What is the basic reason that we have seasons on earth? What is the basic reason that we have seasons on earth? Earth's orbit is not quite a perfect circle. Earth's axis is tilted relative to the ecliptic plane. The amount of energy put out by the sun varies over the course of each year. Earth's distance from the sun varies over the course of each year?

Earth's axis around the sun is not a perfect circle, but instead it has an ecliptic form. Because of this, at certain parts of the year the Earth is closer to the sun, and at certain parts it is further away. It is interesting that the Earth is colder when it is closer to the sun, and warmer when it is further away, and this is because when the Earth is closer to the sun, the sun's gravity pulls it harder and making it move quicker, which decreases the temperature, and when it is further away, the sun'[s gravity pulls it a bit less, so the Earth moves a bit slower, which makes the temperature bigger. Because of this we have the changes of seasons on our planet.