If dark colors absorb sunlight and light colors reflect sunlight, why does the skin get dark when exposed to the sun as a mean of protection. Doesn’t that make the skin absorb even more sunlight since it got darker?
In: Biology
Your skin will absorb the light anyways, but UV doesn’t penetrate as deep, and is by far the most harmful. So, it’s more a question of absorbing at what depth.
And, the deeper skin layer is NOT the part you want damaged. The outermost layers are often dead, or rapidly being replaced, while deeper skin layers have a longer period of time before dying or are responsible for replenishing your skin.
Higher absorbance means less reaches this lower layer.
Imagine you are trying to avoid getting hit by arrows, because they hurt. You put on some big, bulky armour and grab a shield. You have made yourself a bigger target which is easier to hit with arrows. But at the same time, you’ve made it harder to hit the parts of you that arrows can hurt.
Same idea with tanning. Sunburns don’t happen because you absorb sun and get warm. Sunburns happen when UV light damages the DNA in your skin. If we fill skin with more melanin (the stuff that makes your skin darker when you tan), the UV rays hit the melanin first amd damage it before it gets to the DNA. Since melanin is mainly just meant to absorb UV, it getting damaged by UV is way less harmful than DNA getting damaged.
That is the point yes. The surface layer of skin is dead, it doesnt matter what it absorbes, its already dead.
under it is a layer of live skin, if those get hit with high energy UV, there is a chance they become skin cancer.
so you WANT to have more absorbant skin at the surface layer to prevent it getting too deep
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