Shadows cast

People across North America were treated last week to the spectacle of a total solar eclipse. It is a rare event where the moon briefly blocks out the sun, leaving only a slim halo (or corona) visible while day turns to night for a few eerie moments. The sun is about 400 times larger than the moon but also much further away. When the moon is perfectly positioned between the earth and the sun, and closer to earth than usual, it blocks out sunlight over an area around 150km wide. This shadow is called an umbra.

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