THE HIDDEN REALITY by Brian Greene
“Some people recoil at the notion of parallel worlds; as they see it, if we are some part of a multiverse, our place and importance in the cosmos are marginalized. My take is different. I donâ€™t find merit in measuring significance by our relative abundance. Rather, whatâ€™s gratifying about being human, whatâ€™s exciting about being part of the scientific enterprise , is our ability to use analytical thought to bridge vast distances, journeying to outer and inner space and, if some of the ideas weâ€™ll encounter in this book prove correct, perhaps even beyond our universe.”
Review by Devon Shepherd Â (MAR 13, 2011)
Imagine: a spiral galaxy exactly like our own Milky Way, home to a 4.5 billion year-old yellow dwarf 26,400 light years away from the supermassive black hole powering the galactic center, orbited by an iron-aqueous planet, populated with intelligent, bi-pedal, opposable-thumb mammals identical to humans from their DNA on up; and imagine that on this Earth-like planet, there exists a person exactly similar in every respect â€“ physical, mental, historical â€“ to you, sitting as you are right now, hunched over a keyboard at work or curled up, at home, with your laptop on the couch, but instead of scrolling down through the rest of this review, your counterpart leaves MostlyFiction.com to check her status on Facebook, muttering: What a load of rubbish.
Would you believe it if I told you that even according to some of the most conservative theories in physics, parallel worlds like these actually exist? In fact, there might be infinitely many such worlds, in all of which you (or if you prefer, your otherworldly counterpart) exist; of course â€“and Iâ€™m not sure whether this is more comforting or not â€“ there are also infinitely many more worlds where you donâ€™t exist at all.
This â€“the physics of parallel universes, or to put it another way, the theoretical backing for the existence of a multiverse â€“ is the subject of Brian Greeneâ€™s latest book, The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. Greene, a theoretical physicist at Columbia University and author of The Fabric of the Cosmos and the childrenâ€™s book, Icarus at the Edge of Time, is probably best known for his 1999 bestseller The Elegant Universe and the three part PBS series it spawned. Here, in his latest book, Greene walks the reader through theoretical frameworks as varied as cosmology, quantum mechanics, string theory and information theory, all of which suggest that we should prepare ourselves for perhaps the greatest of all Copernican revolutions, for just as our ancient ancestors wrestled with the realization that our planet isnâ€™t at the center of the universe, or even the orbital axis for our neighboring planets and closest star, and just as our great-grandparents struggled to accept that our galaxy is but one of billions, science seems to be setting us up for an existential crisis of our own: parallel universes abound.
Or at least a number of a scientific theories imply they do, and while some of the science Greene discusses is cutting edge and speculative, other science suggestive of multiple universes, or the multiverse as physicists call it, is among the most established, or at the very least, among the most uncontroversial, of our knowledge.
For example, consider two commonly held assumptions in contemporary cosmology, assumptions backed by a large and varied collection of data: that universe is infinite and that matter/energy is finite. The idea here is: if light travels at a finite speed, regions of space more than 14 billion light years apart (the time estimated to have elapsed since the big bang) will be effectively isolated from each other because they havenâ€™t yet had the chance to exchange information (since nothing travels faster than the speed of light). In this scheme, space can be conceptualized as a quilt, each patch 14 billion light years squared, and if our cosmic quilt is indeed infinite, there would be an infinite number of patches. And, if matter is finite, a specific organization of matter will repeat itself. Infinitely. To paraphrase Greeneâ€™s analogy: imagine your wardrobe consists of 3 shirts, 2 skirts and 4 pairs of jeans. If you live forever, the set of all the outfits youâ€™ve worn â€“ letâ€™s say, one for every day of your infinite life â€“ will itself be infinite. However, you only have 6 bottoms and 3 tops, so you will necessarily repeat outfits. In fact, you will repeat outfits infinitely many times, and if all you are is the organization of your matter (Iâ€™ve bracketed another key, perhaps more controversial, assumption: that everything from the behavior of stars to the emotions of a child can ultimately be reduced to the organization of particles), the particular organization that is you â€“like say, a specific outfit such as a red top paired with a pink skirt â€“ will repeat itself. Infinitely.
