“So they have. What else?”

“You want to use these wormholes to transmit visible light photons. Now, quantum-foam wormholes come in at the Planck-Wheeler length, which is ten-to-minus-thirty-five metres. You’ve managed to expand them up through twenty orders of magnitude to make them big enough to pass gamma-ray photons. Very high frequency, very short wavelength.”

“Yeah. We use the gamma rays to carry digitized data streams, which…”

“But the wavelength of your gamma rays is around a million times smaller than visible-light wavelengths. The mouths of your second-generation wormholes would have to be around a micron across at least.” David eyed his father. “I take it you’ve had your engineers trying to achieve exactly that. And it doesn’t work.”

Hiram sighed. “We’ve actually managed to pump in enough Casimir energy to rip open wormholes that wide. But you get some kind of feedback effect which causes the damn things to collapse.”

David nodded. “They call it Wheeler instability. Wormholes aren’t naturally stable. A wormhole mouth’s gravity pulls in photons, accelerates them to high energy, and that energized radiation bombards the throat and causes it to pinch off. It’s the effect you have to counter with Casimir-effect negative energy, to keep open even the smallest wormholes.”

Hiram walked to the window of the little cafeteria. Beyond, David could see the hulking form of the detector complex at the heart of the facility. “I have some good minds here. But these people are experimentalists. All they can do is trap and measure what happens when it all goes wrong. What we need is to beef up the theory, to go beyond the state of the art. Which is where you come in.” He turned. “David, I want you to take a sabbatical from Oxford and come work with me on this.” Hiram put his arm around David’s shoulders; his flesh was strong and warm, its pressure overpowering. “Think of how this could turn out. Maybe you’ll pick up the Nobel Prize in Physics, while simultaneously I’ll eat up ENO and those other yapping dogs who run at my heels. Father and son together. Sons. What do you think?”

David was aware of Bobby’s eyes on him. “I guess -”

Hiram clapped his hands together. “I knew you’d say yes.”

“I haven’t, yet.”

“Okay, okay. But you will. I sense it. You know, it’s just terrific when long-term plans pay off.”

David felt cold. “What long-term plans?”

Talking fast and eagerly, Hiram said, “If you were going to work in physics, I was keen for you to stay in Europe. I researched the field. You majored in mathematics — correct? Then you took your doctorate in a department of applied math and theoretical physics.”

“At Cambridge, yes. Hawking’s department -”

“That’s a typical European route. As a result you’re well versed in up-to-date math. It’s a difference of culture, Americans have led the world in practical physics, but they use math that dates back to World War Two. So if you’re looking for a theoretical breakthrough, don’t ask anyone trained in America.”

“And here I am,” said David coldly. “With my convenient European education.”

Bobby said slowly, “Dad, are you telling us you arranged things so that David got a European physics education, just on the off chance that he’d be useful to you? And all without his knowledge?”

Hiram stood straight. “Not just useful to me. More useful to himself. More useful to the world. More liable to achieve success.” He looked from one to the other of his sons, and placed his hands on their heads, as if blessing them. “Everything I’ve done has been in your best interest. Don’t you see that yet?”

David looked into Bobby’s eyes. Bobby’s gaze slid away, his expression unreadable.

Chapter 4

Wormwood

Extracted from “Wormwood: When Mountains Melt,” by Katherine Manzoni, published by Shiva Press, New York, 2033; also available as Internet floater dataset:

…We face great challenges as a species if we are to survive the next few centuries. It has become clear that the effects of climate change will be much worse than imagined a few decades ago: indeed, predictions of those effects from, say, the 1980s now look foolishly optimistic. We know now that the rapid warming of the last couple of centuries has caused a series of metastable natural systems around the planet to flip to new states. From beneath the thawing permafrost of Siberia, billions of tonnes of methane and other greenhouse gases are already being released. Warming ocean waters are destabilizing more huge methane reservoirs around the continental shelves. Northern Europe is entering a period of extreme cold because of the shutdown of the Gulf Stream. New atmospheric modes — permanent storms — seem to be emerging over the oceans and the great landmasses. The death of the tropical forests is dumping vast amounts of carbon dioxide into the atmosphere. The slow melting of the West Antarctic ice sheet seems to be releasing pressure on an archipelago of sunken islands beneath, and volcanic activity is likely, which will in turn lead to a catastrophic additional melting of the sheet. The rise in sea levels is now forecast to be much higher than was imagined a few decades ago. And so on. All of these changes are interlinked. It may be that the spell of climatic stability which the Earth has enjoyed for thousands of years — a stability which allowed human civilization to emerge in the first place — is now coming to an end, perhaps because of our own actions. The worst case is that we are heading for some irreversible climatic breakdown, for example a runaway greenhouse, which would kill us all. But all these problems pale in comparison to what will befall us if the body now known as the Wormwood should impact the Earth — although it is a chill coincidence that the Russian for “Wormwood” is “Chernobyl”…

Much of the speculation about the Wormwood and its likely consequence has been sadly misinformed — indeed, complacent. Let me reiterate some basic facts here.

Fact: the Wormwood is not an asteroid.

The astronomers think the Wormwood might once have been a moon of Neptune or Uranus, or perhaps it was locked in a stable point in Neptune’s orbit, and was then perturbed somehow. But perturbed it was, and now it is on a five-hundred-year collision course with Earth.

Fact: the Wormwood’s impact will not be comparable to the Chicxulub impact which caused the extinction of the dinosaurs.

That impact was sufficient to cause mass death, and to alter — drastically, and for all time — the course of evolution of life on Earth. But it was caused by an impactor some ten kilometres across. The Wormwood is forty times as large, and its mass is therefore some sixty thousand times as great.

Fact: the Wormwood will not simply cause a mass extinction event, like Chicxulub It will be much worse than that.

The heat pulse will sterilize the land to a depth of fifty metres. Life might survive, but only by being buried deep in caves. We know no way, even in principle, by which a human community could ride out the impact. It may be that viable populations could be established on other worlds: in orbit, on Mars or the Moon. But even in five centuries only a small fraction of the world’s current population could be sheltered off-world.

Thus, Earth cannot be evacuated. When the Wormwood arrives, almost everybody will die.

Fact: the Wormwood cannot be deflected with foreseeable technology.

It is possible we could turn aside small bodies — a few kilometres across, typical of the population of near-Earth asteroids — with such means as emplaced nuclear charges or thermonuclear rockets. The challenge of deflecting the Wormwood is many orders of magnitude greater. Thought experiments on moving such bodies have proposed, for example, using a series of gravitational assists — not available in this case — or using advanced technology such as nanotech von Neumann machines to dismantle and disperse the body. But such technologies are far beyond our current capabilities.