Cosmic Music (String Theory)

by : Aria Ratmandanu

       Einstein once said that if a theory did not offer a physical picture that even a child could understand, then it was probably useless. Fortunately, behind string theory there is a simple physical picture, a picture based on music.

        According to string theory, if you had a supermicroscope and could peer into the heart of an electron, you would see not a point particle but a vibrating string. (The string is extremely tiny, at the Planck length of 10-33 cm, a billion billion times smaller than a proton, so all subatomic particles appear pointlike.) If we were to pluck this string, the vibration would change; the electron might turn into a neutrino. Pluck it again and it might turn into a quark. In fact, if you plucked it hard enough, it could turn into any of the known subatomic particles. In this way, string theory can effortlessly explain why there are so many subatomic particles. They are nothing but different “notes” that one can play on a superstring. To give an analogy, on a violin string the notes A or B or C sharp are not fundamental. By simply plucking the string in different ways, we can generate all the notes of the musical scale. B flat, for example, is not more fun- damental than G. All of them are nothing but notes on a violin string. In the same way, electrons and quarks are not fundamental, but the string is. In fact, all the subparticles of the universe can be viewed as nothing but different vibrations of the string. The “harmonies” of the string are the laws of physics.

       Strings can interact by splitting and rejoining, thus creating the interactions we see among electrons and protons in atoms. In this way, through string theory, we can reproduce all the laws of atomic and nuclear physics. The “melodies” that can be written on strings correspond to the laws of chemistry. The universe can now be viewed as a vast symphony of strings.

          Not only does string theory explain the particles of the quantum theory as the musical notes of the universe, it explains Einstein’s relativity theory as well—the lowest vibration of the string, a spin- two particle with zero mass, can be interpreted as the graviton, a par- ticle or quantum of gravity. If we calculate the interactions of these gravitons, we find precisely Einstein’s old theory of gravity in quan- tum form. As the string moves and breaks and reforms, it places enormous restrictions on space-time. When we analyze these constraints, we again find Einstein’s old theory of general relativity. Thus, string theory neatly explains Einstein’s theory with no additional work. Edward Witten has said that if Einstein had never discovered rela- tivity, his theory might have been discovered as a by-product of string theory. General relativity, in some sense, is for free.

         The beauty of string theory is that it can be likened to music. Music provides the metaphor by which we can understand the na- ture of the universe, both at the subatomic level and at the cosmic level. As the celebrated violinist Yehudi Menuhin once wrote, “Music creates order out of chaos; for rhythm imposes unanimity upon the divergent; melody imposes continuity upon the disjointed; and har- mony imposes compatibility upon the incongruous.

         Einstein would write that his search for a unified field theory would ultimately allow him to “read the Mind of God.” If string theory is correct, we now see that the Mind of God represents cosmic music resonating through ten-dimensional hyperspace. As Gottfried Leibniz once said, “Music is the hidden arithmetic exercise of a soul unconscious that it is calculating.

        Historically, the link between music and science was forged as early as the fifth century b.c., when the Greek Pythagoreans discovered the laws of harmony and reduced them to mathematics. They found that the tone of a plucked lyre string corresponded to its length. If one doubled the length of a lyre string, then the note went down by a full octave. If the length of a string was reduced by two- thirds, then the tone changed by a fifth. Hence, the laws of music and harmony could be reduced to precise relations between numbers. Not surprisingly, the Pythagoreans’ motto was “All things are numbers.” Originally, they were so pleased with this result that they dared to apply these laws of harmony to the entire universe. Their effort failed because of the enormous complexity of matter. However, in some sense, with string theory, physicists are going back to the Pythagorean dream.

      Commenting on this historic link, Jamie James once said, “Music and science were [once] identified so profoundly that anyone who suggested that there was any essential difference between them would have been considered an ignoramus, [but now] someone proposing that they have anything in common runs the risk of being labeled a philistine by one group and a dilettante by the other—and, most damning of all, a popularizer by both.”