Earth has seasons because sometime early in its long history, something very big hit the young Earth to knock it off-kilter. So instead of rotating with its axis perpendicular to its orbital plane, it is tilted Incidentally, that big something that hit Earth also knocked a chunk of it out that became our Moon.
At least that is generally accepted theory. The Earth takes As we move around the Sun during the year, the amount of light each area of the planet receives varies in length. When the Earth's axis points towards the Sun, it is summer for that hemisphere.
When the Earth's axis points away, winter can be expected. The north pole tilts towards the sun. It is Summer time in countries in the Northern Hemisphere. It is Winter time in countries in the Southern Hemisphere. The north pole tilts away from the sun. It is Winter time in countries in the Northern Hemisphere. It is Summer time in countries in the Southern Hemisphere.
The north pole begins to move away from the Sun. The Sun rises lower in the sky so the days start getting shorter. When the Sun is at its mid-point in the sky, we reach the ' autumn equinox ', around 22 September. Day and night are both 12 hours long and its the beginning of autumn. Daytime continues to be longer than nighttime until after the September equinox.
In the Southern Hemisphere, the dates of equal day and night occur before the September equinox and after the March equinox. The chart shown below shows the dates and times for the equinoxes and solstices through Times listed are in Eastern Time. Subtract one hour for Central Time. Source: U. Naval Observatory. The answer is YES. However, you can stand an egg on end, with a large amount of patience, on any day of the year. This idea seems to pop up every year around the equinox.
The thought that an egg can only stand on end on the spring equinox due to gravitational forces of the sun being aligned with the earth sounds like science, but it isn't. According to Chinese tradition, an egg can be made to stand on end at the precise moment winter ends and spring begins.
But, the Chinese calendar had this transition occurring at a variable time each year, determined partly by the Chinese lunar month, usually in early February. More recently, this thought became fixed to the time of the spring equinox. The underlying assumption relating to standing eggs on end is that there must exist some special gravitational balance. There are many forces acting on an egg when you try to stand it on end on a flat surface. Some people think that the gravitational pull of the Sun becomes balanced with that of the Earth to allow for this phenomenon to occur.
However, the Moon exerts a much stronger gravitational effect on the Earth than the Sun, dominating the ebb and flow of the ocean tides. The Moon's effects are different at each of the equinoxes however. The most dominant force of gravity on a standing egg is the one between the Earth and the egg itself. And, likewise, they think Earth is farthest from the Sun in the winter.
It is true that Earth's orbit is not a perfect circle. It is a bit lop-sided. During part of the year, Earth is closer to the Sun than at other times. However, in the Northern Hemisphere, we are having winter when Earth is closest to the Sun and summer when it is farthest away!
Compared with how far away the Sun is, this change in Earth's distance throughout the year does not make much difference to our weather. Earth's axis is an imaginary pole going right through the center of Earth from "top" to "bottom.
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