Karpal asked coolly, 'Are you Hermann?'
'No.'
'Then we'd rather not call you Hermann.'
The worm tipped its head from side to side, in a very Hermannesque way. 'Then call me Contingency Handler.'
Elena said, 'We'd rather not call you that either. Who are you?'
The worm looked dejected. 'I don't know what kind of answer you require.'
Paolo examined the icon carefully, but there was no clue to its true nature. Some very odd programs ran in crevices of the polis, all of them supposedly well-understood and constrained, but over the millennia a few had surfaced in unexpected places. 'What kind of software are you? Do you know that much?' If it was not a citizen, they'd be able to invoke operating system utilities to scrutinize it thoroughly, but it seemed only polite to ask it directly, first.
'I'm a Contingency Handler.'
Paolo had never heard of such a thing. 'You're not sentient?'
'No.'
'Why are you using our friend's icon?'
'Because you know I can't be him, so that should cause the least confusion.' The worm almost succeeded in making this sound reasonable.
Karpal asked, 'Why are you talking to us at all?'
'One of my functions is to greet new arrivals.'
Paolo laughed. 'Elena and I are home-born, and if you're Karpal's automatic welcoming party, you're fifteen hundred years too late.'
Elena took Paolo's hand and spoke to him privately. 'I don't think it means new arrivals to C-Z.'
Paolo stared at the worm. It waved its eye-stalks endearingly. 'Where did you originate? What part of the polis?'
It seemed to have trouble parsing the question. It replied tentatively, 'The outside part?'
'I don't believe you.' He turned to Elena. 'Come on! This is a hoax! How could anyone break into the hardware in interstellar space, enter a scape, and imitate Hermann?'
The worm said, 'Your data protocols were easy to determine from inspection. The appearance of Hermann was encoded in your minds.'
Paolo felt his certainty wavering. The Transmuters might be able to do it: read and decode the whole polis in mid-flight, laying bare their nature, their language, their secrets. Their Orphean selves had done as much with the carpets, short of actively entering the squid's world and making contact with them.
Elena asked the worm, 'Who created you?'
'Another Contingency Handler.'
'And who created that?'
'Another Contingency Handler.'
'How many Contingency Handlers are there in this chain?'
'Nine thousand and seventeen.'
'And then what?'
The worm pondered the question. 'You're not interested in any level of non-sentient software, are you!!!'
Elena replied patiently, 'We're interested in everything, but first we'd like to know about the sentient beings who created the system that spawned you.'
The worm waved one leg at the sky. 'They evolved on a planet, but they're more diffuse now, each individual spread out across the space between a million stars. That makes them much slower to act than you, which is why they can't greet you in person.'
Karpal asked, 'A planet in this universe?'
'No. They came here in the same manner as you, but not by the same route.' It created a diagram of nested spheres floating beside the girder, showing a path leading up through a hierarchy of no less than seven universes. A second path, linking just three universes, met the first path at the top level; C-Z's own route, presumably. The worm's creators hadn't arrived via the same macrosphere; they'd never been near Poincare, let alone Swift. They were not the Transmuters.
Paolo was growing skeptical again. Maybe this was Hermann, disguised as an imitation of himself, an unheralded migrant via the singularity links or a stowaway just out of hiding. Certainly, no one else would attempt such a convoluted prank.
He said sarcastically, 'Seven levels? Why so few?'
'That was the length of their journey. They chose to stop here.'
'But there are more levels? They could have gone further?'
'Yes.'
'How can you know that?'
The worm replaced the diagram with another, showing two neutron stars in orbit. 'The fate of such a system puzzles you?' It gazed at Paolo earnestly; he nodded, unable to reply. Not even Hermann would joke about Lacerta.
The neutron stars circled each other slowly, confined to a translucent plane representing their universe. The worm added two more planes, above and below, with stars drifting across them at random: adjacent universes, separated by one quantum of distance in the macrospherean dimensions. 'The interaction between these universes is very weak, but there are critical values of angular momentum where it reaches a maximum.'
Karpal interjected angrily, 'We know that! But it's too weak to explain Lac G- 1! The effect is orders of magnitude less than gravitational radiation. And there's no chance of a runaway spiral; once the system loses angular momentum and falls below the critical value, the coupling strength plummets and the whole process becomes even slower!'
The worm said, 'With one or two levels, or six or seven, that would be true. A tiny amount of angular momentum would be lost due to random interactions with bodies in adjacent universes, and the effect would be insignificant. But each four-dimensional universe is not surrounded merely in six dimensions by adjacent universes in the same macrosphere. Nor is it surrounded only in ten dimensions, by universes in other macrospheres. There are an infinite number of levels, an infinite number of extra dimensions. So every four-dimensional universe interacts with an infinite number of adjacent universes.'
The two extra planes in the diagram doubled into four, then eight, boxing the orbiting neutron stars in a cube. Then the cube mutated into a series of polyhedrons with an ever-increasing number of faces, each face representing part of an adjacent universe. The polyhedrons blurred into a sphere, swarming with stars passing 'nearby' in a continuum of neighboring universes—all of them weakly tugging on the neutron-star binary.
'The system doesn't lose angular momentum.' The worm placed an arrow at the center of the orbit, pointing up out of the plane. 'Which is why the coupling strength doesn't fall, cutting off the interaction. But with each encounter, the direction of the angular momentum vector is changed slightly.' As stars drifted by, the arrow began to wobble away from the vertical. Its height above the orbital plane represented its component in ordinary 3-space, and as it was jostled further and further from its original direction, the neutron stars began to spiral together. Their angular momentum wasn't being radiated away, by meson jets or anything else. It was being converted into extra-dimensional spin.
Karpal watched the animation with a dazed expression. Elena touched his arm. 'Are you all right?'
He nodded. Paolo knew that this was what he'd joined the Diaspora to find, as much as any planet's refugee. He'd watched from the moon as Lacerta spiraled down, unable to make sense of the process, while thousands of fleshers died because no one could explain it, no one could convince them it was real.
Paolo was feeling disoriented himself. The Transmuters remained as elusive as ever, but this non-sentient tool of another civilization entirely had just casually answered the question that had driven the Diaspora across three universes.
Or half the question.
He summoned up a map of the Milky Way, every star labeled with gestalt tags indicating mass and velocity. 'Can you read this?'
