Moonseed

by Stephen Baxter

  It was an explosion that had been ten thousand times as powerful as all mankind’s nuclear weapons, at their peak, ignited together. From a caldera the size of New Hampshire, blazing material had punched out of the atmosphere—some even entering low orbit—most of it falling back as giant fireballs which ignited what was left of the Earth’s vegetation.

  And from the crater itself a huge fireball, followed by a dust plume, had swept up to the stratosphere, and added to the soot and dust from the burning forests to create a planet-covering pall of darkness.

  Lights out, all over the Earth.

  The atmospheric shock-heating was enough to cause oxygen and nitrogen to combine to nitrous oxide, which had combined with rain water to make acid; and enough acid rain had fallen on the planet to make the top three hundred feet of the oceans sufficiently acidic to dissolve calcareous shell material, so driving still more orders of life to final extinction. The food chains, already tenuous, had finally collapsed. Death soaked the planet, starting with the phytoplankton.

  Ash falling, all over the Earth, like the thin layer that had been found in the rocks following the Cretaceous extinction, once puzzled over by scientists like Henry in bright, clean labs…

  The magma plumes, giant wellings-up in the Earth’s molten substance that originated as deep as the core mantle boundary, had been significant in Earth’s deep history. They had shattered continents, breaking up the Pangaea supercontinent, splitting Gondwanaland into two halves, splitting India, Madagascar and Antarctica from Africa. But all that had taken hundreds of millions of years. Now, the plumes’ violence was manifested on timescales of mere decades, even years.

  There was the mountain building event in Antarctica, for instance, where the Indo-Australian plate had suddenly decided to set off south. More of the great magma plumes under Earth’s hotspots had come boiling through the crust, at the Canaries, under the tsunami-lashed wreckage of Hawaii, under Iceland. And the rift valleys all over the Earth had started to open up, in east Africa and Lake Baikal and the Red Sea, the continents just splitting apart. The river Rhine had disappeared into a crack in the ground, and then the graben through which it once flowed started to bubble with new ocean floor plate.

  What all the volcanism was mostly doing, in addition to killing people and boiling the seas, was pumping out a new atmosphere for the Earth: an unwelcome air of carbon dioxide and sulfur dioxide and hydrogen laced with arsenic and chlorine, that would, the estimates went, finish up ten times as thick as the old nitrogen-oxygen one. Immense greenhouse cycles had already started, and the oceans were evaporating and would soon start to boil…

  And Henry’s beloved Earth was turning into what Venus used to be.

  One large community of people had retreated to what was left of the oceans, sheltering from the heat there. But even the marine invertebrates were choking on ash. And the volcanism had polluted the water with exotic trace elements—like cadmium and mercury and iridium and osmium—and the oceans, the birthplaces of life on Earth, were, in their last days, becoming toxic.

  But, in a way, it was geologist’s heaven. Processes that ought to take millions of years were occurring in mere years, even months. As if the Earth was trying to cram in her best special effects while she still had time. Geology, overwhelmed with unwelcome evidence, was at last becoming a mature science—just as, so he heard, fundamental physics had been galvanized by the study of the Moonseed processes, so that whole new areas of theory and technological achievement were being opened up.

  None of it any use, though, in stitching poor Earth back together.

  Dear Jane had called the sites of the great magma plumes Earth’s chakras. The energy centers, the wheel of light from which Earth’s energies were bleeding away. It was as good a description as any.

  He stepped forward cautiously, keeping an eye on the compass set into his chest pack. The compass was inertial, a little spinning gyroscope system, like they used to use in aircraft and spaceships. It was the only type that was reliable nowadays; the electronic kind that communicated with the GPS satellites was too easily thrown out by the auroras and the big electrical storms that flapped around the planet, and you couldn’t use a magnetic compass, of course, since Earth’s magnetic field had gone to hell. The geophysicists said it was all to do with the melting of the ice caps and the oceans’ evaporation, all that mass redistribution making Earth wobble like a kid’s top after a hefty kick. The reversals in the magnetic field’s polarity were coming about once a year now, thus screwing up the magnetosphere and letting through the cosmic rays, just adding to the fun down here, and coincidentally fouling up Henry Meacher’s map reading…

  But he couldn’t make head or tail of this damn astronaut’s compass.

