Loe raamatut: «Moonseed»

I BIG WHACK

It began in a moment of unimaginable violence, five billion years before humans walked the Earth.

There was a cloud, of gas and dust, slowly spinning. Much of it was the hydrogen and helium which had emerged from the Big Bang itself, but it was tainted by crystals of ice – ammonia, water and methane – and dust motes rich in iron, magnesium and silica, even some grains of pure metal. These were flotsam from older stars, stars already dead.

… And now another star died, a giant, in the conclusive spasm of supernova. A flood of energy and matter hammered into the cloud.

The cloud lost its stability, and began to collapse, to a spinning disc. The central mass shone cherry red, then gradually brightened to white, until – after a hundred million years – it burst into fusion life.

It was the protostar which would become the sun.

Within the disc, solid particles began to crystallize. There were grains of rock – silicate minerals called olivines and pyroxenes – and minerals of iron and nickel, kamacite and taenite. The particles, stuck together by melting ice, formed planetesimals, muddy lumps which swarmed on looping, irregular orbits around the sun.

The planetesimals collided.

Where an impact was head-on, the worldlets could be shattered. But where the collisions were gentle, the worldlets could nudge into each other, stick together, merge. Soon, some aggregations were large enough to draw in their smaller companions.

Thus, young Earth: a chaotic mixture of silicates, metals and trapped gases, cruising like a hungry shark in a thinning ring of worldlets.

Earth’s bulk was warm, for the heat of accumulation and of supernova radioactive decay was trapped inside. The metals, heavier than the silicates, sank to the centre, and around the new, hot core, a rocky mantle gathered. Gases trapped in the core were driven out, and formed Earth’s first atmosphere: a massive layer of hydrogen, helium, methane, water, nitrogen and other gases, amounting to ten per cent of Earth’s total mass.

Earth’s evolution continued, busily, logically.

But something massive was approaching.

‘Look up, Tracy. Look at the Moon. You know, we take that damn thing for granted. But if it suddenly appeared in the sky, if it was Mercury hauled up here from the centre of the Solar System, my gosh, it would be the story of the century …’

It was 1973.

Her father, Jays, had been back from the Moon only a couple of months. Tracy Malone, ten years old, thought he’d come back … different.

‘Look up,’ he said again, and she obeyed, turning from his face to the Moon.

The face of the Man in the Moon glared down at Tracy. It was a composition of grey and white, flat and unchanging, hanging like a lantern in the muggy Houston sky.

‘The Moon looks like a disc,’ said her father, in his stiff school-teacher way. ‘But it isn’t. That’s an optical illusion. It’s a rocky world, a ball. You know that, don’t you, sweet pea?’

Of course I know that. ‘Yes, Dad.’

‘People used to think the Moon was like the Earth. They gave those dark grey patches the names of oceans. Well, now we know they are seas of frozen lava. Think about that. And those brighter areas are the highlands, rocky and old. Now, look for the Man’s right eye: you see it? That distinct circle? That’s what we call the Mare Imbrium. It’s actually one huge crater, big enough to swallow Texas. It was gouged out by a gigantic meteorite impact almost four billion years ago. What a sight that must have been.’

‘But there was nobody around to watch it. Not even the dinosaurs.’

‘That’s right. And then, much later, it got flooded with basalt –’

‘Where did Neil Armstrong land?’

‘Look for the Man’s left eye. See the way it’s sort of sad and drooping? Follow that eye down and you come to Mare Tranquillitatis.’

‘Tranquillity Base.’

‘That’s right. Neil put his LM down just by the Man’s lower eyelid.’

‘Can I see your crater?’

‘No. Most craters are too small for people to see. But I can show you where it is. Look again at that big right eye. See the way the mare’s grey extends beyond the circle, out of the Imbrium basin itself? That’s Procellarum, the Ocean of Storms. That’s where Apollo 12 landed, where Pete Conrad put his LM down right next to that old Surveyor. Well, my crater is on the border there, between Imbrium and Procellarum.’

‘I can’t see it.’

‘It’s called Aristarchus. It’s named after the man who figured out how far away the Moon is, two thousand years ago …’

She looked at his pointing hand. Even though he had washed and showered, over and over, she saw there was still black Moon dust under his fingernails, and ground into the tips of his fingers. It was going to take a long time for him to get clean.

