Authors: Arthur C Clarke
"Here's something to put on your balance sheet," he said cheerfully. "It's the biggest astronomical discovery for years. Come up to the roof."
Sadler dropped the trenchant editorial in
Time Interplanetary
which he had been reading with growing annoyance. The magazine fell with that dreamlike slowness he had not yet grown accustomed to, and he followed Wagnall to the elevator.
They rose past the residential level, past Administration, past Power and Transport, and emerged into one of the small observation domes. The plastic bubble was scarcely ten meters across, and the awnings that shielded it during the lunar day had been rolled back. Wagnall switched off the internal lights, and they stood looking up at the stars and the waxing Earth. Sadler had been here several times before; he knew no better cure for mental fatigue.
A quarter of a kilometre away the great framework of the largest telescope ever built by man was pointing steadily toward a spot in the southern sky. Sadler knew that it was looking at no stars that his eyes could see—at no stars, indeed, that belonged to this universe. It would be probing the limits of space, a billion light-years from home.
Then, unexpectedly, it began to swing toward the north. Wagnall chuckled quietly.
"A lot of people will be tearing their hair now," he said. "We've interrupted the program to turn the big guns on
Nova Draconis.
Let's see if we can find it."
He searched for a little while, consulting a sketch in his hand. Sadler, also staring into the north, could see nothing in the least unusual. All the stars there looked just the same to him. But presently, following Wagnall's instructions, and using the Great Bear and Polaris as guides, he found the faint star low down in the northern sky. It was not at all impressive, even if you realized that a couple of days before only the largest telescopes could have found it, and that it had climbed in brilliance a hundred thousand times in a few hours.
Perhaps Wagnall sensed his disappointment.
"It may not look very spectacular now," he said defensively, "but it's still on the rise. With any luck, we may really see something in a day or two."
Day lunar or day terrestrial? Sadler wondered. It was rather confusing, like so many things here. All the clocks ran on a twenty-four hour system and kept Greenwich Mean Time. One minor advantage of this was that one had only to glance at the Earth to get a reasonably accurate time check. But it meant that the progress of light and dark on the lunar surface had no connection at all with what the clocks might say. The sun could be anywhere above or below the horizon when the docks said it was noon.
Sadler glanced away from the north, back to the Observatory. He had always assumed—without bothering to think about it—that any observatory would consist of a cluster of giant domes, and had forgotten that here on the weatherless Moon there would be no purpose in enclosing the instruments. The thousand centimetre reflector and its smaller companion stood naked and unprotected in the vacuum of space. Only their fragile masters remained underground in the warmth and air of this buried city.
The horizon was almost flat in all directions. Though the Observatory was at the centre of the great walled-plain of Plato, the mountain ring was hidden by the curve of the Moon. It was a bleak and desolate prospect, without even a few hills to give it interest. Only a dusty plain, studded here and there with blow-holes and craterlets—and the enigmatic works of man, straining at the stars and trying to wrest away their secrets.
As they left, Sadler glanced once more toward Draco
,
but already he had forgotten which of the faint circumpolar stars was the one he had come to see. "Exactly why," he said to Wag-nail, as tactfully as he could—for he did not want to hurt the secretary's feelings—"is this star so important?"
Wagnall looked incredulous, then pained, then understanding.
"Well," he began, "I guess stars are like people. The well-behaved ones never attract much attention. They teach us something, of course, but we can learn a lot more from the ones that go off the rails."
"And do stars do that sort of thing fairly often?"
"Every year about a hundred blow up in our galaxy alone, but those are only ordinary novae. At their peak, they may be above a hundred thousand times as bright as the sun. A
supernova
is a very much rarer, and a very much more exciting affair. We still don't know what causes it, but when a star goes super it may become several
billion
times brighter than the sun. In fact, it can outshine all the other stars in the galaxy added together."
Sadler considered this for a while. It was certainly a thought calculated to inspire a moment's silent reflection.
"The important thing is," Wagnall continued eagerly, "that nothing like this has happened since telescopes were invented. The last supernova in
our
universe was six hundred years ago. There have been plenty in other galaxies, but they're too far away to be studied properly. This one, as it were, is right on our doorstep. That fact will be pretty obvious in a couple of days. In a few hours it will be outshining everything in the sky, except the sun and Earth."
"And what do you expect to learn from it?"
"A supernova explosion is the most titanic event known to occur in nature. We'll be able to study the behaviour of matter under conditions that make the middle of an atom bomb look like a dead calm. But if you're one of those people who always want a practical use for everything, surely it's of considerable interest to find what makes a star explode? One day, after all, our sun may decide to do likewise."
"And in
that
case," retorted Sadler, "I'd really prefer not to know about it in advance. I wonder if that nova took any planets with it?"
"There's absolutely no way of telling. But it must happen fairly often, because at least one star in ten's got planets."
It was a heart-freezing thought. At any moment, as likely as not,
somewhere
in the universe a whole solar system, with strangely peopled worlds and civilizations, was being tossed carelessly into a cosmic furnace. Life was a fragile and delicate phenomenon, poised on the razor's edge between cold and heat.
But Man was not content with the hazards that Nature could provide. He was busily building his own funeral pyre.
The same thought had occurred to Dr. Molton, but unlike Sadler he could set against it a more cheerful one.
