It is funny that we consider scientists among the smartest and regard them with utmost respect and awe but when it comes to really finding out what they are doing, we all find excuses to avoid doing so, either out of fear that we will never understand what they are saying or worse, that we make total fools of ourselves and ask completely idiotic questions. This is, I think, especially true when it comes to talking to physicists who have always considered their field superior to other science fields and offer no apologies for this stance. But I have already had my share of sweet embarrassment for many years and have developed a certain chutzpah in the process so my anxiety was overran by my eagerness to simply understand this attempt in physics to come up with the theory of everything. I figured that anything that concerns itself with explaining stuff with the word "every" to nudge it, such as "everything" or "everywhere" deserved our attention. So I went. Stay with me you physics-phobes. I used to be a glorious physics-phobe myself until I found that the best way to get rid of the fear of anything is to try to understand the object of your fear.
I have read both The Elegant Universe and The Fabric of the Cosmos. They both cover attempts in the history of science that led to the theories governing the fundamental forces of Nature we know of today, namely gravity, electromagnetic, weak and strong nuclear forces. "Fundamental" because nothing else can account for their existence, i.e., they just are. Gravity we all know about. Electromagnetic force refers to the forces between charged particles, which accounts for the stability of the atom and how molecules are formed. This law explains, for instance, why we do not go through solid surfaces. A physicist named James Clerk Maxwell figured out that the principles governing the behavior of magnets and electricity could be described in one theory, thus the term "electro-magnetic." "Strong" is, as Greene described it, like the "superglue" that binds protons and neutrons together in the nucleus, while "weak" is the force that allows neutrons to disappear, or turn into protons, emitting an electron and an anti-neutrino in the process. A few decades ago, physicists Steven Weinberg, with Abdus Salam and Sheldon Glashow, came up with a Nobel-earning formula to unite the principles governing the "electromagnetic" and "weak" forces and termed it "electro-weak." So now, we know of three basic forces from the original four governing ALL physical activity in the universe. The first, gravity, which Newton universalized in his theory and Einstein later geometrized in his (i.e., he said that massive bodies such as the Sun warp the woven fabric of space-time and this curvature of space-time is what the planets orbiting it like the Earth follows), governed the movement of everything we can normally experience on Earth as well as the orbit of planets, placement of stars and galaxies and other heavenly bodies in between. The electro-weak and strong forces, however, reign at the level of the atom and its constituent particles called "elementary particles." At this level called quantum physics, it is a totally different world, counterintuitive and uncertain, yet, we know they work because if they did not, there would be no way we could routinely explain and rely on atomic and molecular reactions we conduct in laboratories for the various uses of mankind such as many high-tech medical procedures, drugs, genetics, atomic military weaponry, etc. Since the electro-weak and strong forces are mediated by exchange or "messenger" particles, it seems to make sense to unify them into one. As for gravity, physicist Richard Feynman then tried to make gravity a force as well, i.e., mediated by a particle called a graviton, so that the messenger particles in all the forces could "talk" in a common language in mathematics and perhaps lead to a unified understanding of all three fundamental forces into a grand one. However, when they did the computations, they came up with "infinity" which could elicit heartfelt sighs and moans in weddings but in science, it simply translates to nonsense. And this is the problem that eats physicists. How could there be one fundamental law (gravity) governing "big" things and another set of two (electro-weak and strong forces) governing "small" things? How is it that science cannot grasp with one fell swoop of a theory a universe that does not have trouble existing and being governed by two sets of theories which to scientists still seem at terrible odds with each other? Even Einstein worked till his last years to unite the fundamental forces but failed. So now, you can understand why the race is still on to what they consider the holy grail in science. And Greene, supported by "string" pioneers before him like Dr. John Schwarz of Caltech, and Dr. Edward Witten of Princeton, think they may have the answer, or at least have started to enter into it. And if you think the world of the atom and beyond is weird, you have to sit now to hear what the String Theory proposes. This is what The Fabric of the Cosmos covers in addition.
The String Theory proposes that in order to unite all the fundamental forces, we first have to suspend two things that science has already verified to be true. First, we have to suspend the observed fact that the "smallest" particle are quarks and entertain the possibility that instead of these energetic "dots" inside the deepest level of matter, we have a filament of energy vibrating in different ways: strings. The different vibrations of strings aptly likened by Greene to cello strings correspond to all kinds of particles, perhaps even beyond what we know now, particles whose behavior could reconcile the law of the "big" and the law of the "small." Second, we have to suspend our experienced knowledge about the four known dimensions (back-forth, up-down, left-right and time) and imagine an additional seven dimensions, raising the possibility that our four-dimensional universe may just be a tiny fraction of a much larger universe or universes. Please do not ask me how to help you visualize an 11-dimensional picture of the universe because I get butterflies in my stomach just negotiating a ferris wheel ride so I am all out of ideas on how to imagine our transient existence floating in such an expanse that String produces. But Dr. Greene, like any scientist, was aware that all the mathematical beauty and elegance underlying the String Theory may eventually turn out to have no proof in Nature since even with the most optimistic projections on technology, we could never directly "see" strings and at best, only know their existence as they manifest themselves IF at all they exist. And in science, no proof is no science. It could still be beautiful but it would, as the scientists critical of String say, remain in the realm of philosophy. Dr. Peter Woit of the Math department in Columbia, evaluated the theory, saying, "String Theory has been more successful in its public relations than in physics." I think he is right and if you meet Greene, you would understand why. He is young and energetic, very passionate and determined to communicate his field to the public, going on a world tour and making an excellent show based on his book, The Elegant Universe, which is also now out on DVD. But I also agree with what Greene said when criticized about the outrageousness of what String proposes. He told me: "So what? To ask about the deepest, most fundamental questions about the universe, even if I fail, is still every bit worth the life I devoted to it."
On the subway back, I thought of that last thing he said. The String Theory may really turn out to be just beautiful mathematics and not science but I still like it. Knowing about it latches me on to this exciting quest of good minds to deeply understand this strange universe that holds all I love, all that is, ever was, and will be. A whole new world. Indeed, abracadabra.