever individual entities enter a dimensional portal, they tend to separate in transit. So the remaining members of Team Angel wouldn’t arrive together, even if they jumped through the portal at the same place and time. They could even end up on opposite ends of Pylea. Wesley considers performing a binding spell to prevent such a separation, but there’s a catch there too. While passing through the portal, the effect would be magnified to such an extent that Angel, Wesley, Gunn, and Lorne could end up fused together like some bizarre four-man (or three-man, one-demon) Siamese quadruplet.
The problems are different in real-world physics, but the situation isn’t any less complicated. Let’s assume that wormholes really do spring spontaneously from the foamy fabric of space-time, with no need for reciting from mystical books written in strange consonant languages. That doesn’t make them traversable. Such wormholes would be tiny, about 100 billion billion times smaller than a proton at the center of a single atom. This is far too minuscule to allow for human travel. And most of those tiny wormholes would be unstable. They would only exist for fractions of a second before recollapsing into the quantum foam. Light is the fastest entity in the known universe, yet even a beam of light traveling at top speed wouldn’t have time to pass through a tiny wormhole. How can we inflate a wormhole to macroscopic size and then hold it open long enough for a space probe to pass through to the other side?
That’s not the only problem. Remember the sad (hypothetical) fate of Gene, the time-obsessed physicist, should he happen to fall into a black hole? Once Gene crossed the event horizon, he would be sucked inexorably toward the center and be subjected to such intense gravitational fields that he would be torn apart. Even if he could reach the supposed wormhole at the center in one piece, he would be crushed to death by infinite gravity as he attempted to pass through to the other side—a much more dire effect than simply fusing Team Angel into a freakish Siamese quadruplet. Wesley solves Team Angel’s dilemma when he discovers that iron or other metals counter the effect. By making the jump in Angel’s convertible, they can all arrive together (and unfused). This is completely unrealistic from a physics standpoint, although the sight of the convertible flying through the big swirly hole certainly makes for fantastic television. An even more exotic solution is required in the world of physics.
Physicists thought that they might have found this solution when they discovered that all black holes observed thus far appear to be rotating, some as fast as a million miles per hour. This changes the scenario significantly, because it gives a black hole angular momentum. Conceivably, such an object could produce a stable wormhole. Recall from chapter 4 that Buffy whirls an incense burner on a chain around her head and then releases it to knock Spike out. The rotation creates a centripetal force that pushes outward, much like a merry-go-round. A similar phenomenon occurs with a rotating black hole.
A rotating black hole has two event horizons: the outer horizon that marks the point of no return for objects falling into the black hole, and an inner horizon closer to the center, arising from the hole’s angular momentum. This type of black hole would remain stable because of the intense centripetal force pushing outward, canceling the inward pull of gravity and holding the portal open long enough to allow an object safe passage. Instead of collapsing down into a singularity, a rotating black hole would collapse into a ring. If an object approached this ring gradually, from the side, spiraling closer and closer with each pass, it would still encounter infinite gravity and space-time curvature and be destroyed. However, if the object managed to travel straight through the ring, the gravitational force would be large, but not infinite. It would have a shot at survival. It’s a bit like how the water in a flushing toilet spins around the center of the bowl, whirling faster and faster before it is flushed through the hole at the bowl’s center. If the members of Team Angel fell into a rotating black hole, they might not be crushed to death at the singularity if they fell directly into the ring. Instead, they would be “flushed” completely through the wormhole to the universe on the other side.
There is ample visual evidence that a similar rotating model describes many of the dimensional portals that exist in the Buffyverse. Portals to Pylea appear as big swirly holes. Buffy’s first college roommate, Kathy—a demon who ran away from home to get a college education—is sucked back to her dimension through a swirling vortex when her father finally tracks her down in “Living Conditions” (B-4). Angel accesses a prison dimension operated by the Powers That Be via a mystical key and coin in “That Vision Thing” (A-2). Used in tandem, the objects fit together to form a spinning top that creates a swirling vortex. And in “Get It Done” (B-7), the Scoobies are watching Slayer Shadow Puppet Theater. Carved flat figures mounted on a spinning carousel tell the story of the first Slayer by casting shadows. The carousel starts spinning faster and faster, creating yet another vortex-like portal to another dimension.
