As explained in part 1, there is a significant disagreement between both Quantum Physics and Gravity. For this, what we know in Science today cannot explain everything without the use of different theories. If, somehow, we could coherently explain Gravity with the same Physics used in Quantum and the Standard Model, we would successfully have the theory of everything.
This is where String Theory comes into play; it attempts to explain the said disagreement and gives a communal explanation in hope of becoming a valid theory of everything.
Bridging the gap between Gravity and Quantum Physics has been attempted by Scientists. Referring back to part 1; the Strong, Weak and Electromagnetic interactions, in other words, three out of the four fundamental forces of the Universe, are carried by certain particles, whereas Gravity is not. As a result, Scientists created a new particle, called the Graviton, to allow for Gravity to fit into the same category as the other three fundamental forces . While this sounded like a good idea, the Maths used to verify this creation did not work and in fact, broke down.
The Birth of String Theory
Having seen Maths fail at explaining the Graviton, some Scientists believed that a new story must be devised that does not attempt to marry Gravity to the Standard Model, but rather attempt to explain them and their differences, simultaneously. This story was given the name, String Theory. What String Theory suggests, is the most fundamental building block of anything, that alone is not made up of anything else, is a string of vibrational energy that has different modes of vibration, that produce different particles . Allow me to explain. Just like a guitar can produce different notes due to different vibrations, in String Theory terms, these strings of energy vibrate differently, to produce different particles. So, for example, if you were to zoom into both an electron and a neutrino further and further, you’d see that they are made up of two different strings vibrating in different ways to produce these two different particles. More importantly, String Theory also explains Gravity, thus unifying all four fundamental forces of the Universe . Although this theory sounds all well and good, unfortunately, it comes with strings attached, pardon the pun.
The Maths used to explain String Theory does not work in our Universe of 3 spatial dimensions (x, y and z) and 1 temporal dimension (time); it only works for a Universe of 10 dimensions. Scientists have modelled 10 dimensional Universes, using Maths, and explained them with String Theory; but when they try and remove the 6 extra dimensions to explain our Universe, they couldn’t (that’s not to say one day they will) . There are explanations out there to explain why we cannot simplify String Theory like this and that we need 10 dimensions to explain it. If that happens to be the case, where are these extra dimensions?
Where could these Dimensions be?
Suppose you look out of your window, far into the horizon, and see an object far enough away such that you see it as a point in the distance. Now, let’s say you leave your house and walk towards this point. Soon, you realise that actually, this ‘point’ is now a ‘line’ in the distance; in Physics, a line is referred to as 1 dimensional. Out of curiosity, you walk closer and closer, and realise that this ‘line’ now appears rectangular; this rectangle is now, by definition, 2 dimensional. You are now intrigued. As a result, you walk right up to this object and you see that little ants are walking around a lamp post that you once thought was originally just a point in the distance. The reason for this analogy, is that us humans could be those who are looking out of the window at this 'point', and the ants are those that can see the true dimensions of Space . In other words, we aren’t looking close enough, meaning we cannot access the higher dimensions of the Universe. From the ant’s perspective, it could be walking around the vibrational strings in String Theory, thus having access to all the dimensions of the Universe.
The idea that the entire Universe could be a result of strings vibrating in a specific way to produce the matter around us, is incredible, but if String Theory cannot be simplified to suit the known dimensions of our Universe, one could argue that it is completely useless. Thinking back to part 1, the point particle theory alone, is of great inaccuracy, but alone, it opened so many moor doors for us and allowed us to discover things we had never thought we would. In fact, the point particle is used practically, even today. In summary, I believe that String Theory should not be completely disregarded. Soon, we may have answers we never thought we would have, or maybe, a Scientist may eventually be able to explain our Universe with an altered version of String Theory, that does eventually give us a theory of everything.
If you have any questions, leave them below and until next time, take care.
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