The macrosphere's four-dimensional standard fiber yielded a much smaller set of fundamental particles than the ordinary universe's six-dimensional one. In place of six flavors of quarks and six flavors of leptons there was just one of each, plus their antiparticles. There were gluons, gravitons, and photons, but no W or Z bosons, since they mediated the process of quarks changing flavor. Three quarks or three antiquarks together formed a charged 'nucleon' or 'antinucleon,' similar to an ordinary proton or antiproton, and the sole lepton and its antiparticle were much like an electron and positron, but there was no combination of quarks analogous to a neutron.
Orlando scrutinized the table of particles. 'The lepton is still much lighter than the nucleon, the photon still has zero rest mass, and the gluons still act like gluons… so what shifts the chemical energy closer to the nuclear?'
'You saw what happened with the gravity wells.'
'What's that got to do with it? Ah. Same thing happens in an atom? Electrostatic attraction also goes from inverse-square to inverse-fourth, so there are no stable orbits?'
'That's right.'
'Hang on.' Orlando screwed his eyes shut, no doubt dredging ancient memories of his flesher education. 'Doesn't the uncertainty principle keep electrons from crashing into the nucleus? Even if there's no angular momentum, the attraction of the nucleus can't squeeze the electron's wave too tightly, because confining its position just increases its momentum.'
'Yes. But increases it how much? Confining a wave spatially has an inverse effect on the spread of its momentum. Kinetic energy is proportional to the square of momentum, making that inverse-square. So the effective 'force,' which is the rate of change of kinetic energy with distance, is inverse-cube.'
Orlando's face lit up for a moment with the sheer pleasure of understanding. 'So in three dimensions, a proton can't ever make an electron crash, because the uncertainty principle is just as good as centrifugal force. But in five dimensions, that's not good enough.' He nodded slowly, as if coming to terms with the inevitability of it. 'So the lepton's wave shrinks down to the size of the nucleon. Then what?'
'Once the lepton's inside the nucleon, it's kink—pulled inward by the portion of the charge that's closer to the center than it is itself, which is roughly proportional to the fifth power of the distance from the center. That means the electrostatic force stops being inverse-fourth-power, and becomes linear. So the energy well isn't bottomless; outside the nucleon it's too steep for the lepton to 'brace itself' against the sides, the way an electron does in three dimensions, but inside the nucleon the sides curve together and meet in a paraboloid.'
They moved on to the first chemistry exhibit, which showed the paraboloid bowl at the bottom of the well, with a translucent electric-blue bell-shape superimposed over it: the lepton wave in its lowest-energy, ground state. Orlando reached in and touched it; it flickered into an excited state, breaking apart and deserting the center to form two distinct lobes, one of them color-coded red to indicate an inverted phase. After a few tau the whole wave flashed green, spontaneously emitting a photon, and fell back to its lowest energy level.
'So this is the macrosphere's equivalent of a hydrogen atom?'
Paolo prodded the wave himself, trying to get it to the next highest level. 'More like a cross between a hydrogen atom and a neutron. There are no neutrons in the macrosphere, but a positive nucleon with a negative lepton buried in it to cancel its charge makes a rough imitation of one. Blanca called it a 'hydron.' If you try to join two of them together to make a 'hydron molecule' you end up with something more like deuterium.' The exhibit, overhearing him, obligingly provided an animated demonstration.
Orlando exhaled heavily. 'I don't know how you can take this so calmly. Do you really trust anyone in C-Z to build an entire working polis according to these rules?'
'Maybe not, but if they get it wrong we won't even know about it. I can't see us shipwrecked in the macrosphere with the hardware disintegrating slowly beneath us. It'll be all or nothing: a working polis, or a cloud of random molecules.'
'You hope. How are they even going to make molecules, if every chemical bond triggers nuclear fusion?'
'Not every bond does. If you throw enough hydrous together, the leptons fill up all the energy levels where they're confined tightly within the nucleus, so the outermost ones end up protruding sufficiently to be able to bind two atoms together with a respectable separation between the nuclei. You have to fill up the first two levels completely, which takes twelve leptons—so every stable molecule needs to contain a few judiciously placed atoms of number 13 or higher. Atom 27 can form fifteen covalent bonds; it's the closest thing in the macrosphere to carbon.' The exhibit showed them a three-dimensional shadow of a five-dimensional, sixteen-atom molecule: one atom of 27, joined to fifteen hydrons. Paolo said, 'Think of this as a souped-up version of methane. If you knock off any of these hydrons and substitute a side branch, you can build all kinds of elaborate structures.'
Orlando was beginning to look besieged. As he glanced down the hall toward distant speculation on biochemistry and body plans, something caught his eve. ''U-star polymers.' What does 'U-star' mean?'
Paolo followed his gaze. 'That's just another crane for the macrosphere. U is the ordinary universe, and the star is mathematical notation for its 'dual space'-that's a term used for all kinds of role-reversals. The universe and the macrosphere are both ten-dimensional… but one has six small dimensions and four large, the other has six large and four small. So they're inside-out versions of each other.' He shrugged. 'Maybe it's a better name. 'Macrosphere' captures the difference in size, but that hardly matters; once we're there, we'll be operating on roughly the same scale as any comparable lifeform. It's the fact that the physics has been turned inside-out that will make all the difference.'
Orlando was smiling faintly. Paolo asked, 'What?'
'Inside-out. It's nice to know that's the official verdict. It's how I've felt about it all along.' He turned to Paolo, his expression suddenly, painfully naked. 'I know I'm not flesh and blood. I know I'm software like every one else. But I still half believe that if anything happened to the polis, I'd be able to walk out of the wreckage into the real world. Because I've kept faith with it. Because I still live by its rules.' He glanced down and examined an upturned palm. 'In the macrosphere, that will all he gone. Outside will he a world beyond understanding. And inside, I'll just be one more solipsist, cocooned in delusions.' He looked up and said plainly, 'I'm afraid.' He searched Paolo's face defiantly, as if daring him to claim that a journey through the macrosphere would be no different from a walk through an exotic scape. 'But I can't stay behind. I have to be a part of this.'
Paolo nodded. 'Okay.' After a moment he added, 'But you're wrong about one thing.'
'What?'
'A world beyond understanding?' He grimaced. 'Where do you get that shit! Nothing is beyond understanding. A hundred more exhibits, and I promise you: you'll be dreaming in five dimensions.'
16
DUALITY
Carter-Zimmerman polis, U*
Orlando stood outside the cabin and watched the last visible trace of his universe recede into the distance. The dome of sky above the Floating Island offered a pinhole view of the macrosphere, revealing only two faint stars; the station they'd built beside the singularity appeared just above the western horizon as a tiny, flashing white light, fading rapidly. The singularity itself was invisible at this distance, but the station's beacon echoed the regular stream of photons emanating from it to mark its position.
If the team on Swift ever stopped creating those photons, the singularity would vanish from sight. A massless anomaly in the vacuum, small as a subatomic particle, it would he almost impossible to find. But then, if no one was sending, no one would be listening either, so there'd be no point scouring the vacuum for the home universe; any data blasted back at the singularity would trigger beta decays in Swift's neutrons to no avail. Some people had expected the singularity to be surrounded by Transmuter artifacts, but Orlando hadn't been surprised
