In a lively Royal Institution talk, Dr. Gideon Koekoek asks a deceptively simple question: could a universe exist without light? He argues no, building a clear, hands-on case that light is not just illumination, it is the mechanism that lets reality keep its rules. Using sparking Van de Graaff generators, a compass that twitches when a current flows, and a wobbling magnet that lights a bulb, he revisits the 19th-century path from electricity and magnetism to Maxwell’s equations. He then derives a universal speed limit from everyday “shared numbers,” shows how nature’s love of symmetry clashes with that limit, and explains why information must travel via special particles called gauge bosons. Add a sprinkle of quantum mechanics, where particle “waves” can be rotated, and photons appear as the messengers that enforce symmetry without breaking causality. Light, in short, is the universe’s referee.

Why light must exist, not just illuminate

Dr. Gideon Koekoek opens by reframing light as more than what lets us see. The cosmos is flooded with radiation, including the ancient glow of the cosmic microwave background, but his question is deeper: could a universe exist without any light at all? He contends it could not. Light does not only make observation possible, it ensures that the laws of physics can meaningfully coexist. Two big rules sit in tension throughout his talk: there is a universal speed limit, and nature seeks symmetry. Light is what reconciles the two.

“It makes sure that reality can exist at all.” — Dr. Gideon Koekoek

What light is: electricity, magnetism, and Maxwell’s leap

The talk retraces how 19th-century experiments revealed that electricity and magnetism are two sides of the same coin. With a Van de Graaff generator, Koekoek shows charge building and sparking between metal spheres, a vivid picture of electric fields. With a simple wire and battery, he recreates Ørsted’s landmark result: a nearby compass swings only when current flows, meaning moving charge creates a magnetic field. Reversing the logic, he wobble-drives a magnet so that it induces a current and lights a bulb. The message is simple: moving electricity makes magnetism, moving magnetism makes electricity.

James Clerk Maxwell turned these scattered findings into four coupled equations. When you let electric and magnetic fields “wobble” each other in the math, a self-propagating wave emerges that moves through space at a specific speed. That speed matches the independently measured speed of light, so light must be a traveling electromagnetic disturbance.

“We can scarcely avoid the inference that light consists in the transverse undulations of the same medium which is the cause of electromagnetic phenomena.” — James Clerk Maxwell

A universal speed limit, derived without electromagnetism

Koekoek then asks whether you can derive a speed limit without mentioning light. He uses an everyday “shared number” rule: when two systems each reach equilibrium with a third, they share a common value. A balloon that stops changing size must have matched inside and outside pressure. Two ring thermometers that both settle on a person’s finger settle to the same temperature. Extend that logic to motion, and you get a key insight: different observers, moving relative to one another, must still agree on a special speed. That shared speed cannot be surpassed, because if someone could run alongside it, one observer would measure zero relative speed while another would measure a nonzero value, breaking the shared-number rule. Hence, a universal, highest speed follows from relational reasoning, not from electromagnetism.

“Apparently there exists a velocity in nature that is the highest and is shared with everybody.” — Dr. Gideon Koekoek

Symmetry meets causality: why messengers are required

Now the tension. Nature “loves” symmetries, like the idea that swapping elements in a pattern leaves the overall result unchanged. Koekoek demonstrates with color wheels that different local arrangements can blur to the same global appearance. But making a symmetry change here, then instantly demanding the same change there, would require influence to travel in zero time. That would violate the universal speed limit. The compromise is profound: information about the change must propagate at or below the limit. In particle-physics language, whenever a symmetry needs to be enforced across space, there must be messenger particles to carry the update.

This logic underpins the modern idea of gauge bosons. Strong-interaction symmetries inside protons require gluons to transmit changes among quarks. Nuclear isospin symmetry between protons and neutrons historically led to meson exchanges to communicate changes between nucleons. The pattern is clear: symmetry, plus a finite speed for influence, demands mediators.

“Every time that you have a symmetry… something must have traveled to inform the other side of the universe that it happens.” — Dr. Gideon Koekoek

Quantum phase symmetry: the final step to photons

We are still missing light in this symmetry catalog. The last ingredient is a “sprinkle” of quantum mechanics. In quantum theory, particles are described by waves with an amplitude and a spread. Crucially, these waves can be rotated in phase without changing a particle’s mass or position. That freedom to rotate is itself a symmetry. But by the earlier logic, you cannot rotate a wave here and have a distant wave instantly know about it. The information must be carried across space by a field. When you impose that requirement mathematically, the field that appears must obey a specific set of equations. Those equations are exactly Maxwell’s equations.

In other words, the photon is the gauge boson that enforces local quantum phase symmetry globally, while respecting the speed limit. Turn quantum phase rotations from a global freedom into a local one that can vary point by point, and you must introduce a field to keep the physics consistent. That field is the electromagnetic field, and its quanta are photons.

“Light is nature’s way of being symmetric and making sure that the symmetry gets to support all of the universe without ever breaking the speed limit.” — Dr. Gideon Koekoek

Bringing it together: light as the universe’s referee

Koekoek’s demonstrations and reasoning converge on a single picture. The universe follows two deep imperatives. First, there is a highest speed, so no influence can act instantaneously. Second, nature seeks symmetry, preferring descriptions that can be rearranged without changing observable outcomes. The price of having both is the existence of messenger fields. Historically, electricity and magnetism were separate curiosities. Maxwell showed that their interplay creates waves that move at a universal speed, so they are light. Modern quantum theory deepens this, showing that the very freedom to rotate the phase of a particle’s wavefunction locally requires the electromagnetic field to restore consistency everywhere else. The photon is not an optional decoration, it is the enforcer that carries symmetry information through space in a way that causality permits.

The cosmic bonus is practical. Because light must exist, we get a universe that is visible and measurable. Photons deliver the news of distant events in a consistent, speed-limited way, from the faint microwaves of the early cosmos to the beams that let us see each other across a room. In Koekoek’s framing, reality is readable because it is rule-bound, and those rules require light.