A Time Odyssey Omnibus

by Arthur C Clarke - Stephen Baxter

  She had made the trip for nothing. And the cost turned out to be unexpectedly high. When she had walked back to her faithful Beagle she found it had packed up, just like that. Its supposedly milspec electronics had presumably succumbed to the onslaught from the sun, leaving its essential systems, including life support, as dead as Mars.

  So that was that. Without the rover, she couldn’t get back to Aurora. Her suit reserves would last only a few more hours, which wouldn’t be long enough to get another rover out to her. She was living, breathing, as healthy as she had been a sol before. But she was doomed by the cruel equations of survival on Mars.

  Of course she wouldn’t be the solar system’s only casualty today.

  At least she was special, she told herself. Though she hadn’t been the first person to set foot on Mars, she would become the first human being to die here. Perhaps that was a memorial worth having.

  And she would do her duty to the last. The space agencies had always had procedures for such eventualities. If she had died in space—as had been discussed by NASA planners decades ago when the International Space Station had first been occupied—her body would have been zipped into a bag and tied to a truss until it could be returned to Earth. Here on Mars, her first duty was to the planet and its putative biosphere; she mustn’t contaminate it with her own decaying corpse. All she had to do was stand here, in fact. When her suit’s heaters failed she would quickly freeze solid, thus sealing in any rogue bugs she had brought from Earth, until her body could be retrieved. Probably the suit wouldn’t even topple over. She would be a statue, she thought, a monument to herself, and her own dumb luck.

  She couldn’t bear the thought of dying beside her poor, failed rover, though. So she had decided to walk on into the Martian wilderness, just so she could see a bit more of the planet that was killing her.

  Even then her luck was all bad. She had trudged across a dull plain, to this dull canyon. Here she was in the midst of the greatest catastrophe the solar system had endured since its formation, and everybody else had a better view than she had.

  Something stirred at her feet. On the ground little pits were forming—craters, she thought, but none wider than her thumbnail. Could she be caught in some peculiar micrometeorite shower? But now she heard a pattering on her helmet.

  She looked up. She could see the drops falling out of the sky, big fat low-gravity drops drifting slowly down all around her. When they hit, they smeared the patina of dust on her faceplate.

  It was rain, the first rain on Mars in a billion years.

  The sun breathed fire into the faces of all its circling children.

  On Mercury the sun-side face had melted, craters as old as the planet dissolving into magma palimpsests. Venus had been stripped of much of its crushing atmosphere—the fate that might have become of Earth, if not for the shield. The ice moons of Jupiter were melted to depths of kilometers. In a strange and exquisite tragedy, the rings of Saturn, fragile bands of ice, had evaporated.

  And on Mars volcanoes dormant for a hundred million years had begun to stir. The polar ice caps, thin smears of carbon dioxide and water ice, had quickly sublimed. And now rain was falling. Helena walked forward a few more steps, and watched the Martian rain falling deep into the shadows of the canyon.

  One of her colleagues, excitedly, began to report on his own discoveries. “I found a ship! And what a ship; it looks like the carcass of a beached whale. And it’s covered in Mandarin lettering. But it has a hull rip the size of Mariner Valley. It came down hard…”

  Helena had listened to her comrades’ communications all this long sol. She had reported in at routine intervals, but she had decided against telling them what had become of her—not just yet, anyhow. Now she stood and listened to the voice of a colleague she would never see again.

  “Wait a minute. I’m climbing inside the ship, taking care to avoid all sharp edges… Oh. Oh, dear God.”

  There had been more than a hundred people on the ship. They were all young men and women—all breeding age, including the pilots. Their cargo had included inflatable shelters, mechanical diggers, hydroponic seed beds. The intention was clear. This was what the Chinese had been planning for the last five years: this was what had used up all their heavy-lift capacity, instead of contributing to the shield. And this was how the Chinese had planned to ensure that something of their culture would survive the sunstorm.

