Why are there spring, summer, autumn and winter, and the temperature is different every year? (Simple answer, revolution and rotation know)

To answer this question, we must first look at how the earth works! Our earth revolves around the sun and rotates around its own axis, but the axis is not perpendicular to the orbital plane, but has an inclination of 23 degrees and 27 minutes. It is precisely because of this tilt that the direct point of the sun on the earth's surface moves between the Tropic of Cancer and the Tropic of Capricorn, thus forming four seasons: spring, summer, autumn and winter.

When the sun shines directly on the Tropic of Cancer, the northern hemisphere gets more solar heat, and the day is longer than the night, so the highest temperature in the northern hemisphere is summer. At this time, the sun shines obliquely in the southern hemisphere, getting less solar heat, and the night is longer than the day. Therefore, the southern hemisphere is in the coldest season of the year-winter. When the earth revolves around the sun for half a week, the direct point of the sun moves from the tropic of cancer to the tropic of Capricorn, and the solar heat gained by the northern hemisphere gradually decreases, from summer to autumn, and then to winter; On the other hand, the southern hemisphere goes from winter to spring, and then to summer. But the earth's orbit around the sun is not a standard perfect circle, so the summer in the southern hemisphere is slightly hotter than that in the northern hemisphere, and the winter is colder than that in the northern hemisphere.

There are tropics, frigid zones and temperate zones on the earth. There are only rainy and dry seasons in tropical areas, while there is ice and snow all year round in cold areas. Only temperate regions have obvious four seasons: spring, summer, autumn and winter. The four seasons are divided as follows: in the temperate zone of the northern hemisphere, according to the revolution of the earth, June with the longest sunshine time is divided into spring and summer, and June with the shortest sunshine time is divided into autumn and winter, which is a cycle. According to the change of temperature, the four seasons are divided.