1) Cells are elastic and suspended in water which allows them to survive what you might think of as extreme trauma. (Ever seen someone hammer a nail with a glass bottle filled with water?) Combine that with the elastic nature of connective tissue is what allows you to for example jump without killing off of the cells at the bottom of your feet.
2) Sunlight is EM radiation like X-Rays. However, the vast majority of the energy is harmless and and even UVA / UVB is limited to the top layers of skin. But, as far as those top few layers of skin are concerned it's like your constantly getting very weak X-Ray when standing in sunlight making it a great proxy for low level radiation exposure.
1) Cells are elastic and suspended in water which allows them to survive what you might think of as extreme trauma. (Ever seen someone hammer a nail with a glass bottle filled with water?) Combine that with the elastic nature of connective tissue is what allows you to for example jump without killing off of the cells at the bottom of your feet.
2) Sunlight is EM radiation like X-Rays. However, the vast majority of the energy is harmless and and even UVA / UVB is limited to the top layers of skin. But, as far as those top few layers of skin are concerned it's like your constantly getting very weak X-Ray when standing in sunlight making it a great proxy for low level radiation exposure.
The tiny sliver of red UV that reaches past the atmosphere is what you care about. Dead skin cells block even more, but the tiny fraction of a fraction of energy can still kill you. https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spe...