Evolution of radial and transversal accelerations and L_z around the retrograde interval of the year 1990. Contrary to what was expected, radial acceleration points towards the barycentre (i.e. it is negative) during brief moments when L_z < 0, marked with arrows and depicted in the embedded plots. They are produced by Venus–Earth synodic period perturbations. All the quantities are reckoned in astronomical units and days.