Mass distribution in the ecliptic frame of reference over the course of one year, for a defocussing configuration of the ISM (left panel, 2018–2019) and for a focussing configuration of the ISM (right panel, 2029–2030). Since the three-dimensional flow configuration is virtually constant over these periods of 1 yr, the observed changes reflect the spatial variations of the mass distribution along the Earth orbit, in a similar way to the mass distributions for Saturn, Jupiter and asteroid distances in Sterken et al. (2013).