Why is white skin more prone to sunburns when whiteness typically is better for reflecting light and not absorbing heat, compared to darkness?
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“In general, populations that have originated near the equator and are exposed to more intense sunlight, have more melanin present in their skin to protect it from UV damage, which makes their skin appear brown or black.”
As far as UV is concerned white person skin is transparent. This lets UV damage your DNA which causes sunburn.
If you want to see what actual white skin looks like, slather on some zinc oxide sunscreen. Mineral sunscreens do block and reflect UV.
Melanin works by absorbing UV, like a little beach umbrella to protect your DNA.
In terms of “reflection” / transmission vs absorption, ***the light which damages your skin*** **is UV** (short wavelength / higher frequency light), **which is absorbed by your layers of skin**. Your eyes cannot detect UV very well – it’s pretty much invisible.
If you mapped the absorption of the light by wavelength, you would see larger amounts of absorption at the shorter (invisible) wavelengths, and decreasing absorption at the lower = visible wavelengths of light. The (visible) light is uniformly not absorbed is reflected and therefore perceived by your eyes as a general “white” light.
The effect of melanin is to absorb ALL wavelength of light UV and visible, so what is “seen” is a lack of light – “darkness”, depending, of course on the concentration of melanin.
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Skin tone are caused by the presence of melanin pigment with our skin cells. Melanin works by absorbing harmful UV radiation and stopping it from mutating your cells meaning the more melanin in your skin cell the better they were at absorbing UV radiation (a side effect of which leads to darker skin tones). As humans migrated further from the equator, they would become less exposed to direct UV exposure and thus the need for higher levels of melanin became less and less the further away they went (resulting in lighter skin tones over time). Since lighter skin tones are caused by possess lower levels of melanin in skin cells it means there is now less melanin in the cells absorbing UV radiation thus increasing the risk of skin cell damage/mutation through prolonged exposure.
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