On Day 7, minutes after they had met, he and Amelia had watched Kidney Bean fracture into two big chunks, later dubbed KB1 and KB2 (though attempts had been made at the time to give them cutesy names of their own). Three weeks later Scoop had collided with Big Boy and broken into three pieces, SC1, SC2, and SC3. Big Boy itself was now BB1, still fairly recognizable, plus a whole family tree of bits that had shrapneled off its smaller piece, BB2. These were given code numbers such as BB2-1-3, meaning the third-biggest fragment of the largest fragment of the second-biggest piece of Big Boy. Beyond about that level it became difficult, and somewhat pointless, to keep track of them all. Mr. Spinny had caused all sorts of havoc before finally breaking in half; its wayward children MS1 and MS2 had gone winging off in opposite directions and ended up in big eccentric orbits around the rubble cloud’s shared center of mass, occasionally looping in from a great distance and slamming into one of the slower-moving pieces. MS2 had broken Acorn into three pieces just three days before Doob’s memorable Oval Office chat with the president. While he’d been flying back to L.A., a hunk of it the size of an oil tanker had slammed into the Indian Ocean and kicked up a tsunami that had killed forty thousand people on the west coast of India.
After he got home from his trip to D.C., he and Amelia checked into a suite at the Langham, a palatial hotel in Pasadena, so that they could spend a few days together before he went out on a round-the-world journey. All through their romantic dinner on the terrace he made a concerted effort not to look at the remains of the moon. Later they went back to their suite and made love. After twenty minutes’ postcoital cuddling, Amelia rolled over on her side and went to sleep, inviting Doob to spoon with her, but Doob, unable to relax, pulled his tablet onto his lap, put on his reading glasses, and started killing time on the Internet. The French doors to the balcony were open, and at some point the breeze coming in through them obliged Amelia to snuggle deeper under the blankets. Doob got up and walked over to close the doors, and was confronted by the sight of the moon-cloud, directly in front of him, hanging over the lights of L.A., and now something like four times the diameter of the original moon. It was arresting, partly because it had been so long since he had looked squarely at it, and so he stood there for a while observing. Peach Pit was still largely in one piece, but other than that the original Seven Sisters were no longer discernible.
Out of curiosity he consulted an app that told him when Izzy would be passing over, and saw that it was going to happen in about ten minutes. So he stood there and waited for it. As he waited, his attention turned again and again to the pieces of the moon. What was their future? He knew that they would shatter into an uncountable number of fragments and become the White Sky and then the Hard Rain. But what was the final distribution of sizes going to be, how many big ones and how many small? They had some models based on the simplifying assumption that all moon rock was basically the same, but clearly that wasn’t true.
They had done some analysis on the original chunks, trying to figure out why Peach Pit was so resistant to fragmentation, and determined that it was simply the inner core of the old moon. Which was confirmed anyway by an analysis of its mass: Peach Pit was much denser than the other bits, suggesting that it consisted mostly of iron as opposed to rock. The moon had had an iron core, but, relative to overall size, this was much smaller than the Earth’s; most of the moon was cold, dead stone.
And yet the core was there, and was thought to consist of a ball of solid iron surrounded by a somewhat hotter jacket of molten iron mixed with various other elements. All of this had been stripped bare and exposed to space by the Agent. For the first few hours, Peach Pit had literally glowed with radiant heat. Or so they guessed, since the dust kicked up by the cataclysm had cloaked it for a while. Some of the core’s outer jacket of molten metal must have been torn away, dispersed into the rubble cloud as gobbets and slugs and droplets of melt that soon cooled and hardened. As much was proved by metal-rich bolides that had since plowed into the Earth and been dug up and analyzed. By the time the dust had literally settled to the point where Peach Pit and its siblings were clearly observable, an outer crust had formed over it, consisting of melt that had cooled swiftly as it radiated its heat into space. The cooling had continued ever since. Now, the better part of a year later, Peach Pit, or PP1 as it was now designated, was still warmer than the other parts of the moon. It had shown greater resistance to fragmentation. Other rocks bounced off it, or dashed themselves to pieces on its gleaming surface. A few significant chunks — PP2, PP3, and so on — had been ripped off in the early days when it had still been soft, but now it was clad in a mile-thick armor of solidified iron that was proof against just about any calamity short of a second Agent.
Doob became so absorbed in such thoughts that he almost missed the transit of Izzy across the sky. It angled directly over the rubble cloud, seeming to weave among the giant tumbling boulders, though this was of course an illusion. It had long been the brightest man-made object in the sky, and it was brighter now that so many pieces had been added onto it. The effort had been impressive. Stirring, even. But seeing it against the scale of the disaster behind it forced him to ask himself what was the point. What was the longer-term plan for the Cloud Ark? The swarm concept was a nice architecture, much more survivable than One Big Ship, but where was it going to go?
No one seemed to be talking about that. He understood why. Survival was the first imperative. Long-term strategy came next.
The amount of iron in PP1 was for all practical purposes infinite. It would take humans many thousands of years to find uses for that much metal.
But it was way up high. Hard to reach.
And yet they had to reach it.
And it was closer, easier to reach, than the Arjuna asteroids that Sean Probst was so excited about.
Feeling an idea take shape in his head, like an iron core congealing deep in a moon, he put it on hold and forced himself to turn his attention to more immediate questions. A few days ago in the Oval Office he had formed a resolve to get his ass into space and begin making things happen up there. Which was fine. But he had three months left on terra firma. He couldn’t neglect his responsibilities here. Some of which — the most important — were to his kids, to Amelia, and to their frozen embryo. But on top of that he had been given other jobs, and if he screwed them up badly enough, e.g., because he was standing on hotel balconies in the middle of the night thinking about how much iron was in PP1, then they might not send him up to the Cloud Ark at all. He hadn’t wanted to go, but once he had assented to the idea, he had begun wanting it more than anything, and he now feared that they would take it away from him. And if they sensed that fear, they could use it to control him. Better to overperform, to exceed expectations, to act like it was nothing at all.
SEVENTY-TWO HOURS LATER HE WAS LOOKING OUT THE WINDOW OF a U.S. Navy helicopter banking through a misty Himalayan valley as it lined up its final approach to a runway in Bhutan. Or perhaps the runway in Bhutan was the more correct phrasing.