# The Four Forces Of Physics

The universe is held together by the laws of physics. All the laws of physics are dictated by four forces: gravity, electromagnetism, the weak nuclear force, and the strong nuclear force. These four forces hold our universe together, and without them, the universe could not exist. Each of the four forces, with the exception of gravity, have their own messenger particles that carry the force. What are these forces and how do they operate?

## Gravity

Gravity is perhaps the most well-known of the four forces. Not only was it the earliest force to be identified, but it also operates on the largest scales, making it far more apparent than the other three forces. Gravity was first described by Isaac Newton in the 1660s. Newton sought to describe how objects fall to the Earth, and why other objects, such as the moon, orbit the Earth. Newton devised a mathematical model that described how objects with mass exert a force of attraction, a force he called gravity. The force of gravity is proportional to the mass of an object, with higher mass objects extorting a stronger gravitational force. Interestingly, despite the success of Newton’s theory, he was unable to define what gravity actually was. He knew it was a force of attraction, yet he did not know why objects exerted a gravitational force. It wouldn’t be until the early 20th century, when Albert Einstein published his theory of gravity called General Relativity, that we would have a definition for how gravity is produced. Einstein was able to describe how the gravitational force works. Rather than being a mysterious force between objects, gravity is the warping of space itself. Space can be thought of as a fabric, wherein objects of mass can distort and bend the fabric. For example, the sun creates a kind of indent in space, and all the planets orbit along that curved space. Interestingly, despite gravity being the most recognizable of the four forces, it is by far the weakest force in the universe.

Although Einstein was able to describe what gravity is, it still remains the most mysterious of the four forces. With the advent of quantum mechanics in the early 20th century, the world of physics was thrown into chaos. Most of what we thought was true turned out to be wrong, and the universe proved to be far more mysterious than we could have ever imagined. In this new world of quantum mechanics, gravity has had a hard time finding its place. The other three forces of nature can be described using quantum mechanics, yet no matter how hard scientists try, gravity cannot be accurately described in the quantum realm.