Physics Topics are also essential for space exploration, allowing scientists to study phenomena such as gravitational waves and cosmic rays.
Visualizing the Gravitational Force Holds the Solar System
In the solar system, planets move in almost circular orbits around the sun ; and satellites move in circular orbits around the planets. A force (called centripetal force) is needed to make an object move in a circular orbit (or circular path). In the case of planets moving around the sun, the centripetal force is provided
by the gravitational force of the sun. And in the case of satellites moving around the planets, the centripetal force is provided by the gravitational force of the planets. We will now discuss the case of ‘the sun and the earth’ and that of ‘the earth and the moon’.
Since the masses of the sun (which is a star) and the earth (which is a planet) are very, very large, they exert very large force on one another. It is the gravitational force between the sun and the earth which keeps the earth in uniform circular motion around the sun. Similarly, the gravitational force between the earth and the moon makes the moon revolve at uniform speed around the earth. Thus, the gravitational
force is responsible for the existence of our solar system. The tides in the sea formed by the rising and falling of water level in the sea, are due to the gravitational force of attraction which the moon and the sun exert on the water surface in the sea. Thus, Newton used his theory of gravitation to give the first satisfactory explanation of many natural phenomena such as : motion of planets around the sun ; motion of moon around the earth ; and formation of tides in the sea (or ocean). He also explained Kepler’s laws of
planetary motion. Here are some more applications of Newton’s law of gravitation or universal law of gravitation. The universal law of gravitation is used to determine the masses of the sun, the earth and the moon accurately. It also helps in discovering new stars and planets.