Today, we mostly use the decimal system (base 10) for counting, probably because it’s easy to count on our fingers.
But the first civilizations that divided the day into smaller parts used different systems, like duodecimal (base 12) and sexagesimal (base 60).
Historians believe the Egyptians were the first to break the day into smaller segments, thanks to their use of sundials.
The earliest sundials were just sticks in the ground that showed time based on the shadow's length and direction.
The division of time into smaller units, like minutes and hours, traces back to ancient Egypt. They used sundials calibrated to divide the day into 12 parts, reflecting their duodecimal system, possibly based on lunar cycles or finger joints.
Early sundials, evolving from simple stakes to more sophisticated T-shaped bars, marked the progression of the day. These sundials likely formed the first representation of hours, although the length of hours varied with the seasons.
Nighttime was divided by the appearance of stars. Initially, 36 stars were observed, with 12 marking the passage of the night. Later, a simplified system with 24 stars, marking 12 divisions of night, was used during the New Kingdom.
Clepsydras, or water clocks, were utilized for nighttime timekeeping. Found in temples, these vessels measured time through water flow, offering a precise method for dividing the night into 12 parts during different months.
The division of both light and dark hours into 12 parts established the concept of a 24-hour day, setting the stage for fixed-length hours.
Greek astronomers like Hipparchus proposed the division of the day into 24 equinoctial hours based on observations of daylight and darkness during equinox days.
Babylonians inherited a sexagesimal system from the Sumerians, using it for astronomical calculations. The choice of 60 likely facilitated easy expression of fractions.
Although not used for general computation, the sexagesimal system persists in measuring angles, time, and geographic coordinates.
The circular face of clocks and the sphere of globes owe their divisions to the Babylonian sexagesimal system, demonstrating its enduring legacy.
Eratosthenes and Hipparchus employed sexagesimal divisions to create geographic systems of latitude and longitude, crucial advancements in cartography.
Hipparchus normalized lines of latitude and devised a comprehensive system of longitude, significantly influencing navigation and mapmaking.
The works of ancient astronomers like Hipparchus, Eratosthenes, and Claudius Ptolemy provide valuable insights into the development of timekeeping and geographic systems, shaping our understanding of history and science.