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 →
Everybody knows that the Moon changes its face. Sometimes we have Full Moons, other times it’s a Half-moon, or a crescent, or there’s no Moon at all. And everybody knows that these are called the phases of the Moon. But not everybody knows that these faces follow a regular cycle, or that the common descriptions are misleading at best. A proper understanding of what’s actually happening to make the moon show different faces, and the nature of the “Dark Side … Continue reading →
As the Earth revolves around the Sun, and the Moon revolves around the Earth, it happens sometimes that all three fall into alignment. When this happens at New Moon, the Moon covers up the Sun in our skies, and we have a Solar Eclipse. It is an interesting coincidence that both the Moon and the Sun appear to be the same size in the sky, since both their actual sizes and their distances from earth are radically different, but this … Continue reading →
