What Actually Are Magnetic Fields?

What Are Magnetic Fields, Really? What Makes Them Exist?

At the most fundamental level, a magnetic field is a way nature shows us that electric charges in motion create a force that can influence other charges and magnets, even from a distance. But why does this happen? To understand this, we need to look deeper into the nature of electricity, magnetism, and the particles that make up everything around us.

Electric charges are properties of tiny particles like electrons and protons. When these charges move—like electrons flowing through a wire—they create both electric and magnetic effects. This connection between electricity and magnetism is described by a beautiful set of laws called Maxwell’s equations, which show that changing electric fields produce magnetic fields, and changing magnetic fields produce electric fields. This interplay is what we call electromagnetism, one of the four fundamental forces that govern the universe.

But where does electromagnetism itself come from? It arises from the fundamental nature of particles and fields described by quantum field theory and special relativity. Particles like electrons are not just tiny balls; they also have an intrinsic property called spin, which gives them a tiny magnetic moment—basically, they behave like tiny magnets. This intrinsic magnetism is built into the fabric of the particles themselves.

A magnetic moment is a measure of the strength and direction of a magnet or magnetic particle’s tendency to align with a magnetic field, essentially representing how strongly it behaves like a tiny magnet.

Moreover, the force carriers of electromagnetism are particles called photons—massless particles that mediate the electromagnetic force. When electrons move, they emit and absorb photons, which carry the electromagnetic influence through space. This exchange of photons is what creates the magnetic field around moving charges.

Imagine a magnet attracting a paperclip. The magnet’s atoms have electrons whose spins and movements create a magnetic field extending around the magnet. When the paperclip enters this field, the magnetic moments of its atoms begin to align with the field, turning the paperclip into a temporary magnet. Because opposite magnetic poles attract, the paperclip is pulled toward the magnet. This attraction happens without the two objects touching because the magnetic field acts as an invisible messenger, carrying the force through space.

Why Do Opposite Magnetic Fields Attract?

Opposite magnetic poles attract because their magnetic field lines connect and create a lower-energy, stable configuration by pulling the poles together. Magnets move to configurations that lower the total magnetic potential energy, with opposite poles attracting to reach a more stable, lower-energy state. This force (total magnetic potential energy) arises from the interaction of many tiny magnetic dipoles—like microscopic current loops of electrons—within each magnet, which align and interact so that the combined magnetic fields add together smoothly between opposite poles, effectively “pulling” the magnets together.

Why Do The Tiny Dipoles Attract?

Tiny magnetic dipoles pull on each other because each dipole generates a magnetic field that decreases with distance roughly as the inverse cube of their separation, and this field exerts a force on the other dipole’s magnetic moment; the interaction energy between two dipoles depends on their relative orientations and positions, causing them to align or attract to minimize the system’s energy.

You are just explaining it by itself, without saying why the attraction exists

Yes—in the framework of quantum electrodynamics (QED), the electromagnetic force (which includes magnetic forces) arises from the exchange of virtual photons between charged particles. These virtual photons are not real particles you can detect; rather, they are mathematical entities representing the interaction that mediates electromagnetic forces.

When two magnetic dipoles (like tiny atomic magnets) interact, they do so because their charged constituents—mainly electrons—exchange virtual photons constantly. This exchange transmits momentum and energy, effectively creating the magnetic force between them. The direction and nature of the force (attraction or repulsion) depend on how these virtual photons influence the quantum states of the particles involved.

In simpler terms, the magnetic field you observe is a classical, large-scale manifestation of countless quantum interactions where virtual photons are continuously exchanged, carrying the electromagnetic influence. Opposite magnetic poles attract because this exchange leads to a configuration of lower energy, making the system more stable. The “pull” is the macroscopic effect of these underlying quantum exchanges striving to minimize the total energy.

So, while virtual photon exchange is the fundamental mechanism behind electromagnetic forces, including magnetism, it is a subtle quantum process—not a stream of actual photons flying back and forth like little balls. Instead, it’s a way quantum field theory describes how particles influence each other’s fields to produce forces that cause attraction or repulsion.

Do Virtual Photons Exist or Not?

Virtual photons do not exist as real, detectable particles but are best understood as temporary, mathematical disturbances or “excitations” in the electromagnetic field used in quantum field theory calculations to describe electromagnetic forces[1][5]. They are called “virtual” because they do not obey the usual energy-momentum relation of real particles and cannot be directly observed or detected; instead, they appear as internal lines in Feynman diagrams representing the intermediate steps of particle interactions[1][4]. Although virtual photons are not particles in the traditional sense, their exchange effectively mediates electromagnetic forces—such as attraction or repulsion between charged particles—by transmitting momentum and energy in a way consistent with quantum mechanics and special relativity[1][5]. Thus, virtual photons are a powerful conceptual and calculational tool that encapsulate how electromagnetic interactions occur at the quantum level, but they are not physical particles flying back and forth like real photons of light[2][3][8].

