Then I knew.
In our argument as to the possible speed of the Comet, Garth and I had both been right. In our reference frame, the vessel had put on an incredible velocity, and covered the nine-hundred-odd light-years around Rigel in six months. But from the viewpoint of the moon, it had been unable to attain a velocity greater than that of light. As the accelerating energy pressed the vessel's speed closer and closer toward that limiting velocity, the mass of the ship and of its contents had increased toward infinity. And trying to move laboriously with such vast mass, our clocks and bodies had been slowed down until to our leaden minds a year of moon time became equivalent to several hours.
The Comet had attained an average velocity of perhaps 175,000 miles per second, and the voyage that seemed to me six months had taken a thousand years. A thousand years! The words went ringing through my brain. Kelvar had been dead for a thousand years. I was alone in a world uninhabited for centuries.
I threw myself down and battered my head in the sand.
More to achieve, somehow, my own peace of mind, than in any hope of its being discovered, I have written this narrative. There are two copies, this to be placed in a helio-beryllium box at the terminus of the bridge, the other within the comet[[TN-3]]. One at least should thus be able to escape the meteors which, unimpeded by the thin atmosphere, have begun to strike everywhere, tearing up great craters in the explosion that follows as a result of the impact.
My time is nearly up. Air is still plentiful on the Comet, but my provisions will soon run short. It is now slightly over a month since I collapsed on the sands into merciful sleep, and I possess food and water for perhaps another. But why go on in my terrible loneliness?
Sometimes I waken from a dream in which they are all so near—Kelvar, Garth, all my old companions—and for a moment I cannot realize how far away they are. Beyond years and years. And I, trampling back and forth over the dust of our old life, staring across the waste, waiting—for what?
No, I shall wait only until the dark. When the sun drops over the Grimaldi plateau, I shall put my manuscripts in their safe places, then tear off my helmet and join the other two.
An hour ago, the bottom edge of the sun touched the horizon.