He was still dog tired after the trip. But he couldn’t sleep. Even when he lay flat in his bunk, he said, it felt as if his body was tilted head down. There was, he said, too much gravity here.

A lot of stuff had happened up there, she suspected, that he would never tell her.

He ruffled her hair. ‘You think you’ll ever get to go to the Moon?’

‘What for? There’s nothing there but a bunch of old rocks.’

‘I thought you liked rocks. Your collection –’

‘I like real rocks.’

‘Moon rocks are real.’

‘But they won’t let you touch ’em.’

‘Maybe. Anyhow, you’re wrong. About the Moon. It’s not just rocks. If you lived there you could make metals, and oxygen to breathe, and there’s silica to make glass. And with the water from the Poles, you could farm up there.’

‘Water? I thought there’s no air.’

‘There isn’t. But there is ice at the Poles. Deep in the dark, where the sun never shines.’

‘Really? A lot of ice?’

Her father hesitated. ‘Well, some people think so.’

‘Anyhow,’ she said, ‘I don’t want to be a farmer.’

Her father stared up at the Moon. ‘You know, you’re special. I wrote your name up there, in the dust, and it will be there for a million years.’

‘You told me, Dad.’

‘Yeah.’

A cloud passed over the Moon’s face. It got colder.

They went indoors to watch TV.

One day, human scientists would call it the Impactor.

It had about the mass of Mars, a tenth of Earth’s. Humans would later speculate that it was a young planet in its own right.

But they were wrong. It was not a planet.

The object barrelled through the dusty plane of the Solar System.

But there seemed to be something in the way.

… And on the Moon, the Rover had jolted across the bright dust, climbing gentle slopes under the black sky, bathed in the sun’s flat light.

It must have looked strange, Jays thought, if there had been anyone around to see it. The Rover looked like a beach buggy from somebody’s home workshop. And yet here were the two of them in their shining white pressure suits, like two dough boys riding a construction-kit car, bouncing across the Moon itself.

They rose up a slight incline.

Suddenly there was the rille: Schröter’s Valley, a gap in the landscape in front of them. It wound into the distance, its walls curving smoothly through shadows and sunlight. Jays could see boulders that must have been the size of apartment blocks, strewn over its floor.

Jays tried to keep the excitement out of his voice. ‘Look at that old rille. I’m sure I can see layering in the far side. Look, Tom. Over at one o’clock.’

Tom, distracted by the driving, said, ‘Let’s get up there before we do any geology.’

The Rover jolted to a stop.

Jays released his seat belt, and let it snap back into its frame. He tried to stand up. But the slope was deceptive; it was an effort to haul his suited frame out of the Rover’s lawn seat.

He took a step away from the Rover.

His suit was a stiff bubble around him, shutting out the Moon. He could hear the whir of pumps and fans in his backpack, feel the reassuring breath of oxygen over his face. The sunlight caught scuffs and scratches in his gold-tinted sun visor, creating star-bursts.

He looked up, towards the south, and there was the Earth, hanging in the sky like a blue thumb-nail. He could see a depression over the South Atlantic, a fat white swirl. Other than the Earth and the big white spotlight that was the sun, the sky was empty: save only for a single bright star that tracked across the zenith every couple of hours. That was the Apollo Command Module, waiting in orbit to take them home.

Jays, when you climb off, could you dust off our TV lens, please?

‘Roger.’

He turned back to the Rover. The TV camera, operated from Houston, was a block covered by gold-coloured insulation, mounted on a bracket at the front of the Rover. He could see that dust had kicked up over the lens and insulation and cabling.

He leaned forward. He took a breath, out of instinct, as if he could just blow the thin dust layer away. But this wasn’t Earth; there was no air here, and his head was locked inside a bubble of plexiglass … He looked for the soft lens brush, and swept away the dust.

As soon as he was done the camera turned away by itself, and began to pan across the landscape in eerie silence.

It was, perhaps, the most dramatic collision event in the history of the Solar System. Humans – trying to figure out how their world and its unlikely, huge Moon had come to be – would call it the Big Whack.

