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9 Interesting Facts About Infrared Rays (2024 Update)

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Beautiful sunset picture

Infrared Radiation (IR) is sometimes referred to as Infrared Light/Rays. It’s a form of energy that’s radiant in nature and invisible to the human eye. However, being invisible doesn’t mean that we cannot feel it. Also, we believe all existing objects in our universe emit this energy. Including ice, fire, and the sun.

The first person to discover IR was William Herschel. At the time, he was an astronomer who was working on an experiment meant to determine the variation in temperature between the colors within a visible spectrum. Initially, he thought the colors ended at red.

But as he measured the temperature from blue to red, he noticed the units kept on increasing beyond red. And that could only mean one thing—those warmer temperatures were an indication that there’s a world completely hidden from the human eye.

That discovery led to countless other discoveries and is the reason why we’re here today. So read on if you’d like to learn some fascinating facts about infrared rays.

The 9 Fascinating Facts About Infrared Rays (IR)

1. The Sun Is a Major Source of IR Light

woman in a sunset
Image Credit: Gulcinglr, Pixabay

Light usually travels from an object through space and to our eyes. That’s how we’re able to see the light being emitted by the sun. What you might not know is that light travels in the form of waves. And there are short, medium, and long waves. Some of those waves are visible to us because they have color, but some aren’t. Therefore, we’ve devised special equipment to help us see them.

Infrared light is a fine example of waves that we cannot see, and that’s why we have IR cameras—cameras specifically designed to give our eyes the capability to see those waves. If the image we see glows too much, that would mean that that object is hot. But if it’s dull, it’s an indication that the object is relatively cooler. 

2. Not All of The Sun’s IR Rays Reaches the Earth’s Surface

We’ve estimated that 90% of the vapor found in our atmosphere originates from our water bodies. The remaining 10% is the result of transpiration. That’s a process whereby the plant absorbs water from the soil, uses it for growth and metabolic purposes, and then releases it to the atmosphere via its aerial parts. Namely flowers, stems, and leaves.

The point is, most of the IR radiation from that star usually gets absorbed by that cloud of vapor. And that’s definitely a good thing considering numerous medical studies have revealed that prolonged IR exposure has the potential to cause damage to our retina, cornea, and even eye lens. In other words, if you don’t take the necessary precautions, you could find yourself grappling with retinal burns, corneal ulcers, and cataracts.

3. Humans Emit Infrared Rays

woman in a sunflower field
Image Credit: JillWellington, Pixabay

Celestial bodies like the sun are not the only objects that are capable of emitting infrared radiation or light. While the amount of electromagnetic radiation being emitted varies, scientists have discovered every object in the universe emits some form of radiation.

The radiation wavelength also varies, as this is contingent on their core temperature. To bring the element of temperature into the equation, you’ll find experts referring to that sort of radiation as thermal radiation. 

Humans are no exception, as the radiation we normally emit lies within the infrared zone. Our radiation wavelengths are at 12-micron points.

4. Shiny Materials Are Incredible IR Reflectors

Even if you cannot see IR rays, you can still reflect them. And seeing as they are essentially light, they can be reflected the same way normal light gets reflected. Materials such as aluminum are excellent reflectors, and the reason why IR-proof products are made out of them.

Haven’t you ever wondered why hazmat protective suits—especially those meant to protect scientists working in a nuclear laboratory—are made of aluminum and plexiglass? It’s because they are supposed to shield whoever’s wearing them against the consequences of exposure to certain types of radiation. So, they are also applicable to any situation that requires IR-proof clothing.

5. IR Radiation Speed Is 299,792,458 m/s

Sombrero Galaxy in infrared light hubble space telescope and spitzer space
Image Credit: Picryl

There’s a rumor circulating about infrared radiation being able to travel faster than visible light. Well, we’re here to dispel all of that, by assuring you that it’s all false. All forms of light travel at the same speed, which is 299,792,458 m/s. Having a longer wavelength does not translate to faster or slower speeds.

And while we’re still on this topic of wavelengths, you should know that IR waves are shorter than radio waves but comparatively longer than those found in visible light. The infrared range starts at 700 nanometers (nm) and moves all the way to 1 millimeter (mm).

6. Infrared Is Visible to Snakes

Nature is incredible. Just when you think you’ve seen it all, it introduces you to something different to marvel at. Take the snake, for example. Did you know these creatures (particularly those belonging to the viper family) have protein channels in their systems that can only be activated by the heat emanating from their prey’s bodies?

Other species, such as the boas and pythons, are known to have something called the pit organ, for that exact purpose. And those organs are so effective that they can sense prey from a meter away, in a pitch-black environment.

7. Infrared Is Used in Cancer Treatment

Infrared lasers target tumor cells
Image Credit: Meletios Verras, Shutterstock

So, we’ve already established that even though you can’t see the rays, you can still feel them. Researchers saw this as an opportunity to study them further, with the intention of learning how they can contribute to the betterment of human lives. In the process, they discovered that various cancerous cells can be weakened, and even killed, if the far infrared heat gets raised to 107.6 degrees F.

This type of treatment is called Infrared Hyperthermia, and it’s very common in countries such as Germany and Japan. Because it’s still a fairly new discovery, most countries haven’t embraced it yet. But we recently heard that the US government in collaboration with its National Cancer Institute has organized a group of experts to look into it.

8. Infrared Can Help You Lose Weight

A New York university conducted clinical research and found out that you can actually burn a considerable amount of calories if you visit an infrared sauna three to four times a week, for a 30-minute session. In a 4-month period, all the participants shaved off an average of 4% body fat, without changing their dieting patterns or exercise regime.

And just to be sure that the infrared therapy was the actual reason why they dropped weight, the researchers sought the assistance of a control group. Guess what? Not even a single one registered a significant loss. 

9. The First Electric Oven Was an Infrared Oven

Vintage electric oven
Image By: Charlotte May, Pexels

The history of the oven is a long one. But just to give you a quick rundown, the first ovens relied on wood as fuel. We then moved on to the iron stoves before inventing coal and kerosene-fueled ovens. The gas oven came a few decades later before we finally settled on the electric appliance. This was around the 1890s.

The heat that they produced was far-infrared, generated by a burner that was electrically charged to excite molecules. They were eventually phased out and replaced by the microwave because the hot air dried up people’s food.

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Wrapping up

Infrared radiation has always been part and parcel of our lives. We just didn’t always know it existed, and when we did, we still needed time to figure out how to leverage it. But now we do, and that’s why we’re able to do things that were once thought impossible.

Featured Image Credit: Bruno Scramgnon, Pexels

About the Author Robert Sparks

Robert’s obsession with all things optical started early in life, when his optician father would bring home prototypes for Robert to play with. Nowadays, Robert is dedicated to helping others find the right optics for their needs. His hobbies include astronomy, astrophysics, and model building. Originally from Newark, NJ, he resides in Santa Fe, New Mexico, where the nighttime skies are filled with glittering stars.