Extended Data Fig. 8: Inner core two-stage growth model.
From: Enhanced inner core fine-scale heterogeneity towards Earth’s centre
a, Inner core delayed nucleation and two-stage growth model. The inner core growth is in two steps: I. initial rapid growth stage (red segment); and II. Steady growth stage (blue). The right end of the x-axis is the present time. The left end, i.e., 0, is the moment when the centre of the primordial outer core cooled below its melting point. The y-axis is the normalized inner core radius at time t. RICB is the present inner core radius. The radius at the end of step I is a function of the supercooling temperature, which is shown in b. b, The initial inner core radius at the end of the early rapid growth step (step I) as a function of the supercooling temperature at historical Earth centre, modified from Huguet et al.30. The grey zone denotes the historical inner core radius at the end of Step I in the porosity evolution with delayed nucleation at 0.07–0.12τic, where τic is the presumed inner core age in the conventional growth model (dashed line in a).
