"That is amazing," said Martia, "but—oh!" She read the rest in Henry's mind. The rocket carried the world's first D-C bomb, which letters represented the word, "de-cohesion." In detonation, the bomb was supposed to liberate the cohesive forces of the proton. They were going to observe its effects on the moon.
"I believe," said Henry, "that it produced a sustained reaction in stable matter, and the moon blew to fragments, thus creating the Great Ring. The thermal effects plus orbital perturbations of the Earth destroyed all life on the planet. And I deduce that the free oxygen and hydrogen in our atmosphere made some kind of critical mixture and went foom! The result was H2O, oceans of it. And so time began again, biologically speaking, anyway."
"If Andrew Dearden or any of his kind get back there and manage to abolish the 'D-C' bomb," said Kimnar, "then Xlarn will never have been, and neither you nor I nor Galactic Civilization, with its myriad worlds and metropoli and billions of star people and all their science and culture, shall have ever evolved. And there you have a difficult question. Is it better for us to relinquish our existence for the sake of a civilization that might have continued, or to preserve a greater one that actually exists now?"
Before they could bring much concentration to bear upon this weighty problem, a new situation diverted their attention. Inasmuch as the three of them were standing by the transparent wall of the citadel and facing shoreward, they could not help seeing the small industrial city that suddenly sprang into being there. Again, up on the hill, was a great black rocket, its nose pointing toward the threatening sky.
But this was not New Bretania. Nor was it Texania. Nor was there the slightest evidence of any type of conflict or preparations for defense, except in the design of the rocket, itself.
"That's a different alternate!" said Henry, instantly. "The city is different—more heavily industrialized. See the steel mills? It's even futuristic. Those insulator towers and antenna, for some kind of power transmission—"
"And that rocket is different—more efficient looking," observed Martia. "It seems to carry armament. You can see the firing cupolas."
"You're both very calm about it," said Kimnar. "Somebody has found the Chronotron. Come on!"
A moment after they had stepped through the teleporter, leaving the island citadel deserted, the hyper-space receiver began to react to signals. Lights flickered rapidly for several minutes. Then a human voice boomed into the empty dome. It spoke in a strange language, rapidly, urgently. But there was no operator there to reply....