Sunday, July 11, 2021

The Bridge - String Theory

 

A group of mystics came and started probing the scientists, “Five centuries back, you guys had challenged us that you would give us the theory of everything and find the building blocks of nature, where have you reached?” The scientists answered confidently, “Everything is made up of atoms.” The mystics probed further, “So what are atoms made of?” When the scientist replied, “They’re made of subatomic particles called protons, neutrons, and electrons.” The smiling Rishi asked, “So, what are protons and neutrons made of?” “Even tinier particles called quarks,” The Rishi was persistent, “What are quarks and electrons made of?” At that point, the scientists got stumped and started scratching their heads. Should they accept defeat?

Suddenly in the 1980s, scientists Michael Green and John Schwarz came running. “Stop” they said “Don’t accept defeat, we have fine tuned the superstring theory to such an extent that it can withstand all the questions and establish the TOE.”

Modern physics has two basic scientific laws: quantum physics and general relativity. These two scientific laws represent radically different fields of study. Quantum physics studies the very smallest objects in nature, while relativity tends to study nature on the scale of planets, galaxies, and the universe as a whole. Obviously, gravity affects small particles too, and relativity accounts for this as well.

And that is the problem. Black holes are massive in density. They are so dense and heavy that not even light can escape its gravitational pull. This gravity compresses Supermassive objects with huge mass into a tiny point called singularity. Gravity has compressed all that mass into a tiny point. Because the center of a black hole is both incredibly tiny, yet incredibly massive, you cannot avoid using both general relativity and quantum mechanics at the same time. When you attempt to do just that, 1+1 equals 11. They break down and give nonsensical predictions and answers that don’t make sense. It’s kind of like living in a city with 2 different sets of traffic laws that often conflict with each other. The universe is not nonsensical, 1+1=2 not 11, so something is terribly wrong.

Superstring theory - known less formally as "string theory" and sometimes called the Theory of Everything (TOE), because it is a unifying physics theory, was proposed as the answer to this seeming contradiction.

The essential idea behind string theory is this: all of the different 'fundamental' particles of the Standard model are really just different manifestations of one basic object - a string. How can that be? Well, we would ordinarily picture an electron, for example, as a point with no internal structure. That is a point and thus cannot do anything except move. But, if string theory is correct, then under an extremely powerful microscope, we would realise that the electron is not really a point, but a tiny loop of string. Now, a string can do more than just move- it can oscillate or vibrate in different ways. If it vibrates in a certain way, then from a distance, unable to see the strings within, we see an electron. If it vibrates in some other way, we call it photon or quark or a ...... 

So, if string theory is correct, the entire world is made of strings!

Together with the question of quantum gravity, string theory attempts to unify the four fundamental forces in the Universe - Electromagnetic force, the strong nuclear force, the weak nuclear force and gravity, all together in a single unified theory.

At the most microscopic level, everything in the universe is made up of loops of vibrating strings, and apparent particle differences can be attributed to variations of vibration. An object (such as an apple, for example) and a force (such as radiation, for example) can both be broken down into atoms, which can be further broken down into electrons and quarks, which can be, finally, broken down into tiny, vibrating loops of strings. String theory unites not only the types of particles, but also the ways they behave.

Let me give an example: if a string vibrates in one manner, it could exhibit characteristics of an “up” quark. If a second string is introduced with the same properties, we now have two strings, or basically two “up” quarks. However, when a third string that vibrates in a rather different manner, acts as a “down” quark, the outcome is two up quarks and one down quark. The result of two up quarks and one down quark produces a proton. Thus, a proton is a composite particle built from two up quarks and one down quark, each quark being a manifestation of the string it represents. And similarly, all subatomic particles behave in a manner determined by the strings and its vibration. All forces and particles in nature are derived from variations in vibrations of strings. As an example, gravity is said to arise from the lowest vibration of a closed string.

There were a few skeptics amongst the scientists, they asked, “Your string theory is ludicrous. It presupposes that there are ten dimensions in the natural world (nine spatial dimensions plus time), rather than the four of classical science (the three spatial dimensions plus time). These are all theories, where is the experimental basis? Has anyone seen these dimensions?”

The various dimensions of string
The string proponents said, “What causes the extra six dimensions to be largely unnoticed is that they are considered to be compacted or curled up. The reason that general relativity doesn't work at the subatomic level is because the equation mistakenly includes a figure for point-like particles. Modifying the equation to include a representation of loops of string, instead, makes the equation work”. 

The unbelievers amongst the scientists scoffed, "What is the point in making a theory that has neither been tested nor experimented? What impact will it have on science and mankind? If just seems like mental wrestling." The team of scientists leading the string theory was bristling with anger," 

In 1905, when Einstein first presented his famous equation E=mc2, he felt that it was an interesting relationship, but little did he know that it would result in something as potent as the atomic bomb. He would not have anticipated that the correction to time calculations demanded by his theories of special and general relativity would someday be required to get the worldwide global positioning system (GPS) to operate correctly. Quantum physics, which on the surface is as theoretical of a study as they come, is the basis for the laser and transistor, two technologies that are at the heart of modern computers and communication systems. 

While, we cannot predict with certainty what string theory may lead to, history has shown that it will almost certainly lead to something profound. Who knows - that this theory could probably lead to future understanding of parallel universes or the holographic universe or similar principles that are waiting to be discovered." By this time, both groups of scientists were angry and pushing each other. 

An old, wise scientist intervened, "Cool down guys. Let us go and visit the Rishis and take their advice." So, all the scientists packed their warm clothes and climbed to the cave in the snow clad Himalayan Mountains, waiting for the Rishi to open his eyes and come out of his meditation. As soon as the Rishi opened his eyes, the scientists put forward their arguments and asked him for his views."

The Rishi smiled and said, “Vasudhaiva Kutumbakam” which means that the World is One Family and again closed his eyes and went deep into his meditational trance.

No comments:

Post a Comment