The universe has long puzzled us. Since 400 BC, when Greek philosopher Democritus suggested that atoms were the smallest pieces of matter, our understanding has evolved significantly. In 1897, JJ Thompson found even smaller parts—electrons. By 1912, Ernest Rutherford had discovered that atoms contain nuclei, which in turn held protons and neutrons. These were believed to be the fundamental building blocks of the universe until the 1960s when we learned that protons and neutrons are made of quarks—specifically, up quarks and down quarks.
Today, most of us are taught that everything we see is composed of electrons, up quarks, and down quarks. But modern physicists have known for decades that this isn’t the whole story. The current best theory in physics tells us the universe isn’t made of particles at all; it’s made of fields.
The concept of particles as the building blocks of reality is a simplification. In fact, what we think of as particles are just excitations or vibrations in various fields. These fields are fluid-like substances that can vibrate. Imagine a room heated by a fireplace; temperature varies at every point in that room and forms a “field” of temperature. Similarly, the universe is filled with different fields, each with its own set of properties.
Even what we think of as a vacuum, a space emptied of all matter, isn’t really empty. It is teeming with these fields, constantly in motion. This perpetual motion of fields is due to the Heisenberg uncertainty principle, which asserts that quantum fields can never be completely still.
We interact with and observe only a few of these fields. For example, photons (or light) are vibrations in the electromagnetic field, and electrons are vibrations in the electron field. Up and down quarks, which combine to form protons and neutrons, are vibrations in the up quark and down quark fields. Everything we see around us—phones, desks, flowers—is essentially composed of vibrations in these fields.
The Standard Model, our leading theory in physics, accounts for 17 different fields, including the Higgs field, but potentially more could exist. Even space-time itself is theorized to be a field, though we haven’t fully incorporated it into quantum field theory yet.
Fields offer a better explanation than particles for various phenomena, like how gravity affects objects over enormous distances without physical contact—something even Newton found inconceivable. Einstein’s theory of general relativity explained that gravity results from the curvature of space-time, a field that permeates all of reality.
Fields also explain how particles can appear and disappear. When a neutron decays into a proton, electron, and anti-neutrino, it’s the energy of one field transferring to another that results in new particles.
Ironically, quantum mechanics teaches that the universe is composed of discrete units, while fields are continuous. Quantum Field Theory (QFT) reconciles this by explaining that fields accept energy in discrete amounts, which we perceive as particles. The energy needed to create a particle is its rest mass energy, defined by Einstein’s equation, E=mc^2.
Every electron in the universe is a wave in the electron field. The same applies to up and down quarks. We are composed of ripples in these universal fields, connected in a seamless, continuous fabric.
Despite fields offering profound insights, they don’t explain everything. Mysteries like dark matter, dark energy, and the occurrence of the Big Bang remain unresolved. This indicates that our current understanding is an approximation of a deeper reality.
So, are fields truly fundamental? For now, they are the limit of our comprehension. There may be more profound layers to uncover, but it depends on us asking the right questions. Knowing that, we maintain hope that future discoveries will continue to unravel the complexity of the universe.