As we know that our earth is revolving around the Sun which leads to change in seasons on earth. Not only the planets are revolving around the Sun, but the moons of different planets are revolving around the planets. But why they are revolving? Is there any string which binding them with each other? Well it's not but there is different kind of force which is working as string between them and that force is 'Gravity'. Gravity is a force which form between two masses when they came in contact with a definite distance.
The movements of planets around the Sun can easily understand by this simple activity:
I. Take a string fo length 30cm. (You can take less or much)
II. Tie an apple at one end of the string. (Where apple is refer as a planet)
III.And another end will grabs by your hands. (This place is refer as the Sun)
IV. Start rotating it above your head.
Here string refer as Gravitational attraction between sun and planets. When you apply force in a direction you will observe that apple will form an arc around your head. It is because, when you apply force then it will goes in a direction but as it tied with string that's why it will revolve. And you will observe that the apple will continue to revolve around your head for few seconds after applying the force. It is because, when you start moving it, then it will posses some kinetic energy and apple wants to go in one direction. But as it is tied with string that's why it starts revolving around your head.
And same thing happens with the Sun and planets, their gravity works like a thread between them and the force which created during the 'Big Bang', keep the planets revolving around the Sun. But here a new question arise, 'When we do the above activity with an apple and string, then we have observed that the apple will stops down after few seconds as we stop giving force. But why the Earth and all planets are keep revolving around the Sun? So, it is a very simple answer, on earth there is different types of forces are affecting the revolution of the apple, like air friction, gravity of the Earth, but in space there is not atmosphere or any other force which can affect it's revolution. Even planets have a huge amount of mass in comparison to an apple, that's why it posses a huge amount of inertia.
Earth is continuously revolving around the Sun. When the Earth goes in a direction then it wants to keep going in same direction, as it is given by Issac Newton in his first law of motion. But the gravity of the Sun bend it and forms an arc and again and again this is going on, that is why the Earth is revolving around the Sun.
Johannes Kepler shows the motion of planets by giving his law. And the Kepler's laws of planetry motions shows three scientific laws which describes the motions of planets around the Sun.
1. The orbit of a planet is an ellipse with the Sun at one of the two foci.
2. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
3. The square of the orbital period of a planet is propositional to the cube of the semi-major axis of its orbit.
Kepler's work on his theory 'Kepler's laws of planetry motion' was published between 1609 and 1619. And in the year 1687 Isaac newton showed that relationships like Kepler's would apply in the solar system to good approximation, as a consequence of his own 'laws of motion' and 'law of universal gravitation'.
Thanks for reading this, I wish you like this post. Please visit again and don't forget to share this post with your family and friends.
