Authors: Terry Pratchett
Dev found himself slipping into tour-guide mode. âThis is all very routine,' he said. âWe make hops over in shuttles like this every dayâ'
âWe can do without such trivial observations,' said Roberta mildly. âWe are not â tourists.'
âThe safety record they've achieved is a non-trivial matter,' Stella said to her. âAlthough it has got better yet since
we
showed up and ran a few reviews.'
Roberta considered Dev. âAnd the cultural development here is non-trivial, of course.
Dev Bilaniuk
â I'm guessing your names have different origins? They sound Indian and Slavicâ'
âMother from Delhi, father from Minsk. Both drawn here to the Gap. I'm a second-generation Gapper.'
âYou could surely have moved away, had you chosen to. Evidently you inherited their dream of space.'
Lee leaned forward against her straps. âThat's not so unusual. Especially when you see what else is on offer in the Long Earth. Slaving in factories at the feet of space elevators in the Low Earths, or else wandering around in hand-me-down clothes, picking fruit and chasing after funny-looking deer. I'm a second-generation Gapper too. At least here we're pursuing an authentic human aspiration, one that predates stepping itself. And one you people stay out of, unless you need something.'
Dev said, âLeeâ'
Stella held up a hand. âIt's OK.'
And, under the control of the shuttle's AI, they stepped.
One step further West, they fell into a hole where an Earth should be. Beyond the windows, where there had been washed-out English sunlight, there was only darkness. And as always, without gravity it felt to Dev like they were suddenly falling.
Then the shuttle swivelled sharply and fired its thrusters, producing a fierce deceleration.
Every object on the surface of the Earth, at GapSpace's latitude, was moving through space at hundreds of miles per hour, and in the Gap that velocity had to be shed. And that was what the rocket fire was for.
Dev was glad the transition had put a stop to the conversation. And spitefully glad too to observe discomfort on the faces of the two Next â even Stella, who had made this journey a number of times before. Superhuman intellects they might be, but right now he suspected they were discovering that their inner ears and stomachs were just as human and just as maladapted to shifting gravity as his own.
The hard rocket thrust lasted only seconds, and died quickly. They were briefly weightless again. Then the shuttle turned once more, with pops of attitude thrusters that sounded as if somebody was beating the outer hull with a stick, and with a blip of the main engine began to edge towards its docking station.
Now, through the small window before him, Dev glimpsed structures in space.
Directly ahead of the shuttle was a mass of clustered concrete spheres, huge, marked with sunlight-faded black letters, A to K, with an oddly organic look â like a clump of frogspawn, perhaps. This was the Brick Moon, GapSpace's first reception station here in the Gap, tracking the orbits of the Earths to either stepwise side. Further out, brilliant in the unfiltered sunlight, Dev could see the
O'Neill
, a new and much larger facility, like a glass bottle filled with glowing green light and surrounded by big, fragile constructions, paddles and bowls and net-like antennas. The whole affair rotated languidly on the bottle's long axis. It was only the smaller craft swarming around the docking ports at the structure's circular ends that gave a sense of its scale: that âbottle' was twenty miles long, four miles wide.
And behind all this, dwarfing even the
O'Neill
, hovered a lump of ice and rock. From here Dev could see work going on across its surface: the gleam of mass drivers, the spark of craft landing and taking off. Called only the Lump, this was an immense asteroid that had been nudged, over decades, into a position close to the Brick Moon, and steadily mined for its resources to build such structures as the
O'Neill
and the Cyclops telescope.
âSo that's the Brick Moon,' Roberta murmured. âConcrete mixed by trolls. Ha! What a start to humanity's conquest of space.'
Lee just glared.
Dev began to unbuckle. âWe need not stay long here; this is just a transit point. We've a ferry waiting to transfer us to the
Gerard K. O'Neill
. It's a much more comfortable environment. With gravity, for one thing, provided by the spin. We'd be pleased to show you the projects we're developing out hereâ'
âIrrelevant,' Roberta said simply. âDoes this Brick Moon, this concrete box, have viewing facilities sufficient to view the progress on Cyclops? Also computational support, some kind of AI?'