  Well, maybe it was a little brighter to his left, to the east, where the sun must be rising. Maybe there were miles of cloud above him, the evaporated oceans lofted into the sky; maybe his green Earth had turned to a pearly white ball like Venus had been, where an American needed a spacesuit to walk out of the big underground shelters; but as far as he knew the world was still spinning the right way.

  Anyhow, he might get lost, but wasn’t going to come to any harm, on this plain of mud.

  He stepped forward, carefully…. It still seems remarkable to me to see Nadezhda bounding around in the low gravity without an ounce of self-consciousness.

  Of course she has no memory of the Moon before the modification. It seems perfectly natural to her to lope around the mare with nothing more than cold weather clothing, sunglasses and an oxygen pack! I’ve shown her recordings of the old Apollo Moonwalks, but she doesn’t say much.

  I suspect among the young people born here there is already a conspiracy theory circulating: that the Moon has always been this way—that maybe the old airless Moon never existed—that maybe our “terraforming” is a clumsy attempt to rectify some eco screwup on a previously pristine Moon. God, if only that was true!

  I do know that the images the young ones see of Earth are affecting them in ways we didn’t anticipate.

  For sure, the kids are evolving away from us, Henry. Already. Oh, Nadezhda doesn’t look much different from me at her age, when I was nagging mum to take me to the McDonald’s on Princes Street; it’s going to take generations even to work through the obvious physiological changes—the low G adaptations, for instance; Nadezhda will have to spend her life on courses of treatment against bone calcium loss and body fluid imbalances.

  But her children will be a little taller, and a little more resistant; and her grandchildren a little more so…and so on.

  Humans will survive here. I’m sure of that now. What I’m not convinced about is how much they will care about old Earth.

  The young ones already have their own agenda. It’s hard for them to have any loyalty for the home planet when they see that now you need spacesuits just to survive down there…

  There has already been some trouble at the drop points in Procellarum. Resistance to new immigrants, even to accepting more loads of rocks and frozen bugs from Earth.

  I just hope it all holds together long enough to get the best of it away, before the end.

  Well, maybe it’s inevitable. We’ve done all we can to equip the kids and educate them. Now, the future is theirs…

  As the tectonic events accelerated, predictions were being revised, and it seemed they were approaching the Bottleneck itself, the great, final die-back from which nothing on the surface of Earth, nothing, was going to escape. The laws had gotten harsher. No more children to be born on Earth. Anybody who refused to comply would be refused boarding, for themselves or their children, to the Arks to the Moon.

  It was harsh, and not universally accepted by the governments, and had caused revolution, and more than one war. In South America, where the Pope had mounted his last stand against the managed decline of the population, the fallout of thermonuclear destruction had added to Earth’s final woes.

  And nevertheless—despite the logic and wisdom, despite t
he inevitability of the Bottleneck—there were still children being born on the Earth: the animal response of frightened humans to the threat of death, life trying to propagate in the face of hopelessness. But the helpless new kids were only more moths to the flames, Henry thought.

  In a way, he was glad Jane wasn’t here to see this.

  At least she had lived to see her grandchildren, growing straight and tall in the thin, clean air of the Moon.

  But as for Henry, this was his home.

  He had been in love with the Earth since the first time he opened a geology book, the first time he picked up a pebble from a beach and wondered how it got there. Now it was burning down around him, but he wasn’t about to abandon it.

  He found himself walking on a layer of salt, white and bright in the smoggy twilight, that crunched under his feet.

