Describe why we hvae Different Season?

Answer 1

as the earth revolves around the sun, the orientation of its angle in relation to the sun shifts. therefore, day length varies according to latitude (i am sure that, if you do not live on the equator, you will have experienced this), and thus the amount of sun to which an area is exposed is limited by the day length. to a much greater extent, if the earth is at an oblique angle to the sun, the radiation emitted will have to travel through more lengths of the atmosphere. If the noon sun is only sixty degrees above the horizon, the sun has to travel through a distance of around 2 atmospheres. since the particles in the atmosphere reflect radiation, the lower the angle, the colder the area will be.

the answer is NOT, as is popularly believed, that the distance from the sun varies. in fact, on january 3, a time in the dead of winter for the northern hemisphere, we are closer to the sun than at any other time, at 148 million km. however, in early july, we are 151 million km away from the sun, and this is a time generally considered to be fairly warm in this hemisphere.

Answer 2

The Earth revolves around the sun on a particular plane. It also rotates on an axis. If the rotational axis were ninety degrees to the revolving axis (if the line that we travel around the sun on was flat and the line going through the Earth that it spun around was straight up) we would not have any change in weather as the Earth moved around the sun.

But, the Earth is tilted to one side. It is not straight up and down.

Lets focus attention on the top of the axis for now. If it was pointed toward the sun all the time it was traveling around the sun, there would also be no change in weather as the Earth moved around the sun. The part of the Earth that is north of the Equator would always be the point of the earth that was closest to the sun.

But, what actually happens is that the axis of Earth (the top of the planet) is pointed somewhere else -- let's say that its pointed toward the centre of the galaxy -- and given that the Earth takes one year to travel all the way around the sun to the same position, as the Earth moves around the sun a different part of the Earth is closer to the sun than at other times of the year.

Lets assume that the start point of the Earths journey around the sun is at a point where the sun is between the Earth and the centre of the galaxy. The part of the Earth that is closest to the sun is that part north of the equator (the part above the middle) and so it gets more direct energy from the sun and is hotter. Summer in the north and winter in the south

Now the Earth moves and at a point one quarter of its journey, the top of the Earth is still pointed toward the centre of the galaxy but not pointed at the sun. The section of the Earth which is closest to the sun is the equator (the middle part). About the same temperatures (north getting cooler and south getting warmer) Autumn (Fall) in the north and spring in the south.

At a point halfway on its journey, the top of the Earth is still pointed toward the centre of the galaxy but now it is also pointed away from the sun. The section of the Earth which is closer is the part south of the equator (bottom half) and its now summer in the south and winter in the north.

Three-quarters of the journey gives the same as one-quarter but on the other side of the sun. Spring in the north (coming out of winter) and Autumn (Fall) in the south.

That is how we get seasons throughout the year.

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