History of timekeeping and geological cycles

Humanity has long utilized celestial patterns, such as the sun's position and lunar phases, to track time and organize societal activities. Ancient civilizations, notably Egypt, developed tools like sundials and shadow clocks to regulate agriculture and religious observances.

Beyond human-made tools, Earth's geological and astronomical cycles, known as Milankovitch cycles, have acted as silent clocks. These orbital variations influence solar radiation distribution, driving long-term climate shifts between glacial and interglacial periods that have historically shaped the rise and fall of civilizations.