Ackerman knew. The end-point of this was a blank space in the solar system and a gradual re-establishment of the energy-distribution of the solar system to make up for the missing mass-energy and attraction of the destroyed earth.
"What can I do?" he asked helplessly.
"How did they hit the earth?"
"I don't know," answered Ackerman.
"They had observers, just as we are. They got here by penetrating the no-world between the world-lines as we have done. We—you—must develop a means of our doing that. You, Ackerman, are really the only one in historic time who knows the secret of temperon."
"No, I do not."
Calvin Blaine smiled tolerantly. "I am of the destroyed earth," he said sadly. "We do not know how to penetrate the barrier."
"But you are here," said Les.
Blaine nodded very slowly. "Yes—because you, Les Ackerman, know that secret."
"But I don't—I don't!"