The text describes the astronomical basis for tide height variations, emphasizing the role of the sun, moon, and Earth’s alignment. Tides are primarily driven by the moon’s gravitational pull, with the sun’s gravity playing a secondary but significant role. When the sun, moon, and Earth form a straight line—a configuration known as syzygy—their gravitational forces combine constructively, producing spring tides, which are characterized by higher high tides and lower low tides. This alignment occurs twice each lunar month (approximately 29.5 days), specifically during the full moon (when the moon is on the opposite side of Earth from the sun) and the new moon (when the moon is between Earth and the sun). These events, happening roughly every 14.7 days, result in the most extreme tidal ranges. The text highlights the predictable, cyclical nature of spring tides, driven by the Earth-moon-sun system, and their direct dependence on the relative positions of these bodies. Understanding this phenomenon requires recognizing the gravitational interactions and orbital dynamics that govern tidal patterns, a fundamental concept in Earth science.