Wednesday, January 23, 2013

The Ancient Manipulation of Time: Part 2


The First Computer?

Today clocks are everywhere. In addition the time on your computer, your cell phone or your cable TV is usually in sync with a central atomic clock server which means that clocks now differ only seconds at most. Clocks are a particularly human invention and their ubiquitous presence means that we have accepted them as fundamental to our lives. [1] Yet the invention of clocks involved thousands of years of development -- a story that is as fascinating as any detective movie.

About 4000 years ago, the Babylonian's began the ultimate leap from observations to predictability. In so doing they created the foundations for modern science and technology, which as we all know, has given humans the ability to dominate the Earth. Their work even led to what was arguably the first analog computer, a device that is still in wide use today.

The movement of the sun, moon, stars, constellations and planets were, for the ancients, the way they told the time of day, the month, the seasonal changes, the solstices and equinoxes and the new year. This was essential for knowing when to plant and when to harvest, when the fish ran, when animals migrated and when annual rains or floods would come.

Astronomical movements were to the Babylonians a celestial clock. And since time ruled the lives of people and empires, they looked to understand the complexity of time. Starting about 1800 BCE, the Babylonians kept comprehensive records of astronomical movements on clay tablets written in cuneiform. Known as the Babylonian astronomical diaries, these diaries now combined the power of human memory with the power of the written record.

For the purposes of this blog about time, it is important to note that observations deal with the past while predictability derives from these past observations and then projects into the future. This simple point is a key to understanding the human relation to time and how it has given us so much power.

It is also important to note that when human memory was recorded on clay tablets it was then not dependent on living individuals. Memory was still the key to the power that humans were unlocking, yet now it had achieved a new form, a more permanent form in writing that could be accessed by civilized humans indefinitely into the future. [2] 

Careful astronomers, the Babylonian's measured and recorded the positions of the sun, the moon, the stars, the constellations and the planets over hundreds of years. At some point they grasped the fact that celestial movements repeated. [3]


This is a close up of a section of a cuneiform tablet that recorded the daily movement of the planet Venus over a period of 21 years. It is the first time that the movement of a planet was understood as repeating. Although this tablet has been dated to the 7th century BCE, it is believed to be a copy of a much older record from the 17th century BCE.
(commons.wikimedia.org)

Once having understood these repeating patterns, they created mathematical formulas that correctly matched the previous paths and predicted future movements. 

Historian A. Aaboe said about Babylonian astronomy that "all subsequent varieties of scientific astronomy, in the Hellenistic world, in India, in Islam, and in the West -- if not indeed all subsequent endeavor in the exact sciences -- depend upon Babylonian astronomy in decisive and fundamental ways."

Now lets fast forward just a bit in the ancient world to around 150 BCE. With the conquests by Alexander the Great, the science and discoveries of Babylonian astronomy became known to the Greeks. Building on the Babylonian's knowledge, the brilliant Greek astronomer Hipparchus created the first astrolabe which was perhaps the earliest computer. In later centuries, when the astrolabe became fully developed it could be used for obtaining the time, for nautical navigation, surveying, locating stars and hundreds of other uses. It is still widely used today in parts of the world.



On the left is a drawing of the basic lines for an astrolabe in Chaucer's time, 
in the middle is an actual astrolabe during Chaucer's time, 
on the right is a sexton which is a specialized astrolabe for use at sea. 
(commons.wikimedia.org) 

Screen grab of a digital astrolabe.
Get your own free copy at: 

The construction and calculations of the astrolabe were based on mathematical formulas derived from the movement of astronomical bodies. Early clocks in fact were put together based on formulas carved into astrolabes.

During the Middle Ages and into the Renaissance many astronomical clocks were built -- clocks that displayed the position of the planets, the zodiac, the moon and the sun along with the current time. While the use of these clocks eventually faded in favor of today's clocks that simply give the time of day, they could not have existed without their astronomical ancestry.

Lynn White Jr., Medieval researcher, said, "Most of the first clocks were not so much chronometers as exhibitions of the pattern of the cosmos...Clearly the origins of the mechanical clock lie in a complex realm of monumental planetaria...and geared astrolabes.”


On the left is a drawing showing the moving plates of an astrolabe, 
in the middle is a diagram that shows how a clock based on an astrolabe 
can display the sun's daily and yearly movement. 
The last photo is of Prague Orloj, the famous astronomical clock in Prague 
that was built in 1410 and is still working today. (commons.wikimedia.org)
This chart explains what information can be read from the Prague Astronomical Clock. 
(commons.wikimedia.org)

The point is this: 
Time and yearly changes being critical to human survival and the fact that humans possessed remarkable memory (see my earlier blog: The Genius of Cavemen) led to the discovery of repeating patterns in the heavens that corresponded to seasonal changes and then to the ability to predict future patterns.

SUMMARY:

  • The first time keeper was the movement of the sun, moon, stars, constellations and planets
  • Humans, due to their unique memory, noticed long term patterns and began to correlate celestial movements with changes in the year
  • Civilizations, such as the Babylonians, took these observations to a new level of accuracy via written records
  • After hundreds of years of written data, the Babylonians were able to create formulas that predicted the movement of these celestial bodies
  • These mathematical formulas were eventually built into the astrolabe device that could be used to make calculations derived from sighting objects in the sky; this led to the development of early geared clocks which were often geared astrolabes 
  • This device eventually led in part to today's computers
Modern Note: The computer you are using to read this blog has, at its heart, a CPU (Central Processing Unit) which contains a clock -- and this clock is critical to computer processing as a CPU could not function without it. Simply put the modern world could not function without precise clocks.


Virtually all microprocessors contain a clock which regulates the actions of the chip. 
The chip could not process information without the clock. (commons.wikimedia.org)

To restate what I said in the article before this one

By accurately observing the past and projecting that behavior into the future, humans could now, in a limited way, use time as a resource; they could manipulate time. Being able to predict meant that they not only knew when to plant, but when to start preparing months before the seeds went in the ground, how much grain to store for the winter and how much fire wood to cut. My guess is that over time, the ability to predict seasonal changes in weather, flooding, temperature, prevailing wind etc. lead to a substantial increase in crop yields which in turn led to the rise of complex civilizations. Humans had begun to have, to use the modern term, a handle on the time, which gave them a power possessed by no other animal on the planet.


On the left is a chart of the seasonal winds known in Homer's time, ca. 700 BCE; 
on the right, from Aristotle's book Meteorology, is Aristotle's 'wind rose' showing a much more sophisticated understanding of wind patterns as they related to the seasons about 400 years later after Homer. Aristotle coined the word meteorology and the term 'weather forecast'. (commons.wikimedia.org)


FOOTNOTES:
[1] It is only in the last two hundred years or so that standardized and accurate clocks have become a necessity -- with the need to create time zones and schedules for the railroads, for example, and the need for factory workers to show up on time when the Industrial Revolution took hold.
[2] Even today, astronomers are learning from these clay tablets. For example, the appearance of Halley's Comet was recorded on a Babylonian clay tablet in 164 BCE.
[3] The Babylonians were so good at finding patterns they even discovered the Saros Cycle, which predicted solar and lunar eclipses due to repeating patterns over about 18 years. 



A picture of activity in the Istanbul observatory showing the intense interest in astronomy 
by Islamic and Middle Eastern scientists in the 15th century. 
Arab scientists went on to perfect the astrolabe. (commons.wikimedia.org)





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