Free Ultima by Stephen Baxter

Teutoberg forest a generation earlier. Not so here. Stef supposed that even if they could figure out how history had diverged to deliver this strange new outcome, there was a deeper question of
why
. Why this history—why the change now? And how had she and her companions survived the transformation of human destiny?
    Eilidh, evidently sharply intelligent, was watching her. “Much of this is unfamiliar to you, isn’t it? Someday we must explore our differences fully. Yet, whoever you are, wherever you come from, I see your soul. Watching you at the Hatch, I saw the wonder in your eyes.”
    Stef shrugged. “Guilty as charged. In my—home—I was a philosopher, as the Romans would say. I studied the kernels, and later Hatches, because I wanted to understand how it all worked.” That had been her goal since she was eleven years old and she’d stood with her father on Mercury, and watched a kernel-driven manned spacecraft drive like a spear of light into the heavens. “Where do the kernels get their energy from? How do the Hatches work? What are they for?
Why are they here?
How was it I and my companions came walking out of that thing ourselves? And, frankly, I’m fascinated by what you’ve done here. On this world you’ve gone beyond anything my people ever achieved.
You’ve built a Hatch . . .
”
    Eilidh grinned. “We have, haven’t we?”
    â€¢Â Â Â â€¢Â Â Â â€¢
    Eilidh had the
cetus
pause over the Hatch construction site: the dull sheen of the Hatch installation itself at the center, the land shattered and melted for a wide area around that central point, and a loose cordon of bored-looking legionaries playing knucklebones with fragments of broken rock.
    Eilidh and Stef sipped Xin tea. There was no coffee to be had, one miracle of globalization that evidently hadn’t translated to this timeline. Yuri had joked about going into business cultivating the stuff once they got back to Earth. But Yuri’s health was worsening; he’d been in a continual decline since they’d emerged from the Hatch . . .
    Stef tried to concentrate on what Eilidh was telling her.
    â€œTo create a Hatch is like mating wild boar: a simple act to understand but dangerous in practice, especially if you get in the way . . . You take kernels. You arrange them in a spherical array, with all their mouths directed inward, to a single point in space. And at that center you place one more kernel, its mouth tightly closed. You understand that kernels can be handled with etheric fields?”
    By which, Stef had learned, she meant electromagnetic fields. “Of course. We too first found kernels on Mercury. You can position them, even close or open their mouths to control their energy output.”
    Eilidh frowned. “Some of your terms are unfamiliar, but clearly we agree on the essence. Well then, with sufficient kernels, held with sufficient precision, there is an inward blast of energy. You can only watch this from a distance, and many lives were spent in determining that distance precisely.
    â€œThe configuration holds for only a splinter of time before the arrangement is blown apart. The land, the air all around is shattered, melted, by an outpouring of heat and shock waves—well, you see the result here. But if you get it right, when the glowing gases and the rain of liquid rock and the shocked air have all passed, and you can go back in to see—when all that is done, what is left is a brand new Hatch in its neat installation, just as you see here.”
    Stef frowned. “I’m not sure I understand. You don’t have to construct the Hatch?”
    â€œNo more than we have to ‘construct’ a chicken emerging from the egg. Our
druidh
speculate that there is a Hatch implicit in the form of every kernel. It is merely a question of breaking the egg to release the chick, to use the kernels’ own