Beyond Einstein

Title: Beyond Einstein

Author: Michio Kaku, Jennifer Thompson

Publisher: Oxford University Press 2010 (First published 1987)

ISBN: 978-0-19-286196-2

Pages: 206

A best seller from the leading popularizer of science. Himself being a player in the scientific arena, Kaku’s comments carry weight due to the sharp insight and incisive reasoning that goes behind every one of his works. This book is also not much different. The quest for a unified theory of everything is at the centre-stage of this work. Albert Einstein carried on a futile quest for finding the elusive unified theory which would combine all the four fundamental forces of nature. Though touted as the greatest genius ever lived, Einstein worked in isolation in the latter part of his career and was against the application of quantum mechanics in any sphere of physics. Partly due to these factors, he failed miserably to produce the theory which would explain everything. Kaku describes the work done by other scientists in this field and how much they had moved beyond Einstein. The author was instrumental in some way in the research on superstrings, which is considered to be the most viable (so far) theory of the universe and promotes it in great detail.

Kaku was attracted to science with awe to the great scientist, Albert Einstein. When he died, he was in the search for the unified theory and this impressed the young author so much that he himself wanted to plunge into the arena which baffled even the great intellect like Einstein. Superstring theory unites all forces in nature, but the enormous energy needed to test its postulates prevents us from testing it in the particle accelerators in the world. The Superconducting Super Collider, which was proposed but rejected in the U.S would have tested some aspects of it, but in the present circumstances only the Large Hadron Collider (LHC) in CERN, Geneva can come anywhere close to it.

History of unification of forces begins the Isaac Newton. The common belief during the 17^th century was that celestial and terrestrial objects were obeying different laws, with the celestial objects being perfect in every way. Newton proposed the theory of Gravitation which didn’t differentiate between the position of objects in describing how a force acted between them. No matter what object you are interested in, say, the sun, mars, jupiter, an apple or another human being, all are acted upon by the same force which directly depended on the mass of each object and the square of the distance between them. This was the first unification which combined the celestial and terrestrial objects. The next step came only in 1860, when James Clerk Maxwell proposed his theory of electromagnetism, which showed that electricity and magnetism and different aspects of the same force. As a byproduct, he also found that light is also an electromagnetic wave and its velocity is constant. This theory was the inspiration behind Einstein’s Special theory of relativity published in 1905. He came out with his general theory of relativity in 1915, combining gravity to it. The general theory unified the three dimensions of space and one dimension of time and put forward the idea of space-time. Einstein’s fecundity seems to end with the general theory as the next three decades were fruitless. Until then, he was thinking in terms of abstract mental pictures, but the search for unified theory put him in the wild path of exotic mathematics which finally came to nothing.

Quantum Mechanics developed in the 20^th century with pioneering works of Verner Heisenberg and Erwin Schrodinger. Though the theory is so weird that Niels Bohr once remarked that if anyone was not shocked by quantum mechanics, he hasn’t understood it, no experiment has repudiated it so far. Not only that most of the modern equipments in the electronics and computer fields are the products of quantum mechanics. Computers, lasers, television, medical equipment, the list is endless. However, physicists are unanimous in declaring that the theory is as yet incomplete. It breaks down when the speed of electrons approach the speed of light, that is, relativistic velocities. Quantum field theory combined quantum mechanics with electromagnetism, but was riddled with infinities which came out as the result of mathematical operations on the equations. Richard Feynman proposed Quantum Electrodynamics (QED) to combine these. Electroweak theory was developed by Weinberg, Glashow and Salam which unified electromagnetism and the weak nuclear force. Attempts to integrate this framework with the strong force resulted in more understanding of it as the researches of Murray Gell-Mann came out with quantum chromodynamics (QCD) which postulated that quarks constitute protons and neutrons and gluons were the particles through which the strong force is effected.

