Authors: Terry Pratchett,Stephen Baxter
Tags: #Fiction, #Science Fiction, #Action & Adventure, #General
‘We already have,’ Frank said. ‘Look down.’
Although the gross features of the landscape below the banking gliders endured – the horizon, the mighty carcass of Arsia, the outflow channels – now she saw that details were changing with every heartbeat: a different pattern of newer craters on the older landscape to the south, subtleties in the finer twists and turns of Mangala’s complex of channels to the north. Then there was a blink, she was in a crimson-tinged darkness, and the glider was buffeted as if it had driven into turbulent air. Just as suddenly the darkness cleared, and the gliders flew on.
‘Dust storm,’ called Willis.
‘Yeah. Not very comfortable,’ Frank replied. ‘But we’ve got no vents to clog, no engines to choke. These storms can last months.’
‘But we don’t need to stick around to see it,’ Willis said.
They snapped into the buttery sunlight of the next world, and the next. The Marses slid past below, one every second.
As they flew on, things became relaxed enough that Sally was able to loosen her faceplate and open her suit. The stepping was no faster than the old
Mark Twain
, the prototype stepper airship she rode across the Long Earth with Lobsang and Joshua Valienté fifteen years ago, no faster than a modern commercial cargocarrier, and a lot slower than the fastest experimental craft, or even the best military ships. But it was fast enough, she thought, for this journey into the utterly unknown.
Except that it seemed like a journey into the utterly identical. There were simple step counters in the cabin, and she watched the digits pile up as time passed: sixty worlds a minute, over three thousand an hour. At that rate, on the Long Earth, they would have crossed over sheaves of Ice Age worlds, fully glaciated planets, within the first hour or more; after ten hours or so they would be crossing into the so-called Mine Belt, a band of worlds with quite different climates, arid, austere . . . Even on smaller scales the Long Earth was full of detail, of divergence. Here there was nothing, nothing but Mars and more Mars, with only the most minor tinkering with detail at the margins. And not a sign of life anywhere: dead world after dead world.
She did, however, notice an odd sensation at times, a sense of
twisting
, of being drawn away . . . She knew that feeling from her jaunts on the Long Earth: it was a sense that a soft place was near by, a short cut across the great span of this chain of worlds. She supposed that to someone like Frank that would seem unimaginably exotic. To Sally, these subtle detections gave a glow of familiarity.
The gliders flew on, banking like great birds in the empty skies. They had set off not long after dawn. As the Martian afternoon wore on, Sally decided to try to sleep, asking Frank to wake her when they got to Barsoom.
A
S IT HAPPENED
, Sally slept only a couple of hours before she was woken, not by Frank, but by another sudden lurch of the glider. She sat up with a start, reaching for her faceplate.
The cabin seemed dark, and she wondered if they had fallen into another storm. Then she realized that it was merely that the sun was low, setting in the west, and the colour was draining from the sky – but that colour, in this particular world, was a kind of bruised-purple, not the usual dusty brown.
Frank and Willis were talking quietly over the comms. Frank said, ‘Flying into this world with its thicker air was like slamming into a wall. Worse than the dust storm. We didn’t anticipate that.’
‘Yeah, but the gliders are coping.’
‘Possibly we could rig some kind of cut-out, so we don’t step further. Or maybe go up to higher altitude, where the air will never get catastrophically thick . . .’
As they talked Sally surveyed her surroundings. They were banking over a plain of dust and broken rock, not far north of the mouth of the enduring Mangala feature. In nearly twelve hours of travelling they had crossed more than forty thousand worlds, Sally saw, glancing over Frank’s shoulders at the instruments. And now this, something new and different. The air here was thicker, and oxygenated, and contained water vapour. It wasn’t as generous an atmosphere as Gap Mars, but more so than any other they’d passed through since, it seemed.
And on the ground below there was movement.
At first Sally, peering down, saw what looked like ripples in the dust, but ripples that slid and evolved as she watched. The low sun cast long shadows which made this diorama easy to follow.
Then a kind of body emerged from the dust.
