"Anyway, it's no secret now, so it doesn't matter. Two years ago I sent a confidential message to Paul - oh, sorry, I should have mentioned - he's my uncle - with a summary of my findings. I asked if he could explain them - or refute them.
"Didn't take him long, with all the byte-bashing he's got at his fingertips. Unfortunately, he was careless, or someone was monitoring his network - I'm sure your friends, whoever they are, must have a good idea by now.
"In a couple of days, he dug up an eighty-year-old paper in the scientific journal Nature - yes, it was still printed on paper back then! - which explained everything. Well, almost everything.
"It was written by a man working in one of the big labs in the United States - of America, of course - the USSA didn't exist then. It was a place where they designed nuclear weapons, so they knew a few things about high temperatures and pressures.
"I don't know if Dr Ross - that was his name -had anything to do with bombs, but his background must have started him thinking about conditions deep down inside the giant planets. In his 1984 - sorry, 1981 - paper - it's less than a page long, by the way - he made some very interesting suggestions...
"He pointed out that there were gigantic quantities of carbon - in the form of methane, CH4 - in the gas giants. Up to seventeen per cent of the total mass! He calculated that at the pressures and temperatures in the cores - millions of atmospheres - the carbon would separate out, sink down towards the centres and - you've guessed it - crystallize. It was a lovely theory: I don't suppose he ever dreamed that there would be a hope of testing it.
"So that's part one of the story. In some ways, part two is even more interesting. What about some more of that coffee?"
"Here you are; and I think I've already guessed part two. Obviously something to do with the explosion of Jupiter."
"Not explosion - implosion - Jupiter just collapsed on itself, then ignited. In some ways, it was like the detonation of a nuclear bomb, except that the new state was a stable one - in fact, a minisun.
"Now, very strange things happen during implosions; it's almost as if pieces can go through each other, and come out on the other side. Whatever the mechanism, a mountain-sized piece of the diamond core was shot into orbit.
"It must have made hundreds of revolutions - been perturbed by the gravitational fields of all the satellites - before it ended up on Europa. And conditions must have been exactly right - one body must have overtaken the other, so the impact velocity was only a couple of kilometers a second. If they'd met head-on - well, there might not be a Europa now, let alone Mount Zeus! And I sometimes have nightmares, thinking that it could very well have come down on us...
"The new atmosphere may also have buffered the impact; even so, the shock must have been appalling - I wonder what it did to our Europan friends? - it certainly triggered a whole series of tectonic disturbances, which are still continuing."
"And," said Floyd, "political ones. I'm just beginning to appreciate some of them. No wonder the USSA was worried."
"Amongst others."
"But would anyone seriously imagine they could get at these diamonds?"
"We've not done so badly," answered van der Berg, gesturing towards the back of the shuttle. "In any case, the mere psychological effect on the industry would be enormous. That's why so many people were anxious to know whether it was true or not."
"And now they know. What next?"
"That's not my problem, thank God. But I hope I've made a sizeable contribution to Ganymede's science budget."
As well as my own, he added to himself.
54: Reunion
Whatever made you think I was dead?" cried Heywood Floyd. "I've not felt better for years!"
Paralyzed with astonishment, Chris Floyd stared at the speaker grille. He felt a great lifting of his spirits - yet also a sense of indignation. Someone - something - had played a cruel practical joke on him; but for what conceivable reason?
Fifty million kilometers away - and coming closer by several hundred every second - Heywood Floyd also sounded slightly indignant. But he also sounded vigorous and cheerful, and his voice radiated the happiness he obviously felt at knowing that Chris was safe.
"And I've got some more good news for you; the shuttle will pick you up first. It will drop some urgent medical supplies at Galaxy, then hop over to you, and bring you up to rendezvous with us on the next orbit. Universe will go down five orbits later; you'll be able to greet your friends when they come aboard.
