“Is the creature really such a problem?”

She looked grim. “The debate over what to do about it is the problem. We are the problem. But the problem is tearing us apart.”

“As bad as that?”

She gave him one of her sharp looks. “You know better than most how people can fight over an idea.”

“Indeed. That’s what Aurora said too.”

“Fights over ideas are the most vicious of all. If it were merely food, or water, or shelter, we would work something out. But in the realm of ideas one can become idealistic. The results can be deadly. The Thirty Years’ War, isn’t that what they called the religious war that Europe was fighting during your time?”

“Thirty years?” Galileo exclaimed, dismayed.

“So I seem to remember. And here, now, it may be happening again.”

For a while they flew to Europa in silence, both of them locked in their thoughts. By now the equivalence of change of speed and the physical sensation of weight was firmly established in Galileo’s body and mind, so when he felt pressed back into his chair, he came out of his reverie.

“You’re speeding up?”

“Yes.” She was grim again. “Apparently Ganymede and his group are already there. Four ships in a tight orbit, just over the ice. There’s no good way to stop them now.”

Ahead of them bulked the white ball of Europa. Hera muttered viciously in a language he did not know, tapping hard at her control pad. “Come on!” she complained.

You must be patient, Galileo prevented himself from saying. Instead he asked, “Why does Ganymede want me to be burned at the stake, do you think? What difference would it make? Aren’t there so many potentialities that they all happen or not, cancel each other out or not, so that any one doesn’t matter?”

She looked at him with the expression he had seen before that he could not decipher. Pity? Affection? “All the temporal isotopes have effects downstream. Think again of the braided channels of a river. Say you kick the bank of one stream so hard it crumbles, and the stream wears away the bank until it breaks into a nearby channel, and they both become so strong together that they cut a straighter line, take water from some channels, reroute others…. Well, so, Ganymede thinks you are at a crucial point, a big bend. He’s been obsessed with changing that bend for a long time. He keeps going back to it, I think. And I wonder if he doesn’t want the change he causes to be so profound it alters things even in our time too. I wouldn’t be surprised.”

“But say I am burned—what’s different?”

“Maybe the more accurate question would be, what would be different if you weren’t burned?” She glanced at him, sensing his shudder. “After you, there is a deep divide between science and religion. A war of two cultures, two worldviews. And with you burned at the stake for stating an obvious physical fact, religion is thereafter discredited, even disgraced. The intellectual innovators of the world are secularized, science rises to dominate human culture, religion is seen as an archaic power system, like astrology, and it fades away.”

“But that’s not good. Why would anyone want that? That’s no different than these bastard priests who are attacking me!”

She regarded him carefully. “Interesting to see again the structure of feeling you grew up in. To us it seems clear that your religion was a kind of mass delusion, serving the powerful by justifying their hierarchy.”

Galileo shook his head. “The world is sacred. God made it all, as an expression of mathematical playfulness, perhaps, but however that may be, He did it.” She shrugged at this and he went on. “Besides, how can you say that science dominating civilization is such a good thing? Didn’t you tell me that your histories have been nightmares, that most cultures in most times, including your own, have been to one degree or another insane? Where’s the great advantage in that?”

“The question,” she said carefully, “is whether the alternatives are not even worse.”

This was sobering. Galileo thought it over. “Do you have a tutorial for the history of human affairs between my time and yours, like the one Aurora had for mathematics?”

“Of course,” Hera said, still brooding. “There are many. They describe different potentialities, or attempt to show the whole wave function. But there’s no time for that now. We’re approaching Europa.”

And in fact Europa stood directly before them, growing rapidly larger, blossoming like a white rose, its surface crackled like the ice on the Po just before it broke up in the spring. It was striking how for the longest time in their flights, their objectives remained at the same small size, only growing incrementally, and then in a final rush bloomed to the size of an entire world.

Now Hera was cursing again.

“What’s wrong?” he asked.

“They’re landing,” she said, and pointed. “Just over the north pole.”

Galileo did not have a sense of orientation to apply to this. “You can see them?”

“Yes. There.” She pointed, and Galileo saw a cluster of tiny stars, very close to Europa’s white surface, swirling down toward it. “They’re landing, and the Europans are trying to stop them, but …”

“They don’t have cannons to fire at them?”

“Weapons have been forbidden, as I told you, but there are things that can be used as weapons, of course. Power systems, construction tools, field generators …” She shook her head as she watched her screen and listened to her interlocutors. “I wish they would generate a small black hole in their midst and suck them out of existence!” She cursed in the language that didn’t get translated.

A streak of brilliant white light shot down out of the quartet of firefly ships onto the surface of Europa, and she stopped in her tirade.

“What was that?” Galileo said.

“I don’t know. Possibly one of their ships flew right into the moon, like a meteorite. I don’t know how that could have happened, though. The pilot systems wouldn’t have allowed it, so there must have been an override, or …”

“What?”

She hissed. “Whatever hit the surface just exploded again. Maybe its a reactor. There’s an electromagnetic pulse that has registered that is—ah! See that bright white spot?” She tapped away quickly, then began cursing again. “A lot of them are in trouble now, on both sides. Hold on,” she ordered. “I’m taking us down fast.”

Their ship tilted forward, rocketed down toward the shattered icescape. Only in the last seconds before they would have impacted like a meteor did the invisible ship tilt and shudder and roar, throwing Galileo against his restraints.

Then they thumped down on the tawny ice. Hera began rattling out a long list of instructions to the ship and the various machine intelligences among its crew.

“Shouldn’t you get the rest of your grand council involved in this?” Galileo asked.

“Yes.” She gave him a look. “But we’ll meet with the Europan council for now.”

“Oh I see. Very good.”

“Very bad. We’ve failed to stop Ganymede. I don’t know what he’s done, but that was a big explosion. Possibly one of their ship engines.”

“When they crashed in?”

“Ordinarily that wouldn’t be enough to do it. The engines are secured against almost any accident. But with some time and effort, it might be possible to override the protection.”

They disembarked from the ship, and he soon found out that she had landed them very close to an entry ramp into Rhadamanthys, the under-ice Venice. Down a broad white entrance, through a diaphanous barrier and into a broad ice gallery, where the pulsing blues interlocked in their patterns overhead. Soon they reached the edge of the canal they had taken before, and beside it was a sunken amphitheater where a small crowd of people gathered. This too looked familiar, and though he couldn’t recall the specifics of any previous incident, he assumed there had been one, there on the far side of some amnestic he had ingested. Already seen …