We all live on the planet known as earth. It supports many lives due to its features such as ample water. And all this is possible due to changes in day to night and seasons. The changes occur due to the movement of the earth in different ways.
The movement of the earth is not only responsible for changes in season and days but also contributes in many ways to make life possible on earth. Earth can move in different ways such as rotation and revolution. Some people get confused by both the terms as they considered them the same. But they are both different many times.
Earth’s Rotation vs Earth’s Revolution
The main difference between the earth’s rotation and revolution is that in rotation the earth turns around an internal axis. On the other hand, in revolution, it circles an external axis. To complete a rotation, it took only 24 hours whereas 365 days are required to complete one revolution. The difference in day to night is due to rotation by revolution causes changes in season.
The term ‘rotation’ simply means to spin. When it comes to the earth, the axis is the earth’s basis to rotate. Axis can be defined as an imaginary line that passes through the center of the earth. It takes 24 hours to complete a whole rotation or spin by the earth. Earth rotates in the counterclockwise direction.
The term ‘revolution’ simply means to move around something. When it comes to earth, it revolves around the sun. Revolution can be also called the orbit. It takes 365 days or a whole year to complete a revolution around the sun. The earth too revolves in a counterclockwise direction but around the sun.
Comparison Table Between Earth’s Rotation and Earth’s Revolution
|Parameters of Comparison||Earth’s Rotation||Earth’s Revolution|
|Interpretation||Earth spins on the axis.||Earth moves around the sun.|
|Speed||1,674 km/hr||30 km/s|
|Change in position||No||Yes|
|Location||Within the body of the earth||Outside the earth|
What is Earth’s Rotation?
Earth’s rotation is also known as the earth’s spin. In this, the planet earth rotates around its axis. It moves in prograde motion as it rotates eastward. In the Northern hemisphere, North Pole is the place where the earth’s axis of rotation intersects its surface. In the Southern hemisphere, South Pole is the point where the earth’s axis of rotation links up with the surface.
In ancient times, astronomers believed that planet earth was a fixed body. Everything in this universe such as the moon, the sun, the planets, etc. rotates around the earth. This is known as the geocentric Model or Ptolemaic Model. Later, many questions aroused related to this convention. Hence, in time it was revealed and proved that earth is not stationary. Many philosophers and scientists played an important role to come up with this idea such as Bishop Nicole Oresme (French philosopher).
Suppose you are standing on the ground but someone says you are traveling at speed of 1,674 kilometers an hour. Well, that person is not crazy it is a fact. Everyone is moving at the speed of 1,674 kilometers an hour and this is due to the earth’s rotation. The planet earth takes a whole day or 24 hours to complete a rotation around the sun.
As earth take 24 hours to complete rotation concerning the sun. But with others such as stars, it takes 23 hours, 56 minutes, and 4 seconds. According to scientists, the earth’s rotation with time is slowing slightly. The length of the day is increasing since the 8th century by 2.3 milliseconds per century. Even after consistently slowing down for many decades it had started spinning faster (report of 2020).
What is Earth’s Revolution?
It is a well-known fact that the earth rotates on its axis but it also orbits the sun or it can be said that it revolves around the sun. A fixed path is followed by the earth around the sun. It revolves in an anticlockwise direction or from east West. Earth takes a whole year or 365 days to complete one revolution. It revolves at a speed of 30 kilometers per second.
Previously it was thought that earth was located at the center of the universe. But it was proven wrong by the Stellar Parallax phenomena. As when we orbit, the position of the star changes. Throughout the year sky looks different at night because the earth is away from the sun and we can watch it from one direction. Changes occur whenever the earth orbits. This is the main reason behind at different times of the year we see different constellations.
As it is already stated that earth takes 365 days to complete one orbit. But .25 days are added extra to calendars by every four years. Which in return led to the leap year in every four years. Normally 365 days are mentioned on the calendar but in a leap year, 366 days are mentioned. In February date, 28 extends to 29 leading to one day extra in a leap year.
Earth’s revolution is not only responsible for leap year but also for seasonal changes. Earth experiences direct solar radiation in equal amounts. This is due to the earth from the top is away from the sun and tilted. As a result, the Northern hemisphere receives direct solar radiation in less amount as compared to the southern hemisphere.
Main Differences Between Earth’s Rotation and Earth’s Revolution
- Earth rotates west to east or in a prograde motion as it rotates eastward. On the other hand, the earth revolves around the sun in a counterclockwise direction.
- When it comes to period, the earth while its rotation takes only 24 hours or a whole day. Whereas 365 days or a full year is taken by earth to complete its whole revolution.
- In terms of changes, day to night and night to day occurs due to the rotation of the earth. This is the main reason behind time differences across the world. The Revolution of the earth is the main reason behind changing of seasons.
- Around the central point, the circle is made by every point in the rotation. Hence, from the center, there is equal distance to any point of the earth. On the flip side, revolution is done in orbit or a fixed path that is around the sun and can be called a circumference.
- To make it clearer, the example can be taken from real life. Such as for the earth’s rotation can be spinning top and hands of the clock. While merry go round and round a curve in a car are examples of earth’s revolution.
So, it can be concluded that rotation and revolution are two different terms that seem to be similar but they are not. Rotation and revolution have their different functions to support life on earth. In which rotation is done when the earth spins around its axis whereas in revolution it moves around the sun.
Earth takes 365 days to complete a trip of revolution and led to changes in seasons. This is because the earth is tilted away from the sun by the top. While a day or 24 hours are enough to complete the whole rotation and causes different time over the worldwide. Fortunately, rotation and revolution are done by earth and it prevented from ruining many life species.