1. Think Lewis Carroll or Larry Niven. Your choice.
Authorial convenience notwithstanding, such proximity flies in the face of an ever-lengthening Great Silence. In InterstellarNet: Enigma, I like to think I came up with a new explanation.
Yes, indeed: the opportunity to build universes is a neat perk.
Edward M. Lerner
March, 2015
Behind the Scenes
Did you flip forward out of curiosity, not having yet finished the novel? Then I implore you: avert your eyes! There be mega spoilers ahead!
Do you savor stories for awhile after completing them? Do you enjoy teasing out loose ends, solving for yourself any little puzzles, theorizing about the unexplained details, extrapolating from glimpsed bits of backdrop? You, too, will want to delay reading this section.
But if you’re ready to learn more about the Xool, their plans, and their capabilities, if you wonder about the implications and limitations of Xool technology, this is the place.
(What if this background material proves esoteric for your taste? Then, channeling the Great and Terrible Oz, pay no attention to the science behind the curtain. Skip this section and enjoy the novel on its own.)
The Time-Slowing Field
The technologies to slow time and produce artificial gravity exploit knowledge far beyond present-day human science; we don’t know why they work. But just knowing that such technologies do (somehow) work, they offer—as the Xool discovered—many fascinating and useful applications.
Let’s consider circumstances on Horua (aka, Xool World) while it’s enclosed in a time-slowing field that’s set to a parameter we’ll call X. During the timeframe of the story, X has a value minimally in the thousands, and often much larger.
Incident sunlight: beyond the field, the sun emits energy at its accustomed rate. Horua, its size and orbit unchanged, intercepts as much sunlight as ever. As each second passes within the field, X seconds-worth of solar energy arrive. Slow time by a factor of two, for example, and for each second experienced on the planet two seconds-worth of sunlight arrive. Hence: the slow-time field must reflect incident light in rough proportion to X, lest everyone inside the field roast.
Why only rough proportion? Because some energy, in the form of ultraviolet light, is siphoned off to power the field itself.1 And, as discussed below, the fraction of light permitted through the field must be fine-tuned to adjust for several factors.
1. UV partially powers the field. We’ll get to the other power source.
Magnetic field: Earth’s magnetic field, which extends tens of thousands of kilometers into space, deflects solar wind and cosmic rays, protecting terrestrial life from what would otherwise be an unending stream of deadly radiation. This magnetic field is believed to arise from the circulation of molten iron deep inside the planetary core. Horua once had a significant magnetic field that protected life there—but as seen from outside the slow-time barrier, that protection has greatly diminished. If an external observer could observe the planet within, Horua’s spin would be seen to have slowed by a factor of X. The magnetic field measured outside the field decreases accordingly.
What now protects Horuan life from celestial radiation? The slow-time field itself. Solar wind and cosmic rays—and small meteors—are stopped in their tracks by the vast deceleration caused by encountering the time dilation.
Angular momentum: much like energy and momentum, angular momentum is always conserved. For Horua’s spin to slow by a factor of X, something must spin faster. That something is the slow-time field. The field doesn’t exhibit mass in the familiar sense—but mass is just a form of energy. Energy fields can and do spin.
(What if the field hadn’t absorbed the angular momentum lost by Horua? Then the planet’s angular momentum would have transferred to Horua’s satellite—flinging Blue Moon out of its orbit.)
Any object, whether a spaceship or an asteroid, that enters the slow-time region will surrender angular momentum abruptly to the slow-time field. We’re familiar with the unpleasantness of suddenly losing ordinary/linear momentum—as when, for example, our car hits a tree. Suddenly losing angular momentum is just as undesirable.
In brief: Don’t try to penetrate the barrier without a Xool counteracting-field generator.
Tides: Einstein’s theory of general relativity indicates that an object (say, a planet) distorts the contour of space-time in proportion to that object’s mass. The resulting curvature of space-time then influences the motion of other objects (say, a planet’s moons). We call that influence gravity. Time doesn’t enter into the picture.