The Impactor hit Earth obliquely, like a cue ball kissing its target. Earth, much more massive, absorbed the momentum of the Impactor and spun up its rotation. Mantle material vaporized and entered orbit around the Earth. Earth’s crust melted; Earth became, as if young again, a roiling ball of lava.

The orbital cloud of superheated mantle rock condensed into droplets, a dusty, rocky ring circling the Earth. But the ring was not stable. In a miniature rerun of the formation of the Solar System itself, the debris began to accrete.

It took a mere century for the debris to assemble into a new world: it was the Moon, a ball of magma glowing balefully in Earth’s sky. The remains of the Impactor were trapped in the Moon’s heart.

The new world was coming of age in a Solar System that was still very young, and huge left-over planetesimals continued to bombard its surface. Impact basins formed, wounds huge and deep, and waves of pulverized rock rushed over the surface of the Moon to form gigantic ringed structures. Immense blankets of ejecta were hurled thousands of miles over the battered ground. But so intense was the continuing flux that the formations were themselves soon shattered and covered over.

At last the flux of planetesimals began to tail off. In a moment of geological time, the last great impacts formed basins and mountains which froze forever the face of the Moon.

The Moon became a small, cold world, its evolution over a billion years after its birth, its youngest rocks more antique than Earth’s oldest.

And, far beneath the dusty plains, the remnant of the Impactor brooded, embedded in darkness.

On the Moon, Tom Barber was going through Rover read-outs for Houston. ‘Amp-hours 90,92. Voltages 68, 68. Battery temperatures 101 and about 100; motor temps off scale, low. Bearing is 088, range 1.8, distance 2.5 klicks.’

Thank you …

Jays picked up a couple of sample bags from the stowage in back of the Rover, and took the geology hammer from Tom’s backpack, and his tongs from the Rover’s footpan. He pulled the gnomon out from its stowage sleeve behind his seat. In stowage, the gnomon’s three legs were folded against the central staff to make a slender sheaf. When he extracted it the legs sprang out into a spindly tripod.

Carrying his tools he loped away, towards the rille.

The regolith crunched under his feet, sinking maybe a half-inch, before he settled to a firmer footing. The dust sprayed around his feet, sinking quickly back to the surface. It was like walking on crisp, frozen snow, or maybe a cinder track.

He had to climb up a slight incline to reach the rille’s rim. He was out of breath in a few steps.

Still, he persisted.

He paused for a breath. He turned and looked back at the skeletal Rover. It looked like an ugly toy: squat and low, sitting there in a churned-up circle of dust. Its orange fenders and gold insulation were the brightest things on the surface of the Moon. A few yards beyond the Rover, Tom was working. He was gouging at the surface with a long-handled tool, taking a rake sample of the dust. His red commander’s armbands were bright.

Jays took a swig of water from the bag inside his suit. He felt his chin strap rasp against a week-old beard. He’d promised his daughter, Tracy, that he wouldn’t shave until he got home. After all, in the picture books, the explorers always came home with beards.

The Rover’s television camera was watching him, cold and judgemental. Time is ticking on, it seemed to say, billion-dollar seconds wasting while you stand there and goof off.

He turned and continued.

He reached a flat crest, and came suddenly on the rille.

He stopped. He raised the five-hundred-mil camera from its bracket on his chest, and took a horizontal pan, turning slowly, and then a vertical pan, all the time geologizing, describing what he saw.

The rille was up to eight miles wide, a half-mile deep, and all of a hundred miles long. Schröter’s Valley, the biggest rille known on the Moon. It was a river valley, but cut into the bottom of this dead lunar sea – not by water – by a lava flow, some time in the deep past.

He stepped forward again.

As he approached, the surface of the mare sloped gently towards the rille rim, and the regolith was getting visibly thinner. The rille walls sloped at maybe twenty-five or thirty degrees.

The sun was behind him. The far walls were in full sunlight, and now Jays was sure he could see layers: distinct strata in the rock, poking through the light dust coating.

Excited, he described what he saw. ‘Okay, Joe, I think I can see from top to bottom, one distinct layer about ten per cent, which has multiple layers within it. And another at about forty per cent down, which looks like a solid unit of a somewhat harder, tan-coloured rock, but it’s covered with fines and talus. We haven’t seen to the bottom; I think I’ll get the chance to go further down …’

He felt his heart thump. The rille layers were a record of the Moon’s volcanism, the strata left by ancient basalt floods, driven by an internal heat that had all but died almost as soon as the Moon formed.

