What is the phenomenon known as libration?
Answer
A nodding or rocking motion that the Moon exhibits from our perspective.
Libration refers to the slight, observable wobbling motion that the Moon exhibits when viewed from Earth over time. This motion is crucial because it allows astronomers to see slightly more than the initial 50% of the lunar surface that is tidally locked facing us. This effect is caused by several factors working in concert, including variations in the Moon's orbital speed—as it speeds up and slows down slightly during its elliptical orbit—and the tilt of the Moon's axis relative to its orbital plane. Libration provides a small bonus view, revealing up to about 59% of the total surface over time.
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