Trend Watch

Solar Eclipse Sends People to Look Up 'Syzygy'

An obscure astronomy term goes mainstream

Syzygy was among our top lookups in the days leading up to the solar eclipse occurring on August 21st, 2017, as masses of people began paying considerably more attention to obscure astronomical terms than they usually do.

The grand spectacle of a total solar eclipse is traditionally accompanied by many other rare events. The midday air cools and stills. Birds stop singing and prepare for night. Words like “syzygy” leap off the Scrabble board and into the vernacular. Godfathers are obligated to grant favors.
—Ryan Truchelut, USA Today (, 18 Aug. 2017

We define syzygy as "the nearly straight-line configuration of three celestial bodies (such as the sun, moon, and earth during a solar or lunar eclipse) in a gravitational system." The word comes from the Greek syzygos, meaning "yoked together." The word has been used to refer to celestial matters since the 17th century.

....for there is a double Lunary Month, one called Periodical, being the Space wherein the Moon departing from any Point, returns to the same again, that is, (as is vulgarly computed) in 27 Days, 7 Hours, and odd Minutes The other Lunary Month, is that which they calSynodical, or the Month of the Lunary Syzygior Conjunction, and is that Space of Time wherein the Moon going from the Sun, returns again into Conjuction with him....
—Richard Blome, The Gentleman's Recreation, 1686

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