The book starts off with this gorgeous quote about time and dimensions of space but the entire discussion about time and space happens between a 9th grader and an 11th grader. Brother and sister pin down time in a manner that would make Stephen Hawking proud. Excerpt is from Cat’s Eye by Margaret Atwood – a great Canadian writer who has not shied away from the most peculiar of Sci-Fi theories in her book Margaret Atwood – In other worlds.
Time is not a line but a dimension, like the dimensions of space. If you can bend space you can bend time also, and if you knew enough and could move faster than light you could travel backwards in time and exist in two places at once.
He thinks I should develop my mind. In order to help me do this, he makes a Möbius strip for me by cutting out a long slip of paper, twisting it once and gluing the ends together. This Möbius strip has only one side, you can prove it by running your finger along the surface. According to Stephen, this is a way of visualizing infinity. He draws me a Klein bottle, which has no outside and no inside, or rather the outside and the inside are the same. I have more trouble with the Klein bottle than the Möbius strip, probably because it’s a bottle, and I can’t think of a bottle that isn’t intended to contain something. I can’t see the point of it.
Stephen says he’s interested in the problems of two-dimensional universes. He wants me to imagine what a three-dimensional universe would look like to someone who was perfectly flat. If you stood in a two-dimensional universe you would only be perceived at the point of intersection, you’d be perceived as two oblong discs, two two-dimensional cross-sections of your own feet. Then there are five-dimensional universes, seven-dimensional ones. I try very hard to picture these but I can’t seem to get past three.
“Why three?” says Stephen. This is a favourite technique of his, asking me questions to which he knows the answers, or other answers.
“Because that’s how many there are,” I say.
“That’s how many we perceive, you mean,” he says. “We’re limited by our own sensory equipment. How do you think a fly sees the world?” I know how a fly perceives the world, I’ve seen many flies’ eyes, through microscopes. “In facets,” I say. “But each facet would still have only three dimensions.”
“Point taken,” he says, which makes me feel grown up, worthy of this conversation. “But actually we perceive four.”
“Four?” I say.
“Time is a dimension,” he says. “You can’t separate it from space. Space-time is what we live in.” He says there are no such things as discrete objects which remain unchanged, set apart from the flow of time. He says space-time is curved and that in curved space-time the shortest distance between two points is not a straight line but a line following the curve.
He says that time can be stretched or shrunk, and that it runs faster in some places than in others. He says that if you put one identical twin in a high-speed rocket for a week, he’d come back to find his brother ten years older than he is himself. I say I think that would be sad.
My brother smiles. He says the universe is like a dot-covered balloon that’s being blown up. The dots are the stars; they’re moving farther and farther away from one another all the time. He says that one of the really interesting questions is whether the universe is infinite and unbounded, or infinite but bounded, like the balloon idea. All I can think of in connection with a balloon is the explosion when it breaks.
He says that space is mostly empty and that matter is not really solid. It’s just a bunch of widely spaced atoms moving at greater or lesser speeds. Anyway, matter and energy are aspects of each other. It’s as if everything is made of solid light. He says that if we knew enough we could walk through walls as if they were air, if we knew enough we could go faster than light, and at that point space would become time and time would become space and we would be able to travel through time, back into the past.
This is the first of these ideas of his that has really interested me. I’d like to see dinosaurs and a good many other things, such as the Ancient Egyptians. On the other hand there’s something menacing about this notion. I’m not so sure I want to travel back into the past. I’m not so sure I want to be that impressed, either, by everything he says. It gives him too much of an advantage. Anyway it isn’t a sensible way to talk. A lot of it sounds like comic books, the kind with ray-guns.
So I say, “What good would that be?”
He smiles. “If you could do it, you’d know you could do it,” is what he says.