  “But the Chinese invasion of Mars failed… They came so close. I wonder what kind of neighbors they would have been?”

  Helena suspected everybody would have got along. From here, China was very far away, just as far as Eurasia and America. Here, you were just a human—or rather, a Martian.

  She looked up at the sun. Close to setting, it was smeared out in a ragged ellipse by air laden with dust and unaccustomed rain clouds. She knew the predicted schedule; the sunstorm should be abating by now—and yet something about that setting sun troubled her, as if there was still a nasty surprise to come.

  The dust at her feet stirred. She looked down.

  Amid the pattering raindrops, something was pushing out of the soil. No bigger than her thumb, it was like a leather-skinned cactus. It had translucent sections, windows to catch the sunlight, she thought, without losing a precious drop of moisture. And it was green: the first native green she had seen on Mars.

  Her heart hammered.

  The Aurora crew, during their long exile, had searched in vain for life on Mars. They had even risked a hazardous journey to the South Pole, where they had sought out the oldest, coldest, undisturbed permafrost on all of Mars, hoping to find Martian microorganisms trapped and preserved. Even there they’d found zilch. That epochal discovery would surely have made their years away from home worthwhile; it had been a crashing disappointment to find nothing.

  And now here it was, just bubbling up out of the ground before her.

  She felt a painful pull at her chest. She didn’t need to check her monitors to know her suit was failing. To hell with her suit; she was going to report her discovery. Hastily she turned on her helmet camera, and bent over the little plant. “Aurora, Helena. You won’t believe this…”

  Its roots were buried deep in the cold rock of Mars. It didn’t need oxygen, but fueled its glacial metabolism with hydrogen released by the slow reaction of the volcanic rocks with traces of water ice. Thus it had survived a billion years. Like a spore waiting under a desert on Earth for the brief rains of spring, this patient little plant had waited out an eon for the Martian rains to return, so it could live again.

  46: AFTERSHOCK

  A chain of events stretching back millennia was almost complete. The sunstorm had been wasteful of energy, of course—but not nearly so wasteful as humankind might one day have become, if allowed to infect the stars.

  The sunstorm was ending. Though the sun’s relatively orderly cycles of activity would be disturbed for decades to come, the great release of energy had been cathartic, and the destabilization of the core was resolved. All this was just as Eugene Mangles’s remarkably successful mathematical models of the sun’s behavior had predicted.

  But those models had not been, could never be, perfect. And before this long day was done, the sun had one more surprise for its weary children.

  The sun’s tremendously strong magnetic field shapes the star’s atmosphere, in a way that has no analogies on Earth. The corona, the outer atmosphere, is full of long sheets of gas, like the petals of a flower, that can extend many radii from the sun. The elegant curves of these “streamers” are sculpted by the magnetic fields that control them. The streamers are bright—it is these plasma sheets that are visible around the blocked-out sun during a solar eclipse—but they are so hot, pumped full of energy by the magnetic field, that their spectral peak is not in visible light but in X-rays.

  All this in normal times.

  As the sunstorm subsided, one such streamer formed over the active region that had been the epicenter of the storm. In keeping with the giant in
stability that had spawned it, the streamer was an immense structure, its base spreading over thousands of kilometers, and extending so far out in space that its feathery outer edge reached the orbit of Mercury.

  At the base of the streamer, flux tubes rooted in the sun’s deep interior arched to enclose a cavity. Inside the cavity, contained by the magnetic field’s arches, were trapped billions of tonnes of ferociously hot plasma: it was a cathedral of magnetism and plasma. And as the storm died, this cathedral began to collapse.

  As the “roof” gave way, immense rivers of magnetic energy flowed into the trapped plasma mass. The mass was raised up from the sun’s surface, slowly at first. But then as the magnetic field unwound the plasma was hurled away ever more rapidly, as a stone is hurled from a catapult. The ejected cloud, a tangle of plasma and magnetic field lines, was very rarefied, less dense than most “pure” vacuums manufactured on Earth. But it was not its density but its energy that counted. Some of its particles had been accelerated almost to the speed of light. Energetically it was a hammer blow.

