15.
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 h.e.l.l of it, he put A = 0, B = 1 and so on: CBADDDCCDBDCCBCDBA ...
There were no Es or Fs. 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 subst.i.tution 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: A.
B.
B.
A.
C.
D.
D.
C.
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 nights 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.
9.
Genome Gibson spotted Petrie a couple of hundred metres away. The mathematician was wandering down the long path outside the castle; his head was bowed and he seemed to be muttering. His hands were waving as if he was addressing an imaginary audience. The path went towards the village but Gibson suspected the young man didnt know where he was going.
A light mist was clearing from the trees and the early morning sky was blue, but there was ice in the wind.
Gibson took a short cut over the snow and caught up with Petrie at the church. The mathematicians eyes were bloodshot and he had an overnight stubble. His face was drawn, almost as if he was in pain. He looked at Gibson vaguely, as if he didnt recognise the man.
"For Christs sake, Tom, look at you. Get to bed.
"What about the others? Petrie asked. The words came out slurred.
"They flaked out hours ago.
"What about Freya? Petrie didnt know why hed asked that; it just came out.
"Shes up early, like me. Shes reading a ton of downloads in the computer room.
"Has she made progress?
Gibson made a so-so facial gesture. He was now pacing alongside Petrie; they turned left along a quiet road. A middle-aged man was sitting humped forwards on a hay-cart pulled by a small horse, sacking over his head and shoulders to protect him from the cold. There was an exchange of "Dobryden, and then the horse had clip-clopped past them. The smell of hay and horse lingered in the cold morning air.
"What about you?
Petrie gave Gibson a strange look. He said, "I have something to announce.
Gibson stopped. "Well?
"Get them out of bed, Charlie. I want everyone to hear this together.
"I run this outfit. Tell me what youve got.
"This is for your team to hear.
"Tom!
Petrie relented; the man was like a starved dog waiting for a biscuit. He said, "Okay, I tell the team but you get the preview. The signal is intelligent.
For some seconds Gibson could have been a statue. He peered into Petries eyes, looking for clues. Then he gave a sort of moan, like a man in a trance. He performed a brief Zorba the Greek dance on the road, clicking his fingers and laughing. Finally his eyes widened, he shouted, "G.o.d in heaven! and sprinted back along the road, pa.s.sing the hay-cart and swerving right up the hill towards the castle. Petrie carried on walking, humming to himself.
In a minute Petrie heard running footsteps. He turned. Gibson had reappeared at speed, arms waving to keep balance on the slippery road. His mood had swung from beat.i.tude to desperate anxiety. He stopped at Petrie, his chest heaving with the sprint. "Pulsars. f.u.c.king pulsars. Bleep bleep bleep in the Cambridge radio telescope. A secretive lot, that group, they sat on it for six months because they thought they were detecting little green men only it turned out they werent little green men, they were spinning neutron stars. He glared fiercely at Petrie, looking for rea.s.surance.
"Charlie, pattern recognition is my business. Its why you asked me here, remember? No natural process could produce what you detected. That signal is the product of a mind.
Charlie smiled again, an enraptured saint. "The discovery of all time. The n.o.bel for sure.
"A n.o.bel Prize, Charlie, but thats the least of it. Think about it. Were not alone. There are thinking beings out there. What effect is this going to have on society?
"Who cares? The effect on me is a n.o.bel Prize. Then: "The pattern really is intelligent? Youre absolutely sure?
"Absolutely.
"You said a mind? A signal? Gibsons face was distorted by a ferocious intensity. "Are you saying its a message?
"I dont know what it is.
Gibson took Petrie by the arm and they reversed direction, back towards the castle and the receding hay-cart. His eyes were lit with an evangelical gleam and his words came out rapidly, almost staccato. "Im very concerned about you, Tom, you need sleep, then you can waken up nice and fresh and crack the code, youll do that, wont you, Tom? Youll wake up nice and fresh and crack the code? Then well all get big juicy n.o.bel Prizes, you for cracking the code and me for being the big cheese and well all be famous just so long as you get some sleep and then wake up and crack the f.u.c.king code for Christs sake, please, just as quick as you can.
10.
