"You're both right and wrong, Honey," he explained. "The better the fuel, the less we have to carry for the same distance traveled, and that makes our thrust-to-mass ratio less. We can go home faster than we came out here, because some of our fuel is gone and we have less mass. But that's not what I'm talking about. Theoretically, as I said, there are other ways, none of which our scientists have yet figured out how to use, as far as I know. There could be a complete or partial nullification of gravity or of inertia. Or some type of space warp. Or some method of 'cutting through' the other dimensions, so we could go almost instantly from one point in space to another."
Jak gasped. "Why, how's that possible, Father?"
Jon answered quickly. "I can illustrate, I think. Imagine a sheet of paper, with a dot near either end. The normal way to connect them would be a straight line drawn from one to the other—which is analogous to the way we travel in space now. What Pop's talking about would be the same as if we folded the paper so the two dots touched, and moved from one to the other direct."
"That wouldn't be...."
"That's silly."
The two phrases came simultaneously from Jak and his mother.
"It's not silly, Honey. We merely haven't figured out how to do it yet. But theoretical science knows that there are 'folds' in space. We just haven't learned how to use them yet."
"No," Jak snorted, "and I'll bet you never do."
"And I'll bet they will," Jon blazed. "You just don't realize how wonderful science is—in other lines than your own, I mean. You think it's perfectly natural that medical science has made such tremendous advances in the past couple of centuries. Why shouldn't other branches make just as great strides?"
"Because the advances in medicine and surgery have been logical," his brother began hotly, but their father interrupted.