Digital Interactive Content Light (lower block) – Shadows Lunar eclipse A lunar eclipse occurs when Earth blocks light from the Sun and its shadow is cast on the moon. Solar eclipse When a moon is in a position between the Sun and Earth, it blocks light from the Sun from reaching Earth. Using shadows to tell the time Observe how the length and direction of the shadow cast by a pole changes over time. What can you observe about the length of the shadow at 12 pm?