A photon is an elementary particle that serves as the quantum of light and all other forms of electromagnetic radiation. It is the smallest possible “packet” of energy. Here are the key details about photons:
Massless and Chargeless: Photons have no mass and no electric charge.
Speed of Light: Because they are massless, they always travel at the speed of light in a vacuum (c ≈ 3 × 10⁸ meters per second).
Wave-Particle Duality: Photons exhibit characteristics of both particles and waves, meaning they can behave like a discrete particle while also traveling in a wave-like manner (where electric and magnetic fields oscillate).
Force Carrier: Photons act as the gauge boson (force carrier) for the electromagnetic force.
Energy Generation: Photons are generated when charged particles are accelerated or when electrons change energy states within an atom.
Entire Spectrum: They make up the entire electromagnetic spectrum, including radio waves, X-rays, gamma rays, and visible light.
The concept was theorized by Albert Einstein and Max Planck in the early 20th century.
If you are interested, I can also explain how photons are used in technology or how they interact with electrons. What is a photon? – Symmetry Magazine