The Long Earth

have survived the crucifixion and stepped out of the tomb by the time His disciples came looking for His body – and, it wasn’t much of a leap to conclude, He was probably still out there in the Long Earth somewhere. All this presented public order challenges for the police.
    Clichy pushed away the laptop and massaged the top of his fleshy nose. ‘Who am I, Stephen Hawking? My brain is boiling. Whereas you, on the other hand, Officer Jansson, have taken to all this like a pig to shit.’
    ‘I wouldn’t say that, sir—’
    ‘Just tell it to me the way you understand it. The most basic problem – I mean for Madison’s finest – is that we can’t carry through our pieces intact. Right?’
    ‘Not even a Glock, no, because of the steel parts. No metallic iron can be carried over, sir. Or steel. You can take through whatever you can carry, save for that. I mean, there’s iron ore in the other worlds, and you can dig it up and process it and manufacture iron over
there
, but you can’t carry that stepwise either.’
    ‘So you need to build a forge on every world you settle.’
    ‘Yes, sir.’
    ‘I’ll tell you what puzzles even a doofus like me, Jansson. I thought we all got iron in our blood, or something. How come that doesn’t get left behind?’
    ‘In your blood, the iron’s chemically bound up in organic molecules . Inside your haemoglobin, one molecule at a time. Iron molecules can go over if they are in chemical compounds like that, just not in the form of metal. Why, rust can be carried over, because that’s a compound of iron with water and oxygen. You can’t take your piece over, sir, except for all the rust on the shaft.’
    He eyed her. ‘That isn’t some kind of lewd remark, is it, Jansson?’
    ‘Wouldn’t dream of it, sir.’
    ‘Anybody know why things are this way?’
    ‘No, sir.’ She had been following the discussions, as best she could. Some physicists had pointed out that iron nuclei were the most stable in nature; iron was the end result of the complicated fusion processes that went on at the heart of the sun. Maybe its reluctance to travel between the worlds was something to do with that. Maybe stepping between the worlds was something like quantum tunnelling, a low-probability passage between energy states. As iron had the most stable atomic nucleus, maybe it lacked the energy to escape from its energy well on Datum Earth … Or maybe it was magnetism. Or something. Nobody
knew
.
    Clichy, a practical man, just nodded. ‘At least we know the rules. Kind of a gut-wrench for most Americans to have gun control suddenly imposed on ’em, however. What else? There are no people in these other worlds, right? I mean, except for the ones who leaked over from ours.’
    ‘That’s right, sir. Well, as far as anybody knows. There has been no systematic exploration even of the nearby worlds, not yet. You can’t know what’s hiding over the next ridge. But they have sent up a few spy balloons and such, aerial cameras. No sign of people, anywhere we can see.’
    ‘OK. So there’s a whole chain of these worlds, right? In two directions, East and West.’
    ‘Yes, sir. You just step from one into another, like passing down a corridor. You can go one way or another, East or West – though those are just arbitrary labels. They don’t correspond to real directions, in our world.’
    ‘No short cuts? I can’t just beam over to world two million?’
    ‘Not that anybody knows, sir.’
    ‘How many of these worlds? One, two, many? A million, a billion?’
    ‘Nobody knows that either, sir. We don’t even know how far out people have walked. It’s all –’ She waved a hand. ‘– loose around the edges. Uncontrolled.’
    ‘And every one of these worlds is a whole separate Earth, right?’
    ‘As far as we know.’
    ‘But the sun. Mars and Venus. The fucking moon. Are they the same as ours? I mean—’
    ‘Every Earth comes with its own universe, sir. And the stars are the same. The date is the same, in all the worlds. Even the time of day. The astronomers have established that with star charts; they could tell if there were a slippage of a century, or whatever.’
    ‘Star charts. Centuries. Jeez. You know, this afternoon I have to attend a conference chaired by the Governor about jurisdiction. If you commit a crime in Madison West fucking 14, do I even have the authority to arrest you?’
    Jansson nodded. Not long after Step Day had come to pass, while some people had just