The 7 Hidden Rules that Control the Entire Universe

Physics is the science that writes the rulebook for the universe.

Chemistry, biology, geology, and astronomy then use those rules to explain more complex patterns, like molecules, cells, mountains, stars, and you.

By understanding the rulebook, you'll know how all the other games are played.

We're going to start at the smallest scales and zoom out, keeping one key idea in mind.

Simple rules plus lots of interactions lead to surprising complexity.

First, we need a canvas on which to build our universe.

That canvas is space-time, which consists of three spatial dimensions and one time dimension.

On this canvas, the first toolkit of physics consists of three essential elements.

symmetries, conservation laws, and fields.

A symmetry is any change of perspective or variables that leaves the outcome of a system unchanged.

For example, the laws of physics don't care if you do an experiment in New York or in Beijing.

The rules are the same everywhere.

This spatial translation symmetry results in conservation of momentum.

Similarly, time translation symmetry means the rules stay the same whether you do the experiment today or next week.

This symmetry results in conservation of energy.

These connections are formalized in Noether's theorem, and they explain why certain totals never change in isolated systems.

These symmetry principles are crucial because respecting or breaking them constrains and predicts the particles and forces we find in nature.

I recently made a video on this here if you want to know the details.

Regarding fields, at the fundamental level, elementary particles aren't tiny billiard balls.

They are excitations or ripples in fields that fill all of space-time.

For example, the electromagnetic field is everywhere.

Light is a ripple in that field.

Particles are best thought of as tiny quantized excitations of their respective fields.

So the electron is a ripple in the electron field, the photon is a ripple in the electromagnetic field, and the up quark is a ripple in the up quark field, and so on.

This picture is formalized in quantum field theory, our best framework for how the universe works.