Nova Draconis
was more than two thousand light-years away; the flash of the detonation had been travelling since the birth of Christ. In that time, it must have swept through millions of solar systems, have alerted the inhabitants of a thousand worlds. Even at this moment, scattered over the surface of a sphere four thousand light-years in diameter, there must surely be other astronomers, with instruments not unlike his own, who would be trapping the radiations of this dying sun as they ebbed out toward the frontiers of the universe. And it was stranger still to think that infinitely more distant observers, so far away that to them the whole galaxy was no more than a faint smudge of light, would notice some hundred million years from now that our island universe had momentarily doubled its brilliance…
Dr. Molton stood at the control desk in the softly lit chamber that was his laboratory and workshop. It had once been little different from any of the other cells that made up the Observatory, but its occupant had stamped his personality upon it. In one corner stood a vase of artificial flowers, something both incongruous and welcome in such a place as this. It was Molton's only eccentricity, and no one grudged it to him. Since the native lunar vegetation gave such little scope for ornament, he was forced to use creations of wax and wire, skilfully made up for him in Central City. Their arrangement he varied with such ingenuity and resource that he never seemed to have the same flowers on two successive days.
Sometimes Wheeler used to make fun of him about this hobby, claiming that it proved he was homesick and wanted to get back to Earth. It had, in fact, been more than three years since Dr. Molton had returned to his native Australia, but he seemed in no hurry to do so. As he pointed out, there were about a hundred lifetimes of work for him here, and he preferred to let his leave accumulate until he felt like taking it in one instalment.
The flowers were flanked by metal filing cases containing the thousands of spectrograms which Molton had gathered during his research. He was not, as he was always careful to point out, a theoretical astronomer. He simply looked and recorded; other people had the task of explaining what he found. Sometimes indignant mathematicians would arrive protesting that no star could
possibly
have a spectrum like this. Then Molton would go to his files, check that there had been no mistake, and reply, "Don't blame me. Take it up with old Mother Nature."
The rest of the room was a crowded mass of equipment that would have been completely meaningless to a layman, and indeed would have baffled many astronomers. Most of it Molton had built himself, or at least designed and handed over to his assistants for construction. For the last two centuries, every practical astronomer had had to be something of an electrician, an engineer, a physicist—and, as the cost of his equipment steadily increased, a public-relations man.
The electronic commands sped silently through the cables as Molton set Right Ascension and Declination. Far above his head, the great telescope, like some mammoth gun, tracked smoothly round to the north. The vast mirror at the base of the tube was gathering more than a million times as much light as a human eye could grasp, and focusing it with exquisite precision into a single beam. That beam, reflected again from mirror to mirror as if down a periscope, was now reaching Dr. Molton, to do with as he pleased.
Had he looked into the beam, the sheer glare of
Nova Draconis
would have blinded him—and as compared with his instruments, his eyes could tell him practically nothing. He switched the electronic spectrometer into place, and started it scanning. It would explore the spectrum of
N. Draconis
with patient accuracy, working down through yellow, green, blue into the violet and far ultra-violet, utterly beyond range of the human eye. As it scanned, it would trace on moving tape the intensity of every spectral line, leaving an unchallengeable record which astronomers could still consult a thousand years from now.
There was a knock at the door and Jamieson entered, carrying some still-damp photographic plates.
"Those last exposures did it!" he said jubilantly. "They show the gaseous shell expanding round the nova. And the speed agrees with your Doppler shifts."
"So I should hope," growled Molton. "Let's look at them."
He studied the plates, while in the background the whirring of electric motors continued from the spectrometer as it kept up its automatic search. They were negatives, of course, but like all astronomers he was accustomed to that and could interpret them as easily as positive prints.
There at the centre was the little disk that marked
N, Draconis,
burnt through the emulsion by overexposure. And around it, barely visible to the naked eye, was a tenuous ring. As the days passed, Molton
knew,
that ring would expand further and further into space until it was finally dissipated. It looked so small and insignificant that the mind could not comprehend what it really was.
They were looking into the past, at a catastrophe that had happened 2,000 years ago. They were seeing the shell of flame, so hot that it had not yet cooled to white-heat, which the star had blasted into space at millions of kilometres an hour. That expanding wall of fire would have engulfed the mightiest planet without checking its speed; yet from Earth it was no more than a faint ring at the limits of visibility.
"I wonder," said Jamieson softly, "if we'll ever find out just
why
a star does this sort of thing?"
"Sometimes," replied Molton, "as I'm listening to the radio, I think it would be a good idea if it did happen. Fire's a good sterilizer."
Jamieson was obviously shocked; this was unlike Molton, whose brusque exterior so inadequately concealed his deep inner warmth.
"You don't really mean that!" he protested.
"Well, perhaps not. We've made some progress in the past million years, and I suppose an astronomer should be patient. But look at the mess we're running into now—don't you ever wonder how it's all going to end?"
There was a passion, a depth of feeling behind the words that astonished Jamieson and left him profoundly disturbed. Molton had never before let down his guard—had never, indeed, indicated that he felt very strongly on any subject outside his own field. Jamieson knew he had glimpsed the momentary weakening of an iron control. It stirred something in his own mind, and mentally he reacted like a startled animal against the shock of recognition.
For a long moment the two scientists stared at each other, appraising, speculating, reaching out across the gulf that separates every man from his neighbour. Then, with a shrill buzzing, the automatic spectrometer announced that it had finished its task. The tension had broken; the everyday world crowded in upon them again. And so a moment that might have widened out into incalculable consequences trembled on the verge of being, and returned once more to Limbo.