The faces looked at him silently. Finally Joyce could endure it no longer. "That's just nonsense! You all know it. Grampa's no genius. He's just a tinkerer. One day he happened to tinker out the polarizer. He doesn't know how it works any more than I do."
"Now wait a minute!" Grampa protested. "That's not fair. Maybe I didn't figure out the theory myself, but I read everything the scientists ever wrote about it. Wanted to know myself what made the blamed thing work. What I told you is what the scientists said, near as I remember. Now me—I'm like Edison. I do it and let everybody else worry over 'why.'"
"The only thing you ever did was the polarizer," Joyce snapped. "And then you spent everything you got from it on those fool perpetual-motion machines and those crazy longevity schemes when any moron would know they were impossible."
Grampa squinted at her sagely. "That's what they said about the gravity polarizer before I invented it."
"But you don't really know why it works," Junior persisted.
"Well, no," Grampa admitted. "Actually I was just fiddling around with some coils when one of them took off. Went right through the ceiling, dragging a battery behind it. I guess it's still going. Ought to be out near the Horsehead Nebula by now. Luckily, I remembered how I'd wound it."
"Why won't the ship work then, if you know so much?" Joyce demanded ironically.
"Well, now," Grampa said in bafflement, "it rightly should, you know."
"We're stuck," Reba said softly. "We might as well admit it. All we can do is set the transmitter to send out an automatic distress call—"