The God equation The quest for a theory of everything

Review by Booklist Review

Theoretical physicist and best-selling author Kaku (The Future of Humanity, 2018) eloquently reviews the structure of our universe, highlighting contributions from intellectual giants and those continuing the daunting, decades-long quest for the elusive theory of everything. Lay enthusiasts will appreciate Kaku's clear descriptions that reinforce the simplicity and elegant symmetry of accepted equations representing the particles, fields, and forces that make up and influence all matter. After an illuminating primer, Kaku moves to the formidable search for the so-called God equation that will unify the "four forces of nature: gravity, the electromagnetic force, and the strong and weak nuclear forces." String theory, which argues that at a fundamental level the universe is made of "tiny vibrating strings, with each note corresponding to a subatomic particle," may be the answer, but it is thus far untestable and unproven. Examining this tantalizing theory, Kaku outlines its promises, problems, and the breathtaking, almost inconceivable array of possibilities it presents. Kaku's latest captures the awesome and mysterious beauty of the universe, of our planet, and of ourselves, and will intrigue anyone who ponders existence.

From Booklist, Copyright (c) American Library Association. Used with permission.

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Review by Publisher's Weekly Review

CUNY physics professor Kaku (The Future of Humanity: Our Destiny in the Universe) shines light on a theory that could "unravel the deepest mysteries of space and time" in this riveting work of popular science. Kaku's focus is on string theory, which proposes that "the universe was not made of point particles but of tiny vibrating strings, with each note corresponding to a subatomic particle." The theory, the author writes, offers answers to questions about time travel, wormholes, and parallel universes. Kaku provides a history of string theory, which "emerged accidentally" after a chance rediscovery of an 18th-century mathematician's work in 1968, and breaks down the centuries-long quest for a definitive explanation of how all cosmic forces operate, including the discovery of atoms in ancient Greece, Newton's work that proved symmetry is "one of our most powerful tools in unifying all forces of nature," and Einstein's discovery of general relativity. Kaku lauds string theory for having "seized the imagination of the world's top scientists," but still gives fair credit to pushback against it: "The most glaring problem is that, for all the press extolling the beauty and complexity of this theory, we have no solid, testable evidence." Kaku's expertise at making mind-bending concepts comprehensible makes this a real intellectual eye-opener. (Apr.)

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Review by Library Journal Review

For centuries, scientists have sought a single theory--preferably in concise mathematical form--that explains everything in the physical universe. Kaku (physics, City Univ. of New York; Hyperspace) returns to the subject he last addressed in the 1990s to review this history from Newtonian mechanics through electromagnetism to Einstein's work on relativity and gravity, which he was unsuccessful in unifying with quantum mechanics. Kaku then describes his field, string theory, and how it may hold the answer to unite all of the known natural forces, including gravity. When conveying a highly theoretical topic some sacrifices must be made: the few equations are relegated to the notes, and important concepts like "renormalization" seem to be hand-waved away as too mathematically difficult to describe. The author is convinced that string theory (or the related M-theory) will provide this Theory of Everything, but never offers a convincing scientific rationale why all of these physical forces must be unified under a single equation, or why it must be simple--other than an argument from elegance and parsimony. VERDICT Despite some flaws, this is a solid introduction to the topic, and physics novices may find that it whets their appetite for more.--Wade Lee-Smith, Univ. of Toledo Lib.

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Review by Kirkus Book Review

An expert account of the search for "the holy grail of physics." A veteran science writer, theoretical physicist, and lucid educator, Kaku wisely begins with ancient history, providing an illuminating minihistory of physics. Aristotle got science off on the wrong foot by proclaiming that everything in the universe has a purpose. Thus, objects fall because they yearn to unite with the Earth. Newton restored some order, mostly by taking metaphysics out of physics, and he contributed vital theories of gravity, motion, space, and light. Electromagnetism was a puzzle until the 19th century, when Faraday and Maxwell explained it. The 20th century began with Einstein's theory of relativity, an unnerving but mathematically precise description of space, time, and gravity as it applies to the universe we experience. During the following decades, scientists fleshed out quantum theory, which illuminated the three other forms of energy besides gravity (electromagnetism, strong and weak force), and added a more unnerving but equally precise description of matter and forces at the subatomic level. The 1970s saw the first attempt at a theory of everything with the "standard model," a dazzling achievement but still a flawed "patchwork." Kaku shows why efforts to fix the standard model have failed so far and why the leading candidate is string theory. Saving the bad news till last, the author reaches strings in the final quarter of the book, and he communicates his enthusiasm more effectively than the mechanics of the theory, which propose that subatomic particles are not points but tiny loops whose vibrations produce all physical phenomena. Converting particles to strings was a good idea (physicists hate infinities), and string vibrations produce all forces, including gravity. Sadly, strings are infinitesimally (but not infinitely) small, and their vibrations, describable by complex math, don't produce phenomena that scientists can test. Although a brilliant idea, no concrete evidence exists for the theory. An important work about an ongoing quest that may befuddle those without a solid grounding in its scientific concepts. Copyright (c) Kirkus Reviews, used with permission.

Copyright (c) Kirkus Reviews, used with permission.

