Fig. 2. The number of Solar days per Lunar synodic month as a function of age.

Data points from (8–11, 15, 17, 25–32). As in Fig. 1, the solid black line is the best-fit model including thermal tides, and the dashed red line shows the result of using the same initial condition but setting T_th = 0, while the dash-dotted green line shows the best-fit model when T_th = 0. The tidal rhythmite data older than 1900 Ma (25–27) lie between the two curves (dash-dotted green and dashed red) for which L_EM ≈ const., indicating that those data points correspond to states of the Earth-Moon system with different values of L_EM.