Since ancient times, people tormented by questions about the universe.How and by whom created the earth that is the star, the Sun and the Moon?How is the change of seasons?First on many of these questions answered, Nicolaus Copernicus.He suggested that the change of seasons comes during one revolution of the Earth around the sun.But people doubted for a long time.
well-known fact
Firstly, there is a change of day and night.All this is due to the fact that our planet revolves around its axis.The result is that half of it is constantly in the shade, and there is accordingly a night.Turnaround time - twenty-three hours and fifty-six minutes and four seconds.
Second, our planet, how well has suggested Copernicus, revolves around the sun.And the time that it takes to make a circle of 365.24 days.This number is called a stellar year.As we can see, it's a little different from the calendar, about one-fourth of the day.Every four years, the non-integer numbers add up and get one "extra" day.Last and added to the fourth, forming a leap year.And in it, we know three hundred sixty-six days.
reason
The overwhelming majority of modern scientists, the change of seasons is because Earth moves around the sun.But not only.The axis around which turns our planet by changing the day, is inclined to the plane of its motion around the star at an angle of 66 degrees, 33 minutes and 22 seconds.Moreover direction remains unchanged regardless of where in the orbit.
The experiment
To make it easier to understand, imagine that the axis of the material - like the globe.If you move the latter around the light source, the part that does not face the lamp will be in the dark.It is clear that the Earth as a globe rotates around the axis yet, and one day it will still be all covered.But pay attention to the position of the North and South poles.At one end of the upper part of the orbit the globe is tilted toward the light, and the bottom - from him.And even our impromptu rotating Earth, we can see that the lowest part of the far point of the orbit is completely in the shade.The border has been called the last Southern Arctic Circle.
put our globe on the opposite point of the orbit.Now, on the contrary, its lower part is well covered "sun", and the top - in the shade.This is the Arctic Circle.And the extreme points of the orbit - a winter and summer solstice.Seasons is because the temperature of the atmosphere depends on how much one or other part receives from the star.Solar energy is virtually no atmosphere lingers.It warms the Earth's surface, and is the last transfers heat to the air.And so in those parts of the world that receive the least light, usually very cold.For example, the South Pole and the North.
uneven surface of the Earth
But they are also some, albeit not a very long time, illuminated by the sun.Why is it always cold?The fact is that sunlight, and hence its energy are absorbed differently by different surfaces.And as you know, the Earth is not uniform.Most of it takes Oceans.He warmed slowly land and also slowly loses heat to the atmosphere.North and South poles are covered with snow and ice, and the light reflected from them is almost like from a mirror.And only a small fraction of it is converted into heat.And so for a short time until the last Arctic summer, all the ice melt usually does not have time.Antarctica is also almost completely covered with snow.
Meanwhile, the middle of the planet, where the equator receives solar energy rather evenly throughout the year.And because the temperature is always high, and the change of season takes place mainly formally.And the inhabitants of central Russia, once in sub-Saharan Africa, would have thought that there was always summer.The farther from the equator, the more distinct seasons is because the light falling on the surface at an angle, is distributed more evenly.And perhaps, most evident it is the temperate zone.In these latitudes, summers are usually hot and winters are cold and snowy.For example, in the European part of Russia.We are also not "lucky" that we, unlike the Europeans, the heat does not warm sea currents, with the exception of the Far East "margins".
Other reasons
There is an opinion that is not tilted axis (or much more), and the plane of Earth's orbit to the equator of the sun.The effect is to get the same or even stronger.
also suggests that the change of seasons is because the distance to the light is not always the same.The fact is that the Earth rotates around the circle, and an ellipse.And the closest point to the Sun, located in the 147 million km and the farthest - about 152 000 000. Still, five million kilometers - that's quite a lot!
It is also said that the movement of the Earth and also affects our natural satellite.The moon is so large that is comparable in size to our planet.It is the only such case in the solar system.It is argued that with it the Earth turns and even around a common center of mass - for twenty-seven days and eight hours.
As can be seen from the above, the change of seasons is due, as well as almost everything on the planet, the position relative to the sun.
