The sun illuminates the earth throughout the year almost the same. Only because of the slight ellipsy of the orbit, the Earth either approaches the sun or removed. But different areas on Earth are covered in different ways. At the equator, the sun heats the earth much more than on the poles.
There are several reasons for this:
- Earth elliptical orbit: it is approaching closer to the Sun, then moves away from it. Accordingly changes and illuminated.
- The slope of the earth’s axis to the plane of the ecliptic, which is also constantly changing – precession and gutting. Earth substitutes closer to the sun, one side or the other.
These two reasons are the main reasons that lead to uneven illumination and the change of seasons in antiphase: summer in the southern hemisphere when in the northern winter.
Because the trajectory of the Earth around the Sun is not round, but oval, plus that the Earth rotates around its axis
The orbit of the Earth is not round, but the elliptical and the sun is approaching, then removes to our planet. Further, the Earth itself rotates around its axis and turns to the Sun either with one another side. In addition, the axis of rotation of the earth is tilted, the earth rotates slightly on its side, which allows the sun to show one hemisphere, then the other.
All together leads to the fact that the sun illuminates the earth in different ways.
In winter, the southern hemisphere is more illuminated, in the summer – northern. The sun passes its path along the sky first rising to the moment of the summer solstice, and then falls to the moment of the winter solstice. When we have summer – winter in the southern hemisphere.
How do you think, the day is always equal to the night ? And at the poles this happens ?