The Lure

8 Decode

‘Look at you! You’ve got to eat.’

Petrie stared dully at Freya. It was some seconds before he brought himself back from his world of swirling blizzards. ‘What’s the time?’

She looked at the clock on his terminal. ‘Just after eleven. The others have eaten.’

‘I’m not hungry.’

‘You are. And Vashislav’s made something for us.’

‘It’s probably squashed octopus.’

‘What?’

‘Never mind. Okay, I’ll be along.’

She took him firmly by the arm. ‘Nice try, but you’re coming now.’

‘You remind me of my mother.’

Shtyrkov had been busy. Freya steered him to the first-floor canteen, if canteen was the word for the chandeliered elegance and gleaming silverware which greeted him. She sat him down at a table set for three, spread with a white tablecloth. He surveyed the bowls with brown bread, olives, gherkins, salad and fruit. A bottle of vodka took pride of place at the centre of the table. Through the windows, a flicker of distant lightning briefly lit up heavy clouds and forested hills.

‘Where are Charlie and Svetlana?’

Freya poured the vodkas. ‘Gone to bed.’ She smiled mischievously. ‘Separate beds, that is. Are you making progress?’

Petrie massaged his forehead. He felt as if his head was splitting in two. ‘Maybe. I don’t know. Where does the food come from?’

‘There’s a big freezer. And Vash tells me fresh food will come with the cleaners in the mornings. They’ll be here for an hour each day. The castle administrator is keeping out of it but Charlie has his home number if we need anything.’

‘An entire castle to ourselves. He carries some clout, does our Russian colleague.’

‘And I can cook,’ Shtyrkov boomed, appearing from a side room with a tray. ‘A talent which I owe to my Great-aunt Lidia. First, we have caviar.’ He set a large bowl of some chilled purée on the table and sat down heavily. ‘Poor man’s caviar, that is. A Georgian spread made of aubergines, tomatoes, garlic, sugar, lemon juice and pepper. Tom, tell us what you have found.’

‘Nothing.’

Shtyrkov smiled sceptically. ‘You are a bad liar. You can hardly keep your eyes open. Something is driving you.’

Damn the man. I’m not ready to talk about it. ‘Maybe something.’

Freya’s eyes widened. ‘Maybe something? What exactly?’

Petrie spread the fake caviar on a hard, flat square of bread. It was his first taste of food since Shtyrkov’s commandeered biscuits and he savoured the sharp, tangy taste. He wiped his mouth and said, ‘Patterns. But no more than gusts of wind in a storm. Who knows what furnace these things came out of? I don’t see evidence of an intelligence lying behind them.’

Shtyrkov seemed unperturbed by Petrie’s negative comment. He smiled slyly and poured vodka to the brims of their vodka glasses. He nodded at Petrie’s T-shirt. ‘You play chess?’

‘Sort of. Come on, Vash, what makes you think there’s something in that particle burst?’

Shtyrkov raised four fat fingers. ‘Yon. Tesera. Chetire. Cuatro. Quattre. Quattro. Vier. Four.’

Petrie looked at the Russian with astonishment. Groupings of four, additions up to four, foursome reels, the bewildering fact had come to Petrie as the merest glimmer after hours of mind-breaking work. He said, casually, ‘Okay. But I can’t make sense of it. Not yet.’

Shtyrkov grinned but said nothing. Freya poured tea.

‘People have always assumed that extraterrestrials, if they exist, would send out radio signals,’ Petrie said. ‘Nobody thought about weird particles.’

Shtyrkov sipped the vodka with satisfaction. ‘Ice cold, as it should be. Extraterrestrials, however, may not feel bound by our limitations.’

‘A Harvard/Princeton team are searching for laser pulses,’ Freya said. ‘They’re using a modest telescope and they could pick up signals out to a hundred light years, maybe a thousand.’

‘And let me tell you why, young Miss Freya, or has Anglo-Saxon angst spread to Norway and you prefer Ms?’

