Dear Ms. Scientist,
I know the sun's rays during the summer can be harmful, but how exactly do they cause skin cancer?
You're right, you can get skin cancers like basal and squamous cell carcinoma, and melanoma. As the sun emits light, a small percentage of the spectrum we are exposed to are UVA and UVB rays which cause the tanning and burning of skin, as well as aging and skin cancer. This ultraviolet radiation emits photons that do the real damage. Photons have the energy to alter the chemical composition of the DNA in our skin cells, resulting in pyrimidine dimer mutations. Simply put, these specific damaging mutations make it impossible for our DNA to replicate correctly, resulting in DNA that tells our cells to multiply uncontrollably, causing cancerous tumors.
UV radiation is not entirely bad, however. Exposure to UV rays allows our bodies to manufacture vitamin D, a necessary vitamin that supports our bone health and immune system. Only a few minutes of sun are required for sufficient levels of vitamin D production, so exposure should still be limited.
Ask Ms. Scientist will now be written by Emma Koethe. If you have a burning science question you want her to answer, email it to email@example.com.