String theory is an attempt to reconcile Einstein’s GR with QM.
It unify our beloved forces of Nature in a single Quantum mechanical framework.
That is the main motivation of string theory.
Originally, The story was different. String Theory was intended as a description of the strong nuclear force, Later we realized that it allows for a quantum description of gravity.
The premise of string theory is that at the fundamental level, matter does not consist of point particles but rather one-dimensional “strings” call it "Vibrating filaments of energy" These strings represents the most fundamental aspects of Nature and assumed to be the most fundamental building blocks of the universe.
These strings can be open strings or closed strings. Open strings behave like photons,Gluons etc. While closed strings behave like gravitons. Elementary particles in string theory are just lowest energy vibration/excitations of strings.The mass of fundamental Particles and other properties comes from the ways that these strings are Vibrating in extra-dimensions. This being said, We can say that All elementary particles in Standard Model is made up of the same fundamental identical string and the only difference between them is the Vibrating Patterns.
Important thing to note is that Gravity is a natural Consequence from the Maths of this theory. IOW String theory requires the Gravity to work. But String Theory only makes sense in Extra Dimensions. For Mathematical consistency String theory requires 10 spacetime dimensions. Extra Dimensions are curled up to incredibly small size in Calabi-Yau Manifolds.(This is known as compactification.) These Dimensions are not observable to us. However these Dimensions affect how strings behave in a sense. String theory is a work in progress and sadly There is no experimental evidence that string theory is the correct description of our Univserse.
So Is it right?
Yes, (Mathematically) but Physically? Who knows? We don't know! There not been direct experimental evidence for string theory also obtaining direct experimental evidence may require highly advanced technology beyond our current reach.
Writers- @astrophile_ashish
