After Nature had drawn a few breaths, the star grew cold, and the clever animals had to die.
At the close of the Twentieth Century, the human race stood at the foot of the stars.
An age of imperialism, revolution, and nuclear teeter-totter had passed. Slack-jawed utopianism was dead, too, but things were better than one might have hoped. Man had not blown himself and all his vain works straight to hell, for example. He had not expended all of his resources, or copulated himself into starvation, collapse, and cannibalism. He had given up trying to assassinate God and had made peace, more or less, with his own spiritual imagination. He had not buried himself in his own trash, choked on his own poisons, or submitted himself to the living extinction of universal totalitarianism.
Man stood pat, or more accurately, leaned pat, with his hands in his pockets and a smug expression on his face. He complained constantly about everything imaginable, as creatures do when they have lost all fear. The vast universe of annihilating energies and incomprehensible particles, which ancient philosophers had looked upon with terror, was little more to him than a game, or a joke. He floated in it like a careless bubble.
Comets whipped past him --- missing him by millions of miles.
The human race had passed the test, it seemed. All that remained was to set a few domestic affairs in order before taking his place among the stars, where Eden worlds and civilizations unimaginable were waiting. He had brains to burn, and more technology and science than he had ever taken the time to exploit. He had the necessary means to colonize the Moon at once, and Mars in short order. As for the leap into the great beyond, well, that was surely only a matter of time.
But it was not to be. Though his knowledge grew greater and ever more intricate, the increasingly refined equations continued to churn out the same cruel facts. Even the nearest stars were too far away, and the velocities he could achieve were too meager, for such a venture to be adequately conceived. A journey to Alpha Centauri would take many years, at great risk, with no promise of a secure foothold once it was reached. The more it was pondered, the more the idea of interstellar travel seemed to be yet another naive conceit that needed to be outgrown.
So man pottered about the solar system, with whatever money and resources he could spare. He built small outposts from time to time on neighboring planets, but no permanent habitations: such harsh colonies made no sense to him except as stepping stones to the unattainable stars. He continued to peer at the rest of the universe across the great gulf. But he reconciled himself to the fact that he would never set foot there, and in time he ceased to even think about it.
And time, of course, ran out eventually. The actual mechanism makes no difference. But his world ceased to sustain man, and the day finally came when the last human being drew its last tired breath.
Light-years away, the civilized inhabitants of a thousand stellar nations knew nothing of this. Had they known, they certainly would have cared. Steps would have been taken to rescue at least some human specimens before extinction overtook the race. But they never knew man was there. The cosmos is a big place, and not all of its galaxies have been probed, let alone all of its trillions of back-water planetary systems. And the stellar nations had other affairs to attend to --- affairs so vast and profound that human beings could scarcely have imagined them. They would have welcomed man into that community, and man would have grown immeasurably thereby, but it just didn't work out that way.
Eventually the star Sol reached a critical point in the consumption of its fuel, and growing cooler it shucked off a great portion of its mass, which engulfed the planet Earth and erased whatever remote traces of human habitation still remained on it. No relic or fossil or fragment of man was ever discovered, and so he disappeared completely; another isolated and remote biological phenomenon that the grand history of life simply overlooked.
At the close of the Twentieth Century, the human race stood at the foot of the stars.
In the decades that followed man's burgeoning technology continued to advance, and his impressive knowledge of astrophysics grew ever more detailed. Fusion power gave him access to virtually unlimited energy. But more importantly, man was finding new energies within himself. The petty tribalism that had plagued him for centuries was gradually relinquishing its grip. The human race was beginning to view itself as a unified race, not as a pastiche of grasping and resentful factions.
With this solidarity came a sense of mission never before experienced on such a scale. Visionaries began to speak of other worlds, inhabited by other intelligent beings, to which man would come, bringing his own contributions to the pageant of life. Such talk had been heard before, of course, but had never been taken seriously, even though a preponderance of scientific opinion considered the existence of extraterrestrial life to be highly probable, perhaps even a mathematical certainty. But man's own distressed and disunified condition had always made the very idea of an interstellar extension of the same seem absurd.
Now, however, that objection was no longer a fatal one, and the idea grew deep roots at last. An increasingly educated and technically sophisticated public began to nurture it, and millions of young people made it their obsession.
Not that human relations were idyllic. The society of Man was not a perfect harmony, but it was a near-perfect balance; an accord firmly buttressed by a common intellectual culture that well understood its own limitations. It made no attempt to tamper with men's souls, or even with the natural currents of everyday life. It merely formed a framework of commonality which damped the violence of factionalism and alienation, and this was enough to form a cradle for the birth of Interstellar Man. An unbroken unity of vision was not necessary for this undertaking.
Man does not need (and probably cannot have) an exact definition of himself.
The first steps were slow and tottering. Alpha Centauri, Sirius, Epsilon Eridani, and Barnard's Star: their sparse orbits were silent and empty of life, but wondrous all the same. Pioneering spacecraft ringed them with new lights, and man's domain became a small constellation.
Skeptics had doubted that this new frontiersmanship would be lasting, given that human beings had grown comfortable and individually self-gratifying over the ages. The new planets, with their wistful new names, were barren and hostile beyond belief. Nevertheless domed habitations sprang up on scores of them, and volunteers waited many months for the privilege of crossing the terrific gulfs to occupy these spartan outposts. The crossings themselves took long years, but became ever more frequent. Danger, tedium, and menial labor were suffered, not without complaint, but without despair. Immersed in the elemental routine of frontier life, Man found new value in his own nature, and rejoiced in it.
The slow process of Terraforming, which in time would turn hells into paradises, was begun on a dozen worlds --- then on a hundred more.
When the light-speed barrier was finally broken, a pent-up yearning exploded into the infinite reaches of space. In the space of a few decades, the human race trebled in size, and a far greater multiplication lay ahead as planets were colonized with astonishing rapidity. Man bobbed to the surface of the galaxy. He peered down from its flat keel, raced along its rim, and sailed the fantastic depths of its core.
But he sailed it alone. No voices hailed him, and no strange ships hove into view. Everything was there for him to take. A thousand vanguards had landed on a thousand virgin worlds, but no aboriginal inhabitants had bestirred themselves to greet them. Energetic explorations found nothing: no baroque civilizations, living or ruined, and no alien tribes, not so much as a single sentient individual. Only the random jumble of matter, in which no stone had been stirred by any purposeful hand.
This was strange, but not conclusive. The universe was a big place. Other minds had to be out there, somewhere. So ships never ceased in their probing. Their engines burned in the remotest regions of the Milky Way, and in time, courses were set for fresh galaxies.
The time came at last. It might have taken unnumbered millennia, but it had to come at last. On the last planet of the last unsounded star, at the final fringe of the final galaxy, a ship fired its braking jets and settled onto the surface.
An explorer dismounted, earning celebrity. What Armstrong had been the first to do, this individual would be the last. Striding a few paces through swirling dust, not feeling the feeble wind that swept it away, the explorer knelt and scooped up a handful of soil. The dry, sterile powder drained away between the fingers of the explorer's pressurized glove. There was no life in it, nor had there ever been.
And so the famous words were spoken: "We are all alone."
Or maybe: "Looks like it's just you and me, God."