The sun is essentially a big ball of gases, emitting all kinds of heat and energy down to us here on earth. The energy we’re concerned with is ultraviolet light, or UV light.
The sun is the closest star to earth (yes—our sun is a star!). There would literally be no life on our planet without the sun. There isn’t anything particularly special about this medium-sized star; it shines in the same way as other stars are thought to shine. What makes the sun so important is its close proximity to earth.
The sun is the closest star to earth (yes—our sun is a star!). There would literally be no life on our planet without the sun. There isn’t anything particularly special about this medium-sized star; it shines in the same way as other stars are thought to shine. What makes the sun so important is its close proximity to earth.
The sun affects us in several ways.
- It has a gravitational pull on the earth’s oceans, although it is probably less than half as strong as that of the moon. This affects the tides as well as the weather in general.
- Without the sun’s energy beaming down on plants, there would be no food to eat (no photosynthesis).
- Sunshine or the lack of light can affect our moods.
- And finally, sunlight has a tremendous affect on our bodies and particularly our skin.
UVB is the short ray. It hits the epidermis (our outer skin) and reaches as far down as the uppermost layer of the dermis (the papillary dermis). As UVB rays penetrate the epidermis, they stimulate the production of melanin, a dark pigment that gives you a tan. However, UVB is predominantly known for causing redness and sunburn (UVBurn). It is much more intense than UVA and can cause a lot of damage to the outer skin quickly. Exposure to UVB also causes a thickening of the top layer of skin and accelerates the formation of wrinkles. In short, UVB causes immediate damage.
UVA is the long ray. It goes beyond the surface of the skin and is able to reach deep down into the dermis. UVA can damage collagen and elastin fibers, the substances that keep the skin firm and free from sagging. UVA generally does not cause sunburn like UVB rays but does play a large role in suntans. UVA contributes to destroying DNA, setting up the potential for cancer or precancerous growths down the road. UVA, like UVB, stimulates melanin production that can cause pigmentation irregularities like chloasma (hyperpigmentation). UVA causes long-term damage.
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