POT: Chapter 4
As the priesthood’s timekeeping expertise evolved, so too did their potential for broader applications of their skill. One of the most critical advancements was the ability of these timekeepers to serve as navigators. By using their calibrated internal clocks, the priest could determine the time difference between local noon at a known reference point (such as Greenwich or another fixed location) and local noon at his current position.
Local noon occurs when the sun is directly overhead, which varies based on geographic location. If the priest could accurately observe local noon, he could then calculate the difference between it and the known noon time at a reference location. This time difference would reveal the change in local noon time the priest had traveled east or west, allowing him to estimate his longitude.
To calculate longitude, the priest would need to determine when local noon occurred at his current position, compare it to the time of local noon at a known reference location (such as a fixed point of longitude), and then calculate the difference. Since the Earth rotates 15 degrees of longitude every hour, the priest could then calculate how far east or west he had traveled by measuring the time difference between local noons.
For example, if local noon at his position occurred 2 hours later than at the reference location, this would indicate that he had traveled 30 degrees east (since 15 degrees per hour × 2 hours = 30 degrees). Conversely, if the local noon was earlier, he would know he had traveled west.
This method allowed the priest, by simply adjusting his internal clock through counting heartbeats and calibrating his daily cycle, to serve as a practical and reliable navigator—even on long voyages across vast, uncharted waters.
As a result, the priest’s role evolved from a purely spiritual one to one of practical navigation, contributing not only to the religious needs of the community but also aiding in maritime exploration and map making.
