Authors: Kim Stanley Robinson
Before Bao's time, Galileo saw, which was precisely the beginning of the period known later as the Accelerando, the goal of physicists was to explain everything. He recognized that; it was the
reductio ad absurdum
of science: to know everything. The unspoken desire in that urge was the hope that, knowing everything, humanity would also know what to do. The blank that was their sense of purpose would perhaps also be filled.
But to know everything was asking too much. “They want to be like God!” he said.
“Maybe God is only a prolepsis,” Aurora said. “Our image of what we could be, imagined by contemplating our future.”
“Which would make it an analepsis, no?”
She laughed as they flew. “You like paradoxes, but of course this one is just entanglement all over again. We are extensive in time. Fly on and you will see.”
So they flew. Progress in physics struggled on. Theories of what occurred at the minimum and in postulated extra dimensions were elaborated, considered, challenged, refined. Predictions were made that could sometimes be checked against observation, or involved findings just beyond the realm of current observation. Ideas thus drove technologies. Slowly progress was made. But the unbridgeable abyss made every theory speculative. The wind from Galileo's flight could have knocked down some of these houses of cards, and the collapsed theories he flew through had perhaps been knocked down in just that way, by the offhand remark of some observer like Bao, surveying the whole landscape and taking a completely new line over it.
It wasn't until the twenty-eighth century that a theoretical structure accomplished a substantial part of what had been begun so long before. It was a physics based on Bao's bridge to the minim, and on experiments spanning the solar systemâcontroversial experiments that had entrained significant portions of the system's total potential energy. Bao's work had clarified the ten-dimensional manifold of manifolds theory that had been proposed since the time of Kaluza and Klein. Bao's version had created many cosmological and subatomic questions and predictions that had given them experiments to try, observations to make, the results of which then gave them corrections and surprises, but mainly confirmations, a sense that they were on the right track at lastâand in some ways had been all along, if one made
allowances for the usual eddies and dead ends. Each generation had served as scaffolding for the generations that followed, and the work continued through collapses and reversals, almost one might say mindlessly. “It's like watching ants building a mound,” Galileo observed as he flew through the elaborations. “The mass just keeps grinding.”
“Yes, although it's a strange thing to say about a process that has taken so much brain power.”
“Tell me more about the ten dimensions,” Galileo requested. “Something more than their math. What do they mean? What
can
they mean?”
Aurora flew next to him, so closely that he felt they were intertwined. He dipped and turned, dropped or soared, stooped or gyred, always trying to stay next to her, and he found that she could make writing appear as clouds, or red ingots in the air before him. His body was a flock of bannering thoughts, flying around her in a dance. The landscape under them was a mountain range made of symbols and numbers piled one on the next, gnarled tectonically.
“Recall the Euclidean space that you know and sense,” she said, “having the three dimensions of length, breadth, and height. With Newton we added a different kind of dimension, which is timeâ”
“But I did that!” Galileo objected again. “Falling things accelerate as a square of the time passed! This I found out, and it meant time and space were bound together somehow.” Although, he recalled uneasily, the finding lay still unpublished, buried in his folios out in the workshop.
“All right, call it Galilean space,” Aurora said easily. “Whatever you call it, these four dimensions were understood as if they were an absolute, an underlying invisible gridwork through which physical phenomena moved. That's when you have Laplace declaring that with a sufficient physics and database you could predict the entire past and future of the universe just by entering the numbers for the current moment, and running them through the equations either forward or back, as in an astrolabe. It was a thought experiment only, because no one would ever have the data set to do it. But the implication was that God, or something like it, could do it.”
“Yes. I can see that.”
“It implied a predetermined, clockwork universe that many found
depressing to contemplate. We weren't really choosing to do anything.”
“Yes. But your quantum mechanics destroyed all that.”
“Precisely.”
“Or imprecisely.”
“Ha, yes. With relativity and quantum mechanics we began to understand that the four dimensions we sense are artifacts of our perception of dimensions far more numerous than we knew. We began to see things that made it clear four dimensions were not adequate to explain what was happening. Baryons rotated 720 degrees before returning to their starting positions. Particles and waves both were confirmed even though they contradicted each other as explanations, as far as our senses and reason were concerned. In some cases our observations seemed necessary to make things exist at all. And something otherwise undetectable was exerting very marked gravitational effects, that if caused by a mass would outmass the visible matter of the universe ten to one. Then there appeared to be a kind of reverse gravity effect as well, an inexplicable accelerating expansion of space. People spoke of dark matter and dark energy, but these were names onlyânames that left the mysteries untouched. What they were was better explained by the existence of extra dimensions, first suggested by Kaluza and Klein, and then put to use by Bao.”
Galileo said, “Explain them to me.”
He felt himself become equations in the clouds inside him. Formulas described the motions of the minims, vibrating at the Planck distance and duration, thus small and brief beyond telling, and vibrating in ten different dimensions, which combined into what Bao called manifolds, each with its own qualities and characteristic actions.
“Investigations have by now found evidence for all ten dimensions,” Aurora said. “Even confirmation. The best way to conceptualize some of the extra ones is to imagine them enfolded or implicate in the dimensions we sense.” A long, flat red sheet appeared before him; it rolled lengthwise into a long thin tube. “Seen in two dimensions this looks like a ribbon, but in three dimensions it's obviously a tube. It's like that all through the manifolds. Dark matter has to be very weakly interacting but at the same time registering gravitationally at ten times the mass of all visible matter. That is an odd combination, but Bao considered it as a dimension we only were seeing part of, a hyperdimension
or manifold that enfolds our dimensions. That manifold happens to be contracting, you could say, which gives the effect in our sensible universe of the extra gravity we detect. So that's dimension four.”