Alas, even wormholes at the heart of rotating black holes are inherently unstable. Any accelerating object generates ripples, known as gravitational waves, in the fabric of space-time. This gravitational radiation travels at the speed of light, and could be amplified to infinite energy as it approached the black hole’s singularity, warping space-time around itself so severely that it shuts the “door” to the other universe. The smallest disturbance could cause a wormhole to collapse, closing the entrance to the passage.
This might explain why portals in the Buffyverse only stay open for short periods of time and close abruptly once someone has jumped through them. The person’s mass generates gravitational waves, which then amplify to such an extent that the portal collapses, or closes. It also means that any passage through a wormhole would be a one-way trip. Once you leave a universe, there is no turning back. Assuming a person wasn’t crushed to death, he/she would need to open a second wormhole connecting the parallel universe back to ours in order to make the return trip. This is certainly how things work when it comes to Pylean portals. The members of Team Angel successfully make the jump into Pylea, but the book they use to open the portal in Los Angeles only works in that dimension. The book remains behind when they shoot through the portal. It doesn’t even exist in Pylea. The members of Team Angel must use the priests’ books to locate the relevant “hot spots” there before they can open up a new portal in order to travel back to their home dimension.
NATURE ABHORS
A QUANTUM VACUUM
There is another possible solution to the collapse problem. Ordinary matter simply isn’t strong enough to withstand the gravitational crush of space-time inside a black hole. Some form of antigravity (negative energy) that pushes outward instead of contracting inward would counteract a black hole’s deadly squeeze, holding it open long enough to allow an object to pass through a hypothetical wormhole at its center. Since gravity arises from the curvature of space-time in response to the mass of a given object, the most likely source of antigravity would be an exotic form of negative matter. This is not the same thing as antimatter, which is comprised of antiparticles that have the same (positive) mass but opposite charges as their material counterparts.* Negative matter would have negative mass, producing negative curvature of space-time, giving rise to antigravity.
It’s still very much in the realm of theory, but the idea is that perhaps a wormhole is not empty, but instead contains a “scaffolding” of negative matter that exerts an outward antigravitational push on its walls, sufficient to make the wormhole stable. The catch—and it’s a big one—is that negative matter is purely hypothetical. Scientists have yet to observe even indirect evidence of its existence. In contrast, some form of negative energy is physically possible in very small amounts, but is extremely rare—and fleeting.
For better or worse, negative energy seems to be abundant in the Buffyverse. Illyria has the ability to rearrange the fabric of space-time at will to create dimensional portals whenever she needs one. What is the source of her power? We find a clue when Wesley saves Illyria from self-destructing by siphoning off a large portion of her demonic energy with a device he calls a “Mutari generator.” This supposedly creates a pinhole through which Illyria’s excess power can be channeled into an “infinite extradimensional space.” He also describes it as a “negatively charged pocket universe.”
Wesley might not be entirely sure of the exact nature of this mysterious location, but his comments hint that at least some of the excess mystical energy floating around the Buffyverse might be negative energy—the vital component for the creation of stable wormholes. If that’s the case, no wonder dimensional portals keep opening up all over the place. It hardly seems fair. The real world lacks such tantalizing fictions as negatively charged pocket universes and Mutari generators. But we do have our very own potential source of negative energy in the fluctuations of the quantum vacuum.
The nineteenth-century Serbian inventor Nikola Tesla believed that the vacuum held enormous reservoirs of energy, sufficient to revolutionize human society if we could only devise a means of harnessing it. Tesla was highly eccentric—he ended his days impoverished and with questionable sanity—but his intuition about there being energy in the vacuum turned out to be true. We’ve seen that empty space isn’t really empty. It roils and boils with quantum fluctuations, occasionally spitting out pairs of “virtual” elementary particles and antiparticles. These virtual particles and antiparticles annihilate and disappear back into the quantum vacuum so quickly that the apparent violation of energy conservation incurred by their creation can’t be observed directly.
