Aurora (23 page)

Beaumont, noticing, grinned and nodded approvingly.

“I'm sorry,” she continued, ignoring this, “but I don't know the answer. I'm not sure that anyone knows the answer, even in my day. Normally, the genes for light hair and pale eyes are recessive. Considering the amount of interbreeding between races that has taken place, one would expect darker features to predominate. But the genetic manipulation which took place around the year 4100—and it had nothing at all in common with Nazi-like schemes for an ideal race, I can assure you!—apparently reversed that, probably quite unintentionally. Although, as you have seen, our skin color is actually quite dark; this isn't a suntan—it's been a very long time since I've had a chance to sunbathe, here on Mars!”

She seemed pleased to be able to lighten her narrative with a small joke, and stretched a little, shifting position in her chair. But she still looked pale and strained, and Lundquist prepared to put a stop to the proceedings. She could continue at a later time. There was no need for her to put herself through what was obviously an exhausting ordeal any longer....

“About ten thousand years ago—or in as many years' time, it makes little difference which way I say it, there was another glacial period—another resurgence of the Ice Age—and it caused a great redistribution, and reduction, of the Earth's population. It was beyond the technology of the day to take much effective action; the power of ice is great. The survivors were often those who were not only physically fit but possessed the strongest mental and regenerative powers. So a sort of process of natural selection operated.

“But long before that happened, part of the human race had moved away.

“To Mars.”

* * * *

The transmission continued the next day, Lundquist and Beaumont having finally insisted that Aurora take a rest, despite her protestations that she was quite able to continue.

“Somewhere around the year 2500, humanity, which had once again started making tentative voyages into space—I'm sorry, guys, but most of
our
achievements on this mission seem to have become lost or forgotten!—took the decision to terraform Mars, to convert it into an Earthlike planet, habitable by humans. Having established that there was no indigenous life, and apparently never had been any, many people wanted to get away from Earth, with its blackened, ruined cities and radioactive wastelands, and start a new life with an entirely new lifestyle.

“Plenty of plans were considered. As you know, there are almost two thousand cubic kilometers of water locked inside the polar caps of Mars. That's enough to cover the planet with an ocean fifty centimeters deep. But most of Mars's water lies frozen deep below the crust.

“So the first method used was a rather crude one. Five ice asteroids, each ten to fifteen kilometers in diameter, were diverted from their orbits in the outer Solar System and steered carefully towards Mars so that they would impact in the basin of Hellas. That's already the lowest area on Mars, and was covered by an ocean millions of years ago. They made it an ocean once more. The impacts caused some disruption of the surface of Mars, but not as much as you might expect—Mars has a thick crust, or the asteroid which created Hellas in the first place would have gone right through that crust!

“You can imagine what a maelstrom it must have been, though, as the ice was converted almost instantly into plasma, then superheated steam, finally condensing into thick grey clouds which rose high into the atmosphere, perhaps even precipitating rain....

“Meanwhile, a mass-driver—an electromagnetic launcher—was set up on Phobos to eject the dark, carbonaceous material the moon's made of onto the Martian poles, increasing their absorption of infrared radiation—heat. This also increased the polar energy flux, but the process was accelerated by placing mirrors in orbit. Made of a very thin, metallized material similar to Mylar, these reflected sunlight to warm the polar caps and release carbon dioxide, water vapor, oxygen and nitrogen from the crust. A greenhouse-effect cycle was started.

“Then, genetically engineered plant life was introduced into the system, forming a tundra-like landscape. Carbon dioxide was converted into oxygen. The temperature slowly rose, until it was above freezing point, and then to ten degrees Celsius. Can you imagine the transformation? The sky became deep blue. The Hellas Ocean was seeded with plankton which absorbed carbon dioxide. As it was fed by rivers and streams, the ocean grew in size. Another ocean grew in the northern lowlands—the Boreal Sea. Forests of evergreen trees spread from its borders.

“The crust of the planet contains all the essential elements for life. The ecology became self-sustaining; and, now that the atmosphere had been established, Mars had sufficient mass to retain it for tens of millions of years. It was generally known as the Second Home.

“The first real city—the planet's capital, if you like—was built on the Tharsis Bulge, high above any water-line. The Two Mountains—the volcanoes of Ceraunius and Uranius—were chosen as its site, apparently mainly for aesthetic reasons. They were the right size, and their relative outlines, seen from above, were felt to mimic those of Earth and Mars. That ‘figure-of-eight' symbol has been significant to the inhabitants ever since. It was seen everywhere. You will even notice its echo in the shape of the device we found and called the Beacon, although actually it serves a number of purposes: remote control, transmitter, marker, key, confirmer of identity.... One of our greatest strokes of luck on this expedition was that my genetic material is so similar to that of my parents, otherwise we might not have been able to enter the ship. Indeed, the Beacon, and that glowing light we first saw, might never have been triggered in the first place.”

