He rubbed his bald scalp. “I remember you once worked with me on a homework assignment on cosmology. You always were good at that stuff. Do you remember trying to prove to me that the universe must be finite? You spun me around on an office chair, fast enough for my legs and arms to go rising up. You asked me how I’d know if it was me spinning around in a stationary universe — or if the universe was spinning around me. The two situations seem symmetrical; how could I tell? But if I was stationary, what was pulling my arms away from my body, and making me feel nauseous? It had to be the universe, the whole of it, a great river of matter and energy circling around my body, stars and planets and people, and as it spun it was tugging at my legs, through gravity, relativity, whatever. I thought that was a wonderful thought, how I was connected to everything else.

“But, you said, that showed the universe had to be finite. Because if it was infinite, it would load me down with an infinite inertia. I wouldn’t be able to spin at all. I’d have been trapped like a bug in amber. You see, that’s how I think you are in the world, Dad. You see the complicated real-world problems of ecology and climate and politics and all the rest like an infinite universe that pins you flat. No wonder you’d rather believe it’s all been fixed. By the Stewardship, for God’s sake, the last word in bureaucracy and corruption…”

Well, maybe so. I did wonder if Tom would have preferred me to be a brutal realist like Jack Joy, the Lethe Swimmer.

I got up, walked around a few paces, turned away until I was calmer. “Maybe we ought to keep it down. We might wake the other guests.”

He didn’t smile. “What other guests? Nobody here but us ghosts, Dad. Which reminds me—” Reaching out, he tapped another part of the wall screen.

He brought up a picture of me, standing in that puddle in York in the middle of the night, taken from some security camera. So, suddenly, things had got even more messy.

I sat down. “Who sent you this?”

“Uncle John. Does it matter who? I know what you’ve been doing, Dad. I know about the fucking — ghost.I can’t believe you’re doing this.”

“Believe me,” I said fervently, “it’s not by choice.”

“Oh, isn’t it?” I couldn’t read his mood. He sat back, apparently relaxed. But one fist clenched and unclenched.

And so suddenly my haunting was messing up an already complicated emotional situation. We were entering uncharted territory in our relationship, I thought; put a foot wrong and I could do damage that would last a lifetime. “Tom — I don’t want this. But I see her. Or I see something. I don’t know what to tell you. I’m trying to figure it out myself. But this has been happening to me for a long time…”

“I. Me. Myself.” He said the words in a dead tone, like a metronome, but his gaze was on the floor. “Do you ever listen to yourself, Dad? Do you remember the funeral, when we buried her, and the kid? Did you know I snuck into the church early?”

I hadn’t known.

“I went to her coffin. It was in the aisle, before the altar. I tried to open that fucking box. I wanted to climb in with her. I didn’t want to be left with you. Because I knew that all you would think about was yourself. You even gave more thought to the kid who killed your wife than to me.”

“Tom—” I spread my hands. “Please. I don’t know what to say. Everybody’s fucked up, you know.”

“Oh, I understand that.” He actually smiled. “You know, I forgive you. I’m an adult now, I can see you couldn’t help it. But you should have tried to protect me, even from yourself. You should have tried. ”

“I’m sorry.”

“And now you come to me and tell me you’re being haunted by my mother. No, worse, you don’t even tell me, I have to find it out from somebody else.” He was still, rigid with anger. “How am I suppose to deal with that?”

I had no idea what to say.

At last he sat back. “So what now?”

“I don’t understand.”

“You dragged me home, Dad. You insisted on seeing me, talking to me. Fine. I guess I owed you that much. Have you got what you wanted?”

“I don’t want you to put yourself at risk again.”

He laughed, contemptuous. “You think you can stop me?”

“Not if you don’t want to be stopped. Any more than you can stop me from designing starships…” I shook my head. “You know, the irony is, we’re both right.”

“We are?”

“Sure. I’m right to believe in an expansive future for mankind. The Kuiper Anomaly is proof that it’s possible: somebody else got through their Bottleneck and hung that thing up there. But you’re right to try to deal with the problems of the present, because if we don’t get through the Bottleneck there won’t be any future at all. I’ve had enough of hearing about the differences between us. We should try to find some common ground.”

That took him by surprise. He seemed to think it over. In those few seconds I could feel some of the tension between us drain away. We’d both said what we had come in to say, we had both landed blows.

“All right.” He stood up. “Anyhow, we’ll try not to fight.”

“Amen to that.”

“Dad, I think I need to do some physio, sleep a bit more.”

I took the hint. I stood and headed for the door. “Maybe I’ll see you in the morning?”

“Yeah. Look, Dad — you may be an asswipe, as Uncle John says, but you’re still my dad, and I’m stuck with you.”

“Ditto,” I said fervently.

“But give up on this haunting crap, OK? Get some therapy, for Christ’s sake.”

I sighed. But we had crashed through the barriers to an island of truth; it wasn’t a time for lies or bland reassurances. “You’ll have to tell your mother that. Goodnight, son.”

I closed the door behind me.

On the third day on the Rustball, Alia’s inquisition resumed — for so she had come to think of it.

And today she finally learned what this strange, drab world had to offer her.

She was brought back to that dark, iron-walled room. The three Campocs were here again, Bale, Seer, and Denh, surrounded by a subtly different sample of their relatives. Once again they asked her to talk about her sister. She went back over what she’d said before, and tried to dig out more memories, tease out more meaning.

But the exercise made her feel increasingly uncomfortable. Her jokey stories of how she’d tricked her sister, or out-competed her, or left her embarrassed, no longer seemed so clever.

“There is always a rivalry between siblings,” said Bale’s great-aunt. “It is part of the human condition, no doubt exported from old Earth itself.”

Perhaps. But again and again down the years, Alia had indulged that rivalry at her sister’s expense. It was a kind of bullying, Alia thought now, for Drea had been helpless: Alia was her sister, and no matter what Alia did to her, dear stolid Drea would always come back for more. On some level Alia had known that, and had exploited Drea’s loyalty.

“I’ve been awful,” said Alia.

As she reached this conclusion the Rusties’ faces were watchful, interested, engaged, sympathetic: analytical, not judgmental.

“You’re flawed,” Bale said. “We are all flawed. But it’s best to know about it, to look inward, to see honestly.” There was something intense in the way he said that. He was guiding her, she saw, to a new insight.

Alia looked inward. And she started to understand.

Something was different:something about her perception of herself. Her own memories had never been sharper, more accurate; it was as if she had a scholar inside her head, refurbishing the muddled archives that made up her recollection of the past, her picture of herself. And at the same time she was seeing that picture with a pitiless clarity she had never known before.

She had crashed through a barrier. She had changed, subtly, internally.