Horua’s mass being unchanged by the slow-time field, Blue Moon’s orbital parameters—including its forty-hour orbit around Horua—are unchanged. An observer on Horua’s surface doesn’t see beyond the field (more upcoming about that), so he doesn’t see Blue Moon in the sky. He does, however, experience the gravitational tug, and hence the motion, of Blue Moon.
Surviving the tides: Anyway, an observer on the surface would witness Blue Moon zipping past if the complications doesn’t destroy the planet beneath him. Tidal energies, like solar energies, are multiplied by X. For a slowdown factor of, say, 100,000 (X’s value when Carl and company arrive), Blue Moon will zip around the planet in little more than a second. But the pounding of coastal ecosystems turns out to be the least of the Xool’s problems with the tides ….
Water seeks its own level; when tides rise high above average sea level, it’s clear that energy is involved. Nor do the tides effect only large bodies of water—the crust itself flexes. We don’t notice the crust flexing (although subtle instruments can measure it) because rock, being strong, moves far less under tidal influence than does water. Even so, tidal flexing pumps heat into the crust. Crank X high enough, and all that flexing will melt the crust.
What’s a clever Xool to do? Apply his second super technology: gravity control.
The Xool deploy an array of gravity generators in Horua’s crust and oceans. Pulses of artificial gravity synched to the time-slowing factor X offset the too-rapid tides.2 Yet other gravity generators, deployed in the oceans, throb on a forty-hour cycle (as measured by a surface clock) to emulate Blue Moon’s normal tides.3
2. The synching of gravity generators with time-slowing generators involves only a simple analog control loop—no advanced digital computers required. The tide-induced geothermal power drawn by the slow-time and gravity generators is another input to deciding what tiny fraction of sunlight should penetrate slow time.
3. How strong, on average, are Blue Moon’s normal tides? About the same as Earth’s lunar tides. Blue Moon’s lesser volume, hence its mass, offset the tidal effects of its closer-in orbit.
Such workarounds never compensate perfectly, of course. That’s why, as Corinne and company swoop to a landing on Horua, she spots densely packed standing waves on a lake (but misattributes the waves to a freak wind).4 That’s why, from within the slow-time field, Joshua’s instruments can still detect, and estimate the passage of outside time by, Blue Moon rushing past.
4. Standing water waves, what hydrologists call seiches, occasionally occur on earthly lakes and oceans—even in swimming pools. Wind of just the proper strength and direction can cause seiches, as can seismic events.
Solar tides: A sun’s gravitational pull plus a planet’s rotation about its axis give rise to the solar-tide cycle. With Horua’s rotation slowed by a factor of X, the solar tides the planet experiences likewise slow to a crawl. The Xool emulate normal solar tides (as, we have seen, they emulate Blue Moon normal tides) by the deployment of yet other gravity generators.
Seasons: Earth’s seasons are the result of the planet’s axial tilt. The hemisphere whose pole is tipped toward the sun receives more intense sunlight than the hemisphere whose pole is tipped away. That Earth follows an elliptical orbit, at slightly different distances from the sun at different times of year, has only minor climate effects.5
5. If the Earth’s location along its orbit cause
d the seasons, then northern and southern hemispheres would experience their summers (and winters) together, not half a year apart.
On Horua, wrapped within slow time, matters are more complicated. As measured by an inside-the-field clock, one trip around the sun lasts X years. Seasons would be correspondingly prolonged, to the detriment of crops and other plant life—unless the light/energy permitted to penetrate the field is dynamically adjusted to emulate the traditional seasons.
The sun and stars: with Horua’s rotation slowed by a factor of X, the progress of sun and stars across the sky decreases correspondingly. Only 1/X of the sunlight is permitted to penetrate the field, while X seconds (outside) correspond to each second inside. The effects offset; net sunlight intensity inside the field is unchanged.