Aurora paused and looked down at some notes she had prepared so that she would not lose her thread.

“The psibot—the Beacon—had been buried for nearly eighty years, and after we'd discovered it, it misbehaved at first. It was intended to project a...‘hologram' is as near as I can describe it, which would lead searchers to the ship. But the human shape took a while to...cohere. It's interesting that the Beacon was triggered by the airship on one occasion. Perhaps it confused the Blimp's shape with one of my people's craft?

“Anyway, the two civilizations, one on Earth and the other on Mars, became quite separate. The one on Earth became almost entirely pastoral. The cities were kept, along with all the machinery and technology they housed, as museums of humanity's past—and, to a large extent, of its follies. Science was not exactly banned, but it was excluded by common consent except where it was required for purely practical considerations, as I have already explained.

“The inhabitants turned to the Arts: to painting, sculpture, literature, poetry, music—to all pursuits of the mind, which they raised to incredible new heights. But they did not neglect the body, for all forms of dance were assimilated into the musical and visual arts, creating a whole new art form. I wish I could show you; perhaps I may even be able to give you some idea when I return to Earth and can communicate more directly. And gymnastics and sports, especially team sports—though less violent than, say, football—were also popular.”

Aurora looked into the camera and smiled slightly. She shifted position yet again; sitting still so long for the video was arduous. “The life of the Martians, as they were of course known, followed a similar pattern, but certain types of scientific experimentation and development did continue—pursued mainly for their aesthetic value. Science and mathematics were seen as elegant, beautiful manifestations of Nature, and of human thought. There was rarely any sort of commercial end-product, though should one appear it would not necessarily be rejected.

“Life on both planets could be said to have approached as closely to that of a Utopia as could be imagined. But their inhabitants went about their pursuits sublimely unaware that a visitor was about disrupt their idyllic lives, never to allow them to return to their former perfection.”

ACT FOUR

THE VISITOR

A star was drifting through space. Once, it had been a normal star and had waltzed in a stately dance with a partner, bound to it in the marriage of gravitation. But its mate had become greedy and demanding. It had stolen the outer, hydrogen layers of this star, leaving it stripped and naked, with only its helium core to glow against the eternal night of space.

Its consort had paid the penalty of its greed, though; had grown fat and bloated, and had finally disrupted. Its brightness increased 300 million times as it disintegrated in a final cataclysmic blast of helium, carbon, oxygen, nitrogen....

A supernova.

Released from its unequal marriage partner, but greatly impoverished, the star had become a White Dwarf. It was hurled away from its former mate by the force of the explosion, and now sailed through interstellar space. The chances of it intercepting another body were remote; but a chance remained.

So it was that, after millions or billions of years of roaming alone, the star felt the faint tug of gravity from another sun. This was a commonplace yellow star, but it was surrounded by a retinue of planets, and, at a distance of 50,000 astronomical units, by a vast cloud of a hundred billion insubstantial balls of ice and rock—comets.

The interloper disturbed the orbits of a few of these, which headed inward towards their own sun, to blaze briefly in the skies of the two inhabited worlds of this system like portents of doom. As well they might, for the star which had broken the peace and loneliness of the Oort Cloud was now also on its way towards the center of their system, intent on wreaking a terrible revenge for its own maltreatment.

The white dwarf drifted in at a sharp angle to the ecliptic. The intruder had a diameter of only about 6,500 kilometers, smaller even than the now red-and-green planet known as Mars. But the material of which it was made was so dense that its gravitational force was not far short of that of the Sun itself.

The visitor headed toward the Sun. It passed it at a distance of just over three million kilometers—and the Sun reached out a gravitational hand, spun it around and converted its headlong flight into an extended ellipse. Both stars were affected by the tidal friction as the latest member of the Solar System sped around its new partner and retreated once more into space, to prepare for another embrace in a thousand years' time.

But, while it remained close to the Sun, the star made certain that the inner planets became well aware of its passage. While just within the combined Roche Limit of the two stars—further inside and total tidal disruption would have occurred—it drew hydrogen gas from the surface of the Sun. This gas fell onto the white dwarf and exploded outward, causing a nova outburst.

This was but a pale echo of the supernova which had precipitated its own flight, but still it emitted more than 10,000 times more light than normal, and the star became wreathed in a halo of fluorescing gas as great jets and streamers of red-glowing hydrogen were torn from the tortured skin of the Sun, reaching out for the stranger like grasping fingers.

Mars was fortunate. It was on the far side of its orbit when the star approached the Sun, and, while its inhabitants saw everything, they felt only relatively minor ground tremors. The ozone layer which had been created high in the Martian atmosphere protected them from most of the brief burst of radiation.

Earth did not fare so well. The angle of the white dwarf's approach was such that it passed within a few million kilometers, and the tidal forces were fearsome. Earthquakes reduced buildings and whole cities to rubble; great cracks opened in the ground, belching flame and steam; ancient volcanoes came to life and blackened the sky with clouds of ash and dust, while pouring out rivers of red-glowing lava which devoured everything in their path.

