"It seems as if it could be the key to the whole thing," Hunt said. "Forget all the physics you've heard before, that talks about mass and energy moving through space. That's the physics that happens within a Multiverse reality that you happen to be a part of."

"You mean on some particular time line-like the one we're in here, right now?"

"Exactly. Where serial ordering gives rise to the perception of change, unfolding in ways that differential equations describe. Ordinary physics-and that includes all the Thurien h-space business as well-is expressed in the language of change. But the Multiverse itself is changeless. So crossing it would have to involve something other than physical movement. In the JEVEX matrix nothing actually moves. Cells just flip between states."

Caldwell stared while he digested that. It seemed almost obvious once it was spelled out. "Wouldn't the same underlying cell structure apply everywhere, here included?" he queried. "It's all part of the same MV."

"Yes," Hunt agreed. "In fact, Dirac proposed something very like it: a universe filled with a 'sea' of particles in negative energy states. They become observable when they're kicked up to positive states. Antiparticles are the holes left behind. They can move around too, as if they were particles-like holes in semiconductors."

"Go on," Caldwell said.

Hunt arrived back at the window, stared out for a second, then wheeled around and spread his arms sideways along the sill. "The matrix supports two kinds of physics. One, we just mentioned: the familiar kind that describes change, which applies to the event sequences ordered along time lines. The other involves a different form of cross-propagating cell states."

"What kind of propagation speed might we talking about, do you think?" Caldwell inquired.

Hunt shook his head. "I don't know."

"Have you talked to Sonnerbrandt yet?" Josef Sonnebrandt was a quantum theoretician at the Max Planck Institute in Berlin, who probably knew more about Entoverse physics than anyone else at the Earth end of the Jevlen link.

Hunt nodded. "He thinks we're probably talking about basic elements of the dimensions of Planck length switching in Planck time or something like that, but how any of it would translate into the dimensions that we measure things on is impossible to say right now. The Thuriens might be in a better position to guess. They've been doing the experiments. We and they need to get our acts together."

Caldwell sucked at his teeth while he contemplated the desktop. Silence ensued for perhaps half a minute. Hunt turned and stared out at the dark marble-and-glass bulk of the Biosciences building, looming above trees on the far side of one of the airmobile parking areas.

"Then let's do that," Caldwell said.

Hunt turned back to face him again. Caldwell got the feeling that this was what he had been angling for. "Are we talking about a Thurien trip? That's what it would need, Gregg. Would that be on?"

Caldwell gave him a long, pensive look, then nodded. "Okay."

"Seriously?"

"If I say it's on, it's on." Caldwell studied him for a moment longer. "You know, Vic, you don't seems as surprised as you would have been in days gone by. What's happening? Does it come with getting older?"

"No, it comes from getting to know you. Nothing could surprise me anymore."

"Well, that works both ways." Caldwell turned to one side and touched a key on the desk unit. The face of his secretary, Mitzi, in the outer office, appeared. "Did you talk to Farrell?" he inquired.

"Yes, I did. He says how about ten tomorrow? You're clear then."

"That's fine. And another thing, Mitzi. Could you get on the h-net and see if VISAR can raise Porthik Eesyan at Thurien? Also, I'd like the schedule of the Thurien ships that will be here and when, over, say, the next month."

"Going on vacation?"

"I think we've maybe found another job for Vic."

"I should have guessed. Will do."

Caldwell cleared down and looked back at Hunt. "I think I'm pretty much past surprises, too. The last time I sent you anywhere, you came back with a Universe. This time it's the entire Multiverse. That's it, the ultimate. It has to be. You can't get any bigger than that. Am I right?"

They stared at each other for a second. Then Hunt's face split into a grin. They were in business once again. He obviously liked the feeling. Caldwell allowed his craggy features to soften into the hint of a smile and snorted. "What about Josef in Berlin?" he asked, getting back on track. "Do you figure you could use him along, too?''

"Sure-if he's up to it. Want me to sound him out?"

"Yes, do that. And I guess it goes without saying that Chris Danchekker's going to want to be in on it, too. We can put it to him at the dinner for Owen tonight, after you make the big announcement."

"Sounds good," Hunt agreed.

So far, the story of Hunt's contact with another version of himself had not gone beyond a select few among UNSA's senior management and scientific staff. A dinner was being held that evening in honor of one of the original UNSA founders, who was retiring, at which Hunt was due to say some words of appreciation on behalf of the physical sciences side of the operation. Someone had suggested that this might be a good opportunity to make the news of Hunt's strange experience public. Caldwell's initial reaction had been negative on the grounds that such a bombshell would risk eclipsing Owen on what was supposed to be his night, after all. Hunt had felt that it could just as well work the other way: having one's retirement dinner cited as the occasion when the world had been was told could be the best memorial to a lifetime's work that anyone could wish for. In the end they had decided to put it to Owen and let him decide. Owen's answer was that he could think of no greater honor than to have his name linked with what could qualify as one of the most exciting scientific revelations of all time.

"I take it we're still going ahead," Caldwell said. People did have second thoughts about things like this.

"I was planning to double-check with Owen before I get up to speak," Hunt answered. "I can always switch to a fallback routine of Irish jokes or something if he changes his mind." Caldwell nodded that they were both thinking the same way.

The screen by his elbow came to life again to show an elongated Ganymean head, dark gray in color, with a protruding chin and vertical gothic lines framing large, ovoid eyes. The shoulders were covered by the top of a light orange tunic, with a yellow collar enclosing the neck. The countenance compressed in the way Caldwell had learned to recognize as an alien grin.

"Porthik Eesyan," Mitzi's voice announced. "I told him Vic is with you. He says it sounds like a sure sign of trouble ahead."