This is an answer I gave on Quora.
This is a good question because it is a foundational question in physics. I like to read the answers coming from physicists to see what they have to say about this question. The best answer coming from physicists should start with the statement we don’t know what a particle is. I looked up similar questions concerning particles on Quora. Surprisingly not a whole lot of physicists attempted to answer this question.
Vinay Agarwala, Nuclear engineer who loves theoretical physics.
“The word “particle”, as used in physics, has been very confusing.”
Ali Abdulla, Nuclear physics and Quantum Mechanics professor
“If you have any idea about the known subatomic particles, such as leptons, hadrons(baryons and mesons),and quarks, you should know what is a particle in physics.Just imagine the electron, it is physical entity with measured mass, certain size, intrinsic spin(spinning around its internal axes),it can interact with other particles, all these properties define what is a particle in physical sense.”
This answer really does not say what a particle is other than claiming to define particles as having something to do with the way they interact with each other.
Some physicists try and use a mathematical definition. This is not good unless it is accompanied with a correct physical interpretation.
If you have 10 different physicists answer this question you will most likely get 10 different answers. This is especially true if they use the Quantum Physics paradigm.
Only a person that has solved the Unified Field Theory can answer this question successfully. Since my book has the Unified Field Theory solution in it I can give you a real world physical definition of what a particle is.
Super Relativity Definition of a Particle
The particle according to the Theory of Super Relativity is typically a small field that has a specific dimension and structure that is defined by using several descriptive properties
1. wavelength description.
2. spin property
3. motion property - typically done using a particular momentum type. The type of momentum will tell you whether the particle is mass like or energy like.
4. Mass property - Accelerated motion of a fundamental unbalanced charge gives a particle mass
5. Energy property - Linear, straight line, moving non-accelerated motion of a fundamental particle generates no mass.
6. Charge property - Electrostatic field that gives the particle structure and autonomous velocity within space.
7. Electromagnetic Property. All particles have a charge component structure. This charge structure causes particle motion. Whenever a charge moves a magnetic field emerges alongside the charge field. Both the the electrostatic charge and magnetic field manifest as transverse waves. Transverse waves primarily exist in solids so the fact that particles are composed of transverse waves proves that space (the Aether) is a quasi-elastic solid.
Now for the fun part. All of the above properties give a clue to what a particle is. In order to know what a particle physically is I constructed a particle model that explains the physical meaning of these properties.
The Metaphysical Explanation of what a particle is
There is only one thing that physically exists. Everything is made from this one thing. Space or the aether is the only real thing that exists. Everything else that we can detect using our physical senses is made from this primary fundamental medium. Electromagnetism and gravity emerge as aspects of a single fundamental field. That fundamental field is the aether.
The Particle Properties of Mass, Gravity and Inertia explained.
All particles are composed of an electromagnetic field. The reason some particles have mass is because the way those particles move. Any particle that has mass moves in an accelerated manner. Whenever a particle accelerates a contraction of space happens in and around the particle. The act of contraction is what we call inertia. When a particle continuously accelerates like quarks and electrons do, the result of this continuous acceleration is the manifestation of mass. Particles that have mass, have that mass because those particles are causing a contraction of space in and around the particles as they accelerate and that causes the particle to emit a gravitational field.
Wavelength and Spin explained
Wavelength of a particle is determined by the physical length of the electrostatic component of a particle. The electron has a length because the electrostatic static component (its charge) is composed of a physical twist in the spatial medium. This inversion of space also explains why the particle has spin. Since the medium of the aether is a quasi-elastic solid the charge component of a particle exists in a persistent form. Only persistent stable particles should be classified as particles.
Motion Property explained
All particles are composed of charge. The electrostatic charge is a twist of space. The twisting of space causes a pressure, density and tension gradient to form inside the particle structure. The pressure gradient inside the particle causes all particles to have a velocity. This particle characteristic I call the SlipWave and it is described in detail in my book. The particle velocity is determined by permittivity and permeability of space and the type of motion the particle has.
The Mass Property explained
Photons move at the highest velocity because they move in a straight line and constant velocity. This means they do not generate mass according to my theory.
All other particles have a certain amount of accelerated motion so they move at speeds slower than the speed of light. All other particle generate their own mass because they are in a constant state of orbital acceleration.
The Energy Property explained
Particles that move fast and have little or no mass are classified in the theory of Super Relativity as energetic particles. The faster the particle moves and the less mass it has the more energetic the particle. Photons are classified as the most energetic type of energy particle.
The Charge Property explained
Charge is the twisting deformation of physical space. It is a persistent field of force that moves within a stationary aether medium. It can best be described as moving ripple or configuration field that exists inside the aether medium. When a particle that is made of charge moves within the aether the medium does not move, what actually moves is the charge configuration. So a charge is a field of force that is in motion because of its physical structure.
The Electromagnetic Property described
All charges that move generate a corresponding magnetic field as the result of the charge’s motion. The magnetic field happens as a result of a torsional reaction of the space in and around the charge as it moves. In other words space rotates as the charge passes by. That rotation of space is the magnetic field.
In each case above I described the physical nature of particles. Particles exist as real physical structure in motion and are consubstantial with the medium they reside within. Both Gravity and electromagnetism result as a result of charges moving within space.
A Unified Field Theory is a model that describes Electromagnetism and gravity emerge to be related aspects of a single fundamental field.
So particles are nothing more than physical deformations (fields which are different types of spatial bending) that are in motion. Particles have a real physical size and structure and move at a rate of speed that is determined by the way they physically interact with the space they reside within. The maximum rate of speed is determined by the permittivity and permeability of space.
For more information concerning the definitions of force, energy, matter and particles please see my website. Super Relativity - The Unified Field Theory