The Long Mars

‘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 mille

‘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.

21

PROFESSOR WOTAN ULM, 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 cha

‘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—’