Sun and Earth Relationship

Everyday it gives light to all on earth; a simple fact indeed but it is what most don't know about the sun, and all that it does for us on earth, that interests me. Every second the light of the sun is on the earth energy is absorbed; plants use this energy to perform photosynthesis giving humans breathable air, the suns energy evaporates water on the surface and starts the water cycle. As you continue to look at the intricate relation that exists between the sun and earth the more I hope you will learn to appreciate its workings.

The earth rotates around the sun. This causes the sun to rise and set. The angle of the sun and its intensity on earth is affected by location of the place on the surface of the earth. The length of the atmosphere that the solar radiation has to pass through determines the amount of radiation that reaches the earth's surface. During the day, the sun is directly overhead and radiation travels through least amount of atmosphere on route to the earth's surface. As the sun moves closer to the horizon, the path of the radiation through the horizon lengthens and the intensity of the radiation decreases. Also, at a high elevation, the amount of atmosphere that the solar rays have to travel through is lesser and therefore the energy content is somewhat higher. Because of the earth's tilt and rotation, the length of atmosphere that solar radiation passes through varies with the time of day and month of the year. The path of the earth around the sun is a slight ellipse. As the earth orbits around the sun, it rotates on its axis that extends from the North Pole to the South Pole every 24 hours. The axis is tilted 23.45o from the vertical to the plane of the earth's orbit around the sun. The earth's tilt is responsible for the seasonal variations in weather. The tilt is constant as the earth revolves around the sun. When the Northern Hemisphere is tilted towards the sun, the incoming radiation is closer to