Freya laughed but didn’t rise to Shtyrkov’s provocative bait. The Russian continued, ‘Bandwidth. Red light has a frequency thirty thousand times higher than microwave radio. In the time taken for a radio wave to arrive, thirty thousand light waves do so. Information is transmitted thirty thousand times faster. Equipment is smaller and more mobile: an intelligence could easily fire signals at ten solar systems a second if it was trying to make contact with other life forms. And one other thing. The Galaxy is awash with radio waves, from pulsars, nebulae, even stars. But I very much doubt if, anywhere, Mother Nature fires nanosecond laser pulses. Find one and there can be no confusion with a natural source.’

There was a rumble and lights flickered briefly. Petrie felt the icy vodka burning his lips and then warming his alimentary canal all the way down to the stomach. ‘You mean, why use radio when you have lasers?’

‘Why have cotton when you can have silk? Radio searches happen now because they happened first. They are an accident of history, a hundred-year slice of our technological evolution. Better means to communicate already exist.’

‘If you’re operating on timescales of thousands or millions of years, lasers may have a short shelf life too.’

Shtyrkov nodded. ‘Exactly. To an advanced signaller, they would have the byte rate of smoke signals. You learn fast, young Tom. And because the higher the frequency the more efficient the communication, why stop at electromagnetic radiation at all? Weird particles, as you call them, carrying energy beyond even gamma rays, would be much more effective at transmitting information. A few thousand years down the line and we too will be firing them into space.’

‘I ought to get back to it.’ Petrie pushed back his chair.

Shtyrkov was heaping Georgian caviar thickly on to flat bread. ‘Tom, bypass a thirty-year learning curve by absorbing the following truth, from Ecclesiasticus chapter 38, I think: “A scholar’s wisdom comes of ample leisure.” Did Plato rush to catch a bus? Was Socrates ever twitching to get back to his computer terminal? My chicken tabaka is flattened, fried, crisp and juicy, and it is ready. Ready, that is, to serve with a prune sauce, sour cream and red pickled cabbage. Now, do you propose to insult me by refusing my laboriously prepared feast?’

‘If you put it that way.’

There was a bright flash, and this time the rumble of thunder was closer.

Freya spoke firmly. ‘Look at you, Tom. You can hardly keep your eyes open. When we’ve eaten, I’m taking you to bed.’

Petrie thought that Freya’s command of English was probably less than perfect.

Petrie needed sleep. He had to lie down, put his head on a pillow, shut his eyes and sleep.

Freya, it seemed, had adopted the role of a surrogate mother. After Shtyrkov’s main course — a squashed chicken rather than a squashed octopus — exhaustion had overcome Petrie to the point where he could hardly stand up. Freya had taken him by the arm and led him up the stairs. Even in his exhausted state he had enjoyed the warmth, the scent, the animal femininity of this young Norwegian woman. She had gently eased him into his room and wished him a good night.

He threw off his clothes, pulled down the blankets and flopped.

But the blizzard was still swirling. Petrie could see it in the ceiling, and on the walls, and in all the dark corners of his room.

This was different from Bletchley.

In war, strenuous efforts were made to veil the message. Victory and defeat in battle, and even the outcome of a war, might nowadays depend as much on a contest between distant mathematicians as it once did between armies. If the Germans had known about Bletchley, they might have changed the course of the war with a single bombing raid. But if Shtyrkov’s lunatic conjecture was right, nobody would be trying to hide anything. On the contrary, the signallers would be trying to communicate.

Even so, Petrie thought, his mind whirling, exhausted but unable to stop, how can they judge the mental level of the people they’re trying to reach? He could still be an ape trying to understand a Fortran computer program.

He heard Freya’s door closing next to him, visualised her taking her clothes off, sliding naked between sheets, just a few feet away.

As he drifted off, rain began to batter against the window. And once again Sampson-Kildare, the old horror, was croaking:

And now Sampson-Kildare was high on a ledge in the big cavern, shooting bullets through the lake. He paused to reload his machine gun, but only for a microsecond. The next burst of fire was somehow different from the one before. And then another tiny time gap, and another surge of bullets.

And the bullets were going through the lake faster than light and the lake was glowing and Sampson-Kildare was saying that’s because the eye can’t see flickering faster than a fiftieth of a second in duration, and he was sometimes firing millions of bullets through the lake in a microsecond, and at other times he was smoking and firing only a few thousands at a time.

