Take a moment to look around yourself. Now consider exactly what you’re surrounded by. Most people will come up with a list of various colorful items in their vicinity. Others might also note feeling the warmth of the sun beating down on them. Yet others may glance at the streaming media on their phone. These examples might not seem to have much in common at first. But in reality each of them comes about through invisible electromagnetic waves.
It’s often difficult to remember that we’re essentially swimming in a sea of electromagnetic waves. Our phone signal, heat and even ability to see color come from our relationship to electromagnetic waves. Our ability to perceive these waves varies on a case by case basis. Some areas of the electromagnetic spectrum are fully hidden from us unless we augment our senses with technology. We’re able to perceive other parts of the spectrum through our various biological senses. However, we’re not usually conscious of this process.
When we see color we don’t intellectually calculate values of the light spectrum. Instead this is all handled by our eyes and brain before we become conscious of a color. It’s only by learning about the seven most important types of electromagnetic waves that we can fully appreciate just how much value they add to our lives.
1. Visible Colors of Light
The visible colors of light can be considered both the most and least appreciated types of electromagnetic waves. On one hand we’re all continually amazed by a wide variety of different colors. Almost everyone loves the bright and vivid spectacle we see around ourselves on a daily basis.
We’re far less aware of the fact that we’re perceiving color through reflected light in the form of electromagnetic waves. The lower range of the visual light spectrum is seen as red. If we go a little beneath that we reach a non-visible color known as infrared. In the middle of the visible light spectrum is green. And at the very top of the visible spectrum of electromagnetic waves we can find violet. A little above that and we see another color invisible to the eye – ultraviolet. But between the extremes of infrared and ultraviolet we find wavelengths that deliver every color we’ve ever seen or will see in our lives.
Infrared is located just below red on the electromagnetic spectrum. Humans are only able to see into the infrared range through the use of specially designed cameras. When we do, it basically operates as a heat sensing device. If you’ve ever seen movies where living beings appear to be blobs of color then you already have a good idea of what it’d be like to see into the infrared range. Of course we need to translate that data into the color patterns we’re able to see in order to make use of the data.
Interestingly, snakes may be able to see into the infrared range through their own sensory apparatus. Some snakes possess a special structure called a pit organ. People often assume that the pit organ functions as a heat sensor in a similar way to what we experience when putting our hands near an open flame. However, the pit organ communicates with a snake’s visual system. This means that they truly do integrate infrared data into their vision.
Ultraviolet is the other invisible element of light. Or, rather, invisible to humans. As with infrared we can only see ultraviolet light with special cameras. We also see another shared element with infrared light. As with infrared there are animals which can see into the ultraviolet spectrum. In this case the honor primarily goes to insects. Insects are usually able to see color in a way that’s shifted slightly upward from human perception.
The vision of most insects cuts off at the lower end of what we consider visible light. In practical terms this means that insects are usually unable to see the color red. You might imagine that this would make it harder rather than easier to see the flowers so many insects use as food. But this is where their ability to see into the ultraviolet range comes into play. Insects use their ability to see ultraviolet light to help them navigate patterns on flowers. Though some insects, like the butterfly, are especially attuned to a wider range of color than others.
4. Radio Waves
Don’t be fooled by its name. There’s far more to radio waves than what you can pick up on a radio. Radio waves refer to the bottom of the electromagnetic spectrum. This means that a wide variety of natural and artificial objects emit radio waves. This even includes the sun and stars.
But for most people the radio wave’s claim to fame is their phone. Radio waves are used to transmit data between your phone and cell towers. This can highlight just how well radio waves travel. A cell tower can provide coverage for up to 45 miles. But that pales in comparison to what the signals can achieve outside of the interference on earth. In fact, rovers on Mars are able to use radio waves to communicate with orbital satellites.
Think back to the impressive range of radio waves. Even with all the interference we find on earth a radio wave can travel for miles without much degradation. Microwaves can travel only a minuscule distance in comparison. We usually only see microwaves cover a few centimeters to a foot away from their point of origin.
It might seem like microwaves are severely limited. But what they lack in traveling power they make up for in penetrative capacity. Microwaves are able to move through obstacles which would block or degrade radio signals. For example, microwaves are unperturbed by smoke or clouds.
Of course we’re most familiar with microwaves due to the device of the same name. As you might have guessed, a microwave oven heats food by using microwaves. This also highlights just how well microwaves are able to move through obstructions. A microwave oven heats food by exciting molecules in food. These waves can often penetrate quite far into frozen food.
Microwaves might not be able to fully penetrate an object placed into a microwave oven. But in those cases heat from the food’s outer layer will heat up its inner layer. This is also why some foods have longer cooking times in a microwave oven. It takes more time to heat matter through conduction rather than direct stimulation. In these cases microwaves heat the outer layer of your food. And this outer layer slowly heats up the inner layer.
X-rays are found on the upper end of the electromagnetic spectrum. They’re emitted by the core of the sun, black holes and some similar astronomical phenomena.
Of course today we’re mostly familiar with x-rays through procedures which borrow the name. X-ray machines, as the name suggests, generate and output x-rays. These x-rays travel through someone’s body and will then register within an x-ray receiver. This generates images based on the density of material the x-rays passed through.
7. Gamma Rays
Gamma rays might sound like something out of the latest superhero movie. But gamma rays are very much science fact rather than science fiction. As with x-rays we see them occur within stars and black holes. But we also see gamma rays occur right here on earth during lightning storms.
Gamma rays might not be science fiction but they’re certainly strange. They’re so far up on the electromagnetic spectrum that they can even pass through the empty space of an atom. This would cause a severe risk if gamma rays were more common on earth. Thankfully our planet’s atmosphere blocks most gamma rays from outer space.
A Huge World Filled With Invisible Wonders
These seven items highlight just how immense the unseen world around us really is. We’re only able to directly perceive a small subset of the larger electromagnetic spectrum. But we nonetheless live in a world where they all directly impact our lives in one way or another. From the convenience of microwave food to the bees using ultraviolet light to help them pollinate flowers. All of these items in the electromagnetic spectrum highlight how amazing and intertwined the various complexities of life really are.