(a) Variations in atmospheric density
(b) Apparent shifts in the swing of a Foucault pendulum
(c) Changes in the position of sunspots on the Sun
(d) Eclipses of the Moon
(a) Variations in atmospheric density
(b) Apparent shifts in the swing of a Foucault pendulum
(c) Changes in the position of sunspots on the Sun
(d) Eclipses of the Moon