“Besides,” Angel said. “Not doing it is choosing for them, too. How many people in big cities right now do you think would prefer we do nothing? Russia has thousands of nukes; the United States nearly as many. If the varcolac can control them, it’ll be a long time before it stops.”
“We could chase it,” Alessandra said. “We could track it down and fight it. Stop it from killing anyone else.”
“Could we?”
Alessandra thought about it. “No,” she said. “But then, I don’t think we can send a Higgs singlet back in time, either, not with that kind of control. It’s never been done. It’s never even been attempted.”
“I believe in you,” her mother said.
Alessandra threw up her hands. “I’m no genius like Ryan.”
“That’s probably a good thing,” Angel said. “Look, just explain the principle to me. I won’t understand it, but it’ll help you think through the problem. Between the NJSC and the High Energy Lab, we have the best equipment in the world available to us. You’ll think of something.”
“I’m not so sure.”
“Just start talking. If someone could do such a thing, how would they go about doing it?”
“Gravity,” she said with a sigh. “They would need an immense gravitational pull.” She repeated for Angel the same illustration that Ryan had used with the golden eagle on Hawk Mountain. How the eagle’s possible locations—limited by the speed of light—were shifted by the gravity of a massive nearby object.
Using a shared eyejack space, she started drawing in the air with her finger, making lines that the three of them could see. She drew a simple pair of axes on the board, marking the horizontal axis x and the vertical one t. “Okay. The x axis is for movement in space; the t axis is for movement through time. So, if I draw a V, like this”—she switched to a red color and drew a V shape with its point at the origin—“that represents the area the eagle can theoretically fly, right?”
“As time advances, it can range farther in space,” Angel said.
“Right.” She almost smiled, but then the news feed in the corner of her vision reported that Tokyo and its fifty million people had been erased from the map by a pair of American nukes. It was hard to process. It was so horrible, so far beyond horrible, that her mind was rejecting it. “This is stupid,” she said. “What are we doing? This won’t accomplish anything.”
“Please. Keep talking.”
She sighed. She couldn’t shake the idea that she should be doing something, either fighting the varcolac, or at least finding somewhere far from cities to hide.
“Okay. Let’s say I was standing near a black hole when I turned my light on. The black hole’s gravity would deform space-time toward itself. It would change the cone like this.” She drew a new V, only now it was tilted toward one side.
“The photon could travel farther if it traveled toward the black hole than if it traveled away from it, since the black hole’s gravity is, in effect, pulling it in.”
“Why is it tilted toward the right side?” Angel asked.
“It doesn’t matter which side. It’s just showing that the eagle’s possible travel locations are skewed toward the black hole.”
Her news feed reported the destruction of Karachi and Jakarta. The numbers of dead were becoming inconceivable, meaningless. She stopped talking and just watched as Mumbai was added to the list, then Moscow, and then São Paolo. Images from weather satellites showed mushroom clouds surging with radiant heat.
“He’s going in order,” Angel said. He was watching the same feed.
“What?”
“Ryan has a list of the populations of major world cities. Tokyo was the biggest. Then the three Chinese cities, then Karachi, then Jakarta. After the first few, he just started working his way down the list, killing the largest possible number of people with each blast.”
The sheer coldness of that put a chill down her back. He was a sick, evil man. She couldn’t believe she had talked to him, had ridden in his car. She had put her arms around him when she thought he had come to rescue them. Could the nervous, phobia-driven man she had briefly known really be systematically killing off the world’s population? What she said was, “Where’s New York City on the list?”
“It’s down to number thirty-five. American population growth has been dropping compared to the rest of the world. But New York is seventy-five miles away; we should be safe enough. I mean, we might get an unhealthy dose of radiation, but we’re well outside the blast range.”
Alessandra shook her head. “It’s the EMP I’m worried about. Depending on how high it actually detonates, it could knock out electronics as far as Chicago.”
“This is a high-security government lab. Wouldn’t it be shielded?” her mother asked.
Kinshasa, the news feed reported.
“Maybe,” Alessandra said. “But it’s not the lab that’s the problem. The super collider has thirty miles of electromagnets with associated infrastructure that relies on above-ground power sources. It wouldn’t survive.”
Angel moved his eyes up and down, scrolling through a list. “We don’t have much time, then. He’s been taking out a city every few minutes.”
Alessandra stood up taller and spoke with a stronger voice. “All right, then. Let’s get moving.” She pointed at the light cone again. “This cone is how we define causality. Since nothing can travel faster than the speed of light, only things located inside the cone in space and time could possibly be affected by anything that occurred at the origin of the graph. Anything outside that cone is causally independent.”
“So you’re just telling me that what the varcolac did was impossible,” Angel said.
Mexico City.
Alessandra glanced at the news feed and started talking faster. “An object in orbit around the black hole would travel straight down the middle of this cone. From its own perspective, it would be in free fall—not moving, just staying on its local t axis. But to an outside observer, it’s moving in space, falling into the black hole.”
“I sense the moment coming where you totally lose me,” Angel said.
Delhi, the feed said. They were coming faster. The satellite images scrolling by left no doubt as to the reality of the disasters. Alessandra swallowed back tears and tried to keep talking. “What we need to do is turn the cone backward,” she said. “We need to warp the fabric of space and time so radically that the light cone looks like this.” She drew a new V, this one tilting so far that its edge reached into negative time.
“This would mean the span of possible travel for our particle includes points down here”—she tapped the graph—“earlier in time than where it started.”
Shenzhen.
“I don’t understand,” her mother said. “What are we talking about?”
“Gravity,” Alessandra said. “Like I said, an immense amount of gravity. We need to create a black hole.”
The other two just looked at her. “Um… like, right here?” Angel asked.
“In the collider.”
“A black hole. Like, one of those ultra-massive space things that sucks everything into it and tears it to bits along the way?” Angel said.
“Just a little one.”
Seoul.
“That wouldn’t… you know… destroy the Earth or anything?”
Alessandra shook her head. “Black holes aren’t entirely black. They all give off a small amount of thermal energy, called Hawking radiation. Big ones don’t give off much, but the smaller they are, the more radiation escapes. Any black hole smaller than about the moon gives off so much that it radiates itself away in a fraction of a second. I’m talking about a miniscule black hole, smaller than an atom, even. It would barely last any time at all.”