The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…’ Isaac Asimov
In string theory, all particles are vibrations on a tiny rubber band; physics is the harmonies on the string; chemistry is the melodies we play on vibrating strings; the universe is a symphony of strings, and the ‘Mind of God’ is cosmic music resonating in 11-dimensional hyperspace — Michio Kaku
Science is ridiculously interesting. Just when you think ‘this is it, this is the discovery that changes everything and explains the world’ , you realize you were only staring at the tip of the iceberg. You have no choice but to laugh and soldier on. The study of sub-atomic particles — Quantum physics explained things classical physics could not. Now, there is a new theoretical framework that attempts to tie together gravitational forces, electromagnetism, strong and weak nuclear forces that is being explored further. This framework is called ‘String Theory’. Gabrielle Veneziano (an Italian theorerical physicist), in 1991, published a paper that showed how an inflationary cosmological model can be obtained from string theory, thus opening the door to a description of string cosmological pre-big bang scenarios. This article explains ‘String Theory’ and leaves the reader with a question to mull over this new year.
I was sitting in a local coffee shop ‘Kaldi’s Coffee’ in St Louis with a professional writer. It was a bright winter morning in December. The sunlight passed through the French windows and uplifted my mood. Over the course of our conversation, the pro (I like to think I am an amateur writer) asked me a very profound question ‘does the world need economists?’ He followed up his own question and asked me ‘what is macro-economics? I found it a very funny question not because I thought that the world doesn’t need economists but because people look at many theoretical frameworks with the same suspicion as they would a voodoo doctors incantations or for that matter — organic alternative medicine. A mixture of hocus pocus, conjured up evidence and experts to speak to these frameworks intelligently.
The Power Of Theoretical Frameworks
It is totally understandable because frameworks are a combination of art, your own experience which crafts your judgment and science. Macro-economics provides a framework that explains the functioning of a very complex creature — the global and local economy from a birds eye view. Of course, it is as perfect as the imperfection in calculation of the metric ‘Gross Domestic Product (GDP)’ . Both are far from perfect but they provide a great framework for us to understand the world around us. In the absence of these frameworks and people who create, explain and improve upon these frameworks (macro-economists), we wouldn’t have a clue where to begin. If you stretch this logic, every discipline from physics, psychology and even spirituality provides us a foundation to begin our journey. Needless to say, our own journey leveraging these foundations not only makes our lives diverse and interesting but also creates a feedback loop to go back and improve our original ideas. In that sense, theories are valuable precursors to practice. These principles are equally applicable to physics which attempts to explain the ‘material’ universe around us as they are to biology. Therefore, theoretical physics moves from framework to framework and theory to theory to offer a common thread to create a unifying explanation of physical phenomena in the universe. One such theory is ‘String Theory’
What Is String Theory?
We break down and describe our physical universe using a term called ‘particle’. Any small localized object, without spatial expansion (zero dimensional), to which can be ascribed several physical or chemical properties such as volume, density or mass is called a particle. A particle doesn’t take up space because it is zero dimensional.
In gravitational theory, a particle a very small (infinitesimally small) non-zero ‘point mass’. In electromagnetism, it has a very small ‘point charge’.
Particles vary in size from microscopic to macroscopic. They can also be used to describe the movement of humans on a street because viewed from far enough away (from a satellite), even humans may appear as points.
In quantum mechanics which studies sub-atomic phenomena, ‘point particles’ such as electrons, photons which cannot be broken down further are called ‘elementary particles’ whereas ‘composite particles’ such as a proton or a neutron has an internal structure which is composed of a combination of elementary particles.
In String theory, point particles are replaced by one dimensional objects called strings. String theory is attempting to be a unifying theory — an explanation and self contained mathematical model that describes all fundamental forces and forms of matter. Just like particles, Strings have volume, density and mass. Also, they vibrate. One such vibration causes gravity thus string theory is an explanation of quantum gravity.
The emergence of string theory is because of problems such as quantum gravity which cannot be fully explained by two of the greatest developments in physics ie Einsteins general theory of relativity and quantum mechanics. There were no theories unifying the two explanations of the universe. String theory goes before the Big Bang and attempts to explain multi verses, worm holes and helps conceptualize a time machine between multiverses or two points in time.
All string theories must include closed Strings which resemble circles but not all string Theories include open Strings which resemble a line.
There are many challenges for ‘a unifying theory’. The String theory, developed in the 1960’s is called the ‘Bosonic String Theory’. Bosonic string theory is limited to particles called Bosons. A superstring theory attempts to go beyond Bosons and accounts for both fermions and bosons and incorporates supersymmetry to model gravity. Then, there is M-Theory which unifies all the consistent aspects of supersymmetric string theory (superstring) theory.
Einstein’s general theory of relativity added time as the fourth dimension to the three dimensional space (space has 3 dimensions — height, length and width) and defined a four dimensional ‘spacetime’. These four dimensions generally explain a lot of physical phenomena.
For mathematical consistency in various scenarios, string theory uses more than 4 dimensions. Standard string theory imagines 26 dimensions whereas superstring and M-theory imagine 10 and 11 dimensions respectively. The extra dimensions are needed because some mathematical models need them. Think of these extra dimensions as so curled up that they cannot be observed. Let’s take an example — if you look at a rope from far enough, you can only ‘see’ its length but for an insect on the rope, it can go around its circumference but It can also travel along its length.
String theory uses a technique called ‘compactification’ to view these extra dimensions which would not be observed in an experiment. Two popular models are the Calabi-Yau manifold and the Braneworld where ‘brane’ is short for membrane which says our universe is a membrane with other dimensions extending from it. The Braneworld theory, proposed in a paper by physicists Razieh Pourhasan, Niayesh Afshordi, and Robert B. Mann, called “Out of the White Hole: A Holographic Origin for the Big Bang,” says that our 3D universe was formed by a collapse of a 4D black hole in a bull universe. Thus, this model does not require a Big Bang for the beginning of our universe. Notice, our universe has only 3 dimensions which is intuitive but the extra dimensions in a Braneworld model are needed for mathematical consistency but they are hard to observe in an experiment.
Michio Kaku, the well known theoretical physicist explains the issues with string theory well when he says: “Of course, any theory with this power and majesty has a problem. This theory, because it is a theory of everything, is really a theory of Creation. Thus, to fully test the theory requires re-creating Creation! At first, this might seem hopelessly impossible. We can barely leave the earth’s puny gravity, let alone create universes in the laboratory. But there is a way out to this seemingly intractable problem. A theory of everything is also a theory of the everyday”
I started this article by using theoretical frameworks as a laughing matter for many. However, formulation of an academic theory, proving its existence in the real world and creating a critical mass of supporters is no joke. At the end, a theory should explain how the world works.
Often, researchers are tempted to join the bandwagon of existing ‘popular’ theories instead of charting their own course. This dilemma is very similar to being an entrepreneur and following the herd. Innovation is a lonely place by design. The road less taken is less taken because most fear to tread it. The fear of failure and rebuke from society is more intense when you are alone, and not part of a bandwagon, in formulating your view of the world. I have been there many times and got laughed off stage many times. In his book ‘The Road To Reality’, Roger Penrose wrote : “The often frantic competitiveness that this ease of communication engenders leads to bandwagon effects, where researchers fear to be left behind if they do not join in.”
There is strength in numbers but there is weakness in conforming to society every time. Thus, the journey between discovering a new way of looking at the world and that view becoming a widely accepted world view is one of the hardest journeys in life. The distance between disbelief and belief is the longest distance between two points. We must not let that distance deter us from taking the first step.