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Understanding The Electromagnetic Spectrum

Rhys Hanak - March 28, 2018

Visible light has played an integral role in the evolution of human life on Earth. Through it, humans have been able to achieve a better understanding of the world—and more broadly, the Universe itself.

In this article, we’ll explore not only how visible light works, but also how it has shaped the course of human evolution.

What Is The Electromagnetic Spectrum?

When atoms (or molecules) drop from a higher state of energy into a lower one, they emit what’s called electromagnetic radiation.

As a form of energy that travels through space, electromagnetic radiation comes in a variety of different wavelength frequencies. To provide some semblance of order, the scientific community has organized these frequencies into a range, called the electromagnetic (EM) spectrum.

the electromagnetic spectrum

Source: Columbia University

This spectrum consists of radio waves, microwaves, infrared waves, UV rays, X-rays, gamma rays, and last but not least—visible light, the narrow section of the EM spectrum that makes up the colors we see.

Perhaps NASA describes it best when explaining the biological interaction between the human eye and the electromagnetic spectrum.


“Cone-shaped cells in our eyes act as receivers tuned to [visible light] wavelengths […] Other portions of the [electromagnetic] spectrum have wavelengths too large or too small and energetic for the biological limitations of our perception.”

But why did humans evolve to see visible light instead of other electromagnetic waves?

Why We See Visible Light

Considering that our eyes took hundreds of millions of years to evolve to see visible light, there are some pretty good reasons as to why.

First, visible light is the only type of electromagnetic radiation that propagates well in water. Seeing as how many of Earth’s early organisms lived in water environments, it would only make sense for these organisms to develop a means of better navigating their surroundings.

evolution of the human eye

The first eyes are expected to have evolved over 550 million years ago in water environments.

Even as these organisms moved to land, visible light still proved to be the most useful part of the electromagnetic spectrum to see—radio waves would make it difficult to resolve small objects, X-rays tend to like to pass through matter, and UV rays can damage both our skin and our eyes.

Simply put, the evolution of our eyes can be explained by the survival strategies of Earth’s earliest life forms.

Blade Optics And The Electromagnetic Spectrum

Many of our Blade Optics lens designs—including those found in our proof-of-concept telescope and our DoubleTake product—have been designed to perform well in both visible light and the infrared. This infrared imaging capability presents a number of opportunities for low-light imaging, active night vision, and broad spectrum imaging.

That said, our proof-of-concept and DoubleTake device come equipped with silicon sensors. These sensors are designed to work well in visible light—not infrared. In short, while many of our lens designs offer the potential for exceptional infrared imaging performance, they would require the appropriate sensors to do so.

Innovations In Light-gathering Technology

Behind everything—behind our novel lens designs and our artificial intelligence—is a passion for light. It’s what brought our company together, and what continues to guide us to this day. By creating innovative light-gathering technologies like Blade Optics, we believe that we can enable more engaging experiences with the visible world.

Rhys Hanak

When I’m not sharing NexOptic’s story with the world, you can find me in the mountains hiking or out on a run.