Story of Motions of the Earth

Rotation and Revolution are two motions of the earth. When earth spins or rotates around its axis, that movement of spinning is called Rotation of Earth. And when earth spins or revolves around the sun, that movement is called Revolution of Earth. In this chapter, we will talk about the motions that our planet Earth has. We will discuss the various motions of the Earth and what that results in. By the end of the chapter, all your doubts would have been cleared!

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Motions of the Earth

Earth basically has two types of motions. They are rotation and revolution. These two motions are responsible for different kinds of phenomena. Let us look into them in further detail.

Rotation of the Earth

Rotation is the movement of the earth on its axis. Days and Nights take place because of rotation. So, the days and nights that you see are actually because of this rotation of the earth around its own axis. The axis of the earth, which is an imaginary line, has axis tilted at an angle of 66.5 ° with its orbital plane. The circle that divides the day from night on the globe is called the circle of illumination.

Revolution of the Earth

Revolution is the second type of motion of the earth. It is the movement of the earth around the Sun in a fixed path or orbit. Revolution causes the change of seasons.  It takes 365days and 6hours (one year) to revolve around the sun. It is important to note that we consider a year as consisting of 365days only and ignore six hours for the sake of convenience.

Leap Year

Six hours saved every year are likely to make one day (24hours) over a span of four years.  We add this surplus day to the month of February. Every fourth year, February is 29 days instead of 28 days. This year with 366 days is called a leap year.

More About Revolution

Summer Solstice

The earth goes around the sun in an elliptical orbit. The nights are longer than the days of the winter season. This position of the earth is called the summer solstice.

Winter Solstice

On 22nd December, the Tropic of Capricorn gets direct rays of the sun as the South Pole tilts towards it. It is summer in Southern hemisphere and winter in the Northern hemisphere. This is called winter solstice.

Equinox

On 21st March and 23rd September, direct rays of the sun fall directly on the equator. During this period, the whole earth experiences equal days and equal nights. This is called an equinox.

Question For You

Q. Write about the summer solstice, winter solstice and equinox.

Ans:

• Summer Solstice: The earth goes around the sun in an elliptical orbit. The nights are longer than the days of the winter season. This position of the earth is called as the summer solstice.
• Winter Solstice: On 22nd December, the Tropic of Capricorn gets direct rays of the sun as the South Pole tilts towards it. It is summer in Southern hemisphere and winter in the Northern hemisphere. This is called winter solstice.
• Equinox: On 21st March and 23rd September, direct rays of the sun fall directly on the equator. During this period, the whole earth experiences equal days and equal nights. This is called an equinox.