3001: The Final Odyssey o-4

by Arthur Charles Clarke

  Needless to say, when 'mind-probing', as its critics called it, started coming into general use, there were cries of outrage from civil-rights organizations; one of their most effective slogans was 'Braincap or Braincop?' Slowly – even reluctantly – it was accepted that this form of monitoring was a necessary precaution against far worse evils; and it was no coincidence that with the general improvement in mental health, religious fanaticism also started its rapid decline-

  When the long-drawn-out war against the cybernet criminals ended, the victors found themselves owning an embarrassing collection of spoils, all of them utterly incomprehensible to any past conqueror. There were, of course, hundreds of computer viruses, most of them very difficult to detect and kill. And there were some entities – for want of a better name – that were much more terrifying. They were brilliantly invented diseases for which there was no cure – in some cases not even the possibility of a cure

  Many of them had been linked to great mathematicians who would have been horrified by this corruption of their discoveries. As it is a human characteristic to belittle a real danger by giving it an absurd name, the designations were often facetious: the Godel Gremlin, the Mandelbrot Maze, the Combinatorial Catastrophe, the Transfinite Trap, the Conway Conundrum, the Turing Torpedo, the Lorentz Labyrinth, the Boolean Bomb, the Shannon Snare, the Cantor Cataclysm...

  If any generalization was possible, all these mathematical horrors operated on the same principle. They did not depend for their effectiveness on anything as naïve as memory-erasure or code corruption – on the contrary. Their approach was more subtle; they persuaded their host machine to initiate a program which could not be completed before the end of the universe, or which – the Mandelbrot Maze was the deadliest example – involved a literally infinite series of steps.

  A trivial example would be the calculation of Pi, or any other irrational number. However, even the most stupid electro-optic computer would not fall into such a simple trap: the day had long since passed when mechanical morons would wear out their gears, grinding them to powder as they tried to divide by zero...

  The challenge to the demon programmers was to convince their targets that the task set them had a definite conclusion that could be reached in a finite time. In the battle of wits between man (seldom woman, despite such role-models as Lady Ada Lovelace, Admiral Grace Hopper and Dr Susan Calvin) and machine, the machine almost invariably lost.

  It would have been possible – though in some cases difficult and even risky – to destroy the captured obscenities by ERASE/OVERWRITE commands, but they represented an enormous investment in time and ingenuity which, however misguided, seemed a pity to waste. And, more important, perhaps they should be kept for study, in some secure location, as a safeguard against the time when some evil genius might reinvent and deploy them.

  The solution was obvious. The digital demons should be sealed with their chemical and biological counterparts, it was hoped for ever, in the Pico Vault.

  37 – Operation Damocles

  Poole never had much contact with the team who assembled the weapon everyone hoped would never have to be used. The operation – ominously, but aptly, named Damocles – was so highly specialized that he could contribute nothing directly, and he saw enough of the task force to realize that some of them might almost belong to an alien species. Indeed, one key member was apparently in a lunatic asylum – Poole had been surprised to find that such places still existed – and Chairperson Oconnor sometimes suggested that at least two others should join him.

  'Have you ever heard of the Enigma Project?' she remarked to Poole, after a particularly frustrating session. When he shook his head, she continued: 'I'm surprised – it was only a few decades before you were born: I came across it while when I was researching material for Damocles. Very similar problem – in one of your wars, a group of brilliant mathematicians was gathered together, in great secrecy, to break an enemy code... incidentally, they built one of the very first real computers, to make the job possible.'

  'And there's a lovely story – I hope it's true – that reminds me of our own little team. One day the Prime Minister came on a visit of inspection, and afterwards he said to Enigma's Director: "When I told you to leave no stone unturned to get the men you needed, I didn't expect you to take me so literally".'

  Presumably all the right stones had been turned for Project Damocles. However, as no one knew whether they were working against a deadline of days, weeks or years, at first it was hard to generate any sense of urgency. The need for secrecy also created problems; since there was no point in spreading alarm throughout the Solar System, not more than fifty people knew of the project. But they were the people who mattered – who could marshal all the forces necessary, and who alone could authorize the opening of the Pico Vault, for the first time in five hundred years.

  When Halman reported that the Monolith was receiving messages with increasing frequency, there seemed little doubt that something was going to happen. Poole was not the only one who found it hard to sleep in those days, even with the help of the Braincap's anti-insomnia programs. Before he finally did get to sleep, he often wondered if he would wake up again. But at last all the components of the weapon were assembled – a weapon invisible, untouchable and unimaginable to almost all the warriors who had ever lived.

  Nothing could have looked more harmless and innocent than the perfectly standard terabyte memory tablet, used with millions of Braincaps every day. But the fact that it was encased in a massive block of crystalline material, criss-crossed with metal bands, indicated that it was something quite out of the ordinary. Poole received it with reluctance; he wondered if the courier who had been given the awesome task of carrying the Hiroshima atom bomb's core to the Pacific airbase from which it was launched had felt the same way. And yet, if all their fears were justified, his responsibility might be even greater.

