As far as the effects of sunlight on humans, there are good and bad aspects to spending time in the sunshine. Rays from the sun provide the body with vitamin D, which is an essential vitamin for a healthy body. On the other hand, too much sun can cause skin cancer, sunburn, and it said to cause premature aging. There is also a condition called SAD (seasonal affective disorder) where a person can suffer as a result of not enough sunlight. As well as prescribed drugs, exposure to light through the use of sunlamps are used to help the sufferer of this condition.
Sunlight has a major effect on all living forms in the world. Plants use light from the sun in order to grow and survive. They use rays from the sun to produce sugars to enable them to grow. Certain animals would not survive if they didn't eat plants, therefore the sun is important to them also. From the beginning of time humans have used plants and animals as a means of survival, and so the cycle from the energy created by the sun grows. Ancient plants and animals that have been buried under the earth for many years have been discovered, creating fossil fuels. The energy from the sunlight has enabled these decayed remnants to be used for petroleum, natural gasses, and coal.
Solar radiation is filtered through the atmosphere making daylight. This happens when the sun is above the horizon, during day time hours. However, near the poles, during the summer, the sun may also shine during night time hours, or not shine at all during day time hours. Energy sources from sunlight create photosynthesis, which means light energy from the sun is converted into chemical energy. If it wasn't for the gravity pulling earth towards the sun, our planet would be just a cold rock, floating in space. Without the sun we wouldn't have weather, it gives as heat, and also uses evaporation to create rain from the earths oceans. Being 109 times the size of earth, the sun plays a major role on the effects of everyday life and existence.
The sun is just the correct distance from the planet so as not cause any problems. If the sun were any closer earth would be far to hot to live on, and if it were further away, the planet would be frozen. This glowing ball of heat has had an effect on earth, and life on earth for many years. There have been numerous benefits to sunlight found over time, and surely there will be many more findings in the future.