Photograph: Simon Hill
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What are Moon phases?According to NASA, the Moon takes roughly 29.5 days to orbit Earth, passing through eight distinct phases along the way. Although we always see the same side of the Moon, the amount illuminated by the Sun shifts as it moves, which is why it can appear full, half-lit, or just a thin sliver at different times in the cycle. These shifting appearances are known as the lunar phases, and there are eight altogether:
The early 1970s brought the first big oil shock when the Middle East cut exports and imposed an embargo on the U.S. and others during the Yom Kippur War.