After learning about the general strength and prevalence of lunar tides, students often asked me whether the Moon’s tidal forces can affect human behavior. Yes, provided you had a very, very big head. For example, if your brain were, say, 7,000 miles in diameter (the size of Earth), then the Moon’s tidal forces would indeed give you an oblong-shaped cranium and impart untold consequences on your mental faculties. For normal Homo sapiens, however, the Moon’s difference in gravity from one side of the head to the other is immeasurably small. The weight of an understuffed down pillow imparts a squeezing force that is over seven trillion times larger than the Moon’s tidal force on your head.