Stephen Baxter - Transcendent

“Ah,” said Rosa.

John turned on her. “What do you mean, ah? ”

“That explains the long arms, the high chest. Like our primate ancestors, Alia is evolved for climbing — or for low gravity.” She smiled. “Our ancestors were apes, and so will our descendants be. Bishop Wilberforce must be turning in his grave.”

“Descendants?” That was too big a leap for me. “Alia — are you human?”

“Of course I’m human.” Again she seemed hurt, upset I’d even asked.

Oddly, at times she seemed very young, even adolescent, and easily rebuffed, especially by me. I decided I was going to have to be very gentle, tactful. Or as tactful as you can be with an ape-girl from the future. What a mess, I thought.

Alia said, “But in my time it’s different. Humans have spread out. We have become a family.”

“Across the stars?” Gea asked.

“Across the Galaxy.”

“This is the Expansion you mentioned,” I said. “Or Expansions. ”

“In a human Galaxy, there are lots of different sorts of humans. Just as there are in your time.” She frowned. “Or not. Are there? I’m sorry, I should know.”

Rosa said gently, “It’s some thirty thousand years since the last nonhuman hominid died. Homo sapiens sapiens is alone on Earth.”

“Thirty thousand years? Oh, well.” Alia said this in a flip way, as if thirty thousand years was nothing, her mistake forgivable. Her manner was playful, almost coquettish. But there was a bleak, chilling perspective behind her words, a vastness of empty time.

I said, “All right. Then you are from the future. What date are you from?”

“I can’t say.”

“What date were you born?”

“I can’t say!” She flapped her hands, agitated. “These are slippery concepts. I want to give you answers, but you have to ask the right questions!”

Gea said, “Of course she can’t answer questions about dates.”

John growled, “What are you getting at?”

“Relativity.”

It is a strange consequence of Einstein’s special relativity that time is fragmented. Information cannot travel faster than light, and that finiteness makes it impossible to establish true simultaneity, a universal “now.” And so there is a sort of uncertainty in time, which increases the further you travel. If Alia was born halfway across the Galaxy, that uncertainty could be significant indeed.

“How strange,” Rosa said, “to live in a geography so expansive that such effects become important.”

“Oh, for Christ’s sake,” John snapped.

Gea said to Alia, “Suppose your ancestors had stayed on Earth.”

“Yes?”

“That would eliminate relativity ambiguities. In that case, how long would have elapsed, on Earth, between Michael Poole’s birth and your own? Do you know that?”

Alia said, “Round numbers—”

“That will do.”

“Half a million years.”

There was another stunned moment, a shocked silence. The human race in my day, as I now had to think of it — was only, only, maybe a hundred thousand years old. Alia was remote from me indeed, the species itself many times older than in my time. It was hard to take in such a perspective.

Tom said, “So how did you get here? Did you travel in time?”

Alia cocked her head. “I hate to be boring. Here we go again! Can you rephrase the question?…”

With Gea giving us the lead, we managed to extract a little more.

The universe was finite. It was folded over on itself in spatial dimensions — modern cosmologists knew that much — but also in time, so that the future somehow merged with the past. So to get to the past, you would think, all you had to do was travel far enough into the future — just as Columbus had once tried to find a new route to the east by traveling far enough west around the curve of the Earth.

It wasn’t as simple as that, however, as Alia tried to tell us. “It is a question of information,” she said. “Spacetime is discrete, it comes in small packages, particles. Therefore a given volume can only store a finite amount of information. And that information can be fully described by information stored on the bounding surface of the volume.” She frowned at me. “Is that clear?”

Not to me. But Gea said, “Like a hologram. You have a two-dimensional surface that contains information about a three-dimensional object, the hologram, which is reconstructed when you shine laser light on it.”

“Or like Plato,” John said. “We are prisoners in a cave and all we perceive is shadows cast on the wall outside, shadows of reality.”

“Yes,” I said. “But now Alia is saying the shadows are the reality. I think.”

Gea said to me, “This is like the holographic principle. An early attempt at quantum gravity theory.”

“Never heard of it.”

“It was abandoned, decades ago.”

“Maybe that was a mistake…”

Alia’s time was like a surface bounding the past — bounding all of history, including our own long-vanished time. And everything that could be known about the past was contained in her time, in each successive instant. That wasn’t so hard to grasp; geologists, paleontologists and historians, even detectives, have to believe that the past can be reconstructed from traces stored in the present.

But Alia went further: by manipulating events in her present, she was able to change the information in the past — to project herself here, into what was to her history. It was as if you could tinker with a few dug-up dinosaur bones and change the lives of the creatures of which they were relics.

Something like that.

I was struck, though, by a resonance with something I’d read in uncle George’s manuscript: If time is circular, if future is joined to past, is it possible that messages, or even influences, could be passed around its great orbit? By reaching into the furthest future, would you at last touch the past?… George, or anyhow his strange friends, had intuited something of the truth, perhaps.

Tom laughed, an explosive giggle. “Sorry,” he said. “Every so often I just lose it. I mean, it’s just,” he waved a hand, “you’re asking me to accept that this is a superhuman being from the far future. This ape. Where’s the disembodied brain in a jar? I mean, what can she do but swing on tires?”

I think we all knew how he felt.

We talked on. It was a difficult dialogue. We were the ignorant talking to the uneducated. I got the impression Alia really didn’t know much about all this, and cared less — as a modern teenager wouldn’t know anything about the implants in her body, as long as they worked. And we knew too little to make much sense of what she said anyhow; we had to translate it into terms we understood, interpret the information she gave us in terms of our own modern theories, which might have been as partial, falsely based or just plain wrong as notions of planet-bearing crystal spheres.

And every so often, as we worked our way through these miasmas of interpretation and guesswork, we were confronted by vast conceptual gulfs.

“Our time must be strange to you,” Rosa said. “If you were born on a ship, among the stars. The way we live must seem very alien.”

“Oh, but I prepared,” Alia said. “In the course of my Witnessing. You don’t have to visit Earth to know what it must have been like!”

“I don’t understand,” Tom said.

Alia spread her arms wide, and her long hairs dangled like curtains. “There are things I like, and things I don’t like, that have got nothing to do with being born on a ship. I like open spaces, long prospects. I don’t like enclosed spaces or running water, or rats or spiders, or blood. I grew up in zero gravity, but I can be scared of heights! All these are responses ingrained deep into my system, and the systems of my ancestors, long before they left Earth. So, you see, even if I knew nothing of Earth, I could reconstruct it just from my own responses. In fact, that has been done a number of times, by cultures cut off from their origins — people who forgot where they came from. Even they can deduce something of Earth…”