Free The Nightmare Stacks: A Laundry Files novel by Charles Stross

We know of other once-inhabited planets, too. No, we don’t have a magic space telescope, or any other
Star Trek
shit up our sleeves, but we’ve got the capability to open portals to places compatible with our type of underlying causal logic, where the same laws of mathematics – and physics – hold true. Such gates tend to go preferentially to places that once held intelligent ritual-magic-using life: I say
once
because when we find them they’re mostly extinct, and when they’re not extinct… let’s just say we have a
really strong rule
against opening portals at random. How to do so, and how to do a risk assessment first so that it doesn’t kill you, was in the next stage of your personal development plan until late last night, by the way.”
    “Whu—” Alex bites his tongue. They’ve gone from
Ghostbusters
to
Stargate SG-1
in five minutes. He has an uneasy feeling that if this keeps up he’d better speed-read his way through the entire TVTropes wiki. “Really?”
    “Yes! Did you ever wonder why successive British governments spent decades killing off anything that looked as if it might develop into a space program? They gave up about a decade ago – but only because the horse was already over the horizon and the stables had burned down behind it. Today we’ve got a shiny new national space agency, but for about four decades Mahogany Row had an unofficial policy of trying to ensure that we didn’t accidentally blunder into a real-life version of
Quatermass
just because some glory-hound prime minister wanted a photo-op with an astronaut.” Jez picks up her cup and takes a discreet sip. “Go on, Alex. What else do you know?”
    “Um.” He shakes his head. “I think you just blew a few fuses there. You mean we know about other worlds? Other
inhabited
worlds?”
    “Yes, several of them. And you will be pleased to know that most of them feature alien ruins. The ones we can still get to are all dead, except for the Pyramid of the Sleeper, and nobody’s going
there
in a hurry. That’s GOD GAME BLACK, by the way, you can look it up later but you might have trouble sleeping afterwards. The thing is —”
    She puts her teacup down, empty.
    “— Those ancient alien civilizations didn’t die of old age, Alex; they were murdered.”
     
DEAR DIARY:
    I suppose my punishment for being too nosy about CASE NIGHTMARE GREEN is entirely appropriate. They let me in on the secret, and I wish they hadn’t.
    Let’s see if I can put all the pieces together coherently, starting with the big picture:
    As we all know, the Earth is not the center of the cosmos. It orbits the Sun at roughly 47 kilometers per second; the Sun in turn is orbiting the center of our galaxy at approximately 220 kilometers per second; and we can infer, from studies of asymmetry in the cosmic microwave background, that the Milky Way galaxy itself is moving in the direction of the constellation Hydra at roughly 550 kilometers per second.
    But on a larger scale, the
entire cosmos
is far from stationary. Our four-dimensional universe is embedded on the surface of a higher-dimensional membrane, or brane, which is moving through a twelve-dimensional foam of other branes that play host to an infinity of pocket “universes.” Higher-order resonance effects between our brane and some adjacent ones allow information to leak between universes. We, the structures we collectively refer to as “life,” are patterns of information – temporary reversals of the arrow of entropy within our universe – and conscious minds are the most concentrated such patterns we know of. We’re making an increasing amount of information, generating magical noise and simultaneously weakening the structure of spacetime by
thinking too loudly
. And sometimes other patterns in neighboring universes can sense us, and some of them think we’re edible.
    Back in the 1940s, Enrico Fermi asked a question which has subsequently become more famous than the discovery which won him