Galileo’s Dream. Kim Stanley Robinson

revealing a flight of low black steps. The stranger gestured to Galileo, indicating the entry.

      ‘This is our vessel. We have learned that the Europans are going to stage an illegal incursion into the ocean under this ice. They have ignored our warnings, and the relevant authorities in the Jovian system have declined to interfere, so we are taking it on ourselves to stop them. We think any incursion will be potentially disastrous in ways these people haven’t even considered. We want to intercept them if we can, and keep them from doing harm. And at the very least, see what they do down there. If what happens is as bad as I fear it could be, they will not tell the truth about it. So we must follow them in. With luck we will get down there first, and can stop them when they break through the layer of ice into the water below.’

      ‘And you want me to go with you?’ Galileo asked.

      ‘Yes.’ Ganymede hesitated, then said, ‘You should know the nature of the threat.’

      Then something caught his attention over Galileo’s shoulder, and he looked startled; Galileo turned and saw a silver object on a tripod, like the perspicillum only bigger, coming down on a pillar of white fire, roaring faintly in the thin air.

      The tall man put a hand to Galileo’s shoulder. ‘If there is danger, I will transport you back to your own time. The transition may be abrupt.’

      A slit in the silver craft opened and a figure in white emerged.

      ‘Do you know who this is?’ Galileo asked.

      ‘Yes, I think so. You met her before, when we spoke to the council.’

      ‘Ah yes. Hera, she said. Jupiter’s wife?’

      ‘She thinks she’s that big,’ the stranger said sourly; then added under his breath, ‘It’s almost true.’

      The woman was indeed large: tall, broad-shouldered, widehipped, thick-armed, deep-chested. She approached and stopped before them, looking down at the stranger with her ironic smile. ‘Ganymede, I know you hate what they plan to do here,’ she said. ‘And yet here you are. What’s going on? Are you planning to hurt them?’

      The stranger, who did not look like Galileo’s idea of Ganymede, faced her like an upright axe. ‘You know what they’ll say about this on Callisto if they hear about it. We hold the same view they do. The only difference is that we’re willing to do something about it.’

      ‘And so you bring this Galileo along with you?’

      ‘He is the first scientist, he will be our witness to the council, and speak for us later.’

      She did not think much of this, Galileo saw. ‘You use him as a human shield, I think. While you have him with you, the Europans won’t attack you.’

      ‘They won’t in any case.’

      She shrugged. ‘I want to be a witness too. I want to see what happens, and I am your appointed mnemosyne, whether you acknowledge that or not. Let me join you, or my people will alert the Europans that you are here.’

      Ganymede stepped to the side, gestured at the door of the ovoid vessel. ‘Be my guest. I want everyone to see just how irresponsible their incursion is.’

      Inside the vessel a few people huddled over banks of glass instruments and glowing squares of jewel colour. Their faces, lit from below by the glowing desk tops, looked monstrous. The livid glare of Jupiter seemed to leak out of their eyes.

      Standing beside Galileo, Hera leaned over to speak in his ear; again her words came to him in a rustic Tuscan Italian, like something from Ruzante. ‘You understand that they’re using you?’

      ‘Not necessarily.’

      ‘Do you know where you are?’

      ‘This is one of the four moons orbiting Jupiter. I named them myself; they are called the Medicean Stars.’

      Her smile was wicked. ‘That name didn’t stick. It’s only remembered now by historians, as a notorious example of science kissing the ass of power.’

      Affronted, Galileo said, ‘It was nothing of the sort!’

      She laughed at him. ‘Sorry, but from our perspective it’s all too obvious. And always was, I’m sure. You failed to consider that major planetary bodies are not best named for one’s political patrons.’

      ‘What do you call them, then?’

      ‘They are named Io, Europa, Ganymede and Callisto.’

      ‘Collectively,’ Ganymede interjected, ‘they are called the Galilean moons.’

      ‘Well!’ Galileo said, taken aback. For a moment he was at a loss. Then he said, ‘That’s a good name, I must admit.’ After a moment’s confusion he added, ‘Not greatly different than a name like Medici, if I am not mistaken—’ with a bold look at Hera.

      She laughed again. ‘The discoverer of something is not the same as the discoverer’s patron. His hoped-for patron, to be precise. Making the name a gross bit of flattery, a kind of bribe.’

      ‘Well, I couldn’t very well name them for myself,’ Galileo pointed out. ‘So I had to choose something useful, did I not?’

      She shook her head, unconvinced. But she had stopped laughing at him.

      When he saw a chance, Galileo drifted over to her so they could speak sotto voce again. ‘You all speak as if I am someone from your past,’ he noted. ‘What do you mean?’

      ‘Your time is earlier than ours.’

      Galileo struggled to comprehend this; he had been presuming that the stranger’s device had merely been transporting him across space. ‘What time is it here, then? What year?’

      ‘In your terms it is the year 3020.’

      Galileo felt his mouth hanging open as he struggled to grasp this news. Transported not only to Europa, but to a time some fourteen hundred years after his own…Stunned, he said weakly, ‘That explains many things I did not understand.’

      Her wicked smile again.

      ‘Of course it creates new mysteries as well,’ he added.

      ‘Indeed.’ She was looking at him with an expression he couldn’t read. She was not an angel, or an otherworldly creature, but a human like him. A very imposing woman.

      There was a ping, a small jolt, and the room tilted to the side. Ganymede pointed to a white globe, lit from within, floating in the corner of the room. ‘A globe of Europa,’ he said to Galileo. He explained that its whites were faintly shaded to indicate the temperature of the surface; most of it was pale blue, crisscrossed by many faint green lines. Galileo crossed the room to look more closely at it, checking automatically for geometrical patterns in the surface craquelure. Triangles, parallelograms, spicules, radiola, pentagons…Where the lines intersected, the greens sometimes turned yellow, and in a few cases the yellow shifted to orange.

      ‘The tides break the ice,’ Ganymede explained, ‘and convective upwellings fill some of the cracks in the ice, forming vertical zones like artesian wells, that can serve as channels down to the liquid ocean. On Ganymede we called them flues.’

      ‘Tides?’ Galileo asked. ‘How can there be tides?’

      All the Jovians stared at him. Hera shook her head briefly, as if the explanation would be beyond Galileo’s understanding. Irritated, he looked to Ganymede, who shrugged uncomfortably.

      ‘Gravity, you see…Perhaps we can discuss it another time. Because now we have begun our journey into the interior. We descend by melting the ice as we go, to clear the flue.’

      The craft tilted first at one angle then another. A large rectangular patch on the chamber’s wall was filled with glowing primary colours, as if a rainbow had been used for paint. Ganymede informed him that their vessel was represented by the black pendant in the middle of this rectangle, and flowing upward past it were ribbons of rainbow