When nature so mocks us, she often comes clean every once in a while, as if to offer confession for such a sublime joke. On May 10, 1994, a rare form of solar eclipse, far less spectacular than the conventional lid of darkness, but immensely fascinating for its own more subtle strangeness, enveloped much of North America. The moon's distance from the earth varies quite a bit during its revolution (planetary orbits are also not so regular as the charts in our high-school textbooks implied). If a solar eclipse occurs | when the moon lies at maximal distance from the earth, then the lunar shadow does not fully cover the sun's disc. At totality, therefore, a ring of bright light remains at the sun's periphery. Such eclipses are called annular, from a Latin word for "ring." (Annular eclipses are much less spectacular than total eclipses at normal lunar distances, for a ring of bright sunshine still yields substantial light--as much or more than on an ordinary cloudy day--while the sky turns off | as if God threw a light switch | when the moon's larger disc fully covers the sun).
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