In 1686, Newton discovered the laws of gravitation [1] and predicted the universal gravitational constant . In 1798, with a torsion balance, Cavendish [2] measured . Due to the low intensity of gravitation, it is difficult to obtain reliable results because they are disturbed by surrounding masses and environmental phenomena. Modern physics is unable to link G with other constants. However, in a 2019 article [3], with a new cosmological model, we showed that G seams related to other constants, and we obtained a theoretical value of . Here, we want to show that our theoretical value of G is the right one by interpreting measurements of G with the help of a new technique using cubic splines. We make the hypothesis that most G measurements are affected by an unknown systematic error which creates two main groups of data. We obtain a measured value of . Knowing that our theoretical value of G is in agreement with the measured value, we want to establish a direct link between G and as many other constants as possible to show, with 33 equations, that G is probably linked with most constants in the universe. These equations may be useful for astrophysicists who work in this domain. Since we have been able to link G with Hubble parameter H₀ (which evolve since its reverse gives the apparent age of the universe), we deduce that G is likely not truly constant. It’s value probably slowly varies in time and space. However, at our location in the universe and for a relatively short period, this parameter may seem constant.