 Complete the following phrase:  The main reason for the slowing down of the Earths rotation is tidal friction, which alone would lengthen the day by 2.3 mscentury. Other contributing factors are the movement of the Earths crust relative to its core, changes in mantle convection, and any other events or processes that cause a significant redistribution of mass. These processes change the Earths moment of inertia, affecting the rate of rotation due to the conservation of angular momentum. Some of these redistributions increase Earths rotational speed, shorten the solar day and oppose tidal friction. For example, glacial rebound shortens the solar day by 0.6 mscentury and the 