Without light, the very atoms of your body would dissolve
In short: We often think of light as something we see, but it is actually the glue of reality. Beyond illumination, light serves as the universe's primary currency for energy exchange and the fundamental force that prevents matter from flying apart.
To understand why light exists, one must look past its role in vision to its role in physics. Light is an electromagnetic wave, a fact established by James Clerk Maxwell roughly 50 years before the advent of quantum mechanics. Because the speed of light is determined by the innate properties of empty space—specifically the permittivity and permeability of free space—it became the cornerstone for Albert Einstein’s Theory of Relativity. Simultaneously, the study of light led to the discovery that it behaves as a quantum object. While it has wave-like characteristics, it also exists in discrete packets called photons, which are essentially waves of probability.
The existence of light is tied to the electromagnetic force, which governs how we experience the physical world. In the 1940s, Richard Feynman and others developed Quantum Electrodynamics, revealing that photons mediate this force. This means that your sense of touch is actually a series of electromagnetic interactions between the electrons in your skin and the surface you touch. On a deeper level, light is what holds atoms together; it is the interaction between positively charged nuclei and negatively charged electrons that creates matter. Without these interactions, atoms would not exist, meaning there would be no houses, cars, or people.
If we were to remove the electromagnetic force from the universe, gravity, the strong force, and the weak force would remain. In such a reality, nuclear decay and the formation of nuclei would still occur. Because there would be no electrostatic repulsion between protons, very large nuclei could potentially form. However, the universe would be unrecognizable. Light remains the essential medium for almost every process involving energy exchange, from chemical reactions and thermal radiation to friction and nuclear processes.
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Sources
- Summary by Intellect · source: Why Does Light Exist? What is Its Purpose?
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