âOf course.'
âI have no desire to extend this visit beyond what is necessary. After all, we have to regard the situation as urgent; we have no idea how long we have before the Invitation ceases to transmit, and we must ensure we extract all the information it contains. The Clarke proposal is the one and only reason I am here.' She laughed softly. âNot to sightsee your new toys.'
Lee was fuming, and Dev tried to suppress his own irritation. He said, âWell, let's hope you people are just as happy with
your
new toy, when
we've
built it for you.'
Roberta and Stella exchanged a raised-eyebrow glance. The man-ape was being defiant.
No more was said until the shuttle closed in on the Brick Moon, and docking latches rattled shut.
T
HERE WAS NO
gravity in the Brick Moon. You moved by pulling yourself along ropes slung around the walls, and poles that criss-crossed the spherical chambers.
The big spheres were connected by circular orifices, and as they moved deeper into the interior it was as if they were swimming into the centre of some vast honeycomb â or maybe, as one visitor from the Datum Earth had remarked, it was like a huge old Roman-era drainage system, all concrete vaults and cylindrical passages. And after decades of occupation the Brick Moon smelled that way too, despite periodic flushings of the entire volatile content, the water and all the air: a sour stink of people, of stale food and sweat and blood and piss, seemed to seep out of the very walls.
It wasn't a quiet place; there was an endless clatter of pumps and fans. And the walls, where they weren't hidden by cabling and ducts and pipes, were crusted with decades' worth of junk, from antiquated tablets and comms stations, to the relics of abandoned science experiments, to tokens left by those who had lived and worked here: faded photographs, children's paintings, scribbled notes, graffiti on the concrete. Even the residential area, at the centre of the cluster, with bunk beds and galleys and a medical centre and grimy zero-gravity toilets, couldn't have looked less inviting.
Most long-lived space stations got shabby; they weren't places where you could ever open the windows for a good spring-clean. And after all, this rough, decades-old construction had been humanity's first colony in this Earth-less universe; embarrassment wasn't an appropriate reaction. But Dev couldn't help it.
And he kept an eye on his guests. They had little trouble moving around, though their postures were a bit stiff, and Roberta in particular seemed to be recoiling from touching the grimy walls. Here and there boxes and pots held plants and flowers that grew in splashes of sunlight from the windows. The visitors' eyes were drawn to the green â another primitive reaction, and one Dev found grimly satisfying to observe.
They crossed paths with only a couple of people, both in GapSpace coveralls like Dev and his guests, who stared curiously back at the Next. The Brick Moon was never very crowded. There was a small station staff, rotated frequently, whose main job was to maintain the antique fabric and clean up the air and water. Otherwise there were only ever a few passengers in transit from one shuttle to another.
At last they reached the sphere known informally as the observatory. Here much of the original troll-concrete shell had been replaced by a ribbing of steel and aluminium, and plates of toughened glass. There were bars for hands and feet to help visitors keep from drifting around the bubble. It was dark, the artificial light subdued.
Beyond the windows no sun was visible, and the sky was pitch-black. The four of them spread out in the darkness.
To Dev, whose father had been an Orthodox Catholic, this place always felt oddly like a chapel, and he spoke softly. âIt's best to wait a while to allow our eyes to adjust to the dark. The Brick Moon has some limited manoeuvrability, to maintain its station and its orientation. And it's turned, very slowly, to ensure no one section is over-exposed to the sun. But this chamber is kept facing away from the light permanentlyâ'
âI see a planet,' Roberta said. She pointed at a light, emerging from the dark. She thought for a moment, and Dev imagined calculations processing through her high intelligence: an exercise in celestial mechanics, a determination of what she was seeing. âMars,' she announced.
âYes,' Dev said. â
A
Mars, at any rate, the Mars of this stepwise universe. But its position is subtly different from that of our own Mars because ofâ'
âThe lack of an Earth here. Of course.'
Again she'd cut him off. He suppressed his irritation. These Next did seem to require an awful lot of forgiveness of the dim-bulbs they dealt with.