Could Virtual Particles that Make Magnetic Fields Exist in Another Dimension?

The idea that virtual particles—like the virtual photons mediating electromagnetic and magnetic forces—might exist in another dimension is a speculative concept not part of standard physics but sometimes discussed in theories beyond the Standard Model, such as string theory or models involving extra spatial dimensions.

From the standard quantum field theory perspective, virtual particles are temporary, mathematical disturbances or “excitations” of quantum fields within our familiar four-dimensional spacetime (three space dimensions plus time). They do not exist as real particles or entities traveling through space or other dimensions; rather, they are internal components of calculations (Feynman diagrams) that help predict how forces like electromagnetism operate. These virtual particles appear only transiently and cannot be directly observed.

However, some advanced theoretical frameworks propose that fundamental particles and forces might arise from phenomena in higher dimensions—beyond the three spatial dimensions we experience. In such models, what we perceive as virtual particles could be manifestations or projections of more complex processes occurring in these extra dimensions. For example, string theory suggests that particles are vibrations of tiny strings existing in a higher-dimensional space, and interactions (including virtual particle exchanges) might be influenced by the geometry of these hidden dimensions.

What Is a Vector Field?

A magnetic field is a vector field, which means it has both a magnitude (strength) and a direction at every point in space. You can imagine it like a field of tiny arrows spread throughout the space around a magnet, each arrow showing which way a magnetic force would push or pull on a charged particle or another magnet at that point.

Why Do Magnetic Fields Always Form Loops?

Unlike electric charges, which can exist alone as positive or negative, magnetic poles always come in pairs: north and south. This is because magnetic fields are generated by moving charges or intrinsic particle spins, and the field lines they create never start or end—they always form continuous loops. This looping nature is a fundamental property of how electromagnetism works in our universe.

How Does This Build Everything We Use?

Because magnetic fields arise from the fundamental properties of particles and their interactions, they underpin countless technologies:

– Electric motors and generators convert electrical energy into mechanical motion (and vice versa) by manipulating magnetic fields created by moving charges.

– Transformers use changing magnetic fields to efficiently transfer electrical energy across distances.

– Magnetic storage devices encode data by controlling the tiny magnetic moments of atoms.

– MRI machines use strong magnetic fields to interact with the spins of atoms in our bodies, creating detailed images.

– Navigation relies on Earth’s magnetic field, itself generated by moving molten iron in its core, a massive natural electromagnet.

Can We Cancel, Redirect, or Reverse Magnetic Fields?

Because magnetic fields are physical manifestations of moving charges and intrinsic particle properties, we can manipulate them by:

– Creating opposing fields that cancel each other out locally (magnetic shielding).

– Using materials like iron to guide and concentrate magnetic field lines (redirecting fields).

– Changing the direction of electric currents or flipping atomic spins to reverse the magnetic field.

These manipulations are possible because magnetic fields are expressions of the underlying electromagnetic force, which is fundamental to the structure and behavior of matter itself.

Summary

Magnetic fields are not just invisible forces; they are the natural expression of one of the universe’s fundamental forces—electromagnetism—arising from the motion and intrinsic properties of charged particles. Through the exchange of photons and the quantum nature of particles like electrons, magnetic fields exist as real, measurable phenomena that shape the behavior of matter and energy. Understanding what magnetic fields truly are helps us harness them to build the technologies that power and improve our world.

Glossary of Terms:

– Electric charge: A property of particles like electrons that causes them to experience electric and magnetic forces.
– Electromagnetism: The combined study of electricity and magnetism and how they interact.
– Field lines: Imaginary lines used to visualize the direction and strength of a magnetic field.
– Magnetic flux: The amount of magnetic field passing through an area.
– Magnetic shielding: Using materials to block or redirect magnetic fields to protect devices.
– Electromagnet: A magnet created by electric current flowing through a wire.
– Magnetization: The process of aligning magnetic regions inside a material to create a magnetic field.

 

Read More

^{[1] https://en.wikipedia.org/wiki/Virtual_particle
[2] https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/
[3] https://www.reddit.com/r/AskPhysics/comments/1136b08/if_virtual_photons_dont_exist_whats_actually/
[4] https://physics.stackexchange.com/questions/185110/do-virtual-particles-actually-physically-exist
[5] https://en.wikipedia.org/wiki/Virtual_photon
[6] https://www.youtube.com/watch?v=NkDaQdeoHsk
[7] https://www.vice.com/en/article/ok-wtf-are-virtual-particles-and-do-they-actually-exist/
[8] https://www.forbes.com/sites/startswithabang/2021/05/07/ask-ethan-do-virtual-particles-really-exist/}