(a) Mollweide projection of all impact craters >100 km (∼170) expected to have formed since 4.55 Gyr ago. The picture shows a representative Monte Carlo simulation for our nominal model (see text). Colour code provides epoch of formation. The implementation of the Monte Carlo code follows a recent work40. The simulations track all the collisions with impactors >2 km, but here only the large ones are shown. While old craters are obliterated by subsequent cratering, empirical saturation shows that some 40 craters >100 km should be retained (Fig. 1). (b) Mollweide projection of a Ceres global mosaic showing observed 16 confirmed craters >100 km (yellow lines).