And the bullet patterns were sometimes filling just one patch of the lake, or sweeping round it like a searchlight.

And yet not like a searchlight. It was more of a corkscrew or spiralling motion.

No, more like two searchlights, counter-rotating. And now there were two machine-gunners, the surface of the lake spitting as the stream of bullets danced around each other like a gunfighter’s ballet, and Sampson-Kildare was leaping around grotesquely on the ledge and croaking:

BANG!

Rattling windows; a flash of light penetrating his eyelids. Petrie wakened with a gasp, staring into the dark. Heavy rain was battering on his window.

Impossible! Utterly impossible!

He threw back the blankets, groped for a light and dressed quickly. Shaking, he went out into the darkened corridor and felt his way along it. He could just make out the top of the marble stairs. Another flash momentarily lit them up and he descended cautiously, his eyes adapting to the dark. The headache had gone.

He hurried along to the theological library and groped for light switches. There were three of them and he switched them all on. He realised that he had left his computer running. To his relief, as he tapped at the keyboard, he found that the thunderstorm hadn’t affected it.

He looked again at the particle storm on his screen. Parallel lines, and yet, not just parallel lines. The particles didn’t like to crowd too close together. Petrie thought this might be down to their physics: maybe they repelled each other at short range or whatever. Nothing to do with aliens or similar rubbish.

There had always been a slightly mad streak running through Russian science. The Tunguska meteorite was a crashed flying saucer, or the innermost satellite of Mars was an ancient space station, crap like that. Maybe Shtyrkov was part of that tradition.

And in any case, order could be created out of chaos. Petrie thought there were maybe complicated force laws between the particles and that these forces had generated patterns during the long interstellar journey.

He rubbed his face with his hands and groaned with tiredness. Belousov and Zhabotinskii, more damned Russians. They’d mixed citric and sulphuric acids, added salts and chemicals, and within the mixture, as by a miracle, wonderful red-blue pulsations had appeared, and circular waves had come and gone, and spiral patterns had chased each other around the mixture. And it had all grown just from chaos, from the disequilibrium of the chemical mixture. They’d been beaten to their discovery by forty years, by William Bray, but his contemporaries hadn’t believed you could get chemical reactions to oscillate, hadn’t bothered to follow it up, and the man had died in obscurity, the Russians now collecting the kudos denied Bray by the idiocy of his colleagues.

Instead of looking at an indecipherable mass of lines, why not reduce each particle to a point? Imagine a flat surface, face-on to the flow, and record each particle’s point of intersection with the plate. Like a telescope pointing to the signal source.

That would take programming. Hell, the Earth’s rotation.

Svetlana!

He ran back through the corridors and up the stairs. One, two … seven doors along. He knocked sharply. The sound of a body stirring within. ‘Svetlana!’

A light switched on. Svetlana appeared, wearing an ankle-length yellow gown, curiosity and tiredness on her face.

‘I need help.’

‘What’s the time?’

‘I’ve no idea.’

She disappeared and reappeared in a moment, wearing sandals and putting her arms into the sleeves of a long, red cotton dressing gown. ‘It’s nearly two o’clock.’

He explained as they went. ‘The flow of particles. I need to see them face-on.’

‘You mean turn the trajectories into points?’

‘Yes. Can you do that?’

She slipped a hand under her gown and scratched her shoulder. ‘You’re in luck, Tom. I can swivel the lake around.’

She took the stairs two at a time, leaving a faint trail of perfume. Or was it hair shampoo? In the computer room she fired up, typed, and over her shoulder Petrie saw an erratic, roughly oval blue shape appear on her screen. She flicked her hair back and traced the shape out on the computer terminal with a red-painted fingernail. ‘That’s the lake looking straight down from a great height. And you can spin it so that it’s face-on to the particle flow. Look.’

A single frame appeared on the screen, the lake penetrated by thousands of straight lines. She clicked on a little icon and the picture tumbled and the lines shrank until Petrie found himself looking, not at a confusing jumble of lines, but at a pattern of dots.

