The Long Earth

now. I am officially scared.’
    Lobsang sounded excited. ‘Now can you see why I am so eager to bring on this encounter? We are pursuing a mystery, Joshua, Sally! A mystery from the ends of the Long Earth!’
    Joshua ignored him and kept his attention on Sally. ‘We’re both scared. But we’re going to face this, right? You won’t run away. Animals flee. The trolls have to flee.
We
keep on going, trying to find out what scares us, and deal with it. That’s what humans do.’
    ‘Yeah. Until it kills us.’
    ‘There is that.’ He stood up. ‘Shall I get some coffee?’
    Later, Joshua realized he should have been paying attention, especially in the final few minutes. The last couple of hundred worlds, worlds where the calm green below was broken up by craters punched like great footprints into the ground. Should have stayed alert, despite the gathering pressure in his head. Should have raised the alarm.
    Should have halted the journey, long before the airship fell into the Gap.

45
    SUDDENLY JOSHUA WAS falling. He was rising up into the air, off the floor. The observation deck was still around him, its frame, the big windows, but the glistening display panels on the walls were fritzing out one by one. Through the windows he could see the bulk of the airship, its envelope damaged, torn silvery cloth fragments spilling away from the skeletal frame.
    Beyond that was only the sun, dazzling bright, against blackness. The sun was just where it had been before, but it was all that was left of the outside world now, as if the rest, the blue sky, the green world, was a stage set that had been ripped away to reveal darkness. But now even the sun was drifting slowly to the right. Maybe the gondola was rolling.
    Lobsang was silent, his ambulant unit fixed to the deck but still as a statue, apparently not functioning. The cat was in mid-air, paddling with her limbs, an expression of apparent fear on her small synthetic face. And there was a hand on Joshua’s shoulder: Sally, floating in the air, her hair, loose, rising around her head like a space station astronaut’s.
    The deck creaked. Joshua thought he heard a hiss of escaping air. He couldn’t seem to think. His chest ached when he tried to take a breath.
    Then the gravity came back, and blue sky unfolded.
    They all hit the floor, which was, for the moment, the wall. A kettle full of water spun its way across the deck, much to the apparent terror of Shi-mi the cat, who scrambled to her feet and fled into a compartment. All above and below and around them was a symphony of high technology parting company with itself.
    Joshua said, ‘We found the Joker of Jokers, didn’t we?’ And then his stomach convulsed and he threw up. He straightened, embarrassed. ‘I’ve
never
got nauseous after stepping before.’
    ‘I don’t think it was the stepping.’ Sally rubbed her own stomach. ‘It was the weightlessness. And then the sudden return of gravity. It was like falling.’
    ‘Yeah. It really happened, didn’t it?’
    ‘I think so,’ Sally said. ‘We found a gap. A Gap in the Long Earth.’
    The gondola slowly righted, but now the deck’s lights went out, leaving only the daylight. Joshua could hear the sound of spinning metal things gradually ceasing to spin, worryingly.
    Lobsang suddenly came to life: his head, his face, though his body remained inanimate. ‘
Chak pa!
’
    Sally looked at Joshua. ‘What did he say?’
    ‘Tibetan swearing, I think. Or possibly Klingon.’
    Lobsang sounded oddly cheerful. ‘Oh boy, is my face red! So to speak. Well, to err is human. Is anyone hurt?’
    Sally said, ‘What have you run us into, Lobsang?’
    ‘We have run into
nothing
, Sally, pure nothing. Vacuum. I stepped back in a hurry, but it seems the
Mark Twain
has taken a beating. Some systems are inoperative. Fortunately the gas sacs are intact, but some of my personal systems are compromised. I am checking, but it doesn’t look good.’
    Sally was furious. ‘How did you manage to hit a vacuum
on Earth
?’
    Lobsang sighed. ‘Sally, we stepped into a place where there is no Earth. A total vacuum, interplanetary space. At some point in time there
was
an Earth there, I suspect, but presumably some catastrophe destroyed it. An impact, probably. A big one, one that would make the dinosaur-killer look like pea-shooter fire bouncing off an elephant. One that would dwarf even the Big Whack, the moon impact.’
    ‘Are you saying you anticipated this?’
    ‘As a