He caught Lee grinning at him, her teeth bright in the subdued light.
Roberta ran her finger around the equator of the sky. âAnd there are asteroids.'
Dev could just see them now, emerging as a band of sparkles against a wider scatter of stars.
Stella nodded. âIt is the wreckage of the local Earth, of course. Dead Earth, as they call it. Much of the mass of the planet seems to have been lost in the impact â thrown out of the solar system altogether, probably â but what remains is a new asteroid belt, rich in silicate rock, iron.'
Dev said, âThis local belt has been essential in building up our facilities here. The big
O'Neill
, for example, was constructed of iron and aluminium and stocked with volatiles, all gathered from Dead Earth asteroids. The fact that these rocks are so close to us, compared to the classic asteroid belt, has made life a lot easier.'
Roberta looked out with some interest. â“Dead Earth.” I understand there are some groups who oppose your exploiting this resource. It's likened to grave-robbing.'
Lee said, âBut some say it's as if we're honouring the planet, by making use of its wreckage.' She faced Roberta defiantly. âI suppose
you
think either position is illogical.'
âNot at all. One would have to have a very stunted emotional imagination not to have some response to this, the ruin of a world, of, presumably, a planetary biosphere every bit as mature and rich as that of Datum Earth itself. But what you're doing here is neither right nor wrong. It simply is.' She glanced around the sky. âWhere is Cyclops?'
Stella swam over next to her and pointed. âUp there, at four o'clock.'
Looking that way, Dev could see only a disc of blackness, occluding the stars. He said, âActually what you see is just the baffle, shielding the radio telescope from leakage from the habitats, the shuttles.' He tapped a console, and a big display tablet brought up an image of a vast, lacy dish: the antenna of the spaceborne radio telescope itself.
Roberta glanced up at the baffle, itself an immense structure. âA shame I can't see it with the naked eye, but I sense the scale.'
Stella said, âYou know, astronomy, and particularly radio astronomy, was one of the first great science programmes for the Next, once we had organized our society sufficiently. An area where huge advances in knowledge were available based on a simple expansion of technological scale. We began with a trio of super-Arecibos. On the Datum this was a major radio telescope with its dish built into a volcanic caldera in Puerto Rico. We constructed much larger dishes in calderas on one particular Earth, near Olduvai Gorge, at Pinatubo, one at Yellowstone in North America â a long-dead copy of the parent volcano on the Datum. If you visualize these positions, spread around the globe of the world, you will see we had coverage of the equatorial sky for twenty-four hours of the day.
âBut these efforts will be surpassed as we move into space. Our first design was Cyclops, out there. A single parabolic dish antenna five kilometres wide. We named it after a pre-Step Day proposal, from a century ago, to build such a telescope from a conglomeration of a thousand smaller antennas, constructed on the ground. It might be unfinished, but it's good enough to have acquired the clearest version yet of the Invitation.' She fished her own tablet out of her bag, and tapped it to bring up data on the signal. âIn some ways it's a classic SETI discovery. An extremely strong signal. Polarized, as if it has been broadcast by a radio telescope of the kind we can build ourselves. The frequency is around the minimum of the background noise of the Galaxy. We're aware of a lot of detail below the signal's top-level structure, but much of it is lost in the noise. And what we have is complex. Not decipherable, so far anyhow.'
âWhich is,' Roberta said calmly, âwhy we're all here.'
Dev said, âWe still don't know where it's coming from. The source is stationary against the background of the stars. The source appears to be in Sagittariusâ'
âIt's logical that it should be.' Roberta glanced over her shoulder, and Dev just
knew
she was looking straight towards the position of the Sagittarius constellation in the sky. âThe overwhelmingly most likely location of high intelligence is towards the centre of the Galaxy. The spiral arms, where we live, are waves of star birth washing around the galactic disc. But at the core, where the stars are crowded close, where the energy fluxes are enormous â a dangerous place, but where the first worlds rich in rock and metal formed billions of years before Earth â
that
is where the peak of galactic civilization must reside. And all of that lies in the direction of Sagittarius.'