  And, just as had been planned by cool minds millennia ago and sixteen light-years away, it was aimed squarely at the suffering Earth.

  47: BAD NEWS

  When Mikhail came online with the news, for a moment Bud couldn’t bear it. He escaped the control room, hauled himself to his cabin, and shut the door.

  On a battered softscreen spread out on his bunk, he scrolled slowly through the names of the lost. They were mostly maintenance engineers who had been out there on the shield in the thick of the storm—and volunteers, like Mario and Rose, who had gone out to take their places as they fell. Bud knew them all.

  In the five years of its existence the community on the shield had evolved its own culture, which Bud had done his best to foster. There had been zero-gravity sports tournaments, and music and theater, and parties and dances, and big public celebrations at Thanksgiving, Christmas, Ramadan, Passover, and every other excuse they could come up with. There had been the usual human tangle too, of love affairs illicit and otherwise, marriages, divorces—and one murder, a crime summarily dealt with. Despite all precautions, two babies had been born, apparently with no ill effects from their gestation without gravity, hastily shipped to Earth with their parents.

  But now fully a quarter of this community had died, another quarter lay seriously ill, and the rest had taken a battering, including Bud himself. They all had a hugely increased chance of contracting cancer in the future, or of having their irradiated systems fail in some other way. For what they had done today they had all paid with their life expectancy, or their very lives—and not one had demurred, even when called on to make that final sacrifice.

  Bud had kept up a determined public face. But even before the event he had had to make gruesome calculations of acceptable casualty levels. It felt as if he had planned for these people to die. And with each bright soul he had ordered into the furnace, with each new death added to this tally, he felt as if his heart were being twisted inside him.

  He still had a job to do for the survivors; up to now he had been able to comfort himself with that. After so long in microgravity the heroes from the shield would not get their medals and parades for a while. They would all return to Earth weak as kittens, and would be subject to six months or a year of rehab, massage, hydrotherapy, and programs of exercise to bring up their strength, endurance, and bone mineral levels—until they were fit to stand before a President or two, and take the plaudits they had earned.

  That had been his plan to get his people home, fondly rehearsed in his mind. But now it looked as if none of that was going to happen. For, if he understood what Mikhail and Eugene were telling him, this huge sacrifice might all have been in vain, and they might just as well have stayed home and waited for the storm to torch them all.

  He was doing no damn good here. He took a deep breath and made his way back to the control room.

  Eugene and Mikhail sat side by side in some poky cabin at Clavius.

  “It is called a ‘coronal mass ejection,’” Mikhail said lugubriously. “In itself it is not an unprecedented phenomenon. In normal times there are many such events per year.”

  Bud asked, “I thought June 9 was caused by a mass ejection?”

  “Yes,” Eugene snapped. “But this is bigger. Much bigger, even than that.” Nervously Eugene began to gabble through a description of the latest events on the sun: the gathering of magnetic field lines over the zone of disturbance that had been the epicenter of the sunstorm, the trapping of an immense cloud of plasma beneath those flux lines—and then how the cloud had been hurled upward away from the sun.

  Bud half listened to the words, and watched the two astrophysicists. They were suffering, Bud could see that. Mikhail’s face was grooved with weariness, the shadows deep as lunar craters around his eyes; Bud had never seen him looking so old.

  Eugene’s expression, creasing up that bland jock’s face, was more complicated, but then so was Eugene. Rose Delea used to call Eugene “autistic” to his face, Bud remembered—but poor Rose was dead now. Bud, however, had never thought of Eugene as some inhuman calculating machine, and now Bud thought he could read the emotion in those pale blue eyes, an emotion any military man would sympathize with: The operation is fucked. And I fear, dear God, that it might be me who screwed the pooch.