  This ocean had dried once before, though not in human history. And that had been significant. The ocean had ceased to buffer the local climate, feeding land areas with rainfall and reducing temperature swings. Forests had disappeared, to be replaced by dry grasslands, and the arboreal creatures had faced the choice of migrating, adapting, or dying.

  One group of tree-dwelling primates was forced out of the branches that had hidden them from predators, and pushed onto the new grasslands of Africa, where they were going to need greater size and better locomotion and, above all, to get smarter.

  They had never looked back.

  Now, five million years later, a descendant of those frightened primates, dressed in a fragile spacesuit, stalked across the dried up bed of the Mediterranean, looking for fossils and human artifacts, a few last treasures for the final Arks to the Moon.

  54

  And a final ten years…

  Henry was standing on the Earth’s oldest rocks, and talking to his granddaughter, on the Moon.

  …So here I am, Nadezhda, your honorary grandfather, sixty-five years old and no smarter than I ever was, waiting for the other shoe to fall.

  I don’t suppose you know what that means. I can’t even remember how long it takes a shoe to fall on the Moon. Or if you wear shoes in those domes of yours.

  Whatever.

  I have instruments here, various sensors that show me what is happening inside the planet. I have a whole-Earth image here broadcast from one of your nearside observatories, I think at Kepler. I’m glad you can see the surface, from up there. The giant volcanoes blew off the crud, the Venusian atmosphere that was gathering, and who’d have thought that would be a blessing?…

  He was in Isua, in west Greenland. He was standing on supracrustal rock bounded on both sides by granitoid gneisses: three point six billion years old. Babies for the Moon, but these rocks were the old men of Earth, the oldest, most stable place on the planet.

  It seemed appropriate, to be here, now.

  He was in a concrete, heat insulated, pressurized bunker, which in turn was protected by what he would have called a force field when he was growing up, a piece of the smart stuff the kids on the Moon had been dreaming up. Technological evolution, force-fed by its environment, filling the niches.

  He was here because it was one of the few solid, stable places left on the planet.

  Earth, from space, looked like a jigsaw puzzle, or maybe like a pan coming to the boil, black continent pieces outlined by blood red.

  It was astonishing how events had accelerated, toward the end. It had been faster than anyone had believed.

  He wondered how long he’d last. How much of it he would see.

  …Did you know I was alive when Apollo 8 flew by the Moon? The astronauts, Borman, Lovell and Anders, were the first humans to see the Earth whole. They thought it was blue, and fragile, like a Christmas tree ornament. Well, they were right. Fragile.

  I know you think I’m crazy to stay.

  You know, one of the most beautiful theories of the history of the Earth was published by a guy called the Reverend Thomas Burnet, in England in the seventeenth century. Burnet said the Earth originated from chaos, a fluid mass of particles of matter. The particles grew together to form a perfect sphere with a smooth surface, concentric shells of liquid and air around a solid core. But there was an oily fluid in with the water, and when dust mixed with it, it formed a firm and fertile envelope over the layer of oily water.

  But the sun’s heat made the fertile shell dry and crack. The waters below boiled, vaporized and exploded, and the Earth was flooded. When the agitation settled out, the waters drained back to the low places. Fragments of Paradise were left sticking up as continents and islands.

  And that’s the world I was born on.

  Eventually, though, flames would come to purify the Earth, and it would return to its paradisical state, and finally merge with God by becoming a star.

  Well, it was a theory. That’s the way geology used to be, kid, a thing of dreams and fancies unsullied by brute fact. We only got into all that science stuff when the industrialists came along and started asking where they were going to find coal and iron ore and oil, and why the hell is the world so complicated anyhow?

  We know the answers now, of course: all those eons of mountain building and destruction, the rise and fall of the seas, the compaction, pressure, heating, cooling, sedimentation, erosion. The Earth is a rocky labyrinth.

  Was, anyhow. It’s getting kind of simpler, even as I stand here.

  Strange how Burnet seems to have been right all along, though, doesn’t it?

