Since ancient times, people have been tormented by questions about the universe. How and by whom was the Earth created, what are stars, the sun and the moon? How is the change of seasons? The first to answer many of these questions was Nikolai Copernicus. He suggested that the change of seasons occurs in one revolution of the Earth around the Sun. But people doubted for a long time.
Well-known facts
Firstly, there is a change of day and night. All this is due to the fact that our planet revolves around its axis. As a result, it turns out that half of it is constantly in the shade, and there, accordingly, is night. Turnaround time - twenty three hours fifty six minutes and four seconds.
Secondly, our planet, as Copernicus has successfully suggested, revolves around the Sun. And the time it takes for her to make a circle is 365.24 days. This number is usually called one stellar year. As we can see, it is slightly different from the calendar, about one fourth of the day. Every four years, these non-integer numbers add up and one “extra” day is obtained. The latter is added to the fourth in a row, forming a leap year. And in it, as we know, three hundred sixty six days.
Cause
According to the vast majority of modern scientists, the change of seasons occurs because The earth moves around the sun. But not only that. The axis around which our planet turns when the day changes is tilted to the plane of its motion around the star at an angle of 66 degrees for 33 minutes and 22 seconds. Moreover, the orientation remains unchanged regardless of the place in orbit.
Let's do an experiment
To make it easier to understand, imagine that this axis is material - like a globe. If you move the latter around a light source, the part that is not facing the lamp will be in the dark. It is clear that the Earth, like the globe, also rotates around its axis, and in a day it will all the same be illuminated. But pay attention to the position of the North and South poles. At one end of the orbit, the upper part of the globe is tilted towards the star, and the lower - from it. And even rotating our improvised Earth, we will see that its lowest part at the extreme point of the orbit is completely in shadow. The border of the latter was called the Arctic Circle.
Place our globe on the opposite point of the orbit. Now, on the contrary, its lower part is well lit by the "Sun", and the upper one is in the shade. This is the Arctic Circle. And the extreme points of the orbit are the days of the winter and summer solstice. The change of seasons occurs because the temperature of the planet directly depends on how much this or that part of it receives from the star. Solar energy is practically not delayed by the atmosphere. It heats the surface of the Earth, and the latter transfers heat to the air. Therefore, in those parts of the planet that receive the least light, it is usually very cold. For example, at the South Pole and North.
Uneven surface of the earth
But they are also some, albeit not very long time, illuminated by the sun. Why is there always frost? The thing is that sunlight, and therefore its energy, is not equally absorbed by different surfaces. And as you know, the Earth is heterogeneous. Most of it is occupied by the oceans. It heats more slowly than land and also slowly releases heat to the atmosphere. The North and South poles are covered with snow and ice, and the light from them is reflected almost like a mirror. And only a small fraction of it goes into heat. And therefore, in the short time that the Arctic summer lasts, usually all the ice does not have time to melt. Antarctica is also almost all covered with snow.
Meanwhile, the middle of our planet, where the equator passes, receives solar energy very evenly throughout the year. Therefore, the temperature here is always high, and the change of season occurs mainly formally. And a resident of central Russia, once in equatorial Africa, would have thought that it was always summer there. The farther from the equator, the clearer the change of seasons occurs, because light falling on the surface at an angle is distributed more unevenly. And perhaps it is most obvious in the temperate climate zone. In these latitudes, summers are usually hot and winters are snowy and cold. For example, as in the European territory of Russia. In addition, we were “unlucky" in that, unlike the Europeans, warm sea currents do not heat us, with the exception of the Far Eastern “outskirts”.
Other reasons
It is believed that not the axis (or not only it) is tilted, but the plane of the Earth’s orbit to the equator of the Sun. The effect should be the same or even stronger.
It is also assumed that the change of seasons occurs because the distance to the star is not always the same. The thing is that the Earth does not rotate in a circle, but in an ellipse. And the closest point to the Sun is at a distance of 147,000,000 km, and the farthest - at about 152,000,000. Still, five million kilometers is quite a lot!
They also say that our natural satellite also influences the motion of the Earth. The moon is so large that it is comparable in size to our planet. This is the only such case in the solar system. It is alleged that with it the Earth also revolves around a common center of mass - for twenty-seven days and eight hours.
As can be seen from all of the above, the change of seasons is caused, like almost everything on our planet, by the position relative to the Sun.