If that was it, the only people likely to know anything about unusual files of test data coming in from Earth would be the engineers down at Pithead who had worked on the beacon after it was brought up from beneath the ice. Shannon activated the terminal on his desk and entered a command to access the Jupiter Five personnel records. A few minutes later he had identified the engineering project leader in charge of that work as a Californian called Vincent Carizan, who had joined J5 from UNSA’s Propulsion Systems and Propellants Division, where he had worked for ten years after obtaining a master’s degree in electrical and electronic engineering at Berkeley.

Shannon’s first impulse was to put a call through to Pithead, but after a minute or two of further reflection he decided against it. If Hunt had taken such pains to avoid any hint of the subject being interpretable from what went over the communications network, anything could be happening. He was still pondering on what to do when the call-tone sounded from the terminal. Shannon cleared the screen and touched a key to accept. It was his adjutant officer calling from the command center.

"Excuse me, sir, but you are scheduled to attend the Operations Controller’s briefing in O-327 in five minutes. Since nobody’s seen you this morning, I thought maybe a reminder might be called for."

"Oh . . . thanks, Bob," Shannon replied. "Look, something’s come up, and I don’t think I’m going to be able to make it. Make excuses for me, would you?"

"Will do, sir."

"Oh, and Bob . . ." Shannon’s voice rose suddenly as a thought struck him.

The adjutant looked up just as he had been about to cut the call. "Sir?"

"Get here as soon as you’ve done that. I’ve got a message that I want couriered down to the surface."

"Couriered?" The adjutant appeared surprised and puzzled.

"Yes. It’s to go to one of the engineers at Pithead. I can’t explain now, but the matter is urgent. If you don’t waste any time, you should be able to make the nine o’clock shuttle down to Main. I’ll have it sealed and waiting by the time you get here. Treat this as grade X-ray."

The adjutant’s face at once became serious. "I’ll be there right away," he said, and the screen went blank.

Shannon received a brief call from Pithead shortly before lunch, advising that Carizan was on his way up to Jupiter Five via Ganymede Main Base. When Carizan arrived, he brought with him a printout of a file of data, supposedly relating to tests performed on the Ganymean beacon, that had materialized in the computers at Pithead that very morning after coming in from Earth over the link and being relayed down to the surface. The engineers at Pithead had been puzzled because the file header was out of sequence and contained references that didn’t match the database indexing system. And nobody had known anything about any tests being scheduled of the kind that the header mentioned.

As Shannon had anticipated, the file contained just numbers-many groups of numbers, each group consisting of a long list of pairs; it was typical of the layout of an experimental report giving readings of interrelated variables and would have meant nothing more to anybody who had no reason not to accept it at face value. Shannon called together a small team of specialists whose discretion could be trusted, and it didn’t take them long to deduce that each group of pairs formed a set of datapoints defined by x-y coordinates in a 256-by-256 matrix array; the hint had been there in the crossword. When the sets of points were plotted on a computer display screen, each set formed a pattern of dots that looked just like a statistical scattering of test data about a straight-line function. But when the patterns of dots were superposed they formed lines of words written diagonally across the screen, and the words formed a message in English. The message contained pointers to other files of numbers that had also been beamed through from Earth and gave explicit instructions for decoding them, and when this was done the amount of information that they yielded turned out to be prodigious.

The result was a set of detailed directions for Jupiter Five to transmit a long sequence of Ganymean communications coding groups not into the UNSA net but outward, toward coordinates that lay beyond the edge of the solar system. The contents of any replies received from that direction were, the directions said, to be disguised as experimental data in the way that had thus been established and communicated to Navcomms via the laser link.

Shannon was weary and red-eyed due to lack of sleep by the time he sat down at the terminal in his stateroom and composed a message for transmission to Earth, addressed to Dr. Victor Hunt at Navcomms Headquarters, Houston. It read:

Vic,

I’ve talked to Vince Carizan, and it’s all a lot clearer now. We’re running some tests on it as you asked, and if anything positive shows up I’ll have the results sent straight through.

Best wishes,

Joe

Hunt lounged back in the pilot’s seat and stared absently down at the toytown suburbs of Houston while the airmobile purred along contentedly, guided by intermittent streams of binary being directed up at it from somewhere below. It was interesting, he thought, how the patterns of movement of the groundcars, flowing, merging, slowing, and accelerating in unison on the roadways below seemed to reveal some grand, centrally orchestrated design-as if they were all parts of an unimaginably complex score composed by a cosmic Bach. But it was all an illusion. Each vehicle was programmed with only the details of its own destination plus a few relatively simple instructions for handling conditions along the way; the complexity emerged as a consequence of large numbers of them interacting freely in their synthetic environment. It was the same with life, he reflected. All the magical, mystical, and supernatural forces invoked through the ages to explain it were inventions that existed in the minds of misled observers, not in the universe they observed. He wondered how much untapped human talent had been wasted in futile pursuit of the creations of wishful thinking. The Ganymeans had entertained no such illusions, but had applied themselves diligently to understanding and mastering the universe as it was, instead of how it seemed to be or how they might have wanted it to be. Maybe that was why the Ganymeans had reached the stars.

In the seat next to him, Lyn looked up from the half-completed crossword in the Interplanetary Journal of a few days earlier. "Got any ideas for this-‘It sounds like a lumberjack’s musical number.’ What do you make of that?"

"How many letters?" Hunt asked after a few moments of thought.

"Nine."

Hunt frowned at the flight-systems status summaries being routinely updated on the console display in front of him. "Logarithm," he said after another pause.

Lyn thought about it, then smiled faintly. "Oh, I see sneaky. It sounds like ‘logger rhythm.’"

"Right."

"It fits okay." She wrote the word in on the paper resting on her lap. "I’m glad that Joe Shannon had fewer problems with it than this."

"You and me both."

Shannon’s confirmation that the message was understood had arrived two days earlier. The idea had occurred to Hunt and Lyn one evening while they were at Lyn’s apartment, solving a puzzle in one of Hunt’s books of London Times crosswords. Don Maddson, the linguistics expert at Navcomms who had studied the Ganymean language, was one of the regular compilers of the Journal puzzles and also a close friend of Hunt’s. So with Caldwell’s blessing, Hunt had told Maddson as much as was necessary about the Gistar situation, and together they had constructed the message transmitted to Jupiter. Now there was nothing to do but wait and hope that it produced results.