Question

Why do celestial bodies revolve around the Sun?

A. Sun is in the centre
B. The Sun’s gravitational force keeps them revolving around it.
C. Because of electrostatic attraction force.
D. Because the sun is the source of light and energy.

Answer 1

Hint: A body moves without stopping in absence of friction and drag and if a necessary force is applied on a body to move it. Planets revolve around a star due to absence of friction or drag since the space has no air and is completely empty with no friction.

 Complete step by step answer:
All celestial bodies revolve around the sun due to gravitational force. It can be properly understood by a man who tied a stone with a thread and started revolving it. Now the stone can be considered an earth and the tension in the string can be considered as gravitational force and the man can be considered as the sun.

Similarly, the sun offers sufficient gravitational force to the earth which prevents earth from leaving the orbital trajectory and becoming free. Since the force is provided by the sun pull, hence all celestial bodies revolve around the sun.

The gravitational force is equal to centripetal force necessary for rotation and the centripetal force is balanced by the centrifugal force which is acting outward. Moon also revolves around the earth due to the same principle and that is why the moon is called the satellite of the planet earth.

So, the correct answer is “Option B”.

Note:
A celestial body is called the satellite of another celestial body only and only if it is revolving round the other one. Generally, earth is also a satellite of the sun, but for simplicity it is called the planet of the sun. The gravitational force exerted by the sun on the moon is far less than the earth is exerting on it.