Galileo struggled to imagine a world regurgitating itself, molten rock flowing inside to outside, then sinking down to be melted and thrown up again.
“There isn’t a single drop of water left,” Hera went on, “nor any of the other light and volatile elements you are used to on Earth.”
“What is it made of, then?”
“Silicates, mostly. A kind of rock, mostly melted. And a lot of sulphur. That’s the lightest element not to have been burnt off, and being the lightest, it tends not to sink but to froth on the surface, as you see.”
“Yes. It looks like burnt sulphur.” He had seen pots of the stuff, bubbling in an alembic. He sniffed, but smelled nothing.
“Mostly sulphur, yes, or sulphur salts and sulphur oxides. Here we are near the triple point for sulphur, so it vaporizes when it erupts out of the interior, literally explodes on exposure to the vacuum. It can shoot out of a geyser and land more than fifty miles away.”
“I don’t understand,” Galileo confessed.
“I know.” She gave him a glance. “You are brave to admit it. Although very few people really understand.”
“I’ve noticed that.”
“Yes. Well, I’m not the one to tell you the details of the physics or chemistry involved. But I can tell you more about what you have seen here, and the person who brought you here. And why he and his group are acting as they are.”
“I would appreciate that very much,” Galileo said politely. It was always good to have potential alternative sources of patronage; sometimes one could then balance them, or pit them against each other, or otherwise use them to create a differential advantage, a leverage. “You said they brought me to Europa, and we descended into its ocean—it must be a very different world from here, I must say!—and they were hoping to stop others from descending, because that is a forbidden place. But we had something happen. Some kind of encounter. I almost remember; it was like a waking dream. I seem to recall we were somehow … hailed. By something living in the ocean. There was a noise, like wolves howling.”
“There was. Very good. I’m not surprised you remember it, despite the amnestics they gave you. Abreactions fire across the blocked areas by way of similar memories, so being here helps you to recall your previous visits.”
“Visits?”
“What I am surprised at is that Ganymede took you along on that incursion. It may be that he did not know the timing of the Europans’ descent, and had to include you in something that was not meant for you.”
“Ah.”
“I do know he’s been telling you that his group has brought you to our time to advise them on a matter of fundamental importance.”
“It seemed unlikely,” Galileo said with an unconvincing show of modesty.
She smiled briefly. “According to Ganymede, you are the first scientist, and as such, one of the most important people in history. Nevertheless, to ask your advice was not his reason to bring you here.”
“Then what was?”
She shrugged expressively, like a Tuscan would have. “Possibly he felt your presence would help him defend his actions on Europa. No one else on the council wanted to take the responsibility of interfering with the Europans. Ganymede took the position that what they were proposing was a dangerous contamination of a crucial study zone, so that stopping them would be the best scientific practice, and also the safest for humanity. He brought you forward in a prolepsis that he hoped would support that position.”
“Why should my presence matter?” Galileo wondered.
“I don’t know,” she admitted, frowning as she looked at him. “He’s created so many more analepses than anyone else that it’s hard to get a fix on what he is up to. I wonder if he mainly brings you here to change you, to cause you to do what he wants you to do back in your time. Even with the amnestics blocking your conscious memory, you are still changed here. Then again, when he has you here he flaunts his rashness with the entangler, and thus hopes to scare the council. Or perhaps he thinks you bolster his authority, as you are the first scientist. The patron saint of scientists, you might say. Or of Ganymede’s cult, anyway.”
“Archimedes was the first scientist, if you ask me.”
“Maybe so.” She frowned. “There were analeptic intrusions around Archimedes as well, actually. But you are the first modern scientist, the great martyr to science, the one everyone knows and remembers.”
“People don’t remember Archimedes?” Galileo asked incredulously, thinking: martyr?
She frowned. “I’m sure historians do. In any case, you are right to question Ganymede’s stated rationale. He may want your effect here in a prolepsis, or he may be shaping his analepsis by what he exposes you to here.”
Galileo mulled over the terms, which to him came from rhetoric. “A backward displacement?”
“Yes.”
“What year is it here, then?”
“Thirty twenty.”
“Thirty twenty? Three thousand years after Christ?”
“Yes.”
Galileo swallowed involuntarily. “That’s a long time off,” he said at last, trying to be bold. “Coming back to me is indeed an analepsis.” He recalled the stranger’s face in the market, his news of the telescope. From Alta Europa, Ganymede had said that first time. “How does that work? What does it mean?”
Again she frowned. “You are in need of an education in physics, but I am not the one to give it to you. Besides, there is no time. My seizure of his entangler, and of you, will be causing consequences, which may arrive soon to pester us. In the time we have, I want to talk to you about other things. Because now that they have made this analepsis into your time in Italy, it is likely to endure, and it will have effects on all the other temporalities entangled with it. Including your life, among other things. My feeling is that the more you know of the situation, the more you can resist the effects of Ganymede’s intervention. Which makes it safer for us, as our time is then likelier to endure in substantially its current form.”
“You mean it might not?”
“That’s why analepses are so dangerous. There are many temporal isotopes, of course, and they are all entangled, and braid together in ways that are impossible to comprehend, really, even if you are a mathematician specialized in temporal physics, to judge by what they say. What you need to know is that time is not simple or laminar, but a manifold of different potentialities that interpenetrate and influence each other. A common image is to think of it as a broad gravel riverbed with many braided channels, with the water running both upstream and downstream at once. The channels are temporal isotopes, and they cross each other, shift and flow, become oxbowed or even dry up, or become deeper and straighter, and so on. This is just an image to help us understand. Others speak of a kelp forest in the ocean, floating this way and that. Any image is inadequate to the reality, which involves all ten dimensions, and is impossible for us to conceptualize. However, to the extent that we understand, we see that your moment represents a big confluence, or a bend, or what have you.”
“So—I am important?”
Her eyebrows shot up; she was amused at him. He recognized the glance, felt he had seen it before. She gestured at the hellish surface gleaming below them. “Do you know how people came to be here?”
“Not at all.”