"No more now - except to say how much I'm looking forward to making up for lost time. Waiting for your answer in - let's see - about three minutes..."
For a moment, there was complete silence aboard Bill Tee; van der Berg dared not look at his companion. Then Floyd keyed the microphone and said slowly: "Grandad - what a wonderful surprise - I'm still in a state of shock. But I know I met you here on Europa - I know you said goodbye to me. I'm as certain of that, as I'm sure you were speaking to me just now...
"Well, we'll have plenty of time to talk about it later. But remember how Dave Bowman spoke to you, aboard Discovery? Perhaps it was something like that.
"Now we'll just sit and wait here until the shuttle comes for us. We're quite comfortable - there's an occasional quake, but nothing to worry about. Until we meet, all my love."
He could not remember when he had last used that word to his grandfather.
After the first day, the shuttle cabin began to smell. After the second, they didn't notice - but agreed that the food was no longer quite so tasty. They also found it hard to sleep, and there were even accusations of snoring.
On day three, despite frequent bulletins from Universe, Galaxy and Earth itself, boredom was beginning to set in, and they had exhausted their supply of dirty stories.
But that was the last day. Before it was over, Lady Jasmine descended, seeking her lost child.
55: Magma
Baas," said the apartment's master comset, "I accessed that special programme from Ganymede while you were sleeping. Do you wish to see it now?"
"Yes," answered Dr Paul Kreuger. "Speed ten times. No sound."
There would, he knew, be a lot of introductory material he could jump, and view later if he wished. He wanted to get to the action as quickly as possible.
Credits flashed up, and there on the monitor was Victor Willis, somewhere on Ganymede, gesticulating wildly in total silence. Dr Paul Kreuger, like many working scientists, took a somewhat jaundiced view of Willis, though he admitted that he performed a useful function.
Willis abruptly vanished, to be replaced by a less agitated subject - Mount Zeus. But that was much more active than any well-behaved mountain should be; Dr Kreuger was astonished to see how much it had changed since the last transmission from Europa.
"Real time," he ordered. "Sound."
"...almost a hundred metres a day, and the tilt has increased fifteen degrees. Tectonic activity now violent - extensive lava flows around the base - I have Dr van der Berg with me - van, what do you think?"
My nephew looks in remarkably good shape, thought Dr Kreuger, considering what he's been through. Good stock, of course.
"The crust obviously never recovered from the original impact, and it's giving way under the accumulated stresses. Mount Zeus has been slowly sinking ever since we discovered it, but the rate has speeded up enormously in the last few weeks. You can see the movement from day to day."
"How long before it disappears completely?"
"I can't really believe that will happen..."
There was a quick cut to another view of the mountain, with Victor Willis speaking off camera.
"That was what Dr van der Berg said two days ago. Any comment now, van?"
"Er - it looks as if I was mistaken. It's going down - quite incredible - only half a kilometer left! I refuse to make any more predictions..."
"Very wise of you, van - well, that was only yesterday. Now we'll give you a continuous time-lapse sequence, up to the moment we lost the camera..."
>
Dr Paul Kreuger leaned forward in his seat, watching the final act of the long drama in which he had played such a remote, yet vital role.
There was no need to speed up the replay: he was already seeing it at almost a hundred times normal. An hour was compressed into a minute - a man's lifetime into that of a butterfly.
Before his eyes, Mount Zeus was sinking. Spurts of molten sulphur rocketed skywards around it at dazzling speed, forming parabolas of brilliant, electric blue. It was like a ship going down in a stormy sea, surrounded by St Elmo's fire. Not even Io's spectacular volcanoes could match this display of violence.
"The greatest treasure ever discovered - vanishing from sight," said Willis in hushed and reverential tones: "Unfortunately, we can't show the finale. You'll soon see why."
The action slowed down into real time. Only a few hundred metres of the mountain were left, and the eruptions around it now moved at a more leisurely speed.
