Long before the invention of clocks, humans relied on the sun to gauge time. One simple method was the use of a sundial.
Imagine placing a vertical pole in the ground. As the sun rises in the east, it casts a shadow to the west of the pole. Conversely, as the sun sets, the shadow falls to the east. By measuring how long it took for the shadow to move from one point to another, people could approximate the time of day.
The Challenge of Global Timekeeping
But, this method posed challenges, particularly when people in different geographical locations tried to synchronize activities. For example, the shadow cast by the sun at a specific time in Pakistan would be vastly different from that in Australia due to the curvature of the Earth and their relative positions to the sun.
Establishing a Global Standard
To address these discrepancies, scientists and timekeepers proposed using a common reference point from which all time could be measured. They chose the Royal Observatory in Greenwich, UK, as this reference point. The concept of Greenwich Mean Time (GMT) was born, serving as the basis for coordinating time across the world.
In 1972, Coordinated Universal Time (UTC) was introduced as the new world standard. This system uses atomic clocks to ensure even greater accuracy than GMT, which relies on the Earth’s rotation. Despite popular confusion, UTC is not the same as GMT but is instead a more precise standard that keeps pace with atomic time while also staying close to solar time.