Warped Passages - Lisa Randall [4]
These passages could be flat, like the dimensions we are accustomed to. Or they could be warped, like reflections in a fun-house mirror. They might be tiny—far smaller than an atom—until recently, that’s what anyone who believed in extra dimensions assumed. But new work has shown that extradimensions might also be big, or even infinite in size, yet still be hard to see. Our senses register only three large dimensions, so an infinite extra dimension might sound incredible. But an infinite unseen dimension is one of many bizarre possibilities for what might exist in the cosmos, and in this book we’ll see why.
Research into extra dimensions has also led to other remarkable concepts—ones that might fulfill a science fiction aficionado’s fantasy—such as parallel universes, warped geometry, and three-dimensional sinkholes. I’m afraid such ideas might sound more like the province of novelists and lunatics than the focus of real scientific inquiry. But outlandish as they might seem at the moment, they are genuine scientific scenarios that could arise in an extra-dimensional world. (Don’t worry if you are not yet familiar with these words or ideas; we’ll introduce and investigate them later on.)
Why Consider Unseen Dimensions?
Even if physics with extra spatial dimensions permit these intriguing scenarios, you might still wonder why physicists concerned with making predictions about observable phenomena would bother to take them seriously. The answer is as dramatic as the idea of extra dimensions itself. Recent advances suggest that extra dimensions, not yet experienced and not yet entirely understood, might nonetheless resolve some of the most basic mysteries of our universe. Extra dimensions could have implications for the world we see, and ideas about them might ultimately reveal connections that we miss in three-dimensional space.
We wouldn’t understand why Inuit and Chinese people share physical features, either, if we failed to include the dimension of time that lets us recognize their common ancestry. Similarly, the connections that can occur with additional dimensions of space might illuminate perplexing aspects of particle physics, shedding light on decades-old mysteries. Relationships between particle properties and forces that seemed inexplicable when space was shackled to three dimensions seem to fit together elegantly in a world with more dimensions of space.
Do I believe in extra dimensions? I confess I do. In the past, I’ve mostly viewed speculations about physics beyond what’s been measured—including my own ideas—with fascination, but also with some degree of skepticism. I like to think this keeps me interested, but honest. Sometimes, however, an idea seems like it must contain a germ of truth. One day on my way to work about five years ago, as I was crossing the Charles River into Cambridge, I suddenly realized that I really believed that some form of extra dimensions must exist. I looked around and contemplated the many dimensions I couldn’t see. I had the same shock of surprise at my altered worldview that I experienced when I realized that I, a native New Yorker, was rooting for the Red Sox during a playoff game against the Yankees—something else I never anticipated I’d do.
Greater familiarity with extra dimensions has only increased my confidence in their existence. Arguments against them have too many holes to be reliable, and physical theories without them leave too many questions unanswered. Furthermore, as we’ve explored extra dimensions in the last few years, we’ve expanded the range of possible extra-dimensional universes that can mimic our own, suggesting that we’ve identified only the tip of the iceberg. Even if extra dimensions don’t conform precisely to the pictures I will present, I think they are very likely to be there, in one form or another, and their implications are bound to be surprising and remarkable.
You might be intrigued to know that there could be a vestige of extra dimensions hidden in your kitchen cabinet