In QCD, alas, things are more complicated, and the main reason for this is encoded in the plot above. It shows a compilation of the values for αs, derived from many different experiments, and for different momenta Q of the exchanged gluons. Gluon momentum is measured in GeV/c (and c, the speed of light, is set to 1), and a logarithmic scale has been used to allow to show a bigger range of values