Dr Kreuger fully accepted this principle: he would not believe his nephew's discovery until he could explain it, and as far as he could see that required nothing less than a direct Act of God. Wielding Occam's still highly serviceable razor, he thought it somewhat more probable that Rolf had made a mistake; if so, it should be fairly easy to find it.
To Uncle Paul's great surprise, it proved very difficult indeed. The analysis of radar remote-sensing observations was now a venerable and well-established art, and the experts that Paul consulted all gave the same answer, after considerable delay. They also asked: "Where did you get that recording?"
"Sorry," he had answered. "I'm not at liberty to say."
The next step was to assume that the impossible was correct, and to start searching the literature. This could be an enormous job, for he did not even know where to begin. One thing was quite certain: a brute-force, head-on attack was bound to fail. It would be just as if Roentgen, the morning after he had discovered X-rays, had started to hunt for their explanation in the physics journals of his day. The information he needed still lay years in the future.
But there was at least a sporting chance that what he was looking for was hidden somewhere in the immense body of existing scientific knowledge. Slowly and carefully, Paul Kreuger set up an automatic search programme, designed for what it would exclude as much as what it would embrace. It should cut out all Earth-related references - they would certainly number in the millions - and concentrate entirely on extraterrestrial citations.
One of the benefits of Dr Kreuger's eminence was an unlimited computer budget: that was part of the fee he demanded from the various organizations who needed his wisdom. Though this search might be expensive, he did not have to worry about the bill.
As it turned out, this was surprisingly small. He was lucky: the search came to an end after only two hours thirty-seven minutes, at the 21,456th reference.
The title was enough. Paul was so excited that his own comsec refused to recognize his voice, and he had to repeat the command for a full print-out.
Nature had published the paper in 1981 - almost five years before he was born! - and as his eyes swept swiftly over its single page he knew not only that his nephew had been right all along - but, just as important, exactly how such a miracle could occur.
The editor of that eighty-year-old journal must have had a good sense of humour. A paper discussing the cores of the outer planets was not something to grab the usual reader: this one, however, had an unusually striking title. His comsec could have told him quickly enough that it had once been part of a famous song, but that of course was quite irrelevant.
Anyway, Paul Kreuger had never heard of the Beatles, and their psychedelic fantasies.
II: The Valley Of The Black Snow
15: Rendezvous
And now Halley was too close to be seen; ironically, observers back on Earth would get a far better view of the tail, already stretching fifty million kilometers at right angles to the comet's orbit, like a pennant fluttering in the invisible gale of the solar wind.
On the morning of the rendezvous, Heywood Floyd woke early from a troubled sleep. It was unusual for him to dream - or at least to remember his dreams - and doubtless the anticipated excitements of the next few hours were responsible. He was also slightly worried by a message from Caroline, asking if he had heard from Chris lately. He had radioed back, a little tersely, that Chris had never bothered to say thank you when he had helped him get his current position on Universe's sister ship Cosmos; perhaps he was already bored with the Earth-Moon run and was looking for excitement elsewhere.
"As usual," Floyd had added, "we'll hear from him in his own good time."
Immediately after breakfast, passengers and science team had gathered for a final briefing from Captain Smith. The scientists certainly did not need it, but if they felt any irritation, so childish an emotion would have been quickly swept away by the weird spectacle on the main viewscreen.
It was easier to imagine that Universe was flying into a nebula, rather than a comet. The entire sky ahead was now a misty white fog - not uniform, but mottled with darker condensations and streaked with luminous bands and brightly glowing jets, all radiating away from a central point. At this magnification, the nucleus was barely visible as a tiny black speck, yet it was clearly the source of all the phenomena around it.
"We cut our drive in three hours," said the Captain. "Then we'll be only a thousand kilometers away from the nucleus, with virtually zero velocity. We'll make some final observations, and confirm our landing site."
"So we'll go weightless at 1200 exactly. Before then, your cabin stewards will check that everything's correctly stowed. It will be just like turnaround, except that this time it's going to be three days, not two hours, before we have weight again.
"Halley's gravity? Forget it - less than one centimetre per second squared - just about a thousandth of Earth's. You'll be able to detect it if you wait long enough, but that's all. Takes fifteen seconds for something to fall a metre.
"For safety, I'd like you all here in the observation lounge, with your seat belts properly secured, during rendezvous and touchdown. You'll get the best view from here anyway, and the whole operation won't take more than an hour. We'll only be using very small thrust corrections, but they may come from any angle and could cause minor sensory disturbances."
What the Captain meant, of course, was spacesickness - but that word, by general agreement, was taboo aboard Universe. It was noticeable, however, that many hands strayed into the compartments beneath the seats, as if checking that the notorious plastic bags would be available if urgently required.
The image on the viewscreen expanded, as the magnification was increased. For a moment it seemed to Floyd that he was in an aeroplane, descending through light clouds, rather than in a spacecraft approaching the most famous of all comets. The nucleus was growing larger and clearer; it was no longer a black dot, but an irregular ellipse - now a small, pockmarked island lost in the cosmic ocean - then, suddenly, a world in its own right.