Suddenly, the whole picture tilted; the camera's image stabilizers, which had been holding their own valiantly against the continuous trembling of the ground, gave up the unequal battle. For a moment it seemed as if the mountain was rising again - but it was the camera tripod toppling over. The very last scene from Europa was a close-up of a glowing wave of molten sulphur, about to engulf the equipment.
"Gone for ever!" lamented Willis. "Riches infinitely greater than all the wealth that Golconda or Kimberley ever produced! What a tragic, heartbreaking loss!"
"What a stupid idiot!" spluttered Dr Kreuger. "Doesn't he realize..."
It was time for another letter to Nature. And this secret would be much too big to hide.
56: Perturbation Theory>
From: Professor Paul Kreuger, FRS, etc.
To: The Editor, NATURE Data Bank (Public access)
Subject: MOUNT ZEUS AND JOVIAN DIAMONDS
As is now well understood, the Europan formation known as 'Mount Zeus' was originally part of Jupiter. The suggestion that the cores of the gas giants might consist of diamond was first made by Marvin Ross of the University of California's Lawrence Livermore National Laboratory in a classic paper 'The ice layer in Uranus and Neptune - diamonds in the sky?' (Nature, Vol 292, No. 5822, pp. 435-6, 30 July 1981). Surprisingly, Ross did not extend his calculations to Jupiter.
The sinking of Mount Zeus has produced a veritable chorus of lamentations, all of which are totally ridiculous - for the reasons given below.
Without going into details, which will be presented in a later communication, I estimate that the diamond core of Jupiter must have had an original mass of at least 1028 grams. This is ten billion times that of Mount Zeus.
Although much of this material would doubtless have been destroyed in the detonation of the planet and the formation of the - apparently artificial - sun Lucifer, it is inconceivable that Mount Zeus was the only fragment to survive. Although much would have fallen back on to Lucifer, a substantial percentage must have gone into orbit - and must still be there. Elementary perturbation theory shows that it will return periodically to its point of origin. It is not, of course, possible to make an exact calculation, but I estimate that at least a million times the mass of Mount Zeus is still orbiting in the vicinity of Lucifer. The loss of one small fragment, in any case most inconveniently located on Europa, is therefore of virtually no importance. I propose the establishment, as soon as possible, of a dedicated space-radar system to search for this material.
Although extremely thin diamond film has been mass-produced since as long ago as 1982, it has never been possible to make diamond in bulk. Its availability in megaton quantities could totally transform many industries and create wholly new ones. In particular, as was pointed out by Isaacs et al almost a hundred years ago (see Science, 151, pp. 682-3, 1966) diamond is the only construction material which would make possible the so-called Space Elevator, allowing transportation away from Earth at negligible cost. The diamond mountains now orbiting among the satellites of Jupiter may open up the entire Solar System; how trivial, by comparison, appear all the ancient uses of the quartic-crystallized form of carbon!
For completeness, I would like to mention another possible location for enormous quantities of diamond - a place, unfortunately, even more inaccessible than the core of a giant planet...
It has been suggested that the crusts of neutron stars may be largely composed of diamond. As the nearest known neutron star is fifteen light years away, and has a surface gravity seventy thousand million times that of Earth, this can hardly be regarded as a plausible source of supply.
But then - who could ever have imagined that one day we would be able to touch the core of Jupiter?
57: Interlude on Ganymede
These poor, primitive colonists!" lamented Mihailovich. "I'm horrified - there's not a single concert grand on the whole of Ganymede! Of course, the thimbleful of optronics in my synthesizer can reproduce any musical instrument. But a Steinway is still a Steinway - just as a Strad is still a Strad."
His complaints, though not altogether serious, had already aroused some counter-reactions among the local intelligentsia. The popular Morning Mede programme had even commented maliciously: "By honouring us with their presence, our distinguished guests have - if only temporarily - raised the cultural level of both worlds..."
