Sadly, it doesn’t work like that and the real answer is no, you can’t develop a tan from the moon no matter how full it is. Our bodies develop a tan when exposed to sunlight because invisible ultraviolet light (UV) in the sun’s rays triggers our skin to produce a chemical known as melanin. The UV light that reaches us can be divided into two forms: ultraviolet A (UVA) and ultraviolet B (UVB) – UVB being the most harmful and repeated unprotected exposure can damage the DNA in our skin cells, cause sunburn and potentially lead to cancers. Our body responds to the potentially harmful UV light by producing melanin, which efficiently absorbs the UV light to protect the skin. The more UV light you are exposed to, the more melanin your skin produces and the more tanned you look.
The reason you can’t develop a tan from the sunlight reflected from the moon (aka moonlight), is simply that the moonlight is too weak to trigger the melanin production response in your body. The moon only reflects 13.6% of the total sunlight that reaches it; the rest of the sunlight is absorbed by the moon’s surface. As well as this, the moon does not reflect the UV light as well as visible light so the amount of UV light reflected off the moon’s surface is tiny.
Sadly, those tanning vampires will have to try something else if they want to get a better tan. It’s important to remember that even with a tan, it is always a good idea to follow medical advice when out in the sun for any length of time as damage from the sun can so easily be avoided – especially if you’re pale skinned. Vampires, you have been warned.
Answer by Nathan Beal
Get your questions answered!
Got a question about life, health, nutrition, psychology or science? If there’s something you’ve always wanted to know, or even just something you were pondering whilst taking a shower – let #AskAGuru be the place to go!
We also accept questions via email.
See a list of answered questions here.