According to the universal law of gravitation, gravitational force (F) acting between two objects is inversely proportional to the square of the distance (*r*) between them, i.e.,

𝐹 ∝{1\over 𝑟^2}

If distance *r *becomes *r/2*, then the gravitational force will be proportional to

Hence, if the distance is reduced to half, then the gravitational force becomes four times larger than the previous value.