Chap. 1: What is Light?
Infrared Light Therapy for Recovery, Fitness, Skin Care, and Total-Body Wellness is available on KindleUnlimited at https://amzn.to/3YkaDzj.
What is Light?
Light is all around us and is an integral part of nearly every aspect of our lives. Among other things, it allows us to see, gives objects their colors, warms our bodies, and causes plants to grow. Sunlight is considered a requirement for both physical and emotional well-being. Electric light allows us to continue working and playing even after the sun has gone down.
While light itself is ubiquitous, an understanding of what makes up light and how it functions are not as common—at least outside of science and academia. Fortunately, the fundamentals of light can be explained without opening a single quantum physics textbook.
First, let’s understand what light really is. Light is a type of electromagnetic energy, just like gamma rays, x-rays, microwaves, and radio signals. All of these types of energy are parts of the electromagnetic spectrum, which is a system of organizing these energy types for the purposes of study and discussion.
Each type of energy travels in waves, which have troughs (lowest points) and peaks (highest points) just like waves on the ocean. What makes each type of energy different is the amount of time between the lowest to highest point. This amount of time is called wavelength.
Wavelengths
Energy that goes from trough to crest the fastest known is called short wavelength energy and those that go from lowest to highest point more slowly are called long wavelength energy. To even more precisely categorize these types of energy, scientists have assigned a unit of measure, called the nanometer(nm) to the wavelengths.
Models of the electromagnetic spectrum arrange the various types of energy left to right, starting with the shortest wavelength:
- At the shortest wavelength end the light spectrum is ultraviolet light, which has wavelengths from 10nm-379nm.
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At the longest wavelength end is infrared light, which has wavelengths from 700nm-3000nm. It is further broken down into:
- near infrared light, which is the wavelengths between 700nm-999nm)
- far infrared light, which is the wavelengths between 1000nm and 3000nm)
- In the center, with wavelengths from 380-699nm is the visible light or white light spectrum. We can see these wavelengths and not others because the wavelengths comprising the visible spectrum stimulate the retina in the eye, turning the photons into nerve impulses in our brains.
The visible light spectrum is further broken by the wavelengths that we see as different colors, ranging from violet to red. We can see this separation in nature, when the sun shines through raindrops and creates a rainbow.
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