So how do we know they exist? There is indirect evidence in a phenomenon known as the Casimir effect, named after Henrik Casimir, the Dutch physicist who discovered it in 1933. Normally two uncharged parallel metal plates would remain stationary because there is no electromagnetic charge to exert a force to pull them together (or push them apart). But Casimir found that if the plates are close enough, there is still a tiny attractive force between them. Because the parallel plates are so close together, virtual particle pairs can’t easily come between the plates, so there are more pairs popping into existence around the exterior of the plates than there are between them. The imbalance creates an inward force from the outside that pushes the plates together slightly. The smaller the separation between the plates, the fewer virtual pairs can get between them, and the greater the force of the inward attraction.
If we could figure out a way to harvest just the antiparticle of a virtual pair, we would have a built-in source of negative energy in the quantum vacuum. Alas, that’s a pretty big “if.” Even if we could find a way to harvest this negative energy, it isn’t remotely sufficient for portal purposes. A wormhole only one meter wide would require negative energy equivalent to the total energy produced by our sun over the course of roughly 10 billion years, yet the Casimir effect is quite small, equal to the weight of 1/30,000 of an ant. Any wormhole resulting from it would have to be much smaller than an atom, making travel through it impractical at best. We would need to find a means of amplifying that energy many times over before it would become strong enough to hold open a macroscopic wormhole.
Frankly, the energy contained in the quantum vacuum isn’t nearly as much as Tesla supposed, when one converts it into macroscale units of measurement. Lawrence Krauss estimates that if we could release the energy stored in one cubic meter of the quantum vacuum—an area about the size of a small Dumpster—we would only harvest about one ten-billionth of a joule, not even enough to light a 10-watt bulb. That might make a difference in the subatomic realm, but it hardly seems sufficient to open a dimensional portal, or to perform any other of the impressive magical feats that occur on an almost daily basis in the Buffyverse. No wonder we don’t see such exotic phenomena occurring in our own world.
Nonetheless, CalTech physicist Kip Thorne devised a wormhole model based on negative energy. Hypothetically, his model would permit someone to travel not just between different points in space—as with conventional wormholes—but also between different points in time. Thorne proposed creating two identical chambers, each of which contains two parallel metal plates separated by a very small gap. The electrical field created by the plates via the Casimir effect creates a tear in space-time, so that the chambers become the two “mouths” of a connecting wormhole. Then one chamber is placed on a rocket ship and accelerated to near the speed of light. Since time is moving at different rates in each chamber due to relativistic time dilation (remember that a traveling clock ticks more slowly than a stationary one), the two chambers become desynchronized. They are still connected by the wormhole, yet they exist in different times. Time has passed more slowly in the accelerating chamber, so a person in the earthbound chamber could step through the wormhole and be hurtled into the past. A similar effect could be achieved by connecting a wormhole between the earth and something very heavy, like a neutron star. This also sets up a time difference between the two ends, since mass warps space and time. A clock on the surface of a very dense neutron star would run about 30 percent slower than it does on earth.
In the Buffyverse, we wouldn’t need rocket ships capable of approaching the speed of light, or massive neutron stars, because time already moves at different rates in other dimensions. Relativistic time dilation is built into the system. Angel’s Los Angeles and Pylea each correspond to the mouth of a wormhole, and the two dimensions are moving with respect to each other, as all dimensions do in the Buffyverse. So if the members of Team Angel travel through a portal to Pylea, they are not only traveling to a different point in space, but also to a different point in the past or future, depending on how fast or slow time moves in the respective dimensions. The same goes for Illyria, Jhiera and her compatriots from Oden-Tao, and for any other being that hops between dimensions. They are all unwitting time travelers, whether the difference is 100 years or just a few seconds.