The only other volcanic remnants Apollo crews had found had been dug out by impacts, shattered and melted and reformed, scattered over the surface, heavily processed. In the rille walls, though, he was facing true lunar bedrock. What he had come for.

Samples of basalt from the maria – the lunar seas, like Apollo 11’s Tranquillity – would take you back as far as the age of mare volcanism, when founts of lava had flooded the great impact basins. But if you wanted to look further you had to go find bedrock: dusty windows on even greater antiquity, all the way back to the birth of the Moon.

Bedrock was the core of the mission, as far as Jays was concerned. And a big fat sample of bedrock, maybe from deep inside that old rille, would be his trophy fish.

He felt his soul expanding.

Nobody had ever seen this sight before, nobody. And, no matter who came after him, for whatever purpose, no matter how much smarter they were than him, they could never take that away. Schröter’s Valley would forever be a part of him.

He went over a crest, and was now descending into the rille itself. But there was no sharp drop-off; like every other surface here the rille wall was eroded to smoothness, and the footing was secure, the regolith layer thin.

For a moment he thought he glimpsed a stretch of the very bottom of the rille. Something shining there. But that was impossible, of course. It had to be a trick of the light. A scuff on his faceplate.

… And then he saw it, sheltering beneath a hummock in the regolith. It was a dark basalt, a lava lump about the size and shape of a football. When he brushed away the regolith he could see it was protruding from a rock layer, like the ones he could see so clearly on the far side of the rille.

Jays wanted to get this one right.

He took careful photographs of the rock in its resting place. Then he tried to set up the gnomon beside it, the smart little tripod that would give him scale, local vertical and orientation compared to the angle of the sun.

This was called documenting the sample. The idea was that back on Earth, if they knew exactly how the sample had been taken, the scientists would be able to reconstruct the geology of the area at leisure.

But the documenting turned out to be a scramble. The slope was too steep for the gnomon, and he wasn’t sure the photographs would pick out the rock from its background. He did his best; but the guys in the geology back rooms didn’t always understand how tough their procedures were to follow once you were here … Still, surely the rock would be worth it.

Of course the rock would be given a number of its own. A five-digit code: ‘eight’ for Apollo 18, ‘six’ because this was their sixth survey stop, and a number for the sample in the order they’d taken samples here, which had to be up in the forties or fifties already, he figured.

He bent sideways, stiff in his inflated suit. He was able just to pick up the rock; it fit his hand as if it had been meant for him.

He put his prize in a numbered Teflon bag. Then he photographed the place the rock had come from.

Movement. The dust was stirring, where he’d lifted the rock. When he looked again, the movement wasn’t there.

Never had been there. Been out here too long, Jays.

Tom was calling. They had to complete a rake sample, a random representative selection of the rocks here, and then move on.

He had just arrived, having come all this way, and it was already time to leave.

Jays took a last glance down inside the rille. He tried to peer down as deep as he could, straining to see to the bottom. The slope looked easy; he wished he could go a little further, deeper into the rille. But he knew he mustn’t. He was a long way from Tom’s helping hands, if he ran into trouble. And anyhow, he was behind the timeline.

He knew he wouldn’t mention what he’d seen to Tom.

On impulse, he leaned over, scooped up another fragment of the bedrock sample, stuffed it inside a sample bag and crammed it into a pocket on his leg.

Then, his bedrock under his arm, he snapped shut his sun visor and clambered back up the slope, towards Tom and the waiting Rover.

After a four-billion-year wait, the visit with its burst of activity had lasted only three days, the final flurry of dust settling after only seconds.

At Aristarchus Base, Rover tracks and footprints converged on the truncated base of the abandoned Lunar Module. The blast of the departed ascent stage’s engine had left a new ray system, streaks of dust which overlaid the footprints.

Now the Moon was inert once more, the sculpted hills of the Aristarchus ejecta blanket rising above this puddle of pitted, frozen basalt, their slopes bathed in sunlight, shining like fresh snow.

Waiting.

In places, the disturbed dust stirred. Glowed softly silver.