Thus Horua’s sun could shine in the sky as brightly as ever—if sunup to sundown were permitted to last an average of X/2 days by internal-clock measure. For X values in the thousands or millions, a sun so slowly creeping across the sky would bake one hemisphere and freeze the opposite hemisphere. On the planet’s dark side, photosynthesizing plant life, and much other life dependent on the plants (say, anything that eats plants), wouldn’t survive the years-long night. Between the all but perpetually hot and cold sides, horrendous storms would beset the twilit bands.
Instead, the field must redistribute the fraction of light that is allowed to penetrate. Half the field’s inner surface is kept dark, the other half light. Recall that the field is spinning much more rapidly than Horua, having absorbed angular momentum from the planet; hence, the field generators must modulate lighting very rapidly. The dayside sky diffuses light toward the planet from all directions; for safety’s sake, the night-side sky emits a faint background glow.
Night and day: a day, in the sense of one complete rotation of the Earth about its axis, is fixed in length.6 The daylight/dark split, however, varies with the season and latitude. Anyone living north of the Arctic Circle enjoys (if that’s the correct verb) midnight sun during part of summer and (surely in this case enjoy must be interpreted ironically) round-the-clock darkness during part of winter. The duration of daylight is a biological cue to which many organisms respond, from plants inferring a change in seasons to, in humans, seasonal affective disorder.
6. Well, almost fixed. Over the eons, Earth’s rotation has slowed down slightly for complicated reasons having to do with tides and angular-momentum coupling between Earth and Moon. In recent times, Earth’s day has been lengthening at the rate of about 2 milliseconds per century.
Horua, too, has axial tilt. Once in slow time, the dayside illumination (i.e., the diffuse sky glow discussed earlier) must be adjusted by latitude according to the emulated season. Get the emulation wrong, and that’s one more way in which to mess up the environment.
The climate: to emulate the diurnal and seasonal cycles for which Horuan life evolved, real-time control of sky glow must adjust for: the planet’s spin, the field’s spin, the planet’s axial tilt, the planet’s position along its elliptical orbit, the instantaneous value of X, and, at various points across the globe, the latitude. Over millions of years, the star itself slowly grows hotter; the fraction of sunlight allowed through must also adjust for that effect.
The emulation is less than perfect, and the ecosphere suffers for it, because the Xool, by intent, have only primitive computing with which to run models and control the field generators. Even if the emulation were otherwise perfect, the diffuse nature of the illumination would still adversely impact any phototropic, sun-seeking species (such as terrestrial sunflowers, which turn to track the sun across the sky). As much as the social disincentives of a dictatorship, degradation of the ecosphere is why Carl and company encounter a seedy, rundown economy. Twenty years (inside) are far too short a time for the ecosphere to have adapted.
A virtue from a vice: on Horua, the limited fidelity of emulated diurnal and seasonal cycles is problematical. On other worlds? It can be a tool. There’s nothing like an ice age or a sudden jump in global temperatures to stir the evolutionary pot. More on that to come …
Xool Starships
For all their physical-science prowess, the Xool don’t have interstellar-drive technology superior to what Centaurs invented and humans use.7 In part that’s for the lack of incentive. Xool travelers cross interstellar space in slow time; the folks back home, awaiting the reports of explorers or the results of the Grand Experiment, are likewise in slow time.
7. The T’fru interstellar drive is a significant topic in its own right. If you’re curious, see InterstellarNet: New Order.
But if the Xool could accelerate their ships to near-light speed … they wouldn’t dare. A starship needs time to see and swerve from the path of any space junk it encounters; at near-light speed, there would be virtually no warning. If they did detect something on a collision course, without decent computers they’d be too slow to plot course changes.
