stood before them, in what seemed a kind of vestibule. The stranger touched Galileo lightly on the back of the arm, led him into this antechamber. They passed under another arch. The group fell in behind them without a word. Their faces appeared old but young. The space of the room made a gentle curve to the left, and beyond that they came to a kind of overlook, with broad steps descending before them. From here they could see an entire cavern city stretching to the near horizon, all of it tinted a greenish blue, under a high ceiling of opaque ice of the same colour. The light was subdued, but more than enough to see by; it was quite a bit brighter than the light of the full moon on Earth. A hum or distant roar filled his ears.
‘Blue light goes furthest,’ Galileo ventured, thinking of the distant Alps on a clear day.
‘No,’ the stranger said. ‘The different colours are waves of different lengths, red longer, blue shorter. The shorter the wavelength, the more light tends to bounce off things, even ice or water, or air.’
‘A pretty colour.’
‘I suppose it is. Some spaces in here are illuminated with artificial light sources, to make things brighter and give them the full spectrum.’ He indicated a building that glowed like a yellow lantern in the distance. ‘But mostly they leave it like this.’
‘It makes you look like angels.’
‘We are only people, as I’m afraid you will soon learn.’
The stranger led him to an amphitheatre, sunk into the surface of the city floor so that it was not visible until they came to the curved rim of the highest seats. Looking down into it, Galileo saw resemblances to Roman theatres he had seen. The bottom dozen rows of seats were occupied, and in front of them other people were standing on a round stage. They all wore loose blouses and pantaloons that were blue, pale yellow, or the Jovian tones of Galileo’s group. At the centre of the stage stood a white glowing sphere on a pedestal. Faint black lines crisscrossing it gave Galileo the impression that it might be a globe representing the moon they stood on.
‘The council?’ Galileo asked.
‘Yes.’
‘What would you have me say?’
‘Speak as the first scientist. Tell them not to kill what they study. Nor to kill themselves by studying it.’
The stranger led Galileo down steps into the amphitheatre, now firmly holding him by the upper arm. Galileo felt again the strange lack of his proper weight; he bounced as he would have if standing neck-deep in a lake.
The stranger stopped several steps above the group and made a loud announcement in a language Galileo did not recognize. Only slightly delayed, he also heard the man’s voice say in Latin, ‘I present to you Galileo Galilei, the first scientist.’
Everyone looked up at him. For a moment they were motionless, and many of them looked startled, even disapproving.
‘They look surprised to see us,’ Galileo noted. ‘Perhaps a bit baffled, or abashed.’
The stranger nodded. ‘They want to be sheep, and so should be sheepish. Come on.’
As they descended further, some of the ones dressed in orange and yellow bowed. Galileo bowed in return, as he would have before the Venetian Senate, which this group somewhat resembled, in that they appeared elderly, and somehow used to authority. Many of them were women, however, or Galileo assumed so: they were dressed in the same kind of blouses and pantaloons as the men. If a monastery and convent had merged their populations, and could only express their wealth in the fine cloth of their simple habits, they might look like this.
Despite the scattering of respectful bows, several among the group were now objecting to the stranger’s interruption. One woman, wearing yellow, spoke in the language Galileo didn’t recognize, and again he heard a Latin translation in his ears-Latin in a man’s voice, accented like the stranger’s. It said, ‘This is another illegal incursion. You have no right to interrupt the council’s session, and such a dangerous prolepsis as this will not be allowed to change the debate. In fact it is a criminal action, as you know very well. Call the guards!’
The stranger continued to guide Galileo down the steps and onto the circular stage, until they were among the people standing there. Almost all of them were considerably taller than Galileo, and he looked up at them, amazed at their faces, so thin and pale-beautifully healthy, but manifesting signs of both youth and age in mixtures very strange to his eye.
Galileo’s guide loomed over the protesting woman, and he spoke down to her, but addressed the entire group, in their language, so that again Galileo heard a slightly delayed translation in his ear: ‘Who gets to speak is only contested by cowards. My people come from Ganymede, and we assert the right to speak for it, to help determine what people do in the Jovian system.’
‘You no longer represent Ganymede,’ the woman said.
‘I am the Ganymede, as my people will attest. I will speak. The prohibition against descending into the Europan ocean was made for very important reasons, and the Europans’ current push to rescind that prohibition ignores several different kinds of immense danger. We will not allow it to happen!’
‘Are you and your group part of the Jovian council or not?’ the woman shot back.
‘We are, of course.’
‘But the matter has been discussed and decided, and your position has lost to that of the majority.’
‘No!’ others around them cried.
Many there then spoke up at once, and the debate grew general, and quickly became a shouting match. People jostled around, contracting into knots like rival gangs in a piazza, growing red-faced with expostulation. The Latin in Galileo’s ear broke up into overlapping shouts: ‘Decided already-We asked him to speak!-We will have you removed!-Cowards! Anarchists!-We want the Galileo to speak to this matter!’
Galileo raised his hand like a student in a class. ‘What matter do you discuss?’ he said loudly. ‘Why have you brought me here?’
In the pause that followed, one of the Ganymedeans addressed him. ‘Most illustrious Galileo,’ the Latin in his ear exclaimed, as the man bowed to him respectfully. He continued in his own tongue, which was translated in Galileo’s ear as: ‘-first scientist, father of physics, we here among the moons of Jupiter have encountered a scientific problem so fundamental and important that some of us feel the need of a truly original mind, someone unprejudiced by all that has happened since your time, someone with your supreme intelligence and wisdom, to help us decide how to deal with it.’
‘Ah well,’ Galileo said. ‘There you have it then.’
One woman laughed at this. She was big and statuesque, dressed in yellow. In the midst of all the arguing, she looked partly irritated, partly amused. The others began their raucous debate again, many becoming vehement, and in the din of all the squabbling she circled around to his left side, opposite the stranger. She leaned down toward him (she stood almost a foot taller than he), and spoke rapidly in his ear, in her own language; but what he heard in his ear was Tuscan Italian, somewhat oldfashioned, like that of Machiavelli, or even Dante.
‘You don’t believe any of that shit, do you?’
‘Why should I not?’ Galileo replied sotto voce, in Tuscan.
‘Don’t be so sure your companion has your best interests in mind here, no matter that you are the great martyr to science.’
Galileo, not liking the sound of that, said quickly, ‘What do you think my interests here are?’
‘The same as anywhere,’ she said with a sly smile. ‘Your own advancement, right?’
In the midst of a fierce harangue at his foes, the stranger looked over and noticed the woman and Galileo in conversation. He stopped arguing with the others and wagged a finger at her. ‘Hera,’ he warned her, ‘leave him alone.’
She raised an eyebrow. ‘You are not the one to be telling people to leave Signor