Kathleen Jordan PHY 311 The Hidden Reality Review 1 May 2011

The Hidden Reality Review

For my final project, I read The Hidden Reality by Brian Greene. This book was by far better than any of the four books we read in class, and not necessarily because of fascinating topic of parallel universes. Even though I believe the topic of multiple universes to be mind blowing and incredibly interesting, the topic of alien life on habitable planets could just as easily bring that same level of interest to me. But due to the incredible skills of Brian Greene as a writer at both explaining concepts and creating excitement in a topic, this book left the other four books in the dust, including any book’s I’ve read on alien life. With that said, I would like to go a little into what The Hidden Reality was about in order to better explain why I thought this book was such a good read. The book begins discussing how if the universe extends infinitely in all directions, then there must be infinite copies of you and me out there in other infinite universes experiencing the different versions of our reality, where Greene humorously adds that in some universes we might not want to meet our alternate selves in a dark alley. Greene also gives good background on Einstein’s work including with general relativity and the big bang model to bring the reader up to date with what he is discussing. He brings up the problem with the two that the known idea of gravity and general relativity leads to problems when explaining the big bang. The inflationary theory suggests that the early moments of our universe may not be unique, and parallel universes might be formed by this means all the time. Greene explains, “What’s more, each of these ballooning universes has its own spatial expanse, and hence contains infinitely many of the parallel worlds encountered in Chapter 2”. Brian Greene also discusses string theory and the status of unifying the forces, which is what has brought about the many different kinds of parallel worlds that this book is discussing. String theory’s braneworld scenario is one of these kinds of parallel universes, where our universe is one of many slabs floating in a higher dimension of space. These branes give off flux, like an electric field. This is like the bread slice example in the movie we saw in class. In another version, these branes can hit each other, creating a new big bang with each hit. In yet another version of parallel universes, the extra dimensions of space can take many different shapes and sizes, and every form can be realized when look at with the Inflationary Multiuniverse. Greene explains that we don’t know what these extra dimensions look like, but perhaps one day, after more discoveries, we will be able to use these parallel universe theory’s and scenarios to explain a lot about our universe. In The Hidden Reality, Greene brings up what he failed to in the movie in class: dark energy. He explains that the difference between 0 and .00000000000000000000…000000000001 could be a lot bigger than one would suspect. The cosmology constant fills our universe with dark energy. Accelerating expansion is best explained by this concept, so to date, dark energy is our best explanation, even though we essentially know nothing about it. This explanation is leading us in many different directions with our ideas of parallel universes. Jordan 2

Greene also hits on quantum reality and how you can see definite results when the theory suggests contradictory result occurring in one reality. A prominent example is when shooting electrons at a board with varying number of slits, like we watched in class. Quantum physics brings up an idea of a parallel universe from properties of black holes where we all are experiencing nothing, but seeing a holographic projection of what is happening in a distant reality from us. The last proposal of parallel universes is that every possible universe is known somewhere in a grand multiverse, like a mother ship of universes. Greene also discusses computer-generated universes and how they help us see concepts that otherwise would not be observable. Now as one can see, I could nearly write an entire book about what Brian Greene covers in his, but I want to focus on the book as whole. Brian Green writes with such clarity that you get drawn into his explanations even when your head is about to explode from many of the complex, strange theories. Greene was able to simplify the idea of infinite universes using a girl named Imelda who owns lots of dresses and even more shoes. Not only can he simplify the concepts down to ideas of fashion, but he can do so without suggesting any idea of stupidity or naiveness upon the reader. The problem would come once I set the book down. If I tried to recall one of the incredibly complicated ideas on a parallel universe, I was lost. The subject matter in this book is very must out there for a non-physicist to comprehend, possibly as far out there as some of these parallel universes, however, if anyone is going to take on trying to explain these ideas to the general public, Brian Greene is your man. Green does not try to suggest that any of these theories are absolutely correct, he only tries to give an explanation of where physics is today with our many different options of how to explain the universe and where problems arise when all the puzzle pieces don’t fit together. He makes is very clear that science requires observable experiments and concrete data to back up theories, otherwise the question of “Is this science or philosophy?” comes into play. But as Brian Greene chooses to end the book, “It’s only through fearless engagements that we can learn our own limits. It’s only through the rational pursuit of theories, even those that whisk us into strange and unfamiliar domains, that we stand a chance of revealing the expanse of reality.” The Hidden Reality is full of explanations, comprehendible examples, diagrams, pictures, charts, and anything else you could think of to make this topic more understandable. I even found myself laughing out loud at some of his choices of examples, like when he used the idea of the supreme court justices trying to define pornography when one justice finally said, “You just know it when you see it,” as a explanation of why the definition for universe and other terms in this book will be vague. I’ve heard that this book isn’t as good as Brian Greene’s others books, but having only seen the video of The Elegant Universe, I’m not going to try to make any comparisons. I will say, however, that I can’t imagine that any other author could do a better job at explaining these ideas in such a comprehendible, complete manner. The idea may seem weird to us now, but once we make more discoveries and make some of these theories more concrete, future generations might think nothing of the idea of a parallel universe, and we might even be texting our alternate selves in other universes through graviton signals, who knows.