  And he could not be certain that even the first part of his mission would be successful. Because no circuit could be absolutely secure, Halman had not yet been informed about Project Damocles; Poole would do that when he returned to Ganymede.

  Then he could only hope that Halman would be willing to play the role of Trojan Horse – and, perhaps, be destroyed in the process.

  38 – Pre-emptive Strike

  It was strange to be back in the Hotel Grannymede after all these years – strangest of all, because it seemed completely unchanged, despite everything that had happened. Poole was still greeted by the familiar image of Bowman as he walked into the suite named after him: and, as he expected, Bowman/Halman was waiting, looking slightly less substantial than the ancient hologram.

  Before they could even exchange greetings, there was an interruption that Poole would have welcomed – at any other time than this. The room vidphone gave its urgent trio of rising notes – also unchanged since his last visit -and an old friend appeared on the screen.

  'Frank!' cried Theodore Khan, 'why didn't you tell me you were coming! When can we meet? Why no video – someone with you? And who were all those official-looking types who landed at the same time -'

  'Please Ted! Yes, I'm sorry – but believe me, I've got very good reasons – I'll explain later. And I do have someone with me – call you back just as soon as I can. Good-bye!'

  As he belatedly gave the 'Do Not Disturb' order, Poole said apologetically: 'Sorry about that – you know who it was, of course.'

  'Yes – Dr Khan. He often tried to get in touch with me.'

  'But you never answered. May I ask why?' Though there were far more important matters to worry about, Poole could not resist putting the question.

  'Ours was the only channel I wished to keep open. Also, I was often away. Sometimes for years.'

  That was surprising – yet it should not have been. Poole knew well enough that Halman had been reported in many places, in many times. Yet – 'away for years'? He might have visited quite a few star systems – perhaps that was how he knew about Nova Scorpio, only forty light-ye
ars distant. But he could never have gone all the way to the Node; there and back would have been a nine-hundred-year journey.

  'How lucky that you were here when we needed you!' It was very unusual for Halman to hesitate before replying. There was much longer than the unavoidable three-second time-lag before he said slowly 'Are you sure that it was luck?'

  'What do you mean?'

  'I do not wish to talk about it, but twice I have – glimpsed – powers – entities – far superior to the Monoliths, and perhaps even their makers. We may both have less freedom than we imagine.'

  That was indeed a chilling thought; Poole needed a deliberate effort of will to put it aside and concentrate on the immediate problem.

  'Let us hope we have enough free-will to do what is necessary. Perhaps this is a foolish question. Does the Monolith know that we are meeting? Could it be – suspicious?'

  'It is not capable of such an emotion. It has numerous fault-protection devices, some of which I understand. But that is all.'

  'Could it be overhearing us now?'

  'I do not believe so.'

  I wish that I could be sure it was such a naïve and simple-minded super-genius, thought Poole as he unlocked his briefcase and took out the sealed box containing the tablet. In this low gravity its weight was almost negligible; it was impossible to believe that it might hold the destiny of Mankind.

  'There was no way we could be certain of getting a secure circuit to you, so we couldn't go into details. This tablet contains programs which we hope will prevent the Monolith from carrying out any orders which threaten Mankind. There are twenty of the most devastating viruses ever designed on this, most of which have no known antidote; in some cases, it is believed that none is possible. There are five copies of each. We would like you to release them when – and if – you think it is necessary. Dave – Hal – no one has ever been given such a responsibility. But we have no other choice.'

  Once again, the reply seemed to take longer than the three-second round trip from Europa.

  'If we do this, all the Monolith's functions may cease. We are uncertain what will happen to us then.'

  'We have considered that, of course. But by this lime, you must surely have many facilities at your command -some of them probably beyond our understanding. I am also sending you a petabyte memory tablet. Ten to the fifteenth bytes is more than sufficient to hold all the memories and experiences of many lifetimes. This will give you one escape route: I suspect you have others.'

  'Correct. We will decide which to use at the appropriate time.'

  Poole relaxed – as far as was possible in this extraordinary situation. Halman was willing to co-operate: he still had sufficient links with his origins.

  'Now, we have to get this tablet to you – physically. Its contents are too dangerous to risk sending over any radio or optical channel. I know you possess long-range control of matter: did you not once detonate an orbiting bomb? Could you transport it to Europa? Alternatively, we could send it in an auto-courier, to any point you specify.'

  'That would be best: I will collect it in Tsienville. Here are the co-ordinates...

  Poole was still slumped in his chair when the Bowman Suite monitor admitted the head of the delegation that had accompanied him from Earth. Whether Colonel Jones was a genuine Colonel – or even if his name was Jones – were minor mysteries which Poole was not really interested in solving; it was sufficient that he was a superb organizer and had handled the mechanics of Operation Damocles with quiet efficiency.

