One of the leading theories in particle physics, the specific area of research devoted in part to finding the smallest particles, is called string theory. You may or may not have heard about string theory for its claims and unusual methods of getting there, but even if you haven't not to worry. I am going to give you a very basic intro to string theory as best as I can so you can have an idea as to what we may really be made of.
The central theme of string theory comes right out in its name: strings. The theory goes like this: all matter we see around us is made up of vibrating strings as small as physically possible, at a distance called the Planck length (the smallest unit of space allowed). Every different piece of matter, such as quarks or electrons, is made of a string vibrating at a different frequency. A way to think about strings could be similar to notes on a guitar, every note has a different frequency at which the strings vibrate, just like every constituent of matter is just a different vibrational pattern of the string.
So far I've only mentioned matter, like you and me, but string theory can also be used to describe particles of energy, like a photon, or even a particle which transfers a force, like the different types of bosons, which transmit the strong and weak nuclear forces. Any basic particle of the universe, in theory, can be described by string theory. String theory has even been used to predict elementary particles with corresponding masses and spins to their vibrational patterns.
To me, this part of string theory is quiet elegant. The fact that every particle in our entire universe can be described by the same thing is quiet remarkable. However there are some things that hold string theory back, at least in my opinion.
The first is that it will be nearly impossible to actually observe and test string theory because the things we will be trying to see will be smaller than the things we are trying to see. To be able to observe something precisely, we need to probe it with something smaller than the object we are probing. For example if you were trying to map the surface of a golf ball and its dimples by bouncing something off the surface and measuring its path, you would not get a very precise measurement by using a basketball because it could not go inside the dimples, or even close. In the same way, to measure the exact shape of strings and their properties, we would need something smaller than the string itself. The theory proposes its own problem here, since it says strings are the smallest constituents, there literally shouldn't be anything smaller to probe them with if the theory is correct. So if we can see them, it proves part of the theory wrong, and until we can see them the theory can never really be proven right. Seems like a problem to me.
Another problem is that for the math to work in string theory, which I myself don't yet understand, there must be at least 9 spatial dimensions and 1 time dimension, for a total of 10 space-time dimensions. Even for a someone in physics like me, who can come up with some pretty radical theories and proposals, the idea of 10 dimensions making up our universe does not make sense to me. It doesn't fit our idea of the universe at all, and the theories used describe the dimensions are anything but elegant. And to me, elegance is part of a good scientific theory.
This was a very basic introduction to string theory but I will almost certainly post more about it in the future. It is a very exciting and interesting aspect of physics in todays world, and I myself am very intrigued to see where the theory takes us.
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