The spectacle of the Moon passing through the Earth’s shadow is not as simple as you might expect. Rather than simply passing into the darkness to vanish for a while, before re-emerging into the light, we see quite a complex sequence of events. This is because the Earth’s shadow is composed of two regions: The penumbra and the umbra. The umbra is the fully dark part of the shadow, and is shown in the diagram below as the dark grey … Continue reading →