Solar radiation comes from the sun. It consists of electromagnetic waves, such as light, radio waves, microwaves, X-rays, and gamma rays. When solar radiation hits the Earth, it causes heating effects on objects near the surface. This is why you need to wear sunscreen when outside.
At night, the upper layers of the atmosphere cool down and contract. This means less solar radiation passes through.
If the atmosphere were not there, the sun would burn us alive. However, the atmosphere protects us from the sun’s harmful radiation. Without it, life on earth would be impossible