Is the Gravitational Constant a Tensor or a Constant Derived from Experiment?

[khemist]

Is the gravitational constant in Newton's equations a description of the curvature of space time? if it is, does that mean it is a tensor, or simply a constant derived from experiment?

 

[zhermes]

Its mostly the latter---a scalar constant derived from experiment. But it does have a more physical meaning: its the term that multiplies the stress-energy tensor, so its a conversion factor between standard units of energy and the curvature of space-time.

 

[khemist]

does that mean the constant has units, say of Newtons?

edit: i just looked at wikipedia, and it says it has units or N(m/kg)^2.

Are those units there to simply make the dimensional analysis work?

 

[zhermes]

No, its has units of $$m^3 s^{-2} kg^{-1}$$ in mks, which is force times distance squared over mass squared

Just think about how you could end up with a force in Newton's equation $$F_g = G \frac{m_1 m_2}{r^2}$$

 

[khemist]

sweet thanks for the quick replies.