Diaspora

Yatima was beginning to feel a kind of vertigo. The Fomalhaut Blanca's remote, hypothetical, six-dimensional universe of universes had suddenly become as real as the space of the Diaspora itself. As real, and perhaps accessible. For a space-faring civilization to step into the macrosphere was like a bacterium in a rain drop finding a way to stride across continents—and there was a vestigial ancestral temptation to respond to the scale and strangeness of this revelation with paralytic awe. Yatima struggled to concentrate on the practicalities.

"If we could work out macrosphere physics in enough detail, do you think we could cause the singularity to emit a stream of particles that coalesced into a functioning C-Z clone? Or maybe we could start with a cloud of raw materials, then create nanomachines to fabricate the polis?"

Blanca said, "You're going to need something more like femtomachines, I think. Femtomachines larger than the universe. Do you want the laws of macrosphere physics?" Ve moved down through the scape a few layers, then reached into the blue colloid. As Yatima approached, Blanca opened vis dark palm to expose a single blue speck, which was radiating a gestalt tag.

"What is this?"

"Five spatial dimensions, one time. A 4-sphere as the standard fiber. Physics, chemistry, cosmology, the bulk properties of matter, interactions with radiation, some possible biologies… everything."

"When did you do this?"

"I've had a lot of time, Orphan. I've explored a lot of worlds." Ve spread vis arms to encompass the whole scape. "Every point you see is a different set of rules." Ve ran a hand below the blue sheer from which ve'd plucked the macrosphere rules, "These are six-dimensional space-times. Below is five. Notice how its thinner. But seven is thinner too. Even numbers of dimensions have richer possibilities."

The speck had escaped from Blanca's hand and was drifting hack toward its place in the indexscape, but Yatima had memorized the tag.

"Will you come with me, Blanca? Into the macrosphere?"

Blanca laughed, swimming in worlds, drowning in possibilities.

"I don't think so, Orphan. What would be the use? I've already seen it."

Part Six

Yatima said, "Blanca should he with us. Orlando should be with us."

Paolo laughed. "Orlando would be miserable here."

"Why? Traveling in any kind of scape he liked, with all the comforts of home…"

"You don't know Orlando as well as you think."

"No? Enlighten me."

15

5+1

Carter-Zimmerman polis. Swift orbit

85 803 052 808 071 CST

3 April 4953, 4:33:25.225 UT

A megatau before the cloning, Paolo finally managed to drag Orlando along to the Great Macrosphere Exhibition. A group of physicists had set up the scape, a long hall with an arched roof of leaded glass ribbed with wrought iron, packed with demonstrations of those features of the macrosphere that could be predicted with reasonable confidence. Although Orlando was determined to be part of the expedition, he seemed daunted by the prospect of confronting the exotic reality that the new C-Z clone would inhabit.

Paolo surveyed the hall. Less than a hundred citizens had decided to be cloned, but half the polis had been through the Exhibition. It was almost deserted now, though, and the angle of the light, cued to the number of visitors, gave an impression of late afternoon.

They approached the first exhibit, a comparison of gravity wells in three and five dimensions. The gridded surfaces of two circular tables had been made magically elastic in such a way that placing small spherical weights on them produced funnel-shaped indentations, with the effects of the gradient in each case mimicking the gravitational force around a star or planet in the different universes. The force diminished with distance as if it was being spread out over, respectively, an ever larger two-dimensional surface, producing an inverse-square law, or a four-dimensional hypersurface, yielding a visibly steeper inverse-fourth-power effect. It was a simplified pseudo-Newtonian model, but Paolo wasn't about to scoff; he'd found Blanca's rigorous six-dimensional space-time curvature treatment heavy going, and he'd skimmed over the hard parts where the Einstein tensor equation was derived by approximating the interactions between massive particles and virtual gravitons.

The exhibit said, "These diagrams show the pure gravitational potential, which always produces an attractive force." A disembodied hand appeared and placed a small test particle at the edge of each well, with predictable consequences: both particles fell straight in. "Starting from rest, a collision is unavoidable. But if there's any sideways motion, that alters the dynamics completely." The hand placed a particle on the rim of the first well, but this time gave it a flick that sent it into an elliptical orbit around the central weight.