Poets Dream After the penetrating cold, the warmth of the castle hit Petrie like a sleeping pill. Gibson, however, was in a high state of excitement. He now decided that the young mathematician could endure a little more sleep deprivation in the name of science. He took Petrie by the elbow, guided him upstairs to the common room, propped him in a chair and bustled through to the kitchen. Presently he came back with a mug of strong, sweet, black coffee. "The cleaners turn up about eight, he said for no obvious reason. Then he vanished, singing loudly and tunelessly.
Freya and Svetlana were first to appear, Svetlana in black jeans and sweater, Freya in the same long skirt and red blouse she had worn in the BMW. "Good morning, Tom, Freya said. "You look terrible.
"Like death warmed up, Svetlana added, flopping into a couch. "My great-aunt was a better cook than Vashislavs and she taught me how to make pyzy which have been known to revive frozen corpses.
"Later, Gibson said curtly. He popped out of the door impatiently, popped in again, and repeated the cycle twice before Shtyrkov arrived. The Russian sat down heavily on the couch next to Svetlana; the armchairs looked as if they would be too tight a fit. He grinned expectantly at Petrie.
"Tom has something to announce, Gibson said triumphantly.
Petrie sipped at the over-sweet coffee. Exhaustion was blurring his words. "Vashislavs suspicions were right. The signal cant be caused by any natural phenomenon. Its coming from an intelligent source.
Freya gasped briefly, and then there was a long, stunned silence.
Shtyrkov muttered something in Russian, under his breath. Then Svetlana began to laugh and cry and Shtyrkov patted her shoulder. "Stay calm, child.
Svetlana produced a paper handkerchief, blew her nose and smiled sheepishly. "I suppose the first thing is to be sure that Tom is right.
"I can prove it. But the proof involves a bigger shock. I warn you, itll blow your mind.
"A bigger shock? Bigger than ET? Alarm and greed mingled in Gibsons pale face.
Petrie put the mug on a table. "Come through to the office.
The office smelled slightly of stale sweat. Petrie threw up the cartoon picture of the lake and rotated it to orient his little audience in three dimensions. Then he fired particles through the lake, tapping at the keyboard to progressively slow down the flow. As the movie slowed, the stream appeared at first like a blizzard sweeping through the lake at a shallow angle. And then, with further slowing, individual trajectories became distinguishable, patterns began to appear, complicated and swirling, with blank periods in between.
And then Petrie explained about turning the lake so that it was face-on to the flow, and replacing each particle track by a point so that at any instant the lake was covered by a pattern of dots. And then he zoomed in on some of the fine structure and explained about the four-base arithmetic. And then he told them how he had stacked the microseconds of time on top of each other so that each slice of time became a thin slice in a jelly, so that the stacked slices defined a solid, three-dimensional structure. And then a century pa.s.sed while Petrie tapped in a final set of instructions until, on the screen, slowly rotating and beyond any possibility of mistake or misinterpretation, was the double helix of DNA.
Shtyrkov sang, quietly. Gibson said, "Oh man.
Petrie left it on the screen, tumbling slowly, hypnotising them; even menacing them. He felt his limbs covered with goosepimples. "I dont know whether its even remotely human, but its surely biological.
There was a long silence, eventually broken by Shtyrkov. "How much time does this represent?
"The first minute of the transmission.
"Meaning?
"Its only three per cent of the message. We have another thirty-six minutes to a.n.a.lyse.
Gibson said again, "Oh, man.
Freya said, "They gave us this up-front for a reason.
"Yes, Shtyrkov said. "They didnt want us to miss it. Thats their starting point. Theyre saying, "Hey, were life forms just like you."
"Is this a hoax? Gibson asked hoa.r.s.ely.
Petrie looked up. "If it is, youre not in on it, Charlie. Youre as white as a sheet.
"Look at us all, Freya said.
"No, I mean someone monkeying with the equipment. Or something. But Gibsons voice trailed off as the absurdity of his own suggestion got through to him.
"Hey, Charlie, the lake glowed. Svetlana was speaking quietly, as if all emotion had now been drained out of her.
"An external input of some sort? From a satellite? Look I know its stupid.
"No, no, youre right, Charlee. We have to think it through, Shtyrkov said. "We must eliminate everything, even stupid ideas. Keep them coming.
"What sort of particles were these? Petrie asked. "Can you tell?
Svetlana pointed to a far corner of the lake. "Can you zoom into that?