-> But you're correct, the Earth tends to speed up and slow down, which is
-> one of the reason the equinoxes and solstices aren't at precise
intervals.
-> All this is due to gravitational interaction between the Earth and
other
-> bodies. Even we humans give the earth a wee nudge now and again. :-)
Short-term changes to the earth's rotational speed, especially ones
when it goes faster, are generally ascribed to changes in its moment of
inertia. If material moves from equatorial regions to high-latitude
ones, the effect is like what happens when a figure-skater is doing a
spin and pulls in his arms. The speed of rotation increases. Various
geological (plate tectonic) and climatic (movements of ice) effects can
cause this to happen.
dow
