Are there multiple dimensions?

I’m not a scientist, let alone a physicist. How can a regular person understand this stuff?

Let’s begin at the beginning. This might take a while.

As we all know, there are four dimensions (length, width, height, and time). To understand why many physicists believe that there are additional dimensions, we first need a basic understanding of the physics behind this theory.  

In school, you probably learned about atoms. At one time, atoms were considered to be the basic building blocks of the universe. They contained electrons, protons, and neutrons, and nothing else.

Through experimentation, physicists learned that it goes deeper than that. Everything in the universe (including atoms) is made from fundamental particles, ruled by four fundamental forces. The Standard Model of particle physics best explains how these are related to each other.

These fundamental particles, also called elementary particles, are the building blocks of matter. These come in two basic types, quarks and leptons. Each of these types includes six particles, which are related in pairs, or “generations”.

Let’s start by talking about quarks. 

https://flexbooks.ck12.org/cbook/ck-12-physics-flexbook-2.0/section/20.1/primary/lesson/fundamental-particles-ms-ps/

·       The first generation, with the lightest and most stable particles are the “up quark” and the “down quark,” followed by

·       The second generation, with the “charm quark” and the “strange quark,” followed by

·       The third generation, with the “top quark” and the “bottom quark".

All of the stable matter in the universe is made from particles that belong to the first generation; particles in the second and third generations quickly decay.

We will talk about leptons in our next post.