Regulator of people’s lives the sun, quite significantly, guided and more or less organized their daily activities.
For what is time, after all? It is the rotation of earth on its axis, thus, determining the amount of sunlight on a given place at a given phase during that rotation. Fundamental knowledge in terms of survival.
The first sundial was more than likely the gnomon between 5,000 and 3,500 BC. It had a vertical stick or pillar and its purpose was to designate the time of day, which was indicated by the length of the shadow it cast.
At around 2,500 to 2000 BC, the Babylonians and the Egyptians built obelisks. These were slender, narrowing four-sided monuments (obelisk monument in Lincoln Memorial, Washington D.C). As the earth spun around its axes, these obelisks cast shadows forming a type of sundial. The people of these lands were able to divide the day by signifying noon. Since the shadow cast would lengthen or shorten, they could also designate the longest and shortest days of the year. The people soon realized that this was knowledge necessary not only in dividing the day, but by studying the location of the sun each season (along with other factors) determined the period they would plant and reap their harvests. At a later time, they placed markings around the base of the monument to allocate further time divisions.
Much later, at about 800 BC more detailed sun dials were created by the Egyptians. Still preserved is an Egyptian shadow clock made of green schist (a rock) which dates back to this period. It has a straight base with a raised crosspiece at one end. On its base six time divisions are inscribed and it is placed in an east-west direction. In the morning, the crosspiece is at the east end and in the afternoon at the west end. Here too, it is the shadow of the crosspiece on the base that indicates the time.
At around 300 BC, Berossus, a Babylonian priest and author, describes another sundial. This is a cubical block with a half-sphere hacked into it. At the center is fixed a small bead. As the shadow of the bead moves in a circular arc, it signifies the time during the course of the day. But as the earth orbits around the sun, the length of sunlight varies, thus casting a longer or shorter shadow. Therefore, the hours vary in length from season to season and were named ‘temporary hours’.
The more complex sundials were produced by the Greeks in 250 BC. Apollonius, a Greek astronomer from the ancient Greek city of Perga, used his knowledge of geometry to mark the hours on the surface of a conic block. Thus, devising a more accurate hemicycle (hemi in Greek = semi). Ptolemy, a better known astronomer, used the analemma (in Latin = pedestal) and this tool allowed shadows to be projected geometrically onto flat surfaces which are inclined at different angles to the horizontal.
Knowledgeable, uneasy souls continued in the footsteps of forefathers bringing the keeping of time to another dimension; to what it is today. Nowadays time keeping seems to be taken for granted. Clocks, watches, computers, cell phones, wherever one turns time is kept. Perhaps such ubiquitous reminders of the time are unnecessary, nonetheless without time order would not exist as it is today.
