What is the origin of gravity?

For a long time people have wondered what makes the planets go round the Sun and why anything thrown up comes down. Sir Isaac Newton probed the origin of this mysterious force and gave us the law of gravitation.

According to the law, which we have learnt in school, the force acting between two objects depends on their masses and the distance between them.

  The law makes it clear that the origin of gravity is the object itself- that is, by virtue of its own mass any object will have an influence on another object (mass). But if one were to ask why an object (mass) should exert a force on another, our present scientific knowledge does not provide a clear answer.

It seems that even Newton had thought about this question and tried in vain to get an answer. Finally he too admitted it is a god-given property to all objects.