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In the past century, an “air tide,” or shifting of the atmosphere, has been recognized and studied.
Since 1918, it has actually been measured in the Northern Hemisphere. Although this Moon–linked barometric variation is small—just 1/1,000 inch of mercury—its effects are not.
(Barometric pressure is measured as inches of mercury. When the weather forecaster says the barometer is 29.95 inches, he or she is talking about how many inches of mercury could be supported by the current pressure of the atmosphere.)
Bob Berman, astronomer editor for The Old Farmer’s Almanac, covers everything under the Sun (and Moon)! Bob is the world’s most widely read astronomer and has written ten popular books. Read More from Bob Berman
