"Amazing," Hunt murmured. There were times, he thought, when he would have liked to be able to pull that stunt with Danchekker himself.

A knock sounded lightly on the door. Hunt and Lyn’s heads jerked around to look at it, turned back to meet each other’s questioning looks, then stared at the door again. Lyn shrugged and moved across the room toward it. Hunt switched off the terminal and looked up to find the eight-foot-tall figure of a Ganymean straightening up after ducking through the doorway. Lyn stood speechless with surprise as she held the door open.

"Dr. Hunt and Miss Garland," the Ganymean said. "First, on behalf of all of us, I apologize for the somewhat bizarre welcome. It was necessary for some very important reasons, which will be explained when we all get together very shortly. I hope that our leaving you on your own like this hasn’t seemed too bad-mannered, but we thought that perhaps a short period of adjustment might be beneficial. I am Porthik Eesyan-one of those you were expecting to meet."

Eesyan was subtly different in form from the Ganymeans of the Shapieron, Hunt noticed as they walked. He had the same massive torso lines beneath his loose-fitting yellow jerkin and elaborately woven shirt of red and amber metallic threads, and the same six-fingered hands, each with two thumbs, but his skin was darker than the grays that Hunt remembered-almost black-and seemed smoother in texture; his build was lighter and more slender, his height slightly less than would have been normal, and his lower face and skull, though still elongated significantly, had receded and broadened into a more rounded head that was closer to the human proffle.

"We can move objects from place to place instantaneously by means of artificially generated spinning black holes," Eesyan told them. "As your own theories predict, a rapidly spinning black hole flattens out into a disk, and eventually becomes a toroid with the mass concentrated at the rim. In that situation the singularity exists across the central aperture and can be approached axially without catastrophic tidal effects. The aperture affords an ‘entry port’ into a hyperrealm described by laws not subject to the conventional restrictions of ordinary spacetime. Creating such an entry port also gives rise to a hypersymmetric effect that appears as a projection elsewhere in normal space, and which functions as a coupled exit port. By controlling the dimensions, spin, orientation, and certain other parameters of the initial hole, we can select with considerable accuracy the location of the exit up to distances in the order of several tens of light-years."

Eesyan between Vic and Lyn, they were walking along a broad, enclosed, brightly illuminated arcade of soaring lines, gleaming sculptures, and vast openings, which led into other spaces. There were more Escher-like distortions and inversions here and there in the scene, but nothing as overwhelming as the sight they had first seen from the perceptron. Apparently Ganymean gravitic engineering tricks came with the architecture on Thurien. For this was Thurien. They had emerged from the room and walked through a series of galleries and a huge domed space bustling with Ganymeans, eventually to this place, the illusory blending so smoothly into reality that Hunt had missed the point along the way at which the switch from one to the other had taken place. The meeting between the two worlds was about to take place, Eesyan had informed them, and he had been assigned to escort them there personally. No doubt VISAR could have transferred them there instantly, Hunt thought, but this seemed a more natural way while they were still "acclimatizing." And having an opportunity to get to know at least one of the aliens informally in advance helped the process further. Probably that was the idea.

"That must be how you got the perceptron to Earth," Hunt said.

"Almost to Earth," Eesyan told him. "A black hole large enough to take a sizable object creates a significant gravitational disturbance over a large distance. Therefore we don’t project things like that into the middle of planetary systems; it would disrupt clocks and calendars and so on. We exited the perceptron outside the solar system, and it had to make the last lap in a more conventional way."

"So a round trip needs four conventional stages," Lyn commented. "Two one way, and two the other."

"Correct."

"Which explains why it took something like a day to make it from Thurien to Earth," Hunt said.

"Yes. Instant planet-to-planet hopping is out. But communications is another matter entirely. We can send messages by beaming a gamma frequency microlaser into a microscopic black-hole toroid that can be generated in equipment capable of operating on planetary surfaces without undesirable side effects. So instant planet-to-planet data-links are practicable. What’s more, generating the microscopic black holes needed for them doesn’t require the enormous amount of energy that holes big enough to send ships through do. So we don’t do a lot of instantaneous people-moving unless we have to; we prefer moving information instead."

It fitted in with what Hunt already knew: he and Lyn were really at McClusky, and all the information they were perceiving was being transmitted there through VISAR. "That explains how the information gets sent," he said. "But what’s the input to the system? How is it originated in the first place?"

"Thurien is a fully ‘wired’ planet," Eesyan explained. "So are most of the other planets in the portions of the Galaxy where we have spread. VISAR exists all over those worlds, and in other places between, as a dense network of sensors located inside the structures of buildings and cities, distributed invisibly across mountains, forests, and plains, and in orbit above planetary surfaces. By combining and interpolating between its data inputs, it is able to compute and synthesize the complete sensory input that would be experienced by a person located at any particular place.

"VISAR bypasses the normal input channels to the brain and stimulates symbolic neural patterns directly with focused arrays of high-resolution spatial stress-waves. Thus it can inject straight into the mind all the information that would be received by somebody physically present at whatever place is specified. Also it monitors the neural activity of the voluntary motor system and reproduces faithfully all the feedback sensations that would accompany muscular movements and so forth. The net result is to create an illusion of actually being at a remote location which is indistinguishable from the real thing. Physically transporting the body would add nothing."

"Star travel the easy way," Lyn murmured. She gazed around as they came to the end of the arcade and turned off to begin walking across a curved, sweeping surface that had looked like a wall a minute ago, but now seemed to be pivoting slowly as they moved onto it and lifting the whole of the arcade and the structures connected to it up at an increasing angle behind them. "This is all real and twenty light-years away?" she said, still sounding disbelieving. "I really haven’t come here?"

"Can you tell the difference?" Eesyan asked her.

"How about you, Porthik?" Hunt asked as a new thought struck him. "Are you actually here. . . . there. . . . whatever, in Vranix, or what?"

"I’m on an artificial world twenty million miles from Thurien," Eesyan replied. "Calazar is on Thurien, but six thousand miles from Vranix at a place called Thurios-the principal city of Thurien. Vranix is an old city that we keep preserved for sentimental and traditional reasons. Frenua Showm, whom you were also expecting to meet and will very shortly, is on a planet called Crayses, which is in a star system about nine light-years from Gistar."