The Earth Has Four Seasons, but What Causes Them?

We are moving towards the end of another year. The days are getting shorter, the temperatures are becoming cooler, and the leaves are starting to fall. The hot days of Summer are pretty much over, and Fall appears to be in full swing. Although the average person knows what the different seasons of the year are and can tell you when they arrive, most people can't tell you what causes the different seasons to appear. Let me enlighten you a bit with a little information on how our seasons come about.

Basically, the four seasons that we experience here on earth are caused by the interaction between the earth's tilt and the angle of sunlight that reaches the earth. There's nothing really complicated about the whole process when you break it down. The earth spins on an axis around the sun. In addition to spinning on an axis - a line - around the sun, the earth is also tilted at various degrees in relation to the sun. At certain times of the year, the earth is tilted closer to the sun, which results in a higher proportion of sunlight reaching the earth's surface. When this happens in the northern hemisphere(areas north of the equator) where we live, we are experiencing Summer. We have longer days and shorter nights.

The sun is higher in the sky and more direct sunlight reaches the earth. The opposite of this is when the earth is tilted away from the sun; less sunlight reaches the earth, and the sunlight that does reach the earth is spread out and not direct. This is our Winter. A time when we have shorter days and longer nights. In between these two extremes are when we experience our Spring and Fall; the points when the earth's tilt is starting to shift to one end of the extreme; in Spring, the earth's tilt is starting to track back towards the sun; temperatures start to warm up as more sunlight is beginning to reach the earth's surface. In Fall, the earth's tilt is starting to tilt away from the sun. Less sunlight is reaching the earth and temperatures are cooler. In a nutshell, that's the "science" behind what causes our various seasons.