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INTRODUCTION TO THE FINAL THEORY It was to be the final theory, a single framework that would unite all the forces of the cosmos and choreograph everything from the motion of the expanding universe to the most minute dance of subatomic particles. The challenge was to write an equation whose mathematical elegance would encompass the whole of physics. Some of the most eminent physicists in the world embarked upon this quest. Stephen Hawking even gave a talk with the auspicious title "Is the End in Sight for Theoretical Physics?" If such a theory is successful, it would be science's crowning achievement. It would be the holy grail of physics, a single formula from which, in principle, one could derive all other equations, starting from the Big Bang and moving to the end of the universe. It would be the end product of two thousand years of scientific investigation ever since the ancients asked the question, "What is the world made of? It is a breathtaking vision. Einstein's Dream I first came across the challenge this dream posed as a child of eight. One day, the newspapers announced that a great scientist had just died. There was an unforgettable picture in the paper. It was an image of his desk, with an open notebook. The caption announced that the greatest scientist of our time could not finish the work he had started. I was fascinated. What could possibly be so hard that even the great Einstein could not solve it? That book contained his unfinished theory of everything, what Einstein called the unified field theory. He wanted an equation, perhaps no more than one inch long, that would allow him to, in his words, "read the mind of God." Not fully appreciating the enormity of this problem, I decided to follow in the footsteps of this great man, and hoped to play a small role in finishing his quest. But many others have also tried and failed. As Princeton physicist Freeman Dyson once said, the road to the unified field theory is littered with the corpses of failed attempts. Today, however, many leading physicists believe that we are finally converging on the solution. The leading (and to my mind, only) candidate is called string theory, which posits the universe was not made of point particles but of tiny vibrating strings, with each note corresponding to a subatomic particle. If we had a microscope powerful enough, we could see that electrons, quarks, neutrinos, etc. are nothing but vibrations on minuscule loops resembling rubber bands. If we pluck the rubber band enough times and in different ways, we eventually create all the known subatomic particles in the universe. This means that all the laws of physics can be reduced to the harmonies of these strings. Chemistry is the melodies one can play on them. The universe is a symphony. And the mind of God, which Einstein eloquently wrote about, is cosmic music resonating throughout space-time. This is not just an academic question. Each time scientists have unraveled a new force, it has changed the course of civilization and altered the destiny of humanity. For example, Newton's discovery of the laws of motion and gravity laid the groundwork for the machine age and the Industrial Revolution. Michael Faraday and James Clerk Maxwell's explanation of electricity and magnetism paved the way for the illumination of our cities and gave us powerful electric motors and generators as well as instantaneous communication via TV and radio. Einstein's E = mc 2 explained the power of the stars and helped to unravel the nuclear force. When Erwin Schrödinger, Werner Heisenberg, and others unlocked the secrets of the quantum theory, they gave us the high-tech revolution of today, with supercomputers, lasers, the internet, and all the fabulous gadgets in our living rooms. Ultimately, all the wonders of modern technology owe their origin to the scientists who gradually discovered the fundamental forces of the world. Now, scientists may be converging on the theory that unifies these four forces of nature--gravity, the electromagnetic force, and the strong and weak nuclear forces--into a single theory. Ultimately, it may answer some of the deepest mysteries and questions in all of science, such as: · What happened before the Big Bang? Why did it bang in the first place? 
 · What lies on the other side of a black hole? · Is time travel possible? 
 · Are there wormholes to other universes? 
 · Are there higher dimensions? 
 · Is there a multiverse of parallel universes? 
 This book is about the quest to find this ultimate theory and all the bizarre twists and turns of what is undoubtedly one of the strangest chapters in the history of physics. We will review all the previous revolutions, which have given us our technological marvels, starting with the Newtonian revolution, leading up to the mastery of the electromagnetic force, the development of relativity and the quantum theory, and the string theory of today. And we will explain how this theory may also unravel the deepest mysteries of space and time. An Army of Critics However, hurdles remain. For all the excitement generated by string theory, the critics have been keen to point out its defects. And after all the hype and frenzy, real progress has stalled. The most glaring problem is that, for all the flattering press extolling the beauty and complexity of the theory, we have no solid, testable evidence. Once, it was hoped that the Large Hadron Collider (LHC) outside Geneva, Switzerland, the biggest particle accelerator in history, would find concrete evidence for the final theory, but this has remained elusive. The LHC was able to find the Higgs boson (or the God particle), but this particle was only a tiny missing piece of the final theory. Although ambitious proposals have been made for an even more powerful successor to the LHC, there is no guarantee that these costly machines will find anything at all. No one knows for certain at what energy we will find new subatomic particles that could verify the theory. But perhaps the most important criticism of string theory is that it predicts a multiverse of universes. Einstein once said that the key question was: Did God have a choice in making the universe? Is the universe unique? String theory by itself is unique, but it probably has an infinite number of solutions. Physicists call this the landscape problem--the fact that our universe may be just one solution among an ocean of other equally valid ones. If our universe is one of many possibilities, then which one is ours? Why do we live in this particular universe and not another? What, then, is the predictive power of string theory? Is it a theory of everything or a theory of anything? I admit I have a stake in this search. I have been working on string theory since 1968, ever since it emerged accidentally, unannounced, and totally unexpected. I have seen the remarkable evolution of the theory that developed from a single formula into a discipline with a whole library's worth of research papers. Today, string theory forms the basis of much of the research being done in the world's leading laboratories. This book will hopefully give you a balanced, objective analysis of string theory's breakthroughs and limitations. It will also explain why this quest has seized the imagination of the world's top scientists, and why this theory has generated so much passion and controversy. Excerpted from The God Equation: The Quest for a Theory of Everything by Michio Kaku All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.

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