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?

Question

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

Answer 1

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.