For it was clear that the sudden, unexpected rash of minor volcanism in the Canyon, like that in a dozen other sites around the world, was directly related to the particle cloud that had spread around the planet from Edinburgh: what Henry Meacher called the Moonseed, the alien infection that — for weeks, it seemed — had been raining down out of the stratosphere and was eating into the very rock beneath her feet.

The precedent of Edinburgh for what would follow was not encouraging. And what she needed to find out was what would happen when the Moonseed got into those deep old rocks.

On the way here, she’d had another e-mail, from Alfred Synge.

› Here’s what we think is happening in Venus. And I’m sure you can express it, not to mention understand it, far better than I can. › Take one of your rolled-up ten-dimensional string objects. Pinch it, like compressing a garden hose. As you approach zero width, you generate quantum-mechanical waves, membranes wrapped around the scrunched dimensions. The waves are extremal black holes…

Actually Monica didn’t agree with the nomenclature here. These “black holes” were nothing like the collapsed stars of astrophysics. They were just solitons, clumps of string fields; the physicists preferred to call them black bubbles or black sheets.

But arguments about nomenclature weren’t the most important thing right now, she reflected.

› The black holes are massless, so they flee at the speed of light. But, like massless photons, they aren’t without momentum. So they exert a push. › Monica, we think that inside Venus there’s an organization of mass and energy that is working as a generator of extremal black holes. Maybe that’s what the transformation of the planet is “for’, if you can think of such events as having anything like a single purpose. There is a fountain of black holes streaming from where Venus’s north pole used to be. And it is pushing what’s left of the planet out of its orbit, away from the plane of the ecliptic. It’s like a rocket, Monica, a black hole rocket…

It was fanciful, abstract. The whole Venus event had become a kind of theoretical toy to be kicked around by the young and/or over-enthusiastic, including Alfred, and the hypotheses just got wilder. It was impossible to connect to the grubby reality of a cracked cinder cone, here in this great chasm.

And yet, it seemed, connected they were.

Alfred’s mail ended in rambling, a rant about NASA’s post-Edinburgh decision to destroy its remaining forty-billion-dollar Moonrock stock. The genie is out of the bottle! The horse has bolted! This is vandalism.

No, she thought. You don’t understand. It’s a symbol. Appeasing the gods.

“Tell me about the Inner Gorge rocks,” she said to Scott Coplon.

“Yeah. They’re primarily schists and gneisses. The rocks were formed from pre-existing igneous and sedimentary rocks during mountain-building events in the deep past. A gneiss is what we call granitic rocks which have been exposed to later episodes of metamorphism, and—”

“I know. Go on.”

“Sorry. Well, we know that what’s exposed here is just the top of a much deeper layer. The rocks extend thousands of feet down from the surface and form the basement of the North American continent.”

“The basement?”

He nodded. “Rocks of that age and character underlie most of the continent. But it’s only where they have been exposed, like here, that we can study them…”

Monica knew a little about plate tectonics. She knew that the continents rode like rafts of granite, on the plates that slid on currents in the viscous molten rock that lay beneath. The younger rocks of the ocean floors, gabbro and basalt, were in time subducted — dragged back into the interior of the Earth, to be melted and reborn. But the ancient rocks of the continents, riding above, survived.

And now it looked as if, here and elsewhere, the Moonseed might reach those foundation rocks, the granite core of the continent itself, through this immense wound of rock and strata.

This is not good, she thought. Not good at all.

Well, then, we must do something about it. But what the hell she had no idea.

Scott took her arm, and led her back towards the car.

Scott started talking to her about the river ride she was going to have to take if she wanted to get any closer to those old Precambrian rocks. It meant a descent of five or six thousand feet, a rise in temperature of maybe twenty degrees. She calculated whether she would have the strength to undergo such a trip. And at the same time, she started to figure what she should tell the President, and how.

A black hole rocket engine, firing wildly in the ruins of Venus. Now, what was the meaning of that?

Strangeness. Too much of it, for one lifetime.

The sunset crept on them. The colours deepened to rust, mile-long shadows flooding at perceptible speed across the land, and they walked back to the car.

2

Henry was flown, mostly at low altitude under the ash clouds, the length of Britain.

Once, most of Britain was covered by a shallow ocean, which deposited gigantic chalk layers over the whole country. But then Britain tipped up. And the ice came, scraping most of the chalk off the top half of the island.

Now, as he travelled south from Scotland, he traversed younger and younger landscapes: billion-year-old gabbros and granites and basalts in Scotland, belts of successively younger sedimentaries as he came down through England, until he reached the youngest of all, the marine Pleistocene clays and sands around London, less than sixty million years old.

He could see the old buildings — churches, houses, pubs, even railway stations — which stood like geological markers, constructed of their area’s native rock. Britain was a small island, crammed with ten thousand years of history, a billion years of geology.

The sheer size of London surprised Henry. He’d come to think of everything in Britain as being miniature scale. Even a place like Edinburgh was — had been — pretty small by the standards of many American cities.

London, though, was different. He flew over mile after mile of grey suburbs, knots and twists of terraced houses and semis, spread like blankets over the gentle topography of the chalk landscape. His RAF pilot pointed out some of the logic, if you could call it that, that underlay the sprawl of outer London. It was really a collection of old villages — like Brentford and Harrow and Ealing and Richmond — that had been overwhelmed by the flood of building that had come after the war, but their identities were preserved in their names and the topology of the roads, which curled around the old village centres.

The Thames coursed through the heart of the sprawl, a silver-blue thread, and as they flew over central London it was easy to use the river as a guide to pick out tourist highlights: the big ugly glass developments at Canary Wharf, where the old docks used to be, and ships from Britain’s global empire had once called; the tiny, jewel-like sandstone perfection of the Palace of Westminster, the seat of Parliament; the surprisingly elegant bridges that laced across the water; the spectacular cowl shapes of the Thames flood barrier.

Traffic crowded the streets and highways, the metallic carapaces of cars and buses and lorries glimmering like so many beetles in the sun. Life was, obviously, going on here. It was as if the bad shit that had come down in Edinburgh, a bare four hundred miles away, had never happened.

They landed at a floating heliport on the bank of the Thames, near a bridge the pilot said was called Blackfriars.

Incredibly, he was taken to a hotel for the night; even more incredibly, he was going to have to wait until the next day — in fact, for twenty-four hours — before meeting members of the Government.