The Beef with Isaac Newton: What Exactly Is Light Made Of?

 

One of the greatest scientific beefs in history took place in the 17th century. The cause? A deceptively simple question: what exactly is light made of? The very thing that lets us see the world around us became the center of a fierce debate - one that would eventually reshape our understanding of physics itself. 

Everyone is most certainly familiar with the father of physics, Isaac Newton, the apple guy, arguably one of the most influential scientists to have ever lived. But long before he became the scientific giant we know today, he was a relatively unknown scholar whose ideas about light would spark one of the greatest scientific beefs in history.

At the time, however, Newton wasn't the biggest name in science. That title belonged to Christiaan Huygens. In the mid-17th century, Huygens was the undisputed king of European science. Born into the wealthy Dutch aristocracy, he was intelligent, well-connected, and highly respected throughout the scientific world. By then, he had already discovered Saturn's largest moon, Titan, and invented the pendulum clock. Simply put, Huygens was the scientist to beat. Then came 1672, and a relatively unknown Englishman named Isaac Newton decided to crash the party.

The Particle Panic

Newton sent a paper to the Royal Society of London that turned everything upside down. Using glass prisms, he proved white light was actually a mixture of colors. But then he went a step further, declaring light was made of "corpuscles"—tiny, bullet-like particles traveling at mind-boggling speeds.

The logic seemed airtight, but across the English Channel, Huygens was thoroughly unimpressed. He fired off a critique with a simple, devastating question: 

If light is made of physical particles, when two people look into each other's eyes, why don't those tiny light bullets collide in mid-air and smash into each other, blurring their vision?

Since the world wasn't a constant demolition derby of crashing light particles, Huygens offered his Wave Theory of Light. Inspired by ripples on a pond, he argued that light traveled as expanding waves through an invisible substance called the "ether." It was Team Particle versus Team Wave.

Egos and Echoes

To say Isaac Newton did not handle criticism well would be the understatement of the century. He absolutely loathed it. Newton treated any challenge to his theories as a calculated, deeply personal attack on his character. Huygens' public skepticism sent Newton into a predictable spiral of rage and paranoia. He began firing back furious, defensive letters to the Royal Society, essentially trying to intellectually bully Huygens into submission. Huygens, maintaining his cool aristocratic demeanor, found Newton’s outbursts ungentlemanly and a bit dramatic.

Ultimately, Newton won the historical popularity contest; after publishing his world-altering laws of gravity, his reputation across Europe became practically god-like and entirely untouchable. If Newton said light was a particle, the world accepted it as gospel. For over a century, Huygens’ wave theory was buried and ignored.

The Cosmic Plot Twist

But science always corrects its mistakes. In 1801, Thomas Young shone light through two tiny slits and got an interference pattern—the exact behavior of overlapping water waves. Huygens was vindicated! Light did bend around corners; it was just on a scale too small for Newton to see.

Then came the ultimate plot twist: in 1905, Albert Einstein proved that light also acts like packets of particles (photons).

So, who won? Quantum mechanics finally forced a truce through wave-particle duality. Light is a cosmic shapeshifter: it travels through space as a wave (Team Huygens), but interacts with matter as a particle (Team Newton). The country rebel and the European king were both looking at the exact same truth—each just held a different piece of the puzzle.