Science and Technology

Why do we have seasons?

Four seasons on Earth

Changing seasons is one of the biggest blessings that nature has granted us. Each season comes up with its own treasure to grant us differently. We have seasonal fruits, vegetables, flowers, medicinal plants, etc. Even our mood fluctuation is also seasonal sometimes. The long nights of winter make many people sad or happy. Spring brings a sense of prosperity for its lovers. If these seasonal variations would not be there then maybe we were deprived of many things. A stagnant seasonal will grant you the same fruits and vegetables throughout the year but change will provide you diversity. All beautiful setup makes this nature more attractive and fascinating.

Four seasons on earth
Four seasons

All of these perspectives deserve appreciation but have you ever wondered that how it is happening? How we are able to have such diversity when our earth is the same throughout the year? We are living on the same globe in June and December. But what causes solar radiation to become intensive during June and mild during December? In this article, we will have a detailed discussion that how our planet earth changed for bringing several seasons over there.

Earth revolution causing change:

The basic principle associated with the change is that the Earth’s rotation causes a change of days and nights while the Earth’s revolution causes a change of the seasons. Earth is always revolving around Sun in a tilted manner. It means that it is not always upright with its North and South Pole. Rather it is tilted.  During summer, the North Pole of the Earth is tilted more towards the Sun. As the result, we will have summer. More solar radiations are able to reach the earth’s surface. This is why sometimes these radiations cause sunburn on our skin if we come out in summers without any protective covering. We are facing directly these radiations so these are not bearable.

Earth revolution causing change in seasons
Earth revolution

On the other hand, the North Pole of the Earth has tilted away from the sun. As the result, very less and mild solar radiations are able to reach the surface of the earth. In winters, during extreme weather conditions, we are unable to face these radiations. Even if solar shines, radiations are never extreme as in summer. During the autumn and spring season, the earth neither tilted away from nor towards the sun. Rather its axis points 90 degrees away from the sun. There are no extreme weather conditions during this phase and days and nights are equal in length.

Why does Earth’s tilt matter for seasonal variations?

In order to understand the phenomenon, let’s consider an example. Take a piece of paper and a flashlight. Now place the paper on a table and flashlight over there. You will see a circle of light. A very concentrated amount of light will fall on the paper at that particular place. Now pick up the paper in your hand in a tilted manner. You will observe that the circular figure of the light started changing into an elliptical manner. Obviously, an ellipse is more elongated as compared to a circle. So the number of squares per increases but the amount of light remains the same. The same amount of light now has to spread over a large area. As the result, the intensity of light per unit area will decrease.

The same happens with the earth. When in summers or even in winter, the sun is overhead, we receive more solar radiation. The more radiations hits per unit area. But when the sun lowers, the solar radiations start becoming mild with it. During the revolution, when the Northern hemisphere is facing the sun that part of the earth has the summer season. At that time, in the Southern part of the earth, there will be winters. The weather condition will reverse when the earth’s North Pole will become down and the south pole comes upwards.

What caused the earth to tilt?

It is believed that a long time ago when our solar system came into being, Theia, an ancient planet, hit our Earth. As the result, the Earth became tilted and started revolving in a tilted manner around the earth. It is also believed that this big hit created a big hole on the surface. A large amount of dust and smoke was incorporated into this hole later. And astronomers estimated that it became the moon of our planet Earth later. During the revolution, the tilted angle points in the same direction, so throughout the year different regions of the Earth get Sun rays directly.

Earth tilt causing change in seasons
Earth tilt

Why Antarctica is called as frozen Island?

Antarctica is really cold because it is known as a frozen place. In this region, both the North and South Pole are unable to get solar radiation directly, so they are cold enough due to the lack of heat on that particular part of the Earth. The radiations are always low on the horizon even during the end of the summer. During the winter season, Sun remains far below and it remains unable to rise for months. So during this duration, no one is able to receive solar heat. As the result, the days are just replicas of the nights. They are equally dark and cold like nights. For almost three months, there is complete darkness in the region.

The frozen island of Antarctica

The temperature is below the freezing temperature. However, the summer days are 24 hours shinny. Both the North and South poles are opposite. So the South Pole is colder as compared to the North Pole. The North Pole has a -30 degree temperature which is far less extreme than the South pole temperature which is -60 degrees.

Effect of changing season on Earth:

The change in seasons on Earth brings an entire change over the region. For example, during the spring season plants come back to life, and animals are born. Summer is hot and sometimes it is too extreme to bear. That’s why our kids have summer vacations during these extreme days. At the end of the summer season, crops are harvested. During autumn, plants shed their leave after changing color and children go back to their school. And the winter is cold and you will see snow in some places. Animals like bears, hibernate at this time. The birds migrate in this season towards the warmer areas for their protection.

Wrapping up/ Conclusion:

The changing seasons on the earth are the result of the revolution of the earth around the sun. During the revolution, one part of the earth faces the sun while the opposite part remains below or hidden. In this situation, the upper part will have summer and the opposite part will have winter. Earth is not revolving in an upright position. Rather it is tilted at an angle of 23 degrees. This tilted position of the earth is basically responsible for the whole change around the globe. The Earth’s rotation in a tilted manner causes a change of days into nights. It is estimated by the astronomers that a big theia was collided with the Earth and change the axial tilt of the Earth.

Antarctica is considered a frozen island because both of its north and south poles remain unable to face the sun. The temperature is even below the freezing point. The changing weather comes up with enormous changes on the earth such as fruits, vegetables, daily activities, and human behavior. If we did not have this diversity then maybe life was not possible on planet Earth.

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