Sun Safety Quiz: Test Your Sun Safety IQ

According to the National Aeronautics and Space Administration (NASA), our beloved sun is roughly 10,000° F. The sun is made entirely of gases. There is no solid surface of the sun.

Although the sun is necessary for life, too much sun exposure can lead to adverse health effects, including skin cancer. More than 1 million people in the United States are diagnosed with skin cancer each year, making it the most common form of cancer in the country.

Even though it sits 93 million miles from Earth, the sun is the closest star to our planet. The sun defines the seasons, the harvests, and even the sleep patterns of all living creatures on Earth.

UVA (ultraviolet-A) rays, which are not absorbed by the ozone layer, penetrate deep into the skin and heavily contribute to premature aging. Up to 90% of the visible skin changes commonly attributed to aging are caused by sun exposure.

Powerful UVB (ultraviolet-b) rays, which are partially absorbed by the ozone layer, mostly affect the surface of the skin and are the primary cause of sunburn. With thinning of the ozone layer, the effects of UVB radiation pose an increased threat.

You might think the chance of getting sunburned on cloudy days is less, but the sun's damaging UV rays can pass through clouds!

The term skin cancer typically refers to three different conditions. From the least to the most dangerous, they are basal cell carcinoma, squamous cell carcinoma, and melanoma.

Melanoma is generally the most serious form of skin cancer because it tends to spread (metastasize) throughout the body quickly.

In people with dark skin, squamous cell skin cancer is the most common type of skin cancer, and it's usually found in places that are not in the sun, such as the legs or feet.

In people with fair skin, skin cancer usually occurs on parts of the skin that have been in the sun, such as the head, face, ears, and neck.

A "base tan" gives very little protection against sunburn. And that goes for indoor tans, too. What you don't see is UV damage to deeper layers, where it builds up from every tan and sunburn you've ever had.

Note: There really is no such thing as a "safe tan."

The sun protection factor (SPF) describes how long a product will protect your skin when correctly applied. Fair-skinned people begin to burn in about 15 minutes. Based on this, SPF 15 sunscreen should last about 225 minutes (15 x 15 minutes = 225) and SPF 30 sunscreen should last for 450 minutes (30 x 15 minutes = 450).

However, most people do not apply enough sunscreen to gain the expected amount of protection for any given SPF, and sunscreen must be reapplied frequently.