Q: Why is the sun so dangerous? Q: Why is the sun so dangerous?A: We worry about sun exposure because the sun does not only emit visible light, but also UV-rays that are dangerous. UV-rays are high-energy light waves that can penetrate the layers of our skin. These rays are strong enough to break apart the DNA in our cells and too much DNA damage could result in skin cancer. Talk to your pharmacist about what to use to protect your skin from the sun.