Now the long wait was ending. On yet another world, intelligence had been born and was escaping from it's planetary cradle. An ancient experiment was about to reach it's climax.
Those who had begun that experiment, so long ago, had not been men---or even remotely human. But they were flesh and blood, and when they looked out across the deeps of space, they had felt awe, and wonder, and lonliness. As soon as they possesed the power, they set forth for the stars. In their exploration, they encountered many life in many forms and watched the workings of evolution on a thousand worlds. They saw how often the first faint sparks of intelligence flickered and died in the cosmic night.
And because, in all the Galaxy, they had found nothing more precious than Mind, they had encouraged its dawning everywhere. They became farmers in the fields of stars; they sowed, and sometimes they reaped.
And sometimes, dispationately, they had to weed.
The great dinosaurs had long since perished when the survey ship entered the Solar System after a voyage that had already lasted a thousand years. It swept past the frozen outer planets, paused briefly above the deserts of dying Mars, and presently looked down on Earth.
Spread out beneath them, the explorers saw a world swarming with life. For years they studied, collected, cataloged. When they had learned all that they could, they began to modify. They tinkered with the destinies of many species on land and in the ocean. But which of their experiments would succeed, they could not know for at least a million years.
They were patient, but not they were not yet immortal. So much remained to do in this universe of a hundred billion suns, and other worlds were calling. So they set out once more into the abyss, knowing that they would never come this way again.
Nor was there any need. The servants they had left behind would do the rest.
On Earth the glaciers came and went, while above them the changeless Moon still carried its secret. With a slower rhythm than the polar ice, the tides of civilization ebbed and flowed across the Galaxy. Strange and beautiful and terrible empires rose and fell, and passed on their knowledge to their successors. Earth was not forgotten, but another visit would serve little purpose. It was one of a million silent worlds, few of which would ever speak.
And now, out among the stars, evolution was driving towards new goals. The first explorers of Earth had long since come to the limits of flesh and blood; as soon as their machines were better than their bodies, it was time to move. First their brains, then their thoughts alone, they transferred into shining new homes of metal and plastic.
In these, they roamed among the stars. They no longer built spaceships. Tey were spaceships.
But the age of the Machine-entities swiftly passed. In their ceaseless experimenting, they had learned to store knowledge in the structure of space itself, and t preserve their thoughts for eternity in frozen lattices of light. They could become creatures of radiation, free at last from the tyranny of matter.
Into pure energy, therefore, they presently transformed themselves; and on a thousand worlds the empty shells they had discarded twitched for a while in a mindless dance of death then crumbled into rust.
They were lords of the Galaxy, and beyond the reach of time. They could rove at will among the stars andsink like a subtle mist through the very interstices of space. But despite their godlike powers, they had not wholly forgotten their origin in hte warm slime of a vanished sea.
And they still watched over the experiments their ancestors had started, so long ago.