  It had been a couple of years since the Moonseed made the mantle so hot that plate tectonics effectively stopped. The plates were too hot to behave in the rigid way they used to; and the rock of the mantle was just too runny to support big horizontal movements.

  It had been thought that would reduce the volcanism for a time, but it didn’t turn out that way.

  Still, the map of Earth was recognizable. Just.

  The ocean plates were softening and melting back. The continents showed up in his images as black and dark islands in glowing oceans, the ancient granite cratons surrounded by crumpled greenstone. The cratons were the cores around which the continents had accreted in the first place, crust slabs which had formed in the center of ancient mantle convection cells; now they were being uncovered once more.

  It was as if, Henry thought, someone was winding back Earth’s evolution.

  And there were giant mantle plumes breaking out all over the planet, flood lavas, volcanic domes, cones and even coronae—features never seen on Earth before, only on lost Venus, basaltic domes surrounded by annuli of ridges and grooves. Nowhere was left untouched in the catastrophic resurfacing of the planet.

  Hardly anything of the works of humanity survived.

  There was one consolation, though. For a time, Earth was the youngest place in the Solar System.

  …I want to tell you how much I admire you people up there. My God, you guys think big. Your schemes to bring in comets to graze the Moon’s atmosphere and increase the volatile content. Rebuilding the crater walls and lunar mountains that are already getting eroded by the rain. No plate tectonics on the Moon, to maintain the carbon and oxygen cycles: so you’ll bake the silicate rocks into glass, drive out the carbon dioxide that’s weathered there, and reverse the erosion…Jesus.

  I’m not sure if I agree with your projections that you can reduce the time to true terraforming to a thousand years, but I haven’t had the time to run the math. I don’t think you ought to concern yourself with the objections of the Siberians who have colonized farside. They aren’t even human; let them build their own damn world.

  But you talk about using the extremal black holes from the Earth’s debris to tip the Moon, to give it seasons, then to spin it up. It’s a nice idea. A final gift from the Earth, to its daughter…

  But, Nadezhda, I have to counsel caution. Are you guys sure you know what you’re doing? You’re going to have sixty-feet tides in those new lunar oceans of yours—

  Shit.

  Sorry. That was a surface wave, a big one. I thin
k it will be over soon…

  The continental cores, the ancient cratons, had resisted the magma plumes for billions of years, and, like knots in wood, were tough to crack. But they were not indestructible.

  Even as he watched he could see the last of the African plate—cracking and dissolving like scum—there it went…

  Africa had been the oldest continent, most of it formed more than two and a half billion years earlier, surviving for geological ages as the hard, protected core of Pangaea, the world continent. Now it was gone, just a puddle of magma.

  Good-bye, Africa. Birth place of man. My God.

  And now, where Africa used to be, another huge magma plume was starting. It looked like a solar flare. A fountain of rock blasting straight up, uncurling with perceptible speed…

  No, not a fountain. More like a fist, punching out of a sack. A mass the size of a small moon, thrusting out of the Earth.

  Henry couldn’t begin to compute the energy behind events like that.

  The end must be close now.

  Already there had to be significant mixing between the core and the mantle layers. The planet as a whole used to spin at a different speed from its core…Now the whole globe was coupled, structurally. It must be tearing itself apart, like an unregulated motor.

  Another pressure wave swept beneath his bunker, cracking the floor. Maybe that was the aftershock of the Africa plume.

  He kept to his feet, though.

  Now another plate was gone, after five billion years just crumbling away like sugar in water. He thought that was Indo-Australia—the planet was such a mess now it was hard to be sure—and the other plates were starting to slide and crack.

  …I know you think I’m crazy to have stayed. I know your new generation of Arks, skimming down from the Moon, had the capacity to take off almost everybody who was left. I know you think I’m like the crazy old fucker who wouldn’t get out of his house when they want to build the highway through it.

  Sorry. I guess you don’t know what I’m talking about.