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On the Basis of Light

Light is an amazing thing. It’s everywhere, even when it’s dark, and gives us the ability to see and interact with our world around us. Without it you wouldn’t be able to know where to reach to pick up your cup of coffee, let alone know that you even have a cup of coffee (or be able to read this). With light controlling so much of how we interact with everything, it’s easy to not think about it. Looking at things is almost as easy as breathing in most cases. But what if I told you that we can understand light? That it doesn’t just show you something is there, but also tells you where that something is? What if I told you that we know how your eyes interact with light, and that we can manipulate it in small ways to make major changes in how you interact with your world? 

In order to understand how we perceive light, we need to understand light and how it behaves on its own. There are several different “types” of light- with those “types” being wavelengths. Our eyes only work within a very specific range of wavelengths and completely ignore the remaining ones- this just means that most other wavelengths don’t naturally exist on earth, not that our eyes are lazy. Gamma rays (the stuff that turned Bruce Banner into the Hulk), X-rays (this accidentally discovered wavelength is what’s used to, you guessed it, take x-rays of your bones), Ultra-Violet (this is what causes sunburns), Visible, Infrared (humans [and the earth] naturally produce this wavelength), Microwaves (that instant oatmeal isn’t going to cook it’s self), and Radio (this also includes TV, making it one of the more entertaining wavelengths). While the sun does produce every single wavelength of light, the earth’s atmosphere blocks most of the light the sun sends our way. Luckily for us, gamma rays and x-rays only appear on earth when we decide to create them- if they made it past our atmosphere, we’d all be burnt to a crisp. What we do receive, however, is a whole lot of visible light. These wavelengths were appropriately named as they are what the healthy human eye can process without needing any assistance. Because of this, we are able to perceive colors, distance, size, temperature, emotions, speed, you get the point. Light from a source (this could be the sun, a lightbulb, a screen) is projected in every single direction possible to the first thing in it’s path, and will continue to bounce around until an object absorbs it.

How our eyes process all those different rays of light is not an easy feat, which plays a big part in why our eyes will feel fatigued along with the rest of our bodies at the end of an extremely long day. Sight is given credit to what you know as cones and rods, which are photoreceptors. Photoreceptor are located in your retina, along with nerves that translate the information the photoreceptors receive and send it off to your brain. Cones are the guys who help out with color, as there are three different types: blue, green, and red. The cones in your eyes require a very high amount of light to be fully functioning, but no worries if you’re in the dark- your rods require very low levels of light. Rods are the photoreceptors we use for night vision, since they work with minimal light. However, rods do not have anything to do with your color vision, which is why you see in greyscale at night or in dark areas.

Throughout the next several articles, we will be covering different topics to deepen your knowledge of light. Stay tuned on our Facebook to be one of the first to know when we post Seeing in Color, the next article in our Light series!