Monday, January 25, 2016

The Lighter Side

     Light. It is the head cheerleader, class president, valedictorian, and Academy Award winner of the Universe, and yet we don't even get to appreciate all of it. If you didn't pay attention in middle school science then you must not remember that light consists of photons. Those photons beam to us as waves. And those waves belong to a a club known as the "electromagnetic spectrum." The electromagnetic spectrum consists of radio, microwave, infrared, visible, ultraviolet, X, and gamma rays. Human eyes are only capable of seeing visible light, or the part of the spectrum that ranges from 400-700 nanometers.
     All the galaxies, stars, planets, your desk lamp, warm food, and even you give off other, non-visible forms of light. So why can't we see outside of visible light? Why are we "blind" to microwaves and ultraviolet? It's because of cones. Cone-shaped cells in our eyes are tuned to the wavelengths of the visible spectrum. Think about FM radio. Most world FM radios are tuned to pick up frequencies of 88 to 108 megahertz. Any hertz above and below and your radio can't pick it up, and you can't jam out. That's how cones work for our eyes.
     Just below visible red light you have infrared. Infrared is light in the form of heat radiation. Your body gives off heat, meaning you glow infrared. Non living things give off infrared as well. Any object that can heat up, gives off infrared, including the ground.
     Stars give off ultraviolet, or UV. UV is what turns you into a peeling lobster in the summer. It's also why tanning beds glow purple, and is the cause of 90 percent of all skin cancer cases, the most common kind of cancer. So what does Banana Boat mean on the back of the bottle when they say their product protects from "UVA and UVB" rays? Well UV rays can broken down into nine ranges, but the two that have the most effect on humans are UVA and UVB. UVC rays are completely absorbed by the ozone layer, while some UVB rays are still able to get through. The ozone layer has a very minimal effect on UVA rays, if at all. While UV light does contain some harmful qualities, it also has it's benefits. Ultraviolet radiation pushes along the production of vitamin D in the skin, which is essential. So while we definitely need to bathe our skin in sunlight, don't overdue it, especially when the UV index is high. Tan skin may be all the rage, but melanoma is not.
     A microwave oven cooks your food and it cooks it with light. The constant bombardment from the microwaves into your food cause molecules to vibrate, which heats them up, which heats your food, which cooks it.
     X rays and gamma rays are the toughest forms of light. X and gamma rays have the shortest wavelengths and the highest frequencies. X and gamma rays allow us to peer deeper into the cosmos and discover objects that we can't see with our own eyes, including black holes, gamma ray busts, neutron stars, solar flares, and galaxies.
     So why can we cook with microwaves, but not X-rays or ultraviolet rays? While you are radiating your food with a microwave, the wavelengths for microwaves are longer, meaning your food doesn't get hit with enough radiation to make it harmful, though I still wouldn't stand next to one while it cooked your Stouffers. The length of X and gamma rays are much much shorter, meaning your food would get hit with them more and more, causing more damage to your food, your gamma microwave, and you. Think of it this way: if you stepped in the cage with Ronda Rousey and she punched and kicked you every now and then, you'd (probably) be alright in the end, but conversely if you ended up being punched and kicked repeatedly by Ronda's furious fists, you'd likely be KO'ed less than 30 seconds into round one. Same concept applies here. This is why you have to wear special equipment when getting X-rays, and why radiographers can only give you so much at a time. Radiation therapy fits this as well.
     So I know it's 2016, but you still listen to the radio, right? It's commonly known that your favorite [insert "your number one station for all the hits!!" here] station broadcasts songs and annoying car dealership ads to your car through radio waves that come from radio towers, but did you know those aren't sound waves? Nope. It's light. You can hear sound waves, but if you stood next to that radio tower or next to your car antennae, would you hear any music? No. Be glad you can't see radio waves, as they would look pretty frightening
     So to sum it up: light is everywhere. Our Sun, distant galaxies, your smartphone, and you give it off. If you sit in a dark room, there will be no visible light, but switch your eyes to infrared and you'll appear as a human glow stick. Next time you listen to the radio, cook your food (with or without a microwave), connect to Wi-Fi, go outside, or do much of anything, remember there's always a light.

*Rochester Institute of Technology, Wikimedia, EPA, Creators

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