Earth's shadow has two main regions: the outer shadow, called the penumbra, and the inner shadow, known as the umbra. The penumbra causes faint dimming that can be hard to notice. But the umbra is much darker. As it sweeps over the moon, the eclipse becomes obvious and the darkened portion spreads until the entire moon is covered.
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Professor Ha-Joon Chang is inspired by his passion for food to reflect on why economics matters - or, as he puts it, “a hungry economist explains the world”.