“Genocide in Toyland. There’s never going to be a good day to talk about that. Maybe you could tell her about your Heroic Generation at the same time. Give her some context. It’s not just builders that behave this way.”
“For the thousandth time, it wasn’t my…”
But of course she was only goading him, for the thousandth time. She asked, “What did the ColU want to talk to me about, by the way? Seemed very intense.”
“Oh, one of its theories. Life on Per Ardua. It seems to have got a pretty good family tree for this world now. Lots of bragging about genetic comparisons and stuff. He’s identified major revolutions in the story of life here.”
“What revolutions?”
Yuri thought back. “Photosynthesis, I mean a fancy advanced kind that produced oxygen as a waste product. Then complex cells, with nuclei. Then plant and animal life. The ColU got worked up about the dates it’s established for these events. Meant nothing much to me.”
“What dates?”
He concentrated. “Photosynthesis two point seven billion years ago. The complex cells two billion years ago. And the animals—umm, five hundred and forty-two million years ago, I think.”
Mardina stared at him.
Some distance away, at the fringe of the trodden mud around the new lake, Beth had found something worth shouting about. She jumped up and down, waving. “Mom! Dad! Come see!”
Mardina called, “OK, sweetie.” They began to walk over. “Yuri—are you sure about those dates?”
He felt uncertain, now she pressed him. “Well, I think so.”
“It’s just—I’m no expert, but I took terraforming modules during my ISF training, and we studied the history of Earth life, the key transitions. Yuri, the dates for the similar events on Earth are: two point seven billion years, two billion years, and—”
He guessed, “Five hundred and forty-two million?”
“Yeah. I mean the last particularly is pretty precise, from the fossil record on Earth.”
“Mom! Dad! Come see, before it all gets trampled!”
Mardina said, “Life on two worlds separated by light years having a common sugar base—well, you can wave your hands about panspermia to justify that. But such a precise coordination of the key dates of all those improbable events?”
“What does it mean?”
“Damned if I know.”
“Mom! Dad!” Beth, quite agitated, was almost screaming now.
And when Yuri and Mardina finally got there, at the edge of the pond’s muddy fringe, they could see immediately why.
Beth had found a human footprint.
Chapter 41
The invitation from Earthshine reached Stef at her workstation in the UN kernel lab on the moon.
In a short, low-res holographic message—a cube showing his well-groomed head, his smiling middle-aged-politician-type face—the Core AI requested that she come visit him on Earth, at what he called his “node” in Paris. He said he had a matter to discuss of global importance, but specifically of interest to “you and your sister”. There was also an avowal, in legal wording, that the AI would make no attempt to access the growing knowledge base on kernel physics during his meeting with the sisters. Without that avowal Stef supposed the message would never have been allowed through the various layers of security that surrounded her, here at Verne.
A similar message, an attachment noted, had been sent to Penny on Mercury.
Stef shut down the hologram with a curt acknowledgement of receipt, and spent a full dome-day thinking it over. That was her way when faced with dilemmas she found difficult or personally unpleasant, a way she’d developed of managing her own instincts over nearly thirty-six years of life. Let the news work its way through her conscious and subconscious mind, before formulating a decision. She even slept on it.
For one thing there was the sheer time she would need to take out of her own programme. Right now Stef was in a work jag that she was reluctant to climb out of. Well, she was always in a work jag. Seven years on from the Hatch’s first opening and the Penny incident—as she thought of it—explorations of the Hatch and investigations of its physical properties were shedding some light on the complementary studies of the kernels that had been going on for decades now. It was a slow, painstaking process, and it was full of gaps. Stef had the feeling she had been handed the two ends of a long chain of discovery, and she had a way to go before she worked her way from either end in towards the centre. But it was absorbing—there was more than a lifetime’s work here for her and her colleagues, she was sure. And that was a pleasing thought, since it pushed the need to make any drastic decisions about her own future off beyond the horizon.
Decisions such as about her relationship with her sister.
There was another reason for her to be wary about Earthshine’s note. She was actually working now with Penny. Her sister, who was on Mercury, was running direct experimentation on the Hatch emplacement, trying to detect emissions of various exotic high-energy particles. Unlike some siblings, indeed some twins, the sisters worked well together, as a long string of academic publications to their individual and joint credit from the beginning of their careers proved. In this particular project at this particular time Penny was the experimentalist, Stef the theoretician, but on other projects in the past, the record showed, it had often been the other way around. They were flexible that way, with close but complementary skill sets.
It was all fine and dandy, a family relationship to be admired and envied, and something that both their father and mother would have been proud of. It was just that Stef had no memory of any of this before the damn Hatch on Mercury had opened.
The news of the discovery had quickly leaked, and the Hatch had been a sensation for about twenty-four hours. It was after all evidence of alien intelligence in the solar system. But a Hatch leading nowhere had since been largely forgotten, or dismissed as a hoax, though it still trailed conspiracy theories like a comet tail.
But Stef was left with a massive rewiring of her own past.
Before the Hatch, she had been an only child. After it, suddenly she had a twin. Not only that, she suddenly had a whole different lifetime behind her, intertwined with that of her twin. Papers that had been to her sole accreditation, for instance, were now under joint authorship with her sister. She’d read some of them; they were much as she remembered writing them, but not quite—not significantly better or worse academically—and there were others, reflecting bits of work she couldn’t remember, that she’d never generated herself at all.
Only Stef remembered her solitary past before. Nobody else. Everybody in her life, including colleagues she’d known since her graduate-student days, thought of her now as half of a pair, not Stef alone. Not even King and Trant, who had been there at the moment of transition, remembered the old timeline.
Not even Penny remembered it. As far as Penny was concerned, their joint careers had just carried on, after a hiccup as Stef had tried to absorb what had happened at the Hatch. To Penny, Stef was a sister who had suddenly developed a kind of selective amnesia.
And maybe that was what it was. Some kind of mild craziness, perhaps triggered by some bizarro radiation field leaking from the alien artefact into which she’d climbed. That was the simplest explanation, after all, that her own perception, her memory, was somehow faulty. Though she’d looked hard, Stef hadn’t found a single shred of evidence to contradict the reality of it. The alternative, that history had somehow been changed around her, that the fault lay in the external universe rather than in her own small head, seemed an absurdly over-elaborate explanation by comparison.