quest, the odds against his succeeding. To every hundred thousand suns there was but one, and perhaps not even one, with planets. To every thousand planets perhaps, perhaps there was one sufficiently supplied with water — and suitable for colonization by his kind. There were a hundred million chances to one of Thrall's finding, anywhere in the galaxy, that which he sought. And the other galaxies, even the big, near one in Andromeda, were too far away. . . .
And now the quest was ended.
Thvall's selection of Sol as a star worthy of investigation had not been haphazard. While still beyond the white star Alpha in the constellation of the Centaur he had noted that this modest yellow-white sun was slightly unstable, slightly variable, a star that fluctuated, though to only a minor degree, through a regularly recurrent cycle.
That periodicity might mean almost anything; it might mean that the star was on the verge of blowing up, it might be caused by the resultant of the gravitational attraction of attendant planets, or it might be merely the subsiding spasms of some ancient solar malaise. From Alpha Centauri, Thvall set his course for Sol.
He was fifteen billions of miles beyond the orbit of that planet men have named Pluto when the steadily increasing intensity of Sol's illumination, actuating certain mechanisms, awakened him from the state of completely suspended animation in which he voyaged from star to star. He awoke instantly, feeling neither refreshed nor enervated, and lacking any recollection whatsoever of the passage of time. His first, and almost automatic activity, was to reduce the velocity of his space-craft from a hyper-Einsteinian, interstellar speed to a pace more suitable to interplanetary cruising.
During those first brief, waking moments his ship traveled Solward a billion miles.
Immediately he had slowed the rush of his ship toward the yellow sun, he applied himself to his instruments, and saw at once that the slightly nervous star was plagued with a swarm of planets. The outermost planets were too cold to support life; their atmospheres were raging seas of ammonia and methane. The planet nearest the luminary was without atmosphere; the next was heavily blanketed with an atmosphere, which was, however, full of carbon dioxide; the third planet — the one with the pear-shaped moon — had an atmosphere dripping with water-vapor.
Thvall, looking upon Earth, knew that his quest was ended.
His ship safely landed on Sol's third planet, Thvall began a series of routine tasks. He analyzed the luminary's radiation and the planet's atmosphere with highly encouraging results; his kind could adapt themselves to life on Earth. Next he attempted communication with the green growing life, but, although he quickly learned that Earth's vegetation possessed a dim, vague consciousness, it was obvious that its intelligence was too meager, too instinctive for the development of original thought. Obviously Earth's vegetation could not have constructed the aimless sprawling city in the midst of which Thvall's space-ship lay. It was probable therefore that the city's creators were temporarily absent. Perhaps they were nocturnal creatures, who lived during the day in underground recesses and came to the surface of the planet only at night. Perhaps they
