The Gravitational Constant in the Universe

The gravitational constant doesn't just control gravity, it only controls gravity. So there's no other way to figure it out. The only way to do it is to measure the force of gravity between two things. We can't like tell by, you know, how light bends around a black hole or something like that... But as our calculations in general relativity get more and more precise, we may be able to give us a new handle on how to measure this constant.