# Can the gravitational constant be directly measured?

The value of the gravitational constant $G$ is $6.67384\times 10^-11 {\rm m}^3{\rm kg}^{-1}{\rm s}^{-2}$. This value is used in the formula to calculate the attractive force between two objects with mass, my question is:

since it is a constant why does it have units? As it has unit can it be directly measured?

I understand that the gravitational constant is not the acceleration force exerted by an object with mass such as earth.

is it related to a hypothetical force carrier, the graviton, since the value seems incredibly small? or maybe since the unit contains measurement of units in 3d space it has something to do with special relativity?

• $G$, having units, is not one of the Fundamental constants. the fact that it appears "small" is only a consequence of the units used to express it. $G$ is also not associated with special relativity. only $c$ is. but both $G$ and $c$ are associated with general relativity. – robert bristow-johnson Apr 5 '15 at 6:28
• – Qmechanic Apr 5 '15 at 19:59