She saw a gaping mouth, then a tubular carcass, coated with chitinous plates that glistened in the low sunlight. It was almost like watching a whale surface from the sea. Then that great mouth opened wide, scooping in the sand. Now Sally saw more such shapes emerge from the ground, none of them as large as the first: young, perhaps, immature versions. They glided through the dust, propelled by flippers; Sally counted a dozen pairs of limbs on the big leader.
‘Life on Mars,’ she breathed. ‘Animal life.’
‘Yeah,’ Willis called. ‘Like whales in a sea of dust, filter-feeding. And there’s no Gap
here
. This may have some common root with the life of the local Earth. But it’s a very remote relation indeed.’
‘It’s hard to get a sense of scale.’
Frank said, ‘That big mother is the size of a nuclear submarine. And maybe it, she,
is
a mother . . . What a vision!’
Willis grunted. ‘It’s logic. An ecology shaped by its environment. Here, the dust must be fine enough to act as a fluid, to support something like a marine biota—’
‘Oh, keep the lectures.
Look
down there! It’s like a homage to old science fiction dreams. There was a book I grew up with, published twenty years before I was even born – I learned more about ecology from that novel than I ever did in class – and if you could ever argue that science fiction has no predictive value—’
Sally said gently, ‘Turn it down, fan boy.’
‘Sorry.’
Willis said now, ‘Shall we go back to something resembling rationality? Why are we seeing these – whales – in this particular world? Because it’s warmer and wetter here – not by much, but some. The local air contains a lot of volcanic products. Sulphur dioxide—’
Frank asked, ‘Volcano summer?’
‘I guess so.’
‘Just as you predicted, then, Willis.’
‘We need to confirm it. I’d like to deploy a probe here. A slow drone will do; we have some designed to be carried by balloons. If it was a supervolcano, a Yellowstone, the most likely location is Arabia, a very ancient terrain on the far side of the planet. Maybe that’s where we’ll find the caldera.’
Sally frowned. ‘I’m not following you. What have volcanoes got to do with anything?’
Her father said, ‘I think this world is a Joker. Look, Sally, life – extant, complex, active life anyhow – is going to be rare in the Long Mars. In the Long Earth, the worlds are mostly living, but the Jokers, the exceptions that have suffered from some calamity, are often free of life. Right? Here it’s the other way around. The Long Mars is mostly dead. It’s
only
the Jokers, rare islands of warmth, that can host life . . . When it was young, Mars was warm and wet, with a thick blanket of air, and deep oceans. Like Earth, in many ways. And life got started.’
‘But Mars froze out. Alexei told me about this.’
‘But life persists, Sally, life huddles underground, clinging on as spores, or as bacteria munching hydrogen or sulphides or dissolved organics in long-buried salty aquifers – even as encysted hibernators. Resistant to heat and cold, to radiation, to aridity, to a lack of oxygen, to extreme ultraviolet . . .
‘And sometimes life has the chance to do more. Imagine for instance an icy asteroid captured in Martian orbit, gradually breaking up, raining its mass on to the planet, seeding it with water and other volatiles . . .’
He sketched other ways for a Mars to come alive, if briefly. A massive asteroid or comet impact could leave behind a crater so hot that it might stay warm enough for centuries, even millennia, warm enough to host a liquid-water crater lake. Or there might be ‘axial excursions’, as Willis put it, times when the planet’s rotation axis tipped or bobbed, bringing sunlight to the polar regions, and shaking up the world with earthquakes and volcanism. Again, there was more of that on Mars than on the Earth, because Mars had no massive, spin-stabilizing moon. Indeed, it seemed from their observations so far that most Marses had no moons at all; the twin moons of the Mars of Datum Earth, Phobos and Deimos, evidently captured asteroids, were unusual – the Datum Earth Mars, it turned out, was itself a Joker.
‘And on
this
world,’ he said, ‘this Joker, we’re coming to the end of a volcano summer. Mars is still warm inside. Every so often the big Tharsis volcanoes blow their tops. On Earth, volcanoes are disasters. Here they belch out a whole replacement atmosphere, of carbon dioxide and methane and other products, and a blanket of dust and ash that warms the world up enough for the water to come gushing back out of the permafrost.
