How? I had no idea.
McAndrew did. “If it’s been blown apart to its component atoms,” he said, “we’ll never find it. But if it’s still in one piece, there’s a way that can’t fail.”
We were preparing to leave, and we were not using a ship with McAndrew’s balanced drive. Instead he had picked out an old touring pinnace with a one-gee acceleration limit. After my initial surprise I decided that I knew why (it would turn out later that I was wrong). McAndrew, it seemed to me, wanted time to think. He’d never admit it, but his pride was hurt. It was bad enough that somebody would come up with a basic idea that he had missed, in an area of theoretical physics where he had thought longer and harder than any person alive. That the somebody was his own father — the father who had run off and deserted him and his mother — was even worse.
As the Driscoll eased away from the institute, I compared travel times. Even the most minimal ship equipped with the balanced drive was capable of continuous forty-gee acceleration. With that performance, our destination would have been a mere seventeen hours, standing start to standing finish. On the other hand, at the leisurely half-gee best suited to the Driscoll’s engines, we faced a journey of close to a week.
All right for McAndrew, perhaps; he was sitting barefoot, staring vacantly at the cabin wall and cracking his finger and toe joints in a way that I always found infuriating. I knew from experience that he was likely to sit for days, eating his meals like a zombie and washing only at my insistence. Meanwhile, what was I supposed to do, here in a ship that flew itself?
I reviewed everything we had learned so far. Heinrich Grunewald’s paranoia had not ended when he left Mary McAndrew. The Fafner required a crew of three when it flew in cislunar space. Upon leaving that controlled region, Heinrich as soon as possible had the other two men ferried back to Earth station. He continued alone. His last recorded engine burn placed him in stable orbit in the middle of the Asteroid Belt. Any new engine burn would have been detected. None had been recorded. Any explosion in that location powerful enough to destroy a ship would have been seen. No instruments, on Earth or elsewhere, had seen such evidence.
The ship must be there. The ship was not there. I sat and wondered. Where’s Heinrich?
McAndrew emerged from his trance when we still had a full day of flight time ahead. “I’ve got it,” he said. “Or at least, part of it.”
“Well, isn’t that nice.” I should have known better. Sarcasm is wasted on the man. He smiled at me. I went on, “So you know how changing the strong force would allow somebody to do the things that your father claimed?”
He stopped smiling. “Och, I’ve always known that. It’s obvious.”
“Not to me it isn’t. I don’t suppose you’d consider explaining?”
“The strong force holds nuclei together. So suppose you could make it more powerful and act over a longer range, for an indefinitely long period. That would lead to stable compressed matter, and you’d be able to squeeze anything you like into a smaller space. If you used the strong force to overcome electromagnetic repulsion between protons, you’d also be on the road to easy proton-proton fusion at room temperature.
“Now suppose you work the other way round, and know how to weaken the strong force. Then nuclei will be less strongly bound, and a lot of naturally stable elements will become unstable. That gives you induced radioactivity.”
“But that’s everything.” It seemed to me he had covered everything on Heinrich Grunewald’s list. “Why do you say you only have part of it?”
“Because I slipped something in there at the beginning. I said, suppose you could modify the strong force for an indefinitely long period. That’s the killer, Jeanie. I can see a way to make changes, but they’d be unstable. Worse than that, they’d be unpredictable. You’d never know when the effect would reverse itself and things return to the way they were. And when I try to stabilize the situation over time, I need to assume the existence of isolated quarks. I might find a way around that when I give it a bit more of a think, but I still won’t know what went wrong. Something surely did. There must be a missing piece — some trivial point, some fact that I’ve overlooked…”
He was all set to drift off again. I said, loudly, “Mac, we’d be a lot closer to the something you’re missing if we knew how to find the Fafner. In another twenty-four hours we’ll be sitting out in the middle of the Asteroid Belt, wondering what to do next.”
He stared at me with those pale, vague eyes. “Why, I already know what we’ll do. Why do you think I wanted to take the Driscoll, instead of something with a balanced drive?”
“Because you wanted time to think.”
“Maybe. And I got that. But we’d have a problem if we’d used the balanced drive. The compressed matter plate on any of those ships masses trillions of tons.”
“That’s never given us any difficulty before.”
“Because we’ve never had this situation before. Think about it, Jeanie. If the Fafner’s still in one piece, what’s the one thing about itself it can’t hide?”
“Thermal signature?”
“That’s not a bad answer for a ship that’s alive. Anything with people on board has to generate and give off heat. But the Fafner’s more than likely dead, so there would be no thermal signal. A ship can be at the same temperature as its surroundings, or it can change its size and shape, or it can be coated with an absorbing layer so it’s hard to see. The one thing it still has, no matter what it does, is mass.”
When he spoke that one, final word I could see the rest for myself. We knew from the Fafner’s records the ship’s mass at the time of final engine burn: three hundred and thirty tons. Even if Grunewald had jettisoned material into space, the present value would not be far from that. If we were anywhere close to the ship we could locate it using our mass detector. The instrument was highly sensitive and it could be programmed to correct for every nearby object in the right size range. The trillion-ton mass of a compressed matter plate was something else. On a ship with a balanced drive, the plate’s effects would overwhelm the gravity field of everything in the neighborhood.
It’s my one big complaint with McAndrew. He assumes you understand what he understands. Even when you feel sure you know what goes on inside his head, you don’t. One of his colleagues told me that the difference between McAndrew and other people is that Mac knows how to think around corners. It’s probably true, but it doesn’t help much.
I wondered if he got that talent from his father. I had no idea what Heinrich Grunewald had been doing out here, or why he had disappeared thirty years ago from the face of the Solar System. I thought of Mary McAndrew’s words, “he was a wicked, obstinate, reckless man.” Cut out the wicked part, and you had McAndrew.
I can’t think around corners, but I have excellent instincts for danger. And I was feeling uneasy, more nervous than the situation seemed to justify.
We had arrived, exactly at the place where the Fafner was supposed to be. I cut the drive and used the visible wavelength sensors to scan through a full four-pi solid angle.
Did I see the ship? Of course not. You might say I already knew I wouldn’t, because if it had been there the scopes of the Penrose Institute would have found it before we ever left.
I pointed that out to McAndrew.
“Which is why we had to come out here and take a look for ourselves.” He seemed filled with secret glee, his normal reaction when facing a scientific mystery. “Jeanie, keep the drive off and the displays on, and let’s have a go with the mass detector.”