Giant waves—tsunamis—reared up from the oceans and created more havoc, sweeping away buildings and trees and drowning many millions of people and animals. These were accompanied by the rush of mighty winds, bringing their own forms of destruction.

As if this were not enough, soon afterwards a blast of radiation from the nova outburst engulfed the Earth. The storm of particles lasted for well over the Biblical forty days and forty nights, until the visitor began to move away from the Sun and its brilliance diminished. It was, by cosmic standards, a modest outburst, but it held danger enough. Only the fact that, by the time the radiation arrived, Earth was almost completely shrouded in a thick blanket of cloud, smoke, and dust prevented greater harm from being perpetrated.

The star retreated, gloating. It was watched by the Martians, who had not abandoned astronomy completely, though they now concentrated on the more esoteric aspects of cosmology and were engaged on a search for the answer to the great mystery of the origin and destiny of the Universe. A white dwarf would be invisible beyond a hundred light years even to their sensitive instruments; but such a tiny, insignificant object would never have interested them anyway, had they deigned to notice such a minuscule change in the normal star-patterns when it first became visible.

Communication between the two worlds had been rare in recent centuries. There was little to talk about. But the means for communication still existed. Once some semblance of normality had returned to Earth, its Council of Twelve (now reduced by casualties to seven, until its missing members could be replaced) contacted Mars, requesting asylum.

Before its transformation by terraforming, the surface area of Mars had been almost as great as that of the dry land on Earth. Even now that water occupied the lower portions of the terrain, the few millions living there had plenty to spare. Once upon a time its inhabitants might have held onto that land avariciously, but in this enlightened age they gladly welcomed their cousins from Earth. The spaceships which, thousands of years ago, had lifted their ancestors from the home planet were intact, cocooned in great hangars.

True, there was no one who knew how to pilot them, but records and implanted memories remained, and it was not difficult for young men and women to learn. Indeed, to them it was an exciting and unexpected challenge.

The ships, containing the pitiful remnants of Earth's great final civilization, crossed the abyss between the two worlds in a matter of weeks. The whole migration took many months. But at last the home planet was nearly empty of all but plant and animal life—and even some of the latter, unique to Earth, had been ferried to the new world. A few, mainly older, people chose to remain. They would die naturally long before the star's second coming, and preferred to live out their allotted spans in their own homes.

The people who left Earth took with them crystals on which were stored as much as remained of the home world's art and literature, and even some of its science. It was unlikely that they would ever return.

What remained behind them would be safe for centuries, for the white dwarf was still on its way into the depths of space, still at an angle which kept it clear of the outer planets. But its elliptical, comet-like orbit would bring it back to the inner system again and again. And each time it flung its invisible arms around the Sun and danced its deadly jig it would seize more material from the bigger star and hurl much of it into space. But much it would hug to its own chest, miser-like, growing more massive with each passage. As long as the output of light and radiation remained no more than one-fifth above normal, Earth would be scorched but Mars should escape.

Even so, Martian astronomers knew that each return would shorten the period before the next. One day in the far distant future, enough material would have been transferred from the Sun to the white dwarf that it would have absorbed more helium into its core than it could comfortably contain. It too would erupt in a supernova explosion—and the Sun, now itself nothing but a stripped helium core and so effectively itself a white dwarf, would be hurled away like a cast-off lover. Perhaps to wander one day, millions or billions of years hence, into some other unsuspecting star system....

The Martians, who over the years had assimilated the immigrant culture from Earth—both groups benefiting from the intermixture, and indeed the interbreeding—began to discuss very seriously the possibility of leaving the Solar System altogether in order to find a safer world orbiting another star. A few probes had been sent into interstellar space, millennia ago, but various historical disturbances had prevented further progress in that direction. Finally, the sending of probes had no longer seemed a necessity, or even particularly desirable. Instruments in space, or on the Moon, could provide all the information required.

Until now.

The brains of the Martian scientists were quite capable of designing theoretical drives that would produce speeds close to that of light. Some even wove dreams of there being tunnels through space, evading the need for such a finite and physical limitation. But the technological base, the industrial infrastructure, for the manufacture of starships no longer existed—especially ships capable of effecting the sort of massive evacuation which would be required. At last they rejected the idea of any massive exodus by mechanical means. Should a more elegant method of travelling to another star present itself—such as a matter transmitter—they would embrace it.

In the course of their researches, one scientist came across an ancient plan for another type of vehicle. A ship to cross not space but
time
.

The older and more entrenched scientists shook their heads in disbelief. Time had long been regarded as the one barrier that would never yield to humankind's probings. Yet...the theory behind this proposed machine did seem to be sound. It gave promise of being able to travel backward in time, though never forward, so anyone who attempted such a journey could never return, and those who sent that person would never know for certain whether he or she had succeeded.

Unless it proved possible to tamper with the past.

To change it.