Regardless of our educational backgrounds, some scientists can open the magical world of science to us. If you’ve ever listened to Brian Greene, you know what I mean. Greene, a Columbia university professor and author of the bestseller The Elegant Universe is one of the world’s leading theoretical physicists. He is also one of those rare scientists who can keep a lay audience enthralled for an hour or more while he talks about general relativity, quantum mechanics, space-time and the string theory. His talk leaves you mesmerized at the universe, its origins, space and time, and indeed anything or everything that you see around. No wonder then that you get the same feeling a few times over with The Fabric of the Cosmos: Space, Time and the Texture of Reality.
As a young boy, Greene read Albert Camus’ Myth of Sisyphus and its first few lines -- “There is but one truly philosophical problem, and that is suicide, whether or not the world has three dimensions or the mind nine categories, comes afterward” -- left a lasting impression on him. Later he started wondering about the extent to which the question of whether or not life is worth living would depend on the understanding of reality. The true nature of reality is, of course, unknown, and discoveries since the last century have shown mankind that what we perceive from our experience to be reality is mostly misleading and erroneous. As a physicist seeking to understand the universe he eventually concludes that “though life’s worth is eventually the ultimate question, insights of modern physics have persuaded me that assessing life’s worth through the lens of everyday experience is like gazing at a Van Gogh through an empty Coke bottle.”
The search for reality through the lens of physics is what this book is all about. Starting with Newtonian physics, Greene acquaints readers with the concepts of space, time, motion and relative motion. These concepts are separate static entities in classical physics where motion in always relative to absolute space and time. Time, in Newton’s own words (from Principia), “exists in and of itself and flows equably without reference to anything external.” But in the realm of relativity, the reality of time had to undergo a complete turnabout as Einstein’s Relativity showed that far from being a universal concept, time varies according to the observer, so that time will pass faster for the fellow traveling in space than it would for his identical twin sitting on the earth. If this seems crazy at first, Greene does a great job with examples and illustrations to convey the abstract idea. Thousands of experiments have shown the speed of light to be constant throughout the universe, and since speed is the distance or space traversed divided by time, therefore space and time must both be relative entities to keep the speed of light constant. Indeed, space and time are inseparable as relativity has shown; they are in fact woven together to form space-time, the fabric through which everything, including our own planet, moves.
From relativity, Greene moves to the quantum theory, and uncertainty and probability take over the world of physics. But this is no longer the large macro universe; instead, we are now looking at the subatomic micro-level. The quantum theory was a great discomfort to Einstein, who was never comfortable with physicists playing bookies and often uttered his now famous quote “God does not play dice with the universe.” But as we all know now, God does play dice, and although physicists are not always betting, they are pretty uncertain when it comes to a sub-atomic particle’s motion and position, the two entities that can never be accurately determined simultaneously. The leap from quantum mechanics to String Theory introduces another unperceivable slice of reality: a world with ten dimensions. That we see only three (or four, if you count the dimension of time) is because they are either too big or two tiny, and the problem, according to Greene, lies not in them but with the limited vision of the human eye.
The book is written keeping in mind the uninitiated reader, so that large parts need to be skipped by people with some background in physics. Nevertheless, with each chapter Greene unfolds layer after layer of physical reality that modern physics has discovered. The revealing of a universe and our experience in it will always remain so exciting and stimulating a pursuit that Greene’s lines from an earlier interview come to mind:
“When you learn these different features of the universe, it changes your perspective on what it means to be alive. What it means to be part of the universe, since the whole notion of universe is so beyond what experience would lead you to believe.”
So rejoice and enjoy; remember you carry your own clock (time is relative, in case you’ve forgotten), you tell your own story (space is relative too). But don’t forget to check periodically the happenings in the world of physics. That will certainly be a cause for constant rejoicing.