A Brief History of Time.

 Lasting only a moment, a second is still widely employed in life today. From timing your morning exercise to complex scientific and financial activities, the second serves as an important unit of time. The concept of the second originates from our species' desire to understand our environment and observe the flow of time. This article explores the long history of one second, from its ancient roots to its modern definition and applications.

Throughout history, civilizations have employed various methods to measure the passage of time. The Ancient Egyptians were recognized as the pioneering civilization in this regard, using sundials and water clocks to gauge the hours in a day. Meanwhile, the Ancient Greeks developed a more precise system based on observation of cosmic movements. Whereas the Ancient Greeks established a more accurate way based on following the movements of stars, splitting the 24 hours into 12 segments that matched up with each of the zodiac constellations. This same system was then adopted by the Romans, eventually becoming our current system for measuring time.

Designed in 1862, the gnomon is a triangular blade with an inclined edge.

The 18th and 19th centuries saw a major shift as the steam engine and Industrial Revolution ushered in a need for a more precise measure of time.  With the telegraph and railways developing later, having an exact unit of time became even more critical for synchronizing schedules. To fulfill this purpose, the Royal Observatory in Greenwich, England was designated as 0° longitude and became the world's standard in 1848 by observing solar movements.

The International System of Units (SI) was eventually established in 1866, providing a uniform definition for the second. This stated that the second should correspond to 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. As such, it provided an accurate and consistent measure of time. Consequently, it was accepted as the standard by the International Astronomical Union in 1967.

The Babylonians, Sumerians, and Egyptians all utilized a sexagesimal system (base-60) for their mathematical calculations that were later adopted by the Roman Empire. This base-60 allowed for simple computations and dividing time into smaller units. To this day, the Romans' decision to divide an hour into 60 minutes and each minute into 60 seconds continues to be employed around the world.

Advances in technology have enabled even more exact measurements of time. Atomic clocks, relying on atoms' vibrations to measure time, are currently in widespread use and boast precision up to a few billionths of a second. Such clocks have many uses, from navigation systems such as GPS to synchronizing computer networks and financial transactions. Moreover, the emergence of GPS technology has produced the ability to easily align clocks all around the world, highlighting the significance of an accurate and common definition of the second.

In conclusion, the evolution of timekeeping from ancient sundials and water clocks to the precise and uniform measure of time we have today has been paramount for many industries and technologies. The second will remain a fundamental element in our daily existence, whether we're timing our exercise routine, arranging a business gathering, or hurrying for the train. It is easy to overlook how precise its measurements are, but it has become so pervasive in our lives that this accuracy is something we take for granted.