There was still no sense of scale. Although Floyd knew that the whole panorama spread before him was less than ten kilometers across, he could easily have imagined that he was looking at a body as large as the Moon. But the Moon was not hazy around the edges, nor did it have little jets of vapour - and two large ones - spurting from its surface.
"My God!" cried Mihailovich, "what's that?"
He pointed to the lower edge of the nucleus, just inside the terminator. Unmistakably - impossibly -a light was flashing there on the nightside of the comet with a perfectly regular rhythm: on, off, on, off, once every two or three seconds.
Dr Willis gave his patient "I can explain it to you in words of one syllable" cough, but Captain Smith got there first.
"I'm sorry to disappoint you, Mr Mihailovich. That's only the beacon on Sampler Probe Two - it's been sitting there for a month, waiting for us to come and pick it up."
"What a shame; I thought there might be someone - something - there to welcome us."
"No such luck, I'm afraid; we're very much on our own out here. That beacon is just where we intend to land - it's near Halley's south pole and is in permanent darkness at the moment. That will make it easier on our life-support systems. The temperature's up to 120 degrees on the Sunlit side - way above boiling point."
"No wonder the comet's perking," said the unabashed Dimitri. "Those jets don't look very healthy to me. Are you sure it's safe to go in?"
"That's another reason we're touching down on the nightside; there's no activity there. Now, if you'll excuse me, I must get back to the bridge. This is the first chance I've ever had of landing on a new world - and I doubt if I'll get another."
Captain Smith's audience dispersed slowly, and in unusual silence. The image on the viewscreen zoomed back to normal, and the nucleus dwindled once more to a barely visible spot. Yet even in those few minutes it seemed to have grown slightly larger, and perhaps that was no
illusion. Less than four hours before encounter, the ship was still hurtling towards the comet at fifty thousand kilometers an hour.
It would make a crater more impressive than any that Halley now boasted, if something happened to the main drive at this stage of the game.
16: Touchdown
The landing was just as anticlimactic as Captain Smith had hoped. It was impossible to tell the moment when Universe made contact; a full minute elapsed before the passengers realized that touchdown was complete, and raised a belated cheer.
The ship lay at one end of a shallow valley, surrounded by hills little more than a hundred metres high. Anyone who had been expecting to see a lunar landscape would have been greatly surprised; these formations bore no resemblance at all to the smooth, gentle slopes of the Moon, sand-blasted by micrometeorite bombardment over billions of years.
There was nothing here more than a thousand years old; the Pyramids were far more ancient than this landscape. Every time around the Sun, Halley was remoulded - and diminished - by the solar fires. Even since the 1986 perihelion passage, the shape of the nucleus had been subtly changed. Melding metaphors shamelessly, Victor Willis had nevertheless put it rather well when he told his viewers: "The 'peanut' has become wasp-waisted!"
Indeed, there were indications that, after a few more revolutions round the Sun, Halley might split into two roughly equal fragments - as had Biela's comet, to the amazement of the astronomers of 1846.
The virtually non-existent gravity also contributed to the strangeness of the landscape. All around were spidery formations like the fantasies of a surrealistic artist, and improbably canted rockpiles that could not have survived more than a few minutes even on the Moon.
Although Captain Smith had chosen to land Universe in the depths of the polar night - all of five kilometers from the blistering heat of the Sun - there was ample illumination. The huge envelope of gas and dust surrounding the comet formed a glowing halo which seemed appropriate for this region; it was easy to imagine that it was an aurora, playing over the Antarctic ice. And if that was not sufficient, Lucifer provided its quota of several hundred full moons.
Although expected, the complete absence of colour was a disappointment; Universe might have been sitting in an opencast coal mine: that, in fact, was not a bad analogy, for much of the surrounding blackness was due to carbon or its compounds, intimately mixed with snow and ice.
Captain Smith, as was his due, was the first to leave the ship, pushing himself gently out from Universe's main airlock. It seemed an eternity before he reached the ground, two metres below; then he picked up a handful of the powdery surface, and examined it in his gloved hand.
Aboard the ship, everyone waited for the words that would go into the history books.
"Looks like pepper and salt," said the Captain. "If it were thawed out, it might grow a pretty good crop."
The mission plan involved one complete Halley "day" of fifty-five hours at the south pole, then - if there were no problems - a move of ten kilometers towards the very ill-defined equator, to study one of the geysers during a complete day-night cycle.
Chief Scientist Pendrill wasted no time. Almost immediately, he set off with a colleague on a two-man jet-sled towards the beacon of the waiting probe. They were back within the hour, bearing prepackaged samples of comet which they proudly consigned to the deep-freeze.
Meanwhile the other teams established a spider's web of cables along the valley, strung between poles driven into the friable crust. These served not only to link numerous instruments to the ship, but also made movement outside much easier. One could explore this portion of Halley without the use of cumbersome External Manoeuvring Units; it was only necessary to attach a tether to a cable, and then go along it hand over hand. That was also much more fun than operating EMUs, which were virtually one-man spaceships with all the complications they involved.