That said, Xool ships have their pluses. Human ships must sustain a life-friendly biosphere for years on end, recycling everything. Xool ships, with their crews normally in slow time, dispense with the cost, bulk, and complexities of sophisticated, closed-loop life-support systems. When a Xool crew emerges into real time, they have artificial-gravity technology to offset the unpleasantness of acceleration and, while in orbit or otherwise coasting, of free-fall conditions.
The Grand Experiment
Simply put, the Xool set out to evolve and nurture intelligences in many solar systems, steering each group’s cultural development so that the ultimate consequences of particular distrusted technologies could be observed.
In practice, there is nothing simple about it.
Evolution and climate: the Xool fear genetic engineering, so gene-tweaking isn’t a tool in their toolbox. Instead, over and over, they stress ecosystems to force evolution. To operate the slow-time field around a planet and not stress its environment would have been difficult.
On Horua, as we’ve seen, the Xool permit through the slow-time field—to the extent their primitive computers can manage it—such fractions of sunlight as correspond to what the various regions of the planet would naturally receive. On the experimental worlds, the Xool sometimes dial up or down, whether globally or regionally, the amount of sunlight getting through. Aggregate illumination is a straightforward control knob for Joshua to explain—unlike, for example, how the Xool can also muck about with the emulated seasons and tides.
Experiment overview, phase 1 (in theory): the experimenters cause a thermal climate shock, wait out in slow time a few million years of evolutionary recovery, emerge for a quick look-see, then repeat as needed. If evolution on a planet hasn’t progressed according to their schedule, they dial up time dilation and squeeze in extra cycles. If on one planet evolution progresses too quickly, the Xool need only slow down time there, but without further stresses, to maintain that world on the common schedule.
Experiment overview, phase 1 (in practice): the observer teams find themselves always rushed. The longer they spend in real time—whether reworking a planetary environment, assessing the effects of the latest induced stresses, speculating how emergent phyla might further develop, or doing upkeep on their own facilities—the more they age with respect to the families left behind on Horua. Generations of experimentation would be appropriate—except that the dictator on Horua is determined to see the project finished within her lifetime.
As one visible token of the observers’ perpetual state of haste, the copper walls (electromagnetic shielding) of their hidden bases receive only the minimum patching that keeps them air-tight and more-or-less functional.
Experiment overview, phase 2 (in theory): Episodic forced evolution under Xool control continues until the very end of the process, when modern humans (or, on other worlds, other intelligent life) has emerged. Had the sky vanished during historical times, someone would have noticed!
In this final stage of the experiment, the time-slowing generators (and related tide-mitigating gravity
generators) remain off. The Xool indoctrinate and rely upon their native agents to steer civilizations and technological developments—sometimes encouraging, sometimes (by planting Frankenstein-like myths) discouraging a technology. Throughout this phase, until the experiment’s final years, the native agents have the benefit of Xool technology advanced beyond human norms.
Having used time dilation when/as needed to keep their scattered “Petri dishes” on schedule, the Xool complete their experiment by again putting Earth (and the other worlds) in slow time. That shift to slow time serves two purposes: (1) more opportunity to observe and (2) protection from the (presumed) technological contagion within. The supervising Xool set a timer to trigger the slow-time field, then head for home.
Automated Xool ships periodically swoop inside the barrier for updates from native agents and snippets of local news broadcasts. That information is then beamed back to the home system. By observing technological crises in detail, the Xool will learn whether and how the various technologies that have long been suppressed on Horua may be allowed to advance.
Thereafter, test worlds will be held safely in slow time “for a few million years” until they and Horua have moved far apart. If need be—because, say, a Berserker robot plague developed—a planet can be maintained indefinitely in quarantine.
Technologies: apart from physics, the Xool do all they can to keep their technology behind what has become cutting-edge InterstellarNet technology. The ultimate purpose of their experiment, after all, is to preview if and how specific scary technologies lead to disaster. Hence, the Xool encourage, say, genetic engineering on one world, nanotech on another, and artificial intelligence on a third.
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