I present the theory and analysis behind the experiment by Fomalont and Kopeikin involving Jupiter and quasar J0842+1845 that purported to measure the speed of gravity. The computation of the $v_J/c$ correction to the gravitational time delay difference relevant to the experiment is derived, where v_J is the speed of Jupiter as measured from Earth. Since the v_J/c corrections are too small to have been measured in the Jupiter/quasar experiment, it is impossible that the speed of gravity was extracted from the data, and I explain what went wrong with the data analysis. Finally, mistakes are shown in papers by Fomalont and Kopeikin intended to rebut my work and the work of others.

I compute the v/c correction to the gravitational time delay for light passing by a massive object moving with speed v, and I find disagreement with previously published results. It is also argued that the speed of gravity formula that was recently used in the conjunction of Jupiter and quasar J0842+1845 is frame dependent.