Evolution of the Earth’s obliquity, precession frequency, and precession period with time. The evolution of a_M (Fig. 3) and LOD (Fig. 5) are used to compute the evolution of obliquity and precession by Eqs. (A.6) and (A.7). The geological data of the precession frequency from tidal rhythmites and cyclostratigraphy are also plotted on top of the curve (Tables D.1 and D.2). We note that the precession frequency is the directly measured observable in cyclostratigraphy.