Schild's ladder

Review by Booklist Review

Some 23 centuries from now, the laws of quantum physics are pretty much settled, but one researcher bends time and space in a blindingly quick experiment. She inadvertently creates a «nono-vacuum» that expands at half the speed of light, eating up the familiar vacuum of space. Over several thousand years, humanity leapfrogs from planet to planet in order to survive. Meanwhile, parked in a ship just ahead of the nono-vacuum, two contingents of scientists poke at the nono-vacuum's border and field a hypothesis: the unknown universe may be as complex as the known. But is it breachable? Tchicaya--the hero, if this tale could be said to have characters at all--postulates Schild's Ladder, a geometric theory that suggests it is. Thereafter, he finds the marooned researcher who unraveled the universe in the first place--and a great deal more. Very much in the manner of Hal Clement, Egan writes rather forbidding novels, always grounded in real science and imbued with serious scientific speculations. This is his most uncompromising book to date. John Mort.

From Booklist, Copyright (c) American Library Association. Used with permission.

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Review by Publisher's Weekly Review

Australian Egan (Teranesia) writes some of the hardest SF around in terms both of difficulty and cutting-edge scientific content, as shown in his latest challenging novel, set some 20,000 years in the future. Though superhuman by our standards, Egan's characters often disembodied intelligences who prefer to live as programs in virtual reality or in still stranger, high-tech media are still capable of making mistakes. At the start, an experiment in quantum physics goes badly astray, creating another universe with physical laws that differ from our own. Its border expanding at half the speed of light, this new universe swallows planetary systems whole. Fortunately, humanity is so highly developed that entire populations can be quickly evacuated with little if any loss of life. Soon the scientific community divides into two groups, those who would destroy the new universe, and those who would study it. The debate becomes even more tense when evidence of life is found behind the rapidly expanding border. Characters invariably speak the language of quantum physics fluently, and the author makes little effort to bring their discussion down to the layman's level. Not until the end, when scientists begin to explore the new universe, does Egan make any real attempt to engage the reader's senses or emotions. The pleasures of this impressive novel, although considerable, are almost entirely intellectual. (May 8) Forecast: Winner of a Hugo and a John W. Campbell award, Egan tried to counteract his reputation for leaving out emotion and sense impressions by developing appealing characters and place in his last novel, Teranesia. But his return to "coolness" may limit his appeal largely to quantum physicists who read SF. (c) Copyright PWxyz, LLC. All rights reserved

(c) Copyright PWxyz, LLC. All rights reserved

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Review by Library Journal Review

About 20,000 years into the future, an evolved human race has mastered the secret of effortless space travel only to discover no other intelligent life in the galaxy. When an experiment in quantum physics creates a mysterious vacuum that quickly begins expanding, threatening everything in its path, rival factions pursue opposing tactics. One group wishes to destroy the threat, while the other group desires to explore the phenomenon, which seems to be creating new life forms. Sf veteran Egan (Terenesia) focuses on the wonders of quantum physics, bringing a complex topic to life in a story of risk and dedication at the far end of time and space. A good choice for libraries with a demand for science-heavy sf adventure. (c) Copyright 2010. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

(c) Copyright Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

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Review by Kirkus Book Review

Another mind-boggling vision from the author of the demanding but immensely rewarding Diaspora (1998). Twenty millennia from now, matter and space can be shaped to order by "quantum graph" techniques deriving from the Sarumpaet rules; only the speed of light remains inviolate, so space travelers eventually become estranged from their origins. Murder is unknown; people are immortal and, until stirred by physical attraction, asexual, when they rapidly develop the requisite organs. But no other intelligent life exists and, lacking challenges, human society has grown vegetative. Physicist Cass's experimental "novo-vacuum," expected to endure only for an instant, instead expands at half the speed of light, swallowing solar systems as it goes. Six hundred years later, investigators aboard a ship coasting just in front of the expanding boundary are split into two mutually hostile factions: Tchicaya and the Yielders wish simply to study the phenomenon; Mariama, Tchicaya's former lover and rival, and the other Preservationists intend to destroy the novo-vacuum using space-chewing constructs called Planck worms. The novo-vacuum, however, composed of Planck-scale "vendeks," appears to be alive! Even more astonishing, somebody within seems to be signaling! The factions quickly agree on a moratorium. But the Preservationists have been infiltrated by "anachronauts," refugees from the 23rd century who regard modern society as psychotic and are determined to destroy the novo-vacuum with its competing life-forms-and they launch virulent Planck worms before the Yielders can react. Still mutually suspicious, Tchicaya and Mariama join forces and enter the novo-vacuum, hoping to find intelligent beings and find a way to defeat the Planck worms from within. No writer takes ideas as far or presents them so convincingly, from a spellbinding dramatization of a physical and ethical clash in a society that knows little of either up to an utterly brain-blasting exploration-explication of physics-as-biology.