The Standard Model of particle physics consists of 36 quarks. The heaviest quark was termed ‘top quark’ and was observed in particle experiments in 1994. This variety tells us that a deeper level of unification is possible at which the number of particles are lesser. We know that it cannot be the final theory because:

1. It has such a bizarre collection of quarks, leptons, gluons and W, Z bosons

2. It has exactly three generations, in both the quark and lepton sector, which are indistinguishable (except for their masses)

3. It has nineteen arbitrary parameters, including the mass of the leptons, the mass of the W and Z particles, the relative strength of the strong and weak interactions, and so on. (p.76)

Grand Unified Theory (GUT) integrated the electro-weak theory and the strong force. Though elegant, the theory was still riddled with arbitrary constants.

In 1968, Gabriele Veneziano and Mahiko Suzuki found the relationship behind the strong interaction in a formula developed by Euler in the 18^th century. The hypotheses was further improved by John Schwarz, Andre Neveu and Pierre Ramond and came to be known as superstring theory in 1970. The theory flew against commonsense as it required ten dimensions to operate as compared to the four familiar dimensions of spacetime. Everyone thought that it was nothing more than a mathematical curiosity and it was promptly abandoned around 1974. The principle was enunciated as a solution to the strong force, but gravitons and photons appeared in it. In 1976, Joel Scherk and John Schwarz suggested that the theory be reinterpreted as the universal theory of everything. Such arbitrary propositions met with strong skepticism. In 1984, Michael Green and John Schwarz found superstring theory possess enough symmetries to ban all anomalies. This development provided a facelift for the theory.

Superstring theory considers the Big Bang as the byproduct of a much stronger explosion in which a pre-existing ten-dimensional universe broke into a four-dimensional one familiar to us. All systems tend to be in a low energy state like water which flows to the lowest level at which it is stable. However, water can be made to stay at a level at which the energy is not the lowest, for example, in dams. Such states are called ‘false vacuum’ and the system rushes to its true low-energy state whenever it gets a chance. Perhaps, the ten-dimensional word might have been in a false vacuum which spontaneously turned into a 4-dimensional one which is having lower energies.

The book also explains state of the art concepts like dark matter and how it was confirmed through the painstaking cosmic observations by Vera Rubin. Cosmic strings are not related to superstrings, but scientists believe that gigantic cosmic strings stretching across millions of light-years formed immediately after the Big Bang. These cosmic string create ripples in the fabric of spacetime called gravitational waves. Experiments are in full swing to detect these waves which was one of the predictions of general relativity.

The book is an essential ingredient in the book shelf of a science enthusiast. The description is very lucid and clear. A lot of diagrams are included which brings out the concepts in pictorial detail. Even readers who have only a glancing familiarity with scientific concepts can enjoy the work. The author’s gentle admonition of the western way of thinking makes interesting reading, “This peculiar hostility (to new ideas from junior colleagues) comes from the unconscious tendency of most physicists who suffer from the mechanistic process of thinking, often found among physicists in the West, which tries to understand the inner workings of an object by examining the mechanical motions of its individual parts. Although this thinking has produced undeniable success in isolating the laws of particular domains, it blinds one from seeing the overall picture and noticing larger patterns” (p.106). There was also one quote from Stephen Hawking arresting our attention, “When one’s expectations are reduced to zero, one really appreciates everything that one does have”. This was when the gifted scientist was denied his freedom of movement by the motor neuron disease.

The book is however marred by the salesman’s tone’ expressed by Kaku in promoting the string theory. He brings it up every now and then, when describing the drawbacks of previous theories and promptly declares that it is taken care of in string theory. The early research in strings was dominated by Japanese scientists and one may also wonder whether there is indeed a patriotic tinge to the passionate arugments of the author to prop up the theory. The glorification of lesser known scientists like Mahiko Suzuki, Nambu, Yukawa, Bunji Sakita etc seems out of place. Another drawback is that the book is outdated as the latest concepts described in it are of 1995. A lot of research and observations were made thereafter but the book fails to incorporate them. For example, the observation that the expansion rate of the universe is slowing down prompted scientists to came out with the explanation that 73% of the universe is in the form of dark energy, 23% as dark matter and 4% as ordinary matter. Dark energy is not even mentioned in the book and dark matter is stated to compose about 90% of the universe. This reduces the suitability of the book of matters of recent origin.

The book is highly recommended.

Rating: 3 Star