“Brian Greene is perhaps the single best explainer of abstruse science in the world today.” – The Washington Post
“A pure intellectual adventure, this is about as good as it gets…Greene’s book stands out for its sweeping ambition… stripping down the mystery from difficult concepts without watering down the science.” – Newsday
“Sends the reader’s imagination hurtling through the universe on an astonishing ride… his excitement for science on the threshold of vital breakthroughs is supremely infectious.” – The New York Times
Brian Greene’s earlier book, The Elegant Universe, was, for the longest time, my favourite book of any genre. It grabbed the reader by the scruff of the neck and took them on a mind-bending tour of the structure of the Universe. String theory, hidden dimensions, Calabi-Yau manifolds, quantum mechanics, the beginning and end of the universe—could there be any other topics more exhilarating?
So one may easily imagine the delicious thrill of anticipation I felt when I saw he had released a new book, The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. I’m glad to report that Brian Greene doesn’t disappoint. Once again, he’s delivered the goods—complete with ribbons of multiverses, bows of doppelganger particles, and baubles of parallel dimensions.
In brief, the book takes the reader on a tour of the different types of multiverses that might exist, based on current theories and cutting-edge Mathematical equations. He talks about a Quilted Multiverse where each parallel universe is part of a single spatial expanse separated by unimaginable distances. He talks about anInflationary Multiverse, where each bubble universe is sharply divided from the next by the value of the intervening inflaton field. He also explains the concept of Brane Multiverse where our familiar universe resides in a three-dimensional brane with other parallel universes residing in higher dimensional branes. He also talks about a Cyclic Multiverse, with universes forming and dying out over unimaginable eons; and a Landscape Multiverse, where upto 10500 universes might exist with different values for the different cosmological constants. (It goes without saying, that this is an inconceivable large number). He goes on to elaborate on three other species of Multiverses: Quantum Multiverse (every possibility is embodied in its probability wave and is realised somewhere in the vast ensemble of parallel universes); Holographic Multiverse (which asserts that our universe is exactly mirrored by phenomena taking place on a distant bounding surface); and Simulated Multiverse (the idea that our universe is simply one computer-generated programme among many).
What is especially enthralling about the book is how Greene is at pains to explain to the reader the consequences and ramifications of the concept of infinity. Consider for instance, the possibility that space is infinite. Then, the closer in time to the big bang we get, the smaller in size the universe is. However, regardless of this shrinkage in size, in an infinite universe, space will always be infinite: when the universe shrinks, its contents will be ever closer and the universe will be ever denser, but its overall extent will be infinite. After all, half of infinity is still infinity.
Perhaps for me the most startling revelation in the book (and trust me, this book is absolutely filled with startling revelations) is the notion that space is the same as information. He elaborates upon this in what I believe is the most enthralling chapter in the book: “Black Holes and Holograms: The Holographic Multiverse.” Traditionally, physics focuses on things: particles, atoms, planets etc. John Wheeler (that doyen of the particle physics world) suggests that these things—matter and radiation—should be considered as secondary—as carriers of a more fundamental and abstract entity: information. (The skyscraper is but a physical realisation of the information in the architect’s blueprint. Therefore, from this perspective, the universe can be considered as an information processor). Black holes, from this perspective can be viewed as regions in the space-time fabric that have maxed out their information-carrying capacity and withdraw from the continuum of reality.
Greene is an unabashed proponent of String Theory. (His friend and colleague, the superstar physicist, Lawrence Krauss, is not entirely convinced about its explanatory powers.) This book is based on the consequences of string theory and there are far too many references to it to elaborate in a review. However, if there’s one feature that impresses the reader most about string theory it is that properties of subatomic particles are determined by the size and shape of tiny, curled-up extra dimensions. (Just as the air streams flowing through a wind chime have vibrational patterns dictated by the instrument’s geometrical form; or just as a single string on a guitar can create different notes based on the structure and composition of the string)
String theory and superstring theory are important because they’re the only theories we have at the moment that claim to unite quantum theory with gravity; unify all forces; explain particle properties; confirm experimental observations; cure singularities; and explain black hole entropies.
It would be easy for the scientifically illiterate lay person to scoff at the predictions made in this book. But they would do so only because they are ignorant of the scientific method. Predictions (real predictions: like the existence of antiparticles, neutrinos, the perihelion of Mercury, the magnetic dipole moment of electrons, the energy released when uranium splits into barium and krypton…) in science result from detailed Mathematical calculations based on solid physical theory that produce precise, testable numbers.
In a world where people are obsessed with what Kim Kardashian ate for breakfast or where Paris Hilton threw up after her binge night out, we need more thinkers like Brian Greene, who point out that the difference between 0 and 0.000000000000000000000000000000000000000000000000000000000000000000000000 0000000000000000000000000000000000000000000001 may not seem like much, but it is what accounts for a radical shift in how we envision reality.
Perhaps it’s fitting to end with a quote from Timothy Ferris of the New York Times, who says in his review, “If extraterrestrials landed tomorrow and demanded to know what the human mind is capable of accomplishing, we could do worse than to hand them a copy of this book.”
Our grandchildren will grow up taking for granted that we live in a cosmos where there are not only parallel universes, but parallel parallel universes. Reality is not only expansive, but abundantly expansive. They will laugh at our parochial notion of a single universe. Much as we laugh at our forebears for thinking our sun was the only star with planets around it.