Crazy, right? And thatâ€™s not the only theory to imply that you might have parallel existences. The need to solve something known as the horizon problem in cosmology â€“ a problem Iâ€™ll ignore, but that Greene does an excellent job of explaining in the chapter on the Inflationary Multiverse â€“ lead researchers to postulate the existence of a particle called the inflaton. A capricious little particle, the inflaton can exist in states of high or low energy, as well as a number of states in between, and while itâ€™s most stable, and thus more abundant, at low-energy, itâ€™s in its higher energy state that the inflaton has the potential to create universes. Much like a ball at the top of a slide has the potential to roll down if released, the inflaton has the potential to expand space if pushed from its high-energy perch. Such expansions would be enormous and rapid, and would in effect create isolated universes in an explosive conversion of energy to matter. Rather than a quilt, here the multiverse looks more like a block of Swiss cheese, each universe a bubble.
But does inflaton expansion lead to universes parallel to ours? Again it depends on the extent of space. The total composition of matter in a new-born bubble universe is directly related to the end state of the fallen inflaton, or to put it another way, the specific makeup of primordial matter depends on how far the ball has rolled down the slide. If the inflaton can only exist in a finite number of states, then there can only be finite collections of matter (say, 3 shirts, 3 skirts, 4 pants; 6 shirts, 4 skirts, 2 pants; and 4 shirts, 1 skirt, 9 pants). If space, and the number of bubble universes, is infinite, these collections, and consequently, specific organizations of matter, would bound to repeat themselves; in a vein similar to the Quilted Multiverse, there would be infinitely many universes exactly similar to ours, and infinitely many counterparts of you.
Not to worry, though. Not all of the possible approaches to multiverse entail parallel worlds and your concurrent existence. String theory, and its expanded counterpart, M-theory, see universes as infinitely large energy membranes, membranes that form the very substrate of space and matter. Although membranes can orbit and collide with one another, producing eternally cyclic patterns of creation and destruction, the specific frequency of vibration of the strings bound to any membrane, and hence, the specific composition of matter, need not be similar to ours. And while the Many-Worlds interpretation of quantum mechanics holds that all possible states of a particle are equally real (presumably all possible states of collections of particles such as yourselfâ€“ reading this review, turning on the television, toggling over to Facebook â€“ actually occur as well), this is just math, its physical representation far from clear.
But worrying about our multiple existences might be misguided if the physicists studying entropy and black holes are correct, and the visible world is nothing more than a projection of the information encoded on the boundaries of our universe, much like a hologram is a 3-D projection of information etched onto a plate. And if all thatâ€™s not enough to keep you up at night, Greene explores a futuristâ€™s multiverse â€“ the possibility of uploading human consciousness to a computer, of simulated universes, of universe/consciousness creation â€“ that will be familiar, and fascinating, to fans of The Matrix.
Greene, gifted in the art of analogy and metaphor, manages to explain some very complicated science without resorting to jargon or math, all without sacrificing content. However, even in his conversational style, this book is extraordinarily dense, and since, with a few edits, each chapter could stand alone, I couldnâ€™t help but feel that the bookâ€™s form didnâ€™t best serve its content. It would have been better conceived as a collection of essays, inviting pauses and pondering between each essay, allowing the mind-boggling implications to sink in and further pique curiosity, whetting the appetite for more.
But, donâ€™t let that turn you off this book. If youâ€™re even moderately interested in the possibility of parallel universes, buy this book, but savor it, slowly.
|AMAZON READER RATING:||from 69 readers|
|PUBLISHER:||Knopf (January 25, 2011)|
|AVAILABLE AS A KINDLE BOOK?||YES! Start Reading Now!|
|AUTHOR WEBSITE:||Wikipdedia page on Brian Greene|
|EXTRAS:||Nova interview with Brian GreeneExcerpt|
|MORE ON MOSTLYFICTION:||The multiverse in fiction:
Not yet reviewed by MostlyFiction:
- The Elegant Universe (1999)
- The Fabric of the Cosmos (2005)
- Icarus at the Edge of Time (2008)
- The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos (January 2011)