“That is a very simple problem—only mental arithmetic for me. Wait. Let us go further.”
“Yes,” said Tubby. “Go on.”
“The distance Light travels in one year is called a Light-year. Now, some of the stars are so far away that it takes light many centuries to come from them, traveling at that speed I have just mentioned. Thus we measure their distance from us as so many hundred Light-years. Do you see?”
“Yes,” said Tubby. “How—how many miles away from us is the farthest star—the very farthest?”
The professor leaped to his feet. “Ah, I was expecting you to ask that.” His face was beaming. “You are a clever man. But I’m ready for you. I figured it all out this afternoon and wrote it down. I’ll show you.”
He led Tubby to a corner of the room. Tubby saw a perfectly enormous roll of narrow paper tape, like the tape that comes from a stock ticker, or is rolled up around baby ribbon. Only this roll was bigger than he was. It was hung vertically on a spindle, which had a handle to rotate it so that the tape could be unwound and wound again easily. A few feet away there was a similar spindle, but empty.
“I wrote it down for you,” the professor repeated—“the distance in miles of the furthest star from the Earth. I wrote it down—on this.”
He took the loose end of the tape and reeling off a few feet hooked the end onto the empty spindle.
“Watch closely,” he said. “I’m going to show you the number.”
He started to wind up the tape on the empty spindle. Tubby stood close beside the strip of tape stretching the space between the two spindles; it passed directly under his face.