Copyright (c) Kirkus Reviews, used with permission.

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Schild's Ladder Chapter One In the beginning was a graph, more like diamond than graphite. Every node in this graph was tetravalent: connected by four edges to four other nodes. By a count of edges, the shortest path from any node back to itself was a loop six edges long. Every node belonged to twenty-four such loops, as well as forty-eight loops eight edges long, and four hundred and eighty that were ten edges long. The edges had no length or shape, the nodes no position; the graph consisted only of the fact that some nodes were connected to others. This pattern of connections, repeated endlessly, was all there was. In the beginning? Waking more fully, Cass corrected herself: that was the version she remembered from childhood, but these days she preferred to be more cautious. The Sarumpaet rules let you trace the history of the universe back to the vicinity of the Diamond Graph, and everything you could ask for in a Big Bang was there: low entropy, particle creation, rapidly expanding space. Whether it made sense to follow these signposts all the way back, though, was another question. Cass let the graph's honeycomb pattern linger in the darkness of her skull. Having relinquished her child's-eye view of the world, she was unable to decide which epoch of her life she actually inhabited. It was one of the minor perils of longevity: waking could be like to trying to find your way home on a street with ten thousand houses, all of which had once been your own. That the clues on the other side of her eyelids might be more enlightening was beside the point; she had to follow the internal logic of her memories back into the present before she could jolt herself awake. The Sarumpaet rules assigned a quantum amplitude to the possibility of any one graph being followed by another. Among other things, the rules predicted that if a graph contained a loop consisting of three trivalent nodes alternating with three pentavalent ones, its most likely successors would share the same pattern, but it would be shifted to an adjoining set of nodes. A loop like this was known as a photon. The rules predicted that the photon would move. (Which way? All directions were equally likely. To aim the photon took more work, superimposing a swarm of different versions that would interfere and cancel each other out when they traveled in all but one favored direction.) Other patterns could propagate in a similar fashion, and their symmetries and interactions matched up perfectly with the known fundamental particles. Every graph was still just a graph, a collection of nodes and their mutual connections, but the flaws in the diamond took on a life of their own. The current state of the universe was a long way from the Diamond Graph. Even a patch of near-vacuum in the middle of interstellar space owed its near-Euclidean geometry to the fact that it was an elaborate superposition of a multitude of graphs, each one riddled with virtual particles. And while an ideal vacuum, in all its complexity, was a known quantity, most real space departed from that ideal in an uncontrollable manner: shot through with cosmic radiation, molecular contaminants, neutrinos, and the endless faint ripple of gravitational waves. So Cass had traveled to Mimosa Station, half a light-year from the blue subgiant for which it was named, three hundred and seventy light-years from Earth. Here, Rainzi and his colleagues had built a shield against the noise. Cass opened her eyes. Lifting her head to peer through a portal, still strapped to the bed at the waist, she could just make out the Quietener: a blue glint reflecting off the hull a million kilometers away. Mimosa Station had so little room to spare that she'd had to settle for a body two millimeters high, which rendered her vision less acute than usual. The combination of weightlessness, vacuum, and insectile dimensions did make her feel pleasantly robust, though: her mass had shrunk a thousand times more than the cross sections of her muscles and tendons, so the pressures and strains involved in any collision were feather-light. Even if she charged straight into a ceramic wall, it felt like being stopped by a barricade of petals. It was a pity the same magical resilience couldn't apply to her encounters with less tangible obstacles. She'd left Earth with no guarantee that the Mimosans would see any merit in her proposal, but it was only in the last few days that she'd begun to face up to the possibility of a bruising rejection. She could have presented her entire case from home, stoically accepting a seven-hundred-and-forty-year delay between each stage of the argument. Or she could have sent a Surrogate, well briefed but nonsentient, to plead on her behalf. But she'd succumbed to a mixture of impatience and a sense of proprietorship, and transmitted herself blind. Now the verdict was less than two hours away. She unstrapped herself and drifted away from the bed. She didn't need to wash, or purge herself of wastes. From the moment she'd arrived, as a stream of ultraviolet pulses with a header requesting embodiment on almost any terms, the Mimosans had been polite and accommodating; Cass had been careful not to abuse their hospitality by pleading for frivolous luxuries. A self-contained body and a safe place to sleep were the only things she really needed in order to feel like herself. Being hermetically sealed against the vacuum and feeding on nothing but light took some getting used to, but so did the customs and climate of any unfamiliar region back on Earth. Demanding the right to eat and excrete, here, would have been as crass as insisting on slavish re-creations of her favorite childhood meals, while a guest at some terrestrial facility. A circular tunnel, slightly wider than... Schild's Ladder . Copyright © by Greg Egan. Reprinted by permission of HarperCollins Publishers, Inc. All rights reserved. Available now wherever books are sold. Excerpted from Schild's Ladder by Greg Egan All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.

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