supergiant, deflecting its evolution into realms of light and energy never before seen in the history of the universe. And that emerald colour, visible even to a naked archaic human eye, was the symbol of that achievement.
It was a hell of a thing, a Promethean triumph, monkey paws digging into the collapsing heart of a supergiant.
Nobody knew how far humans had got from Earth, or what technical and other advances they had achieved, out there on the rim. But if we don’t have to fear supernovas, he thought, we need fear nothing. We’ve come a long way since the last time I climbed into the belly of a VentureStar, down there at Canaveral, and breathed in my last lungful of sea air …
… an assignment, the Weissmans were saying to him.
Earth swam close, and was growing closer.
We want to right the ancient necrosis as far as we can. We want you to help us.
‘Me? Why me?’
It is appropriate. You are an ambassador from exponent zero. This is a way of closing the loop, in a sense. The causal loop. Do you accept?
‘I don’t know what you’re talking about. I accept. I don’t know what you mean …’
… The walls of the hab module dissolved around him. Suddenly he didn’t have hold of anything, and he was falling.
Oh, shit, he thought.
But there were shadows around him, struts and blocks. And a heavy, liquid mass at his lower body he hadn’t felt for a long time.
Legs. He had legs.
His breathing was loud in his ears. Oxygen hissed over his face.
He was back in his Shuttle-era pressure suit, and he was encased in his PMU once more, the original model, its spidery frame occluding the dusting of stars around him.
He grasped his right-hand controller. It worked. There was a soft tone in his helmet; he saw a faint sparkle of exhaust crystals, to his left.
Still, Earth swam before him.
It is time.
‘Wait – what –’
Earth was gone.
Ra-Shalom sailed through the space where the Earth had been, its meniscus shimmering with slow, complex waves as it rolled, the life at its heart a dim green knot against the blue.
My God, he thought. They pushed Earth aside. I didn’t know they got so powerful –
‘What did you do? Is it destroyed?’
No. Earth is in a stable orbit around Jupiter. The ice will return, for now. But later, when the sun starts to die, Earth will be preserved, as it would not have been –
‘Later?’
We must plan for exponent seven, eight, nine. Even beyond. The future is in our hands. It always has been.
‘But how –’
Goodbye, the Weissmans said, a tinny voice in the headphones in his Snoopy hat. Goodbye.
And now there was another hulking mass swimming into view, just visible at the edge of his faceplate.
He worked his attitude thrusters, and began a slow yaw. Strange, he didn’t seem to have forgotten any of the old skills he had practised in the sims at Houston, and in LEO, all those years ago.
He faced the new object.
It was an asteroid. It looked like Ra-Shalom – at any rate, how that rock had looked when he first approached it – but it was a lot bigger, a neat sphere. The sun’s light slanted across craters and ravines, littered with coal-dust regolith. And there was a structure there, he saw: tracings of wire and panelling, bust up and abandoned, and a big affair that stuck out from the rock, a spider-web of wires and threads. Maybe it was an antenna. Or a solar sail.
Artefacts.
It looked like the remains of a ship, in fact. But not human.
Not human. My God, he thought.
And now the light changed: to the stark planes of the sun’s eternal glow was added a new, softer glow.
Water blue.
He turned, clumsily, blipping his attitude thrusters.
Earth was back, a fat crescent, directly ahead of him. This is a hell of a light show, he thought.
But Earth looked different. It had spun around on his axis. Before he’d been over the Pacific; now he could make out, in a faint dawn glow, the familiar shapes of the continents – North and South America, painted over the ocean under bubbling wisps of cloud.
There were no lights, anywhere. And the arrangement of continents didn’t look right. Earth didn’t match his memories of schoolroom globes, under the Stars and Stripes, back in Iowa.
The Atlantic looked too skinny, for instance.
This new rock was heading for Earth, just like Ra-Shalom had been. It couldn’t be more than a few minutes from reaching the atmosphere. And it looked to him as if it was going to hit somewhere in Mexico …
Oh, he thought. I get it.
This was the dinosaur killer, the original, destined to gouge out a two-hundred-kilometre crater at Chicxulub, and to have its substance rained around the planet.
He shielded his eyes with a gloved hand, and studied the stars.
They were different. The stars were bone white: no green, anywhere.
He was displaced in time, a long way. But this was not the far future, but the deep past.
He turned again to face the plummeting rock, with its fragile cargo of artefacts.
One last time the kerosene thrusters fired, fat and full. The asteroid started to approach him, filling his sky. The suit was quiet, warm, safe.
He just let himself drift in, at a metre or so a second. The close horizon receded, and the cliff face turned into a wall that cut off half the universe.
He collided softly with the rock. Dust sprays were thrown up from around the PMU’s penetrator legs. Greenberg was stuck there, clinging to the surface like a mountaineer to a rock face.
He turned on his helmet lamp. Impact glass glimmered a few centimetres from his face. He reached out and pushed his gloved hand into the compacted-snow surface, a monkey paw probing.
… There was something here. Something alive, something sentient, inside the rock. He could feel it, though he couldn’t tell how.
Maybe the Weissmans were using him as some kind of conduit,