The attack was aimed chiefly at Willis, Mihailovich and M'Bala, who had been a little too enthusiastic in bringing enlightenment to the backward natives. Maggie M had created quite a scandal with an uninhibited account of Zeus-Jupiter's torrid love affairs with Io, Europa, Ganymede and Callisto. Appearing to the nymph Europa in the guise of a white bull was bad enough, and his attempts to shield Io and Callisto from the understandable wrath of his consort Hera were frankly pathetic. But what upset many local residents was the news that the mythological Ganymede was of quite the wrong gender.
To do them justice, the intentions of the self-appointed cultural ambassadors were completely praiseworthy, though not entirely disinterested. Knowing that they would be stranded on Ganymede for months, they recognized the danger of boredom, after the novelty of the situation had worn off. And they also wished to make the best possible use of their talents, for the benefit of everyone around them. However, not everyone wished - or had time - to be benefited, out here on the high-technology frontier of the Solar System.
Yva Merlin, on the other hand, fitted in perfectly, and was thoroughly enjoying herself. Despite her fame on Earth, few of the Medes had ever heard of her. She could wander around, in the public corridors and pressure domes of Ganymede Central, without people turning their heads or exchanging excited whispers of recognition. True, she was recognized - but only as another of the visitors from Earth.
Greenburg, with his usual quietly efficient modesty, had fitted into the administrative and technological structure of the satellite and was already on half a dozen advisory boards. His services were so well appreciated that he had been warned he might not be allowed to leave.
Heywood Floyd observed the activities of his shipmates with relaxed amusement, but took little part in them. His chief concern now was building bridges to Chris, and helping his grandson plan his future. Now that Universe - with less than a hundred tons of propellant left in its tanks - was safely down on Ganymede, there was much to be done.
The gratitude that all aboard Galaxy felt towards their rescuers had made it easy to merge the two crews; when repairs, overhaul and refuelling were complete, they would fly back to Earth together. Morale had already been given a great boost by the news that Sir Lawrence was drawing up the contract for a greatly improved Galaxy II - though construction was not likely to begin until his lawyers had settled their dispute with Lloyd's. The underwriters were still trying to claim that the novel crime of space hijacking was not covered by their policy.
As for that crime itself, no one had been convicted, or even charged. Clearly, it had been planned, over a period of several years, by an efficient and well-funded organization. The United States of Southern Afric
a loudly protested innocence, and said it welcomed an official enquiry. Der Bund also expressed indignation, and of course blamed SHAKA.
Dr Kreuger was not surprised to find angry but anonymous messages in his mail, accusing him of being a traitor. They were usually in Afrikaans, but sometimes contained subtle mistakes in grammar or phraseology which made him suspect that they were part of a disinformation campaign.
After some thought, he passed them onto ASTROPOL - which probably already has them, he told himself wryly. ASTROPOL thanked him, but, as he expected, made no comments.
At various times, Second Officers Floyd and Chang and other members of Galaxy's crew were treated to the best dinners on Ganymede by the two mysterious out-wonders whom Floyd had already met. When the recipients of these (frankly disappointing) meals compared notes afterwards, they decided that their polite interrogators were trying to build up a case against SHAKA, but were not getting very far.
Dr van der Berg, who had started the whole thing - and had done very well out of it, professionally and financially - was now wondering what to do with his new opportunities. He had received many attractive offers from Earth universities and scientific organizations - but, ironically, it was impossible to take advantage of them. He had now lived too long at Ganymede's one-sixth of a gravity, and had passed the medical point of no return.
The Moon remained a possibility; so did Pasteur, as Heywood Floyd explained to him.
"We're trying to set up a space university there," he said, "so that off-worlders who can't tolerate one gee can still interact in real time with people on Earth. We'll have lecture halls, conference rooms, labs - some of them will only be computer-stored, but they'll look so real you'd never know. And you'll be able to go videoshopping on Earth, to make use of your ill-gotten gains."