NEGATIVE FEEDBACK
Thorne’s wormhole design is quite ingenious; in fact, it formed the basis for Carl Sagan’s novel Contact. Yet once again, there is a catch. Quantum vacuum fluctuations would almost certainly destroy such a wormhole before it could be used as a portal, thanks to what amounts to a devastating feedback loop, similar to what Oz’s band, Dingoes Ate My Baby, might experience with their guitar amps during a sound check. In such a model, virtual particles pass through the wormhole to the past. But then they must travel forward through space and time, eventually reentering the wormhole and traveling back to the past again in a never-ending cycle. Each time this occurs, the radiation from the particles increases in intensity until it becomes strong enough to destroy any physical object that tries to pass through to the other side. Ultimately it would even destroy the wormhole.
To get an idea of how this works, let’s revisit Lindsey’s suburban Misner prison, where the boundary “walls” correspond to the mouths of a wormhole. Normally these walls are stationary, but what happens if they are moving with respect to each other, like the different dimensions in the Buffyerse? Imagine that Lindsey’s prison is being squeezed to further torment the inhabitants. Anxious to escape his increasingly claustrophobic existence, Lindsey walks repeatedly toward the left wall of his prison, only to find himself reappearing from the right wall. Perhaps he figures that if he repeats the action often enough, a statistical quantum anomaly will occur and he will find himself outside the prison dimension. Instead, he is sowing the seeds of his own destruction. If the right wall is moving toward Lindsey at 2 mph, and he walks through the left wall traveling at 2 mph, when he returns back through the moving right wall, his speed will have increased. He is now traveling at 4 mph, because the two speeds add together. Every time he completes a circuit, his speed increases by another 2 mph. Something similar happens if Lindsey shines a flashlight at the left wall. The beam will gain energy every time it emerges from the right wall, making the Misner prison unstable. The light loops around and around until it becomes so energetic, it creates an enormous gravitational field of its own, which collapses the walls.
Any attempt to use a wormhole as a time machine would give rise to similar subatomic fluctuations. The wormhole would self-destruct. Because they are also technically wormhole “time machines,” the dimensional portals in the Buffyverse should be subject to the same intense radiation feedback loops that plague real-world models of wormholes. A portal should collapse every time someone (or something) tries to pass through it. Even if it didn’t, the intense radiation emitted should be sufficient to kill any aspiring dimensional jumpers.
Lindsey’s experience of being squeezed inside his Misner prison might seem suspiciously akin to a closed timelike curve, à la Buffy’s loopy day at the Magic Box or the Russian ballerina condemned by Count Kurskov to dance the same performance for eternity. It should. Some wormhole models—namely, the time-machine variety—can form different kinds of closed timelike curves. In fact, a new type of doughnut-shaped closed timelike curve, proposed in 2005, offers the possibility of a traversable wormhole enabling time travel into the past without the need for such exotic elements as negative matter or energy. Every slice of time after the time machine was created would exist somewhere in the vacuum inside the gravity doughnut’s “hole.” A traveler in a rocket ship could hypothetically zip around inside the doughnut, receding a bit farther into the past with every completed circuit. Of course, physicists have yet to figure out how to curve space-time sufficiently to form the gravity doughnut in the first place—the energy required would be truly astronomical—and even if they managed to do so, the resulting wormhole would still suffer from the same quantum feedback effects, leading it to self-destruct.
Thus far, the obstacles to building big swirly wormholes have proven largely insurmountable. Yet theorists are a tenacious bunch and are not so easily dissuaded. The search continues for a feasible wormhole model that might one day serve as a portal to other universes, or to other points in time. Various inhabitants of the Buffyverse have clearly outpaced real-world physicists in solving the dilemma, even if they don’t fully understand the underlying physical mechanisms behind the magic. We must look to Fred, the intrepid physics student, and her post-Pylean foray into string theory, for further insights into this exotic feature of the Buffyverse.
*Physicists have yet to find evidence that antimatter exists naturally in the universe today, but they have been able to create small amounts of antiparticles in atom smashers. Those antiparticles exist for mere fractions of a second before annihilating into radiation.