Svetlana scribbled a few lines in a spiral notebook and tore the sheet out. ‘Here are the instructions. You can take it a frame at a time, freeze it, run it forwards or backwards at any speed and so on, just like a video recorder.’ She pressed the return key and a little cluster of dots appeared near the edge of the lake. In the next frame they had vanished, but a second cluster had appeared, near the far end of the lake. ‘And here’s the disk, you can copy it over.’

‘Svetlana, I’ll buy you summer roses.’

She screwed up her nose.

In the library, Petrie started again, but this time with dots rather than lines; and this time the patterns showed up with great clarity. He ran the frames like a slow-motion movie. Clusters of dots waltzed slowly around each other; but frame by frame, the number of dots in each cluster changed.

Then nothing — the particle flow had stopped — and then another sequence of changing patterns, looking completely different from the last.

He went back to the previous batch, the one with the waltzing clusters. And the thing which had been trying to crawl up out of his unconscious mind began to surface. A thing even crazier than Shtyrkov’s rantings.

He put it aside, didn’t dare to think of it.

He zoomed into the clusters. At higher magnification there were clusters within clusters: in each cluster in each frame, the particles were grouped. But one level of clustering was different; at this level, there were never more than four dots together. Sometimes a particle was solitary, sometimes it had a single companion or two or three, sometimes there were two pairs. But never more than four.

He wrote down the pattern on Svetlana’s spiral notebook, and saw for the first time that his hand was trembling. He put them in order:

1, 2, 3, 1, 1–1, 1–2, 1–3, 2, 2–1, 2–2, 2–3, 3, 3–1, 3–2 …

Drop the dashes. Put them into an array:

What about zero? How would zero particles be recorded? Without worrying about that, Petrie put in zeros where they seemed to make sense:

He said, ‘Oh God!’ aloud.

Four-base arithmetic. A counting system. The one we’d have developed if we’d had only four fingers. Converted to the familiar ten-base, the same numbers read by a ten-fingered creature were:

He went back to the spirals. Here the signallers were counting up to three, no further. Here, if anywhere, he was going to crack the code — if there was a code.

He took a pulse at random, 7.34159 seconds into the particle blast. They had tracked across the lake in two counter-rotating spirals, a fact which he ignored. He counted the little clumps along one of the spirals, a frame at a time, converting them to four-base arithmetic: 210333223132212310 …

For the hell of it, he put A = 0, B = 1 and so on: CBADDDCCDBDCCBCDBA …

There were no E’s or F’s. It looked utterly random. All he could say was that they were using a four-letter alphabet.

A four-letter alphabet.

They.

Petrie had come across a four-letter alphabet before. His mouth was dry.

He went to the second spiral of particles, the one which had waltzed with the first one. The particles here too were bunched in little groups of up to four. He did the same letter substitution and asked the computer to line up the letters from each spiral, in two long columns.

A pattern.

The two columns were thousands of rows long, each one looked totally random, and yet no two rows had the same letter. In fact, A in column one was invariably matched by B in two. B in one was matched by A in two and so on. He wrote:

He glanced at the computer clock for the first time in hours. It was five past four. And now the excitement which had been growing inside him was at the point where he felt himself going faint.

He stacked the movie frames one on top of the other, starting at the beginning of the blizzard. The program took an hour to put together. He kept making elementary blunders and knew he could have done the job in a third of the time had he been fresh. Finally he had something cobbled together. The clock said 5.40 a.m.; it would soon be dawn. He was light-headed with exhaustion.

He stacked the frames into a solid, three-dimensional shape. He made the shape tumble slowly on the screen.

And he felt something like fear.

Now, at last, he took the time to sum up his night’s work.

There were the rotating spirals: the double helix, now slowly tumbling on his screen, joined by rungs.

There was the four-lettered alphabet which ran through the rungs of the spiral ladders.

There was the complementarity, each letter on one half of the rung being matched by a consistent, different letter on the other half.

ABCD, an arbitrary choice of letters. Replace by AGCT.

Adenine, guanine, cytosine, thymine.

The building blocks of DNA.