Gauss intended his constant to be defined using a mean distance of Earth from the Sun of 1 astronomical unit precisely. With the acceptance of the 1964 resolutions, the IAU, in effect, did the opposite: defined the constant as fundamental, and the astronomical unit as derived, the other variables in the definition being already fixed: mass (of the Sun), and time (the day of seconds). This transferred the uncertainty from the gravitational constant to uncertainty in the semi-major axis of the Earth-Sun system, which was no longer exactly one au (the au being defined as depending on the value of the gravitational constant).