According to Newton's law of gravitation, every object attracts every other object.
Thus, if the earth attract an apple towards itself, the apple also attracts the earth towards itself with the same force. Why then does the apple fall toward the earth, but the earth does not move towards the apple ?

Explanation

(i) The apple attract the earth with the same force with which the earth attracts the apple
(ii) According to newtons's third law , these two forces are equal and opposite in direction
(iii) For same magnitude of force, the acceleration produced in a body is inversely proportional to its mass
(iv) As the mass of the earth is very large compared to that of the apple, the acceleration of the earth is too small compared to the acceleration of the apple that it cannot be noticed .
Hence , the apple falls towards the earth while the earth does not move towards the apple .