The importance of universal law of gravitation is that it explains:

(i) The gravitational force of attraction of the Earth binds all terrestrial objects to the earth.

(ii) The gravitational force of earth keeps the atmosphere close to earth.

(iii) The moon revolves around the earth.

(iv) The gravitational pull of the sun on the planet keeps them revolving around the sun.

(v) The tides formed by the rising & falling of water level in the oceans are due to the gravitational force of sun & moon on the water.