If the following seems ridiculous, far-fetched or just outright outlandish to you, rest assured: It is. It will probably hurt your brain, as it has hurt mine,
and as it most definitely hurts the brains of those who come up with this stuff for a living. The following asks you to accept ideas that are counter to the fundamental basis of our experience, the framework through which we comprehend everything from setting down a coffee cup to the arc of a home run as it sails into the upper deck. The basic point of what follows—and by the way, what follows is not fanciful provocation but has been worked into contemporary consciousness by the brainiest physicists alive today—is that everything that you have ever experienced has in some small but significant way been an illusion. Why? Because everything you have ever experienced you have understood as happening in three dimensions of space—up-down, left-right and front-back. Yet this is not how things happen. Things happen in more than three dimensions of space; to see them in only three is to succumb to a trick that the universe is constantly playing on us.
dimension - 1: a measure in one direction; 2 : the number of variables needed to locate a particle; 3 : a property of space, or the space-time continuum, related to extension in a direction.
Space as you know it is a lie. What follows is an approximation of the truth, or at least of various conceptions of the truth. There is no one model of the extra dimensions in the universe, no one statement of fact that all physicists can agree on and create in their computers. Alas, things are not that simple. There are at least two and possibly three completely different theories of what these extra dimensions should look like. And in each of these theories, the specific form of the extra dimensions—their shape, whether it be Gehry-esque or nail-straight—is unknown. But let’s not let that intimidate us. Let’s get started.
Type of possible space #1: A 10-dimensional universe made up of the normal three dimensions of space, plus one of time, plus six-dimensional Calabi-Yau manifolds located at every point in normal three-dimensional space.
Excellent question #1: What the hell is a Calabi-Yau manifold?
Attempted answer #1: It is arguably impossible to imagine what a Calabi-Yau manifold is, because it has six dimensions. But let’s try anyway. A Calabi-Yau manifold looks kind of like a balled-up piece of paper, except it’s one whose curves and twists and turns are intricate and Mbius-like, looping back over and around themselves with clear disdain for Euclidean geometry. A Calabi-Yau manifold knows no straight lines. I try to imagine myself inside one of these manifolds: I think it’s probably much like a fun house, mirrors everywhere deflecting your gaze in every which direction, so that at any time you could be looking straight ahead and see, for instance, your back. Except it’s not quite that—there are no mirrors in a Calabi-Yau manifold, there is only space itself. So while you can still look forward and see your back, you could also, theoretically, throw a baseball at it, only to feel the little missile smacking your spine two seconds later. That baseball might have traveled up and around, roller-coaster-like, through six dimensions, eventually ending up at your back. A Calabi-Yau manifold is a strange thing indeed.