Extended Data Figure 4 : A snapshot of QE/k2,E = 200 simulation shown in Fig. 1 (black line) at 34.6 Myr.

From: Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth

Extended Data Figure 4

At this time, eccentricity excitation (a) and the associated variation of Earth’s obliquity (b) are not due to Kozai perturbations, but owing to the slow-varying near-resonant argument Ψ = 3Ω + 2ω − 3γ (c), where Ω and γ are longitudes of the lunar ascending node and Earth’s vernal equinox, respectively, and ω is the Moon’s argument of perigee. This near-resonant interaction is responsible for the substantial reduction of Earth’s obliquity seen in Fig. 1.