Solar Studies : Sun Rays and Skin Safety

The light from the sun, flashlights and other lights that we can see with our eyes is called visible light.  This light is a part of a much broader range of wavelengths that we cannot “see”, yet know they are present.  Have you ever been sunburned, listened to a radio or watched television, or possibly used a microwave?  Along with visible light and the warmth of the sun, these items use waves are a part of the electromagnetic spectrum. 

Graphic: https://mynasadata.larc.nasa.gov/basic-page/electromagnetic-spectrum-diagram

On the ‘slower’ end of the spectrum are the longer wavelengths like radio, television, and microwaves.  When you change the channel on a radio or TV, you are changing the “frequency” of the electronics to pick up the station assigned to that channel’s frequency.  Longer, slower waves do not occur as “frequently” as those that are closer together and moving quicker.  Microwaves are right next to Infrared in the spectrum, so it might not be too hard to remember that they are also associated with cooking or heating objects.

Infrared waves carry the heat of the sun and other ‘hot’ objects give them off as seen in an IR Camera. The name infrared tells you where this wavelength is located near visible light.  Infra- means below. So infrared is “below red”.

Visible Light is detected by the human eye and made up of the colors of the rainbow.  Remember the popular memory tool or mnemonic to remember their order   ROYGBIV  (Red-Orange-Yellow-Green-Blue-Indigo-Violet).  On the other side of the narrow band of visible light, wavelengths are faster and closer together.  The first of these is just “beyond violet” or ultra-violet.

Ultraviolet (UV) waves are close enough together to also be called “rays”.  UV light is responsible for sunburns and damage to your skin and eyes.  This is why you might put on UV filtered sunglasses and sunblock to filter these rays when you are playing outdoor athletics or going to the lake.  UV is useful in killing bacteria and some viruses, so it is becoming more widely discussed  now.

It is safe to say that UV light and all of the wavelengths that are faster frequencies are not good for your body and need to be used by professionals with proper care.  The earth’s atmosphere protects us from most of these harmful wavelengths or rays. X-rays are fast enough to pass through your body’s tissues, but not your bones, so it is used for taking photographs of your skeleton or teeth.  Gamma rays are generated from nuclear sources are used to kill cells that cause cancer. Gamma rays are studied by astronomers looking for neutron stars, pulsars and black holes which give off bursts of gamma radiation.