‘On this Mars a recent eruption has warmed the air, for a hundred or a thousand or ten thousand years. Seeds, dormant perhaps for megayears, sprout hungrily, and the Martian equivalent of blue-green algae get to work enriching the volcanic soup with oxygen. Those little bugs have evolved to survive, and to be
efficient
when they get their chance. It must be an incredible sight, Mars turning green in just a few thousand years, like a natural terraforming. And life forms like the whales down there have their moment in the sun. But then, sooner or later, quickly or slowly, the heat leaks away, and the air starts to thin. The end, when it comes, is probably rapid.’
Sally nodded. ‘And then it’s back to the dustbowl.’
‘Yes. The Datum scientists believed they had mapped five such episodes, five summers lost in deep time, on
our
copy of Mars. The first was about a billion years after the planet formed, the last one a hundred million years back . . .’
‘And similarly,’ she said, ‘if we travel across the Long Mars, we’re going to find rare islands of life – as rare in stepwise space as those episodes on a single Mars are rare in time.’
‘Something like that. That’s my theory, anyhow. And it seems to be borne out so far.’
‘Look at that,’ murmured Frank, looking down. ‘One of those babies got separated from the pack.’
Sally looked down to see. The infant whale, if it was an infant, had indeed become detached from the pack that surrounded the big mother.
And a new type of creature emerged, as if out of nowhere, to attack the lost little one. Sally glimpsed huge forms, with flexible armour plates but much more compact than the whales, like big hungry crustaceans with eyeballs on stalks. They all scooted across the surface of the dust, or just under it.
When they caught the infant whale, they fell on it. The whale thrashed and struggled, throwing up great sprays of dirt.
Willis called, ‘Are we recording this, Frank?’
‘You got it,’ Frank said. ‘Each of those crustacean predators is the size of a truck. And notice how they move: low down on the surface, or even under it. I bet that’s a low-gravity adaptation; they’re clinging to the ground for traction, for speed. You want we should go down, take some samples? My vote is no, by the way; it looks kind of hazardous down there and our gliders are somewhat fragile.’
‘We go on,’ Willis said. ‘After all, it’s not life I’m after but sapience, and I don’t see much sign of that down below. Another hour? Then we’ll pick some safely dead world to camp for the night. On my zero: three, two—’
Sally caught one last glimpse of the scene on the torn-up ground below. What looked like blood seeped from a dozen wounds in the baby whale’s hide, as the crustaceans ripped and tore: blood that was purple in the low light.
And then the scene was whisked away, to be replaced by lifelessness, a plain of scattered rocks that might not have moved for a million years, casting long meaningless shadows as the sun set on another eventless day, on another dormant Mars.
P
ROFESSOR
W
OTAN
U
LM
, now of the University of Oxford East 5, author of the bestselling if controversial book
An Untuned Golden String: The Higher-Dimensional Topology of the Long Earth
, appeared on a news channel run by the Britain West 7 Broadcasting Corporation, responding to questions on the nature of ‘soft places’, as those mysterious short cuts, widely rumoured to be more than mere stepper legends, were increasingly becoming known.
‘I do see that going through a soft place would be like wearing seven-league boots, Wotan – may I call you Wotan?’
‘No, you may not.’
‘But it would help if I understood
how
you can make these seven-league-boot jumps.’
‘Actually a better metaphor for a soft place is a wormhole. A fixed passageway between two points. As in the movie
Contact
. You remember that?’
‘Is that the porno where—’
‘No.
Stargate
, then. What about that? Oh, for some modern cultural references. Never mind! There is in fact some relevant theory. Young man, have you ever heard of a Mellanier Sequence diagram?’
‘No.’
‘It’ll never be properly drawn until they invent n-dimensional printing, but basically it portrays the Long Earth as a tangled ball of string. Or, if you can stomach it, as a vast intestine. Datum Earth is a dot somewhere in the region of the appendix. Mathematically this tangle may – and I emphasize the “may” – be represented by a solenoid, a particular mathematical structure like a self-crossing string, a mixture of linear order and chaos . . . You look as blank as a chimp faced with a banana fitted with a zip. Well, never mind.
‘The point is that simple Stepper technology allows us to move “up” or “down” the gut, you see, along the string of worlds. But Mellanier, even before the existence of the soft places started to become widely known, argued on theoretical grounds that it might be possible to break through into an adjoining strand. Rather than walk all the way around the string, you see. An effective short cut.’