It’s cool! It’s Flashy! IT COULD UNIFY THE FOUR FORCES!?!?!
IT’S STRING THEORY!
What’s this interesting theory that mesmerizes the public and physicists alike?
Well, it’s essentially an attempt to create a grand unified theory that would combine the four forces (electricity and magnetism, weak, strong, and gravity). Now we already have combined electricity and magnetism and they are well connected and studied and they’re apart of the basic physics education. Electricity and magnetism have been combined with the weak force (the force which causes radioactive decay) to make up the electroweak force. The strong force (which holds the nucleus or core of an atom together) is on the same level as electricity and magnetism and the weak force in that it is quantized (which means that we can describe it using quantum mechanics). The force we struggle the most with though is gravity. Einstien created the perfect way to describe gravity on a macroscopic (large) scale that is the basis of modern day cosmology which covers things like inflation, dark energy, dark matter, and black holes. The problem is we have been unable to come up with a successful quantum theory of gravity.
But the good news is we have already named the particle responsible for it! The graviton! We just need to do everything else!
Now, where does string theory relate to this?
Well, string theory is a quantum theory of gravity (though not the only one). And one of the key features of string theory is that the theory contains more than the normal amount of dimensions.
Normally we think of three dimensions which you can think of as up and down, left and right, and forward and backward (or x, y, and z or any other three letter or symbol combination). But in standard general relativity, we have four dimensions, the three above (if in the standard coordinate system we humans think of [but we can actually work in spherical or other systems that may make a problem easier]) and time. Yes time. From my understanding of string theory, there can be up to 11 dimensions.
Having more than 4 dimensions isn’t new, in fact, the idea of 5 dimensions is about 100 years old. This doesn’t mean that the current theory of stringy theory is that old, but it isn’t young either. String theory is actually about 50 years old, with a lot of work being done in the 60’s and 70’s.
The problem with string theory is that it’s hard to make experimental observations which is the step needed to verify or rule out a theory.
Even though some of the aspects of string theory are crazy and there are no major alternatives (yet), it is still the big kid in town and is here to stay for the time being.
(Note: as my research interests lie elsewhere, this post is not complete and will take some time to grow. Keep an eye out for updates on this post in the future.)