“I thought you said time was the fourth dimension,” Galileo said.
“No. For one thing, what we call time turns out to be not a dimension but a manifold, a compound vector of three different dimensions. But put that aside for a second, and let's finish with the spatial manifold. Dimension four we still call dark matter, as a gesture to our first awareness of it.”
“Four,” Galileo repeated.
“Yes, and dimension five in some ways counterbalances the action of four, as it is the perceived accelerating expansion of space-time. Aspects of this dimension are called dark energy.”
“Do these dimensions pass through each other, then?”
“Do length and breadth and height pass through each other?”
“I don't know. Maybe they do.”
“Maybe the question as formulated does not have an answer, or maybe the answer is simply yes. Reality is composed of all the dimensions or manifolds, compounded or coexisting in the same universe.”
“All right.”
“Now let us come to time. Mysterious from the start, it seems mostly absent from our perception, but crucial as well. Past, present, and future are the aspects of time commonly spoken of as perceived by us, but they and other phenomena are the result of sense impressions compiled by living in three different temporal dimensions, which together make the manifold, in the same way our impression of space is a manifold. All three temporal dimensions impact on us even though we mostly have a very strong sense of moving forward in a manifold, so that we can only remember the past, and only anticipate the future, both of which remain inaccessible to us in any sensory way. Our senses are stuck in the present, which appears to move in only one directionâinto the future, which does not yet exist, leaving behind the past, which exists only in memory but not in reality.
“But that present moment: how long is it, of what does it consist? How can it be as short as a single Planck interval, 10
43
of a second, while even the briefest of phenomena that we are aware of takes much
longer to happen than that theoretical minim? What can the present be? Is it a succession of Planck intervals, a clutch of them? Is it even real?”
“God knows,” Galileo said. “I count it in heartbeats. The beat of the moment is my present, I pray.”
“That's a long
durée
, in effect. Well, look at Bao's temporal equations, and see how neatly every present that we sense, like your long
durée
of a heartbeat, gets explained.”
They flew into something like a cathedral, or an immense snowflake, made of intersecting numbers and figures: a lacing of equations, the details of which now completely escaped Galileo. He tried to hold to the architectural shapes they made, but he was no longer following the math.
“Her equations postulate a temporal manifold made of three dimensions, so that what we sense as time passing, what we call time, is a compound with a vector made up of the three temporalities. We can see it here, in something like a Feynman drawing for elementary particles. Indeed we can fly in the drawing, see? The first temporality moves very fastâat the speed of light, in fact. This explains the speed of light, which is simply the rate of movement in this dimension if you consider it as a space. We call that time therefore speed of light time, or
c
time, from the old notation for the speed of light.”
“How fast is that again?”
“Two hundred thousand miles a second.”
“That's fast.”
“Yes. That component of time is fast. Time flies! But the second temporal dimension is very slow, by comparison. It's so slow that most phenomena seem suspended within it, almost as if it were that absolute grid of NewtonianâI mean Galileanâspace. We call this one lateral or eternal time, thus
e
time, and we have found it vibrates slowly back and forth, as if the universe itself were a single string or bubble, vibrating or breathing. There is a systolic/diastolic change as it vibrates, but the vibration is weakly interacting with us, and its amplitude appears to be small.”
“All things remain in God,” Galileo said, remembering a prayer he had once learned, when as a boy he had briefly attended the monastery school.
“Yes. Although it is still a temporality, a kind of time we are moving in. We vibrate back and forth in this time.”
“I think I see.”
“Then lastly,” she went on, “the third temporal dimension we call antichronos, because it moves in the reverse direction of
c
time, while it also interacts with
e
time. The three temporalities flow through and resonate with each other, and they all pulse with vibrations of their own. We then experience the three as one, as a kind of fluctuating vector, with resonance effects when pulses from the three overlap in various ways. All those actions together create the perceived time of human consciousness. The present is a three-way interference pattern.”
“Like chips of sunlight on water. Lots of them at once, or almost at once.”
“Yes, potential moments, that wink into being when the three waves peak. The vector nature of the manifold also accounts for many of the temporal effects we experience, like entropy, action at a distance, temporal waves and their resonance and interference effects, and of course quantum entanglement and bilocation, which you yourself are experiencing because of the technology that was developed to move epileptically. In terms of what we sense, fluctuations in this manifold also account for most of our dreams, as well as less common sensations like involuntary memory, foresight, déjÃ
vu, presque vu, jamais vu
, nostalgia, precognition,
Rückgriffe, Schwanung
, paralipomena, mystical union with the eternal or the One, and so on.”
“I've felt so many of those,” Galileo said, buffeted as he flew by memories of his lost times, his secret times. “In the sleepless hours of the night, lying in bed, I feel these phenomena often.”
“Yes, and sometimes in the broad light of day too! The compound nature of the manifold creates our perception of both transience and permanence, of being and becoming. They account for that paradoxical feeling I often notice, that any moment in my past happened just a short time ago and yet is separated from me by an immense gulf of time. Both are true; these are subconscious perceptions of a delaminated
e
time and
c
time.”
“And the sense of eternity that occasionally strikes? When you ring like a bell?”
“That would be a powerful isolated sense of
e
time, which does in fact vibrate in a bell-like way. Then in a different way, the sense of inexorable dissolution or breakdown we sometimes call entropy, also the feeling called nostalgia, these are the perceptions of antichronos passing backward through
c
and
e
time. Indeed Bao's work leads to a mathematical description of entropy as a kind of friction between antichronos and
c
time running against the grain of each other, so to speak. By their interaction.”