“Yes,” said the professor. “That’s where it goes—out into the realms of Space.
“Now what you must understand is that light can be reflected, refracted, polarized, but never destroyed.” He pointed to his instruments on one of the tables. “I can do all those things to it—and a thousand more—but I cannot destroy it.”
“Right,” said Tubby. “But if you put it out you can’t never get it back, can you now?”
The professor beamed on him genially. “Your brain works too keenly,” he said. “You anticipate me. No, I cannot get it back. But it comes back. That’s just the point—it comes back. That’s what nobody in the world knows except me—me and you.
“The sun,” he went on, “gives us most of our light—it gets here to the earth from the sun in a few minutes. The moon gives us reflected sunlight. It is the same light, only it comes to us from the sun by way of the moon. It takes a little longer that way.”
“How much?” Tubby asked.
“Not much—just a few seconds—the moon is not far away. Now all this light that strikes the earth is reflected back into space. In a hundred years—less or more according to the distance—it strikes the different stars. There it mingles with other light. And then, mark me well, and then”—the professor paused impressively—“then in another hundred years it comes back to us again—the same light—mixed with other light of course—but some of the same light we had two hundred years before. Do you understand?”
“No—yes,” said Tubby.
“That,” said the professor, “is the Oats Theory of the Rationality of Light. I call it that because it is rational—it is in accordance with all known physical laws.
“Some others I could name”—the professor’s voice shook with suppressed passion; his eyes gleamed again wickedly—“some others are not so scrupulous. Their theories do not coincide with recognized physical laws—they transgress them all. Mere astronomical outcasts—mathematical lepers—scientific pariahs—”