Ultraviolet (UV) radiation is a form of energy that the sun produces. You can’t see UV radiation because its wavelengths are shorter than visible light.
The UV energy that the sun produces reaches the Earth and provides vitamin D for your body to help you survive. You can also find UV radiation in human-made sources like tanning beds. Exposure to too much ultraviolet radiation greatly increases your risk of developing skin cancer.
There are three different types of ultraviolet radiation based on the size of the wavelength:
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Exposure to the sun causes changes to your skin. While many people think that a glowing complexion means good health, changes to your skin tone from being in the sun can speed up the effects of aging and increase your risk of developing:
Over time, the sun’s ultraviolet light damages the fibers in your skin called elastin. When these fibers break down, your skin begins to sag, stretch and lose its ability to go back into place after stretching. Your skin also bruises and tears more easily, in addition to taking longer to heal. So, while sun damage to your skin may not be apparent when you’re young, it’ll show later in life.
Changes in your skin related to sun exposure include:
Too much ultraviolet radiation causes skin cancer. Your body needs some UV light for vitamin D, which is a vitamin you need to survive. When your skin has too much exposure to UV radiation, it damages your cells. Within your cells, you have DNA. DNA tells your cells how to form and function within your body. Too much UV radiation targets the DNA in your cells, which causes them to misunderstand their function. As a result, your cells divide and replicate too frequently. Your cells then clump together to form tumors, which can be cancerous.
Ultraviolet radiation from the sun is the primary cause of skin cancer, but UV light from tanning beds is just as harmful. Exposure to sunlight during the winter months puts you at the same risk of exposure during the summertime.
Cumulative sun exposure causes basal cell and squamous cell skin cancer, while episodes of severe blistering sunburns, usually before age 18, can cause melanoma later in life.
Skin cancer is the uncontrolled growth of skin cells. While healthy cells grow and divide in an orderly way, cancer cells grow and divide in a rapid, haphazard manner. This abnormal growth causes tumors that are either benign (noncancerous) or malignant (cancerous). There are three main types of skin cancer:
Basal cell and squamous cell cancers are less serious types and make up 95% of all skin cancers. These cancers are nonmelanoma skin cancers. This means that they’re highly curable when treated early.
Melanoma, made up of abnormal skin pigment cells called melanocytes, is the most serious form of skin cancer and causes 75% of all skin cancer deaths. If left untreated, melanoma can spread to other organs and is difficult to control.
Anyone can get skin cancer from ultraviolet radiation. The risk is greatest in people who have:
People who have a darker skin tone can get skin cancer, but their risk is lower than people who have a lighter skin tone.
In addition to your complexion, other risk factors include:
Aurorae are caused by high-energy waves that travel along a planet's magnetic poles, where they excite atmospheric gases and cause them to glow. Photons in this high-energy radiation bump into atoms of gases in the atmosphere causing electrons in the atoms to excite, or move to the atom's upper shells. When the electrons move back down to a lower shell, the energy is released as light, and the atom returns to a relaxed state. The color of this light can reveal what type of atom was excited. Green light indicates oxygen at lower altitudes. Red light can be from oxygen molecules at a higher altitude or from nitrogen. On Earth, aurorae around the north pole are called the Northern Lights.