The passengers watched all this with fascination, listening to the radioed conversations and trying to join in the excitement of discovery. After about twelve hours - considerably less in the case of ex-astronaut Clifford Greenburg - the pleasure of being a captive audience started to pall. Soon there was much talk about "going outside" except from Victor Willis who was quite uncharacteristically subdued.
"I think he's scared," said Dimitri contemptuously. He had never liked Victor, since discovering that the scientist was completely tone-deaf. Though this was wildly unfair to Victor (who had gamely allowed himself to be used as a guinea pig for studies of his curious affliction) Dimitri was fond of adding darkly "A man that hath no music in himself, Is fit for treasons, stratagems and spoils."
Floyd had made up his mind even before leaving Earth orbit. Maggie M was game enough to try anything and would need no encouragement. (Her slogan 'An author should never turn down the opportunity for a new experience' had impacted famously on her emotional life.)
Yva Merlin, as usual, had kept everyone in suspense, but Floyd was determined to take her on a personal tour of the comet. It was the very least he could do to maintain his reputation; everyone knew that he had been partly responsible for getting the fabulous recluse on the passenger list, and now it was a running joke that they were having an affair. Their most innocent remarks were gleefully misinterpreted by Dimitri and the ship's physician Dr Mahindran, who professed to regard them with envious awe.
After some initial annoyance - because it all too accurately recalled the emotions of his youth - Floyd had gone along with the joke. But he did not know how Yva felt about it, and had so far lacked the courage to ask her. Even now, in this compact little society where few secrets lasted more than six hours, she maintained much of her famous reserve - that aura of mystery which had fascinated audiences for three generations.
As for Victor Willis, he had just discovered one of those devastating little details that can destroy the best-laid plans of mice and spacemen.
Universe was equipped with the latest Mark XX suits, with non-fogging, non-reflective visors guaranteed to give an unparalleled view of space. And though the helmets came in several sizes, Victor Willis could not get into any of them without major surgery.
It had taken him fifteen years to perfect his trademark ("A triumph of the topiary art," one critic had called it, perhaps admiringly).
Now only his beard stood between Victor Willis and Halley's Comet. Soon he would have to make a choice between the two.
17: The Valley of Black Snow
Captain Smith had raised surprisingly few objections to the idea of passenger EVAs. He agreed that to have come all this way, and not to set foot upon the comet, was absurd.
"There'll be no problems if you follow instructions," he said at the inevitable briefing. "Even if you've never worn spacesuits before - and I believe that only Commander Greenburg and Dr Floyd have done so - they're quite comfortable, and fully automatic. There's no need to bother about any controls or adjustments, after you've been checked out in the airlock.
"One absolute rule: only two of you can go EVA at one time. You'll have a personal escort, of course, linked to you by five metres of safety line - though that can be played out to twenty if necessary. In addition, you'll both be tethered to the two guide-cables we've strung the whole length of the valley. The rule of the road is the same as on Earth; keep to the right! If you want to overtake anyone, you only have to unclip your buckle - but one of you must always remain attached to the line. That way, there's no danger of drifting off into space. Any questions?"
"How long can we stay out?"
"As long as you like, Ms M'Bala. But I recommend that you return just as soon as you feel the slightest discomfort. Perhaps an hour would be best for the first outing - though it may seem like only ten minutes..."
Captain Smith had been quite correct. As Heywood Floyd looked at his time-elapsed display, it seemed incredible that forty minutes had already passed. Yet it should not have been so surprising, for the ship was already a good kilometer away.
As the senior passenge
r - by almost any reckoning - he had been given the privilege of making the first EVA. And he really had no choice of companion.
"EVA with Yva!" chortled Mihailovich. "How can you possibly resist! Even if," he added with a lewd grin, "those damn suits won't let you try all the Extravehicular Activities you'd like."
Yva had agreed, without any hesitation, yet also without any enthusiasm. That, Floyd thought wryly, was typical. It would not be quite true to say that he was disillusioned - at his age, he had very few illusions left - but he was disappointed. And with himself rather than Yva; she was as beyond criticism or praise as the Mona Lisa - with whom she had often been compared.
The comparison was, of course, ridiculous; La Gioconda was mysterious, but she was certainly not erotic. Yva's power had lain in her unique combination of both - with innocence thrown in for good measure. Half a century later, traces of all three ingredients were still visible, at least to the eye of faith.
What was lacking - as Floyd had been sadly forced to admit - was any real personality. When he tried to focus his mind upon her, all he could visualize were the roles she had played. He would have reluctantly agreed with the critic who had once said:
"Yva Merlin is the reflection of all men's desires; but a mirror has no character."
And now this unique and mysterious creature was floating beside him across the face of Halley's Comet, as they and their guide moved along the twin cables that spanned the Valley of Black Snow. That was his name; he was childishly proud of it, even though it would never appear on any map. There could be no maps of a world where geography was as ephemeral as weather on Earth. He savoured the knowledge that no human eye had ever before looked upon the scene around him - or ever would again.