“I am familiar with the chain of command that has been improvised,” Julia returned. “To answer your question, Dr. Harris, I am talking to you precisely because you are an astronomer, and well positioned to answer the questions and concerns among the AC about the exact nature of the dirty space threat. This news from Arklet 52 is going to raise questions about the effectiveness of Ivy’s current strategy.”
“It is a statistical problem,” Doob said. “On about A+0.7 it stopped being a Newtonian mechanics problem and turned into statistics. It has been statistics ever since. And it all boils down to the distribution of bolide sizes, and of the orbits in which they are moving, and how those distributions are changing over time—which we can only know from observation and extrapolation. And you know what, Julia? Even if we had perfect knowledge of every single one of those statistical parameters, we still wouldn’t be able to predict the future. Because we have an n of 1. Only one Cloud Ark, only one Izzy to work with. We can’t run this experiment a thousand times to see the range of different outcomes. We can only run it once. The human mind has trouble with situations like that. We see patterns where they don’t exist, we find meaning in randomness. A minute ago you were casting doubt on whether dirty space was really that dirty at all—obviously arguing in favor of Dump and Run. Then I told you about what just happened to Arklet 52 and now you’re swinging around to the other point of view. You are not helping, Julia. You are not helping.”
Julia did not look to be accepting Doob’s remarks in the spirit intended. Instead she squinted through the screen at him and shook her head slightly. “I don’t understand the intensity of your reaction, Dr. Harris.”
“This conversation is over,” Doob said, and hung up on her. He then fought off a temptation to slam the tablet down on the table. Instead he sat back in his chair and looked Luisa in the eye for the first time in a while. On one level he’d wanted to watch her face the whole time. But Julia would have noticed that, would have figured out that someone else was in the room, silently listening.
Just as someone had probably been doing at Julia’s end.
Luisa just sat there in her listening shrink mode.
“It would be easier,” Doob said, “if I could figure out what the hell she wanted.”
“You’re assuming,” Luisa said, “that she has a plan. I doubt that she does. She is driven to seek power. She finds some way to do that and then backfills a rationalization for it afterward.”
Doob pulled his tablet closer and started trying to find Tav’s blog. “To what extent do you imagine she really is reporting facts about the AC? As opposed to creating the reality she describes?” Doob asked.
“What’s the difference?” Luisa asked.
DINAH LOOKED UP AND SAW THAT THE EARTH WAS THE SIZE OF A grapefruit. She took a nap, ate some food, and buckled down to work again, then looked up to see that it was the size of a basketball. Still not that big; and yet such was their speed that it was only an hour away.
They had a final briefing session in Ymir’s common room, which had become a makeshift bridge for this ungainly ship.
Dinah had scrounged three flat-panel monitors from various parts of the command module and zip-tied them to the common room table. These were covered with overlapping windows of various sizes. Some were terminal windows showing log entries or editors showing code, but most were video feeds showing different robots’ points of view on the mining operation. Only one of them looked outward: she’d positioned a redundant Siwi on the stern, toward the nadir, and aimed its camera at Earth. Other than that, her only “situational awareness” would come from a celestial navigation program that would display, in a small window, a three-dimensional rendering of the Earth with Ymir’s trajectory superimposed on it as a geometric curve. Along the bottom of that window was a series of graphs plotting velocity and altitude versus time. Their velocity at the moment was some six thousand meters per second, up from four thousand just a couple of hours ago; within the next hour it would double if they took no action, then begin to drop again as they left perigee behind and coasted away into space.