Question

What makes Newton's gravitational law universal?

Answer 1

Newton's gravitational law

1. Because it applies to all masses at all distances, regardless of medium, Newton's law of gravitation is known as the universal law of gravitation.
2. If $G$ is universal gravitational constant, the gravitational force between two masses ${\mathrm{m}}_1$ and ${\mathrm{m}}_2$ separated by a distance $d$ is always:

${\mathrm{F}}_{\mathrm{g}}=\mathrm{G}\frac{{\mathrm{m}}_1{\mathrm{m}}_2}{{\mathrm{d}}^2}$

Therefore, this is a universal law.