  'Well, Frank – it's on its way. Will be landing in one hour, ten minutes. I assume that Halman can take it from there, but I don't understand how he can actually handle – is that the right word? – these tablets.'

  'I wondered about that, until someone on the Europa Committee explained it. There's a well-known – though not to me! – theorem stating that any computer can emulate any other computer. So I'm sure that Halman knows exactly what he's doing. He would never have agreed otherwise.'

  'I hope you're right,' replied the Colonel. 'If not – well, I don't know what alternative we have.'

  There was a gloomy pause, until Poole did his best to relieve the tension.

  'By the way, have you heard the local rumour about our visit?'

  'Which particular one?'

  'That we're a special commission sent here to investigate crime and corruption in this raw frontier township. The Mayor and the Sheriff are supposed to be running scared.'

  'How I envy them,' said 'Colonel Jones'. 'Sometimes it's quite a relief to have something trivial to worry about.'

  39 – Deicide

  Like all the inhabitants of Anubis City (population now 56,521), Dr Theodore Khan woke soon after local midnight to the sound of the General Alarm. His first reaction was 'Not another Icequake, for Deus's sake!'

  He rushed to the window, shouting 'Open' so loudly that the room did not understand, and he had to repeat the order in a normal voice. The light of Lucifer should have come streaming in, painting the patterns on the floor that so fascinated visitors from Earth, because they never moved even a fraction of a millimetre, no matter how long they waited...

  That unvarying beam of light was no longer there. As Khan stared in utter disbelief through the huge, transparent bubble of the Anubis Dome, he saw a sky that Ganymede had not known for a thousand years. It was once more ablaze with stars; Lucifer had gone.

  And then, as he explored the forgotten constellations, Kahn noticed something even more terrifying. Where Lucifer should have been was a tiny disc of absolute blackness, eclipsing the unfamiliar stars.

  There was only one possible explanation, Khan told himself numbly. Lucifer has been swallowed by a Black Hole. And it may be our turn next.

  On the balcony of the Grannymede Hotel, Poole was watching the same spectacle, but with more complex emotions. Even before the general alarm, his comsec had woken him with a message from Halman.

  'It is beginning. We have infected the Monolith. But one – perhaps several – of the viruses have entered our own circuits. We do not know if we will be able to use the memory tablet you have given us. If we succeed, we will meet you in Tsienville.'

  Then came the surprising and strangely moving words whose exact emotional content would be debated for generations:

  'If we are unable to download, remember us.' From the room behind him, Poole heard the voice of the Mayor, doing his best to reassure the now sleepless citizens of Anubis. Though he opened with that most terrifying of official statements – 'No cause for alarm' – the Mayor did indeed have words of comfort.

  'We don't know what's happening but Lucifer's still shining normally! I repeat – Lucifer is still shining! We've just received news from the interorbit shuttle Alcyone, which left for Callisto half an hour ago. Here's their view -, Poole left the balcony and rushed into his room just in time to see Lucifer blaze reassuringly on the vidscreen.

  'What's happened,' the Mayor continued breathlessly, 'is that something has caused a temporary eclipse – we'll zoom in to look at it... Callisto Observatory, come in please...'

  How does he know it's 'temporary'? thought Poole, as he waited for the next image to come up on the screen.

  Lucifer vanished, to be replaced by a field of stars. At the same time, the Mayor faded out and another voice took over:

  '– two-metre telescope, but almost any instrument will do. It's a disc of perfectly black material, just over ten thousand kilometres across, so thin it shows no visible thickness. And it's placed exactly – obviously deliberately -to block Ganymede from receiving any light.

  'We'll zoom in to see if it shows any details, though I rather doubt it...'

  From the viewpoint of Callisto, the occulting disc was foreshortened into an oval, twice as long as it was wide. It expanded until it completely filled the screen; thereafter, it was impossible to tell whether the image was being zoomed, as it showed no structure whatsoever.

  'As I thought – there's nothing to see. Let's pan over to
the edge of the thing...'

  Again there was no sense of motion, until a field of stars suddenly appeared, sharply defined by the curving edge of the world-sized disc. It was exactly as if they were looking past the horizon of an airless, perfectly smooth planet.

  No, it was not perfectly smooth...

  'That's interesting,' commented the astronomer, who until now had sounded remarkably matter-of-fact, as if this sort of thing was an everyday occurrence. 'The edge looks jagged – but in a very regular fashion – like a saw-blade...'

  A circular saw Poole muttered under his breath. Is it going to carve us up? Don't be ridiculous...

  'This is as close as we can get before diffraction spoils the image – we'll process it later and get much better detail:'

  The magnification was now so great that all trace of the disc's circularity had vanished. Across the vidscreen was a black band, serrated along its edge with triangles so identical that Poole found it hard to avoid the ominous analogy of a saw-blade. Yet something else was nagging at the back of his mind...

  Like everyone else on Ganymede, he watched the infinitely more distant stars drifting in and out of those geometrically perfect valleys. Very probably, many others jumped to the same conclusion even before he did.