Unless they had planted, among the Arkies or the General Population, fifth columnists with orders to execute a coup d’état if necessary.

“Markus?” Dr. Harris asked. “Are you hearing me? Do you understand what I just said?”

“I beg your pardon, Dr. Harris, I just got distracted thinking about the kind of things that Sal is supposed to think about.”

“Feel free to delegate some of that,” Sal said. “I know it’s not your strong suit, but—”

“Close the door, please,” Markus said.

Dr. Harris did.

“I am reasonably sure of no surveillance in here.”

“Noted.”

“It is Dinah, isn’t it, Doob?” Markus asked.

Doob nodded. “She’s talking to Sean Probst over an encrypted channel.”

Markus shook his head admiringly. “What a girl! My god, she is trouble.”

Doob and Sal were silent. During their silence, Markus thumbed out a one-word text message to Tekla.

“Sal,” Markus said, “I declare PSAPS.”

“I don’t think we are yet authorized to—”

“Who is going to stop us?”

Doob and Sal, again, were silent on the matter.

“Is Julia—I do not call her the president anymore—going to nuke us?” He was continuing to thumb out messages as he talked.

“She, or the Russians, or the Chinese, might have other ways of removing you from your position—”

“I have thought about this,” Markus said. “About the possibility that there are plants. Military guys with Tasers or whatever. Waiting for such an order. I have talked to Fyodor, to Sheng, to Zeke, trying to sound them out, to get a feel for it.”

“Markus,” Doob said, “with respect, I don’t think that this is what you ought to be focusing on right now.”

“Which is why I am delegating the constitutional side of it to Sal and the operational side of it to her.” Markus nodded toward the door, which had swung open without a knock. Tekla glided through and closed it behind her. “We don’t have to announce to the whole world that we are going to PSAPS. We have five hours in which to begin preparations, quietly. I will contact Moira, and tell her that we must begin preparations to disperse the genetic samples to the arklets. I will tell Ulrika that we must pull the trigger on the Surge.” By this, Markus meant a long-planned burst of launches that was supposed to happen in the few days’ grace period between the White Sky and the onset of the Hard Rain. “We can be working on these things quietly. Five hours from now, it will happen or it will not. If it does not, we go back to as we were and consider this a dress rehearsal.”

The door opened again, this time after a knock, and in came a young man named Steve Lake, preceded by his laptop and followed by his dreadlocks. For Steve, in his year and a half aboard Izzy, had not succumbed to the vacubuzzer’s siren song, but he had gotten tired of messing with his long hair and had allowed it to congeal into red ropes. Formerly employed by a consulting firm in northern Virginia that hired hackers to do secret work for intelligence agencies, he had been yanked and sent up to support Spencer Grindstaff, the networks and communications specialist who’d been one of Izzy’s original crew on Zero. Spencer was an NSA man through and through, recruited straight out of MIT to work on spooky crypto stuff. Steve seemed to be an altogether different sort of character. He looked a bit mystified just now.

“Steve,” Markus said. “It is time for us to have a conversation about power.”

Steve’s brow furrowed. “You mean, electrical power or—”

“The other kind.”

“Okay, and is this going to be, like, an abstract philosophical discussion or—”

“No, it is going to conclude with me telling you, under my PSAPS authority, to change all of the passwords and keys for Izzy’s control systems.”

“Wow!” Steve said. “Shouldn’t you be talking to Spencer then? Because he’s above me in the org chart.”

“I am familiar with the org chart,” Markus said. “Under PSAPS I have the authority to change it.”

“What is this PSAPS thing you keep talking about, Markus?”

“Sal will explain it later. For now, we may set it aside. Fundamentally we speak of your loyalty, your allegiance. I think that Spencer is extremely loyal to powers that be on the ground. I do not wish to put him in an impossible bind. He will later come with us, or he will not. You I believe to be a different kind of fellow. I ask you, in effect, to now become loyal to the Cloud Ark and the Cloud Ark alone. Not to Washington. Not to Houston. And to accept the authority of whoever is the boss of the Cloud Ark. Which for now is me.”

“Okay.”

“You’re supposed to think about it first, Steve. Not just say okay.”

“I’ve been thinking about it for a while. But I have to tell you, there might be back doors. I can change all the codes I know about. The ones I don’t know about are a different matter.”

“Then we shall just have to be vigilant.”

White Sky

DOOB COULDN’T GUESS HOW MANY TIMES DURING HIS LIFE HE HAD noted a cottony tuft of cloud in a blue sky, then looked up hours later to discover that it had developed into a bank of clouds that covered the sun and told of a change in the weather. Such phenomena happened too slowly for the mind to discern them as happening at all. During the last hours of A+1.335, something like that occurred in the cloud of lunar debris that had been hanging in the sky for the last seven hundred days. Later they would watch the movies of it in time-lapse, compressing a day’s changes into a minute of video, and it would look like an explosion. Or an epidemic of explosions. If you watched the video carefully enough, frame by frame, you could see it progress from one part of the cloud to the next as the Eight Ball shot through. Like a particle lancing through a cloud chamber, it was invisible save for the trail of consequences it left in its wake. A few months earlier it might have passed through without touching anything, but today the density of rocks in the cloud was such that it could not avoid smashing into some of them on its way through. Doob, making a crude statistical calculation, put the likely number of collisions at ten, plus or minus five. Not a large number in a cloud that now contained millions of rocks, but enough to push the system, trembling on the precipice of an exponential explosion, over the edge. Around its unseen track the White Sky took form and fury. The cloud bloomed and evoluted like cream in coffee, spreading and paling, though from place to place one could see fresh bursts as rocks hurled out in earlier collisions found distant targets and touched off smaller chain reactions of their own. In places it took on a cellular structure as curved detonation fronts spread, contacted others, and merged into lacy foams of white arcs. It had an austere, monochromatic beauty about it. There was no fire and no light other than what cold sunlight the rocks bounced back to the eye. Later, when they began to enter the atmosphere, there would be fire and plenty of it. But for now the world was ending in a fractal blooming of dust and gravel, an apocalypse in a gravel quarry.

“You pretty much nailed it,” someone told Doob, “when you called it the White Sky.”

“Being right does not always bring satisfaction,” he said.

The Bolide Fragmentation Rate shot up through all meaningful thresholds within a few hours of the Eight Ball’s arrival and Doob stopped paying attention to it. The number was probably wrong now. It was just an estimate, produced by a consortium of observatories based on the amount and distribution of light coming out of the cloud. All the assumptions that went into its calculation had now become obsolete.

He tried aiming his optical telescope at where PP1 and PP2 and Cleft—the large, metal-rich children of Peach Pit—ought to be, but saw nothing except, possibly, some local highlights in the density of the cloud, perhaps caused by rocks dashing themselves to pieces on the steely surfaces of those dark bolides. He wondered if he would ever see them again.