How do seasons occur?

Answer 1

The seasons result from the Earth's axis being tilted; it deviates by an angle of about 23.50 degrees. Thus, at any given time during summer or winter, one part of the planet is more directly exposed to the rays of the Sun. This exposure alternates as the Earth revolves in its orbit. At any given time, the northern and southern hemispheres experience opposite seasons

Answer 2

The Earth rotates around the Sun and takes one year to complete one full rotation.

The earth has a Northern hemisphere and a Southern Hemisphere with the Equator round the middle. The Equator transits the Ecliptic twice a year, once in March and the other in September. It also has the Tropic of Capricorn in the Southern hemisphere and the Tropic of Cancer in the Northern hemisphere. Each of these are positioned 23.5 degrees from the Equator and represent the extremes of the motion of the Sun as it appears to stop and change direction.

The Earth rotates around the Sun at an angle of 66.5 degrees relative to the ecliptic and it is this which causes the seasons over the twelve month period. (90-23.5 = 66.5)

When the Northern hemisphere is tilted away from the sun this is Winter in the Northern hemisphere because the Sun's rays are less concentrated (more spread out) and the Sun is lower in the sky.

At the same time when the Southern hemisphere is tilted towards the Sun the Sun's rays are more concentrated and the Sun is higher in the sky - this would be Summer in the Southern hemisphere and this is how it happens....hope this works

Answer 3

It is the tilt of the Earth's axis at 66.5 degrees to the ecliptic in combination with the rotation of the planet around the Sun, that are the essential parts of seasonal changes.

The first thing that needs clarification is that the tilt relative to the true North Pole and the plane of the Ecliptic, is always pointing at the same Star in outer space, no matter what the season. The ecliptic is the enclosed area traced by the Earth as it moves around the Sun and as it is ~circular, it can be divided into four quarters, each of 90 degrees. (Not to be confused with Lunar quarters which are monthly where-as these are annual.)

The easiest way to visualize this, is to put yourself on the North Star at which the Earth's North Pole points, and look back at the Ecliptic - the Earth - and the Sun. The Earth's North Pole will be pointing straight at you all the time. Unfortunately you have to choose an arbitrary "up" and I like to see the ecliptic with the top as the March equinox. That means half way between mid-summer and mid-winter for the Southern Hemisphere, and moving towards Winter.

(When looking from the North Star, the Earth is moving counter-clockwise around the Sun and this counter-clockwise direction would be reversed if we were looking outwards from the inner galaxy onto the South Pole.)

Obviously the bottom of the ecliptic is the September equinox. Half-way between mid-winter and mid-summer for the Southern Hemisphere and moving towards Summer.

90 degrees of this rotation is also called three months and three months after each of these equinoxes, each of the hemispheres will be in either Mid-Winter or Mid-Summer. So the equinoxes were either Autumnal or Spring depending in which hemisphere you live.

It is also said that the equinox is the moment at which the Sun crosses the Equator whether going North or South. This may or may not be helpful as that moment may be night or day, so saying that it occurs on a particular day is a minor misrepresentation. Not to mention it's timing relative to the International Date Line. In reality the Equator of the Earth is crossing the Ecliptic and given the 66.5 degree tilt of the Earth's axis relative to that Ecliptic, the duration of transit would very short indeed.

Answer 4

the seasons are caused by the earth's tilt and its rotation around the sun