During the 1900s, Albert Einstein discovered the theory of relativity which helped him come up with the equation, E= MC^2. This earned him fame throughout the scientific community.
His theory explains how the what we think is the forces of gravity is actually the curves of space and time. The object is able to evolve, warp, and stretch.
General relativity explains the movement of the planets, the physics behind how black holes work, and how light bends from distant stars and galaxies.
Quantum Mechanics, the theory of atoms and subatomic particles. Quantum Mechanics is very radical and explains about that everything is made of waves and particles.
Quantum Mechanics is always discrete. It goes in integers, never weird factions like 1/2. It also is impossible to predict the outcome of a experiment in the quantum system. The effects also get smaller the larger the objects is.
Einstein also came up with something called entanglement which assume that the quantum theory is incomplete.
The String Theory is a theory that proposes that everything is made up of tiny string like strands of energy that vibrate. This theory attempts to unify the four fundamental forces in the universe.
This theory has led to the invention of extra dimensions just like ours that have tiny differences.
String Theory attempts to unify the Quantum physics theory and the general relativity theory. It is the most promising theory as of today.
The strings can have two types of form, closed or open, and have five different types of shapes. All the particles in the world are divided into bosons and fermions. String theory proposes something called supersymmetry which states that a fermion must exist for every boson and vice versa.