  Bud rubbed his eyes and tried to focus, to think. After his own six-hour jaunt out on the shield, he was still in his grimy thermal long johns. He could smell the sweat and vomit crusted on a face that had been cocooned in a bubble helmet for too long, every muscle was stiff as a board, and he ached for a shower.

  He said carefully, “Eugene, you’re telling me your models didn’t foresee this.”

  “No,” Eugene said miserably.

  Mikhail said gently, “There’s really no reason why they should, Colonel Tooke. Oh, perhaps some such ejection might have been foreseen. The turbulence at the heart of the sunstorm was like an active region. Such regions spawn flares, and they are sometimes, but not always, associated with mass ejections too. If there is a causal link it is a deep one we have yet to untangle. We have yet to understand the basic physics, you see. And besides, our models could see only as far as the great outpouring of energy of the sunstorm itself—which we got mostly right. But beyond that point our models ran into a singularity—a place where the curves shot off to infinity, and the physics broke down altogether.”

  “We patched in a solution for the follow-up,” Eugene said desolately. “Continuous to the third-order derivatives. Over most of the sun the patch seems to be working out. All except for this vicious bastard.”

  Mikhail shrugged. “In retrospect that anomalously high gamma flux we observed at the start of the storm may have been a precursor. But we had no time for remodeling, not then, as the storm itself broke—”

  Bud said, “You feel like the sun itself has let you down, don’t you? Because it didn’t behave like you told it to.”

  Mikhail said, “I have tried to explain to Eugene that no fault is attached to this. Eugene’s is the single most brilliant mind I have ever worked with, and without his insights—”

  “We would never have seen the storm coming, would never have got the shield built—would never have saved all those lives.” Bud sighed. “You mustn’t feel bad, Eugene. And we need your help now, more than ever.”

  “We don’t have much time,” Mikhail said. “It’s moving a lot more quickly than a normal mass ejection.”

  “But this isn’t a normal day, right? How long?”

  “We have an hour,” Mikhail said. “Maybe less.”

  The answer was ridiculous; Bud could barely believe it. What could he do about this in an hour? “So what comes first?”

  “An advance shock wave,” Eugene said. “More or less harmless—it will give us a lot of radio noise.”

  “And then?”

  “The bulk of the cloud will hit,” Mikhail said. “A fog bank as wide as the sun itself, more than a million ki
lometers across, heading right for Earth. Unusually, it is quite shallow, a kind of lens. Its shape is an artifact of its unusual formation, we think. It is made up of relativistic particles—mostly protons and electrons.”

  “Relativistic, meaning moving close to the speed of light?”

  “Yes. And very energetic. Very. Colonel, a proton can’t outrun light, but in getting closer to that final limit it can take on board an awful lot of kinetic energy—”

  “And those energetic particles will do the damage,” Eugene said. “Colonel, it will be a particle storm.”

  Bud didn’t like the sound of that.

  On June 9, 2037, a similar cloud of fast-moving particles had hurled itself against Earth. Most had been trapped by Earth’s magnetic field. The bulk of the damage done that day had been caused by fluctuations in the Earth’s field, which had induced electrical currents in the ground.

  “This time it will be different,” Mikhail said. “The ground will be directly engaged.”

  Bud snapped, “What does that mean? Stick to English, damn it.”

  Eugene replied, “These solar particles are so energetic that most of them will cut through the magnetosphere, and atmosphere, as if they aren’t there—”

  “Like bullets through paper,” Mikhail said.

  A lethal hail of radiation and heavy particles would slam onto land and sea. For an unshielded human, it would be like a trillion tiny explosions going off inside her cells; her delicate biomolecules, the proteins that built her and the genetic material that governed her structure and growth, would be smashed apart. Many people would die immediately. For those who lived, the suffering was only postponed. Even unborn children would suffer mutations that could kill them on their emergence from the womb.

  Every living thing on Earth, every one of them reliant on proteins and DNA, would be similarly affected. Even where individuals survived, ecologies everywhere would be devastated.