Genesis of the Four Seasons

Reference: http://www.arcticworld.net/season.htm

The Four Seasons are formed by the revolution of the Earth around the sun. The Earth's orbit is elliptical, called the ecliptic, and the sun is in one of the focal points, so the Earth's distance from the sun is constantly changing and repeating itself. The Earth's revolution is one year. However, the alternating seasons are not due to changes in the Earth's distance from the sun. The earth is too far away recently for the 147,000,000km, the furthest is the 153,000,000km, the difference between the two is not big, the Earth and the sun distance in 150,000,000km +/-2% within the range.

The genesis of the Four Seasons is that the direction of the earth's axis of rotation is fixed by reference to the ecliptic surface. For example, the earth's axis of rotation is not perpendicular to the ecliptic surface, but relative to the ecliptic plane deflection of 23 degrees, which leads to a different date, the Earth South, one of the northern hemisphere is more inclined to the sun, the sun in the Earth's direct point, in the equator south, northern latitude of about 23°5 ' range of reciprocating movement, which formed the so Tropic of Cancer, direct Sun Point, moving between the Tropic of Cancer in the south. During the year, the direct Sun Point reaches south, the Tropic of Cancer once, and passes the equator two times.

For the Northern hemisphere, the date of the solar direct point at the equator is called the vernal Equinox (vernal equinox) and the Autumnal Equinox (Autumnal Equinox), the date of the solar direct point at the Tropic of Cancer is called the Summer solstice (Summer Solstice), The date of the Sun's direct point at the southern regression line is called the Winter Solstice (Winter solstice). In the vernal equinox and Autumnal Equinox, day and night looks and so on. After the vernal equinox, the northern hemisphere began to tend to the sun, the day is short, long hours of sunshine, temperature rise, spring into the summer. Daylight is the longest day of the summer solstice. After the summer solstice, daylight time began to decrease, until after the autumnal equinox, the northern hemisphere began to stay away from the Sun, day short night long, the temperature fell, autumn and winter. On the winter solstice, the daylight time is shortest and the night time reaches the longest. After the winter solstice, the daylight time began to grow and the night time became shorter until the vernal equinox. This has formed a year of four seasons.

In the southern hemisphere, the seasons are opposite to the northern hemisphere, spring to autumn and summer to winter. China is in the northern hemisphere.

Genesis of the Four Seasons