Why is Gravitional Constant, G = 6.67x10-11 Nm2/kg2 such a small quantity?
What are values of the masses taken for them ?
The reason why gravitational force is so feeble is still not know although there are many theories trying to explain it. One of the is string theory which asserts that the gravitational structure is embedded in our cosmos in a small quantity and the rest exists in other dimensions or universes.