"But there must be someone else that can do it. What if you died?"
"Oh, there are others trained in this sort of job in that case."
"Why not let one of them take it, then?"
Paul shook his head again. "I'm all right," he said. He realized that his insistence was too vigorous and that his reasons were too lame. But he could not let them know why it was so important that Paul Grayson go in person. If Haedaecker got wind of what Paul carried in his spacecraft, there would be hell to pay. He thought of a plausible excuse. "Most of them aren't on earth right now."
"Couldn't you call one of them?"
Paul smiled ruefully. "They're outside of the solar system."
The sergeant nodded. "The Z-wave can't cross interstellar space," he said. It was a statement thrown in to display his knowledge to the technician from the Bureau of Astrogation, and also a leader for more conversation.
Paul did not bite.
"That's Haedaecker's Theory," added the sergeant. "Isn't it?" he added after another moment of silence.
"Haedaecker's Theory is that the Z-wave propagates only in a region under the influence of solar activity," explained Paul. He looked out of the police car and saw the spaceport only a few moments away. Then he talked volubly to fill in the time so that he could be off without further questioning. Haedaecker had plenty of evidence to support his theory, but they all were missing one point that was as plain as the nose on Haedaecker's face.