The Long Mars

‘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.’

‘Mellanier. I do remember him. Face all over the media a few years after Step Day. Princeton, isn’t he?’

‘That’s him. He got a lot right, but only dipped his toe in the theoretical waters.’

‘You don’t seem to like him very much, Wotan. Why should some rival academic from Princeton get your goat?’

‘Because Claude Mellanier is a fraud who fed off the analyses of Willis Linsay, and mine, repackaged them, dumbed them down, and passed them off as his own.’

‘The man won a Nobel Prize, didn’t he, Wotan?’

‘That’s because the Nobel committee are idiots nearly as blithering as you.’

‘Also he published a bestselling book—’

‘And don’t call me Wotan. Oh, must you plant me before these pithecine buffoons, Jocasta?’

22

BY THE END OF February, the Armstrong and Cernan had passed Earth West 30,000,000. There was no particular celebration – and nor had there been a few days back, when the ships had passed 20,000,000, and so beaten the five-year-old Chinese record. Not in the public spaces anyhow, at Maggie’s quiet order.

With the sheaf of worlds dominated by crabs and other crustaceans far behind, now they passed through a band of worlds where – as the biologists discovered on scooping up samples of pond scum – not only was there no multicellular life, no animals, no vegetation, there was often no evidence of complex cellular life: that is, no cells with internal nuclei, like those of Maggie Kauffman’s own body. Only the most simple of bacteria dwelled here, in mats and banks.

The crew called these ‘purple scum worlds’.

Still, in such worlds there could be complexity, of a different sort. They found structures like stromatolites, mounds of bacteria built up layer by layer in the sunlight, mindlessly cooperating in what might on Datum Earth have been called primitive ecosystems. But after billions of years of a different evolution, there was nothing primitive about these structures. Especially not the ones that crept up on an unwary crewman, taking samples with her back turned . . .

Two days’ flight later, at around Earth West 35,000,000, after millions of scum worlds all more or less identical, they encountered another band of worlds with their own peculiarity. Here oxygen levels in the air were very low, carbon dioxide high. The airships stopped at random on one such world – Earth West 35,693,562. Biologists in oxygen masks cautiously explored the shore of an arid continent. Even by the standards of the ‘purple scum’ worlds, this was an Earth poor in life.

It took some detective work on a larger scale to figure out the cause. Under Gerry Hemingway’s prompting, Maggie authorized the launch of balloons, sounding-rockets, and one of their small stock of precious nanosat launchers, and a global map was assembled. Here, North America had united with most of the world’s other continents, rafts of granite floating on mantle currents, to form a single supercontinent – like the Datum’s Pangaea, Maggie was told, which had broken up a quarter of a billion years back. One huge continent, and nothing else but ocean.

And supercontinent worlds, it turned out – just as the Chinese had found, Maggie discovered, consulting with Wu Yue-Sai – weren’t particular hospitable to life. The continent’s vast interior was worn down and arid; it was like one gigantic Australia, with only the coastal regions showing any kind of fecundity. The expedition pushed on, across one supercontinent world after another – the ‘Pangaean Belt’, the geographers called it. They saw no sign of life more complex than stromatolites at the coastal fringes, and if some kind of exotic critter roamed the tremendous plains of some footprints of these world continents, well, Maggie was content to leave the discovery to future travellers.

The Pangaean Belt turned out to be about fifteen million worlds thick. Fifteen million: sometimes Maggie struggled to grasp the significance of such numbers. The width of the Pangaeas alone was ten times the stepwise distance between the Datum and Valhalla, for instance, a reasonable measure of the width of the Long Earth as colonized by human beings in the generation since Step Day. Yet, travelling at the airships’ nominal cruise speed, they crossed it in a week.

After the Pangaeas, fifty million worlds from home, they entered yet another purple scum belt, where at least the scattered continents provided varied scenery. The atmospheric and climate conditions were often close enough to the Datum that Maggie could authorize shore leave without significant protective clothing, and her crews of very healthy, mostly very young people could escape from the roomy but confined interiors of the gondolas. But there was nothing to do down there, nothing to see – pond scum didn’t count – and people kind of clowned around aimlessly. There was only so much fun you could get out of lobbing rocks at stromatolites.

Snowy, the beagle, was different, however. Maggie watched him stride alone across the most featureless of landscapes, his extra ordinary animal-human body held erect in the Navy uniform Maggie had had specially tailored for him, his wolf eyes glittering, his head tipped back so his nostrils could drink in the local scents. He seemed to find something of interest in every world they called at. And he kept his own log, a vocal record rigged up for him by Harry Ryan since his people mostly lacked conventional literacy. Maggie promised herself to get that log transcribed and studied. She had the feeling it would describe a voyage perceived quite differently from the human crew’s experience. Which, of course, was why Snowy was here.

She tried to talk to Mac about Snowy, and whatever problem the two of them had. All she got was stony silence, a Mac speciality when he was in the mood.

When Snowy was off the ship Shi-mi would come out of Maggie’s rooms and run around the gondola of the Armstrong, presumably letting off steam in her own way, and submitting to being spoiled a little by the crew. Save for Mac, of course.

They pushed on, thousands upon thousands of steps. Even Jokers seemed sparse out here. Maggie fretted that the journey was turning into a kind of experiment into mass sensory deprivation. An unexpected hazard for a pioneer, she thought.

At first they kept the nominal cruise speed at a little over two million steps a day, achieved by stepping at fifty steps per second for around twelve hours’ run-time per day. Maggie was mindful that she was ru