Invisible yet Impactful: UV Light.

Who doesn’t love the beach? You can spend an entire day with friends and family playing in the water and building sand castles. The beach is one of the best ways to relax and have fun, making it one of the most desirable places to go during summer. However, a good beach day can result in something that can ruin the rest of your week: a sunburn. 

Now what even is a sunburn and why does your skin get red because of it? Well, as we all know, the sun emits light, but what some of us don’t know is that it emits many different wavelengths of light, and one of these wavelengths is called ultraviolet or UV. UV lightwaves are between 100-400 nm long making them invisible to human eyes. Even though we cannot see them, they can go into our skin and wreak havoc. When UVB lightwaves (UV rays between 280-315 nm) enter our skin, their photons (packets of energy) interact with the skin’s DNA and make them “excited” by giving them energy. This causes DNA to link up incorrectly during DNA replication, creating “bad” cells. When there are too many “bad” cells, they cannot all be fixed, so the immune system must come in and fix the problem. Since our immune systems are so powerful, they are able to clear out all of the “bad cells”, so good ones can take over again. However, in order for the immune system to do its job, immune cells and extra fluid must go into the space between skin cells and its other structures. This fluid is the reason why your skin becomes red and tender. However, after a few days, the immune cells can do their job and then leave your skin, making it healthier than it was before. 

But why do some of my friends tan and I get burnt? Our skin has natural defense against the sun called melanin: a group of dark pigments that color your cell’s nuclei. Melanin blocks radiation from UV rays, and by doing so prevents you from getting sunburnt. Some people are naturally born with more melanin than others which also makes their skin a darker shade. However, just because you are born with less melanin does not mean that you cannot build it up. UV radiation triggers cells called melanocytes which produce melanin in order to protect your skin. This increase in melanin makes your skin darker which eventually leads to a tan! However, everybody's body responds to UV light differently, and for some, they are unable to produce melanin making it very hard for them to tan. So essentially, one’s ability to tan is purely genetic and depends on whether their genes allow their body to produce melanin as a result of being exposed to UV rays. 

In conclusion, UV rays, although invisible are able to have a significant effect on our skin. Whether they alter our DNA and cause a sunburn, or trigger our melanocytes and give us a tan, it is important that we defend ourselves against them and stay protected in the sun.