A Short History of Time

A Short History of Time
John Best

A very condensed history of how time, one of the greatest human inventions, came to be.

Let us take ourselves back to an era not long after the emergence of modern humans. What was time to these early humans? One might expect that even primitive languages would have some words for past and future, and a word for day, being the period when the sun is up. Maybe our distant ancestors could talk about things that happened yesterday, and their plans for tomorrow, but their concept of time didn’t extend beyond this. Were they able to talk about say, something that will occur three days from now, or something that happened twelve days ago, without having words for the numbers? A group of linguists determined that the language of a remote primitive tribe in the Amazon region did not have words for any quantities, not even one.1 Before the invention of numbers, primitive humans probably relied on sign language using their fingers to represent quantities, as we still occasionally do today. It could be said that the decimal system has existed for as long as humans have had ten fingers. One enviable aspect of not having any numbers beyond ten fingers is that people probably went through life without knowing how old they are! The earliest symbolic representation of a number encountered by archaeologists is the representation of the number one by marks scratched on a piece of bone. Higher numbers may not have existed until several thousand years later, when the ancient Sumerians used tokens to represent higher numbers, maybe around 4000 B.C.. They refined their use of numbers, and in the third millennium B.C. they developed a sexagesimal number system based on 60. No one knows for sure the how or why behind the choice of 60 as the base. Maybe its use was convenient because a solar year has approximately 360 days and also 12 lunar cycles or months, and each month has approximately 30 days, all multiples of 6. In our modern society, the use of multiples of 6 to represent quantities is ubiquitous: think a dozen eggs, or 360 degrees in a circle, or in the case of the current discussion, 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute – all multiples of 6. The use of 6 based numbers in timekeeping may also be related to the use of such numbers to represent angles. This is may be because it was recognized that the sun followed a circular path around the earth (we now know that it is the path of the earth around the sun), and the shadow of the gnomon of a sundial, one of the earliest clocks, follows a circular path around a circular base. The ancients, after they learned to count that high, knew that there were roughly 360 days in a year, and for about a millennium, until the 8th century B.C., this was the number of days in a calendar year. This number may have been chosen over the more exact 365, because it was evenly divisible. It would have made sense that a circle would have 360 degrees, so that each day of the earth’s orbit of the sun, it would describe an arc that subtends one degree of a circle. In ancient Egypt, there were many obelisks. Their purpose was more than decorative; they were used as shadow clocks in the manner of sundials.

The ancients could measure long spans of time by referring to observations of the sun, moon, and stars. They could note that it is midday when the sun is at high noon. Measurement of periods shorter than this was a problem however. The circular sundial solved this problem. Other primitive clocks such as the hourglass could only measure a given span of time, but the sundial was capable of precisely representing any span of time during the daylight hours. This allowed ancient Egyptians to subdivide the day into smaller parts. The earliest known sundial, discovered in the Valley of the Kings in Egypt, and dating from around 1500 B.C., divided the sunlit portion of the day into 12 units. By dividing the day into 12 parts, the first standard unit of time was created – today we call it the hour.

Egyptian sundial

Egyptian sundial

This early “clock” had some serious shortcomings however; it couldn’t be used at night or on cloudy days, and the sunlit portion of days changed length depending on the time of the year. Several other early clock designs were capable of operation after dark. These ranged from candle and incense clocks, to water clocks. The problem of hours varying in length wasn’t solved until much later however, when Abu’l-Hasan Ibn al-Shatir made an improvement to the sundial in 1371 A.D. His polar-axis sundial displayed equal-length hours at any time of the year. Improved precision of later mechanical timekeeping devices, such as those using pendulums, allowed hours to be subdivided into 60 minutes, and a minute to be subdivided into 60 seconds. At this point, we can say that the invention of time, as a practical method of comparing and quantifying change, is complete.

There have been many clock designs over the centuries, but until recently, solar, lunar, and celestial cycles have been the final arbiter or standard for what the correct time is. The second was defined as a fraction of a mean solar day, then redefined in 1956 to be a fraction of a certain tropical year. Since 1967, the second has been based on emissions of a radioactive cesium isotope. Accuracy of billionths of a second per year is ascribed to this clock type. The first atomic clocks were standardized against astronomical time, but they did not maintain perfect agreement with astronomical time, so in some jurisdictions, “leap” seconds are used to force continued agreement between atomic time and astronomical time. Now, there can be two opinions on what time it is, depending on whether atomic time, which is purely a count of the emissions of the radioactive isotope, or astronomical time is used. This factor can influence high precision measurement of the duration of events

It is claimed that atomic clocks must be corrected for altitude due to “gravitational time dilation” as predicted by Albert Einstein. This is the idea that where gravity is stronger, clocks run more slowly, and where it is weaker, they run faster. According to this theory, all possible clocks or timekeeping methods are affected equally. This idea that time is like a substance that is either stretched or compressed, depending on the strength of the gravity that the clock is experiencing, leads to numerous impossible paradoxes: The gravity on earth is much stronger than it is on the moon; therefore, according to this theory, time runs faster on the moon than on earth. If the timekeeping method is based on the yearly orbit of the earth around the sun (the solar year), does this mean that the moon orbits the sun faster than does the earth, so that a year will be shorter on the moon? Wouldn’t the moon have to become detached from the earth for this to be the case? How about the difference in gravity between the top of a tall skyscraper and its base? This difference in gravity due to elevation is small but significant. Is the length of the solar year different at the base than at the top of the building? Why doesn’t the building tear itself apart? The same question applies to any solid object. Due to the association of gravity with mass, all solid objects have gravitational gradients, and would therefore have time gradients. How can one part of an object be older than another part of an object, if the entire object was created at the same instant?

The silliness isn’t limited to gravitational time dilation. According to Einstein, there is also time dilation due to velocity. In the interest of keeping this a short history, we won’t go there. Proponents of time dilation claim that the phenomenon is “proven” based on very minute measurements. However, something that is impossible cannot be proven by any math or measurements. It does not require exotic instruments to see that the claimed effect is quite impossible – only common sense. Unfortunately, time, one of the most brilliant inventions of the human mind – a method for comparing and quantifying change, has been corrupted into absurdity masquerading as science.

1) “Numbers and the Making of Us: Counting and the Course of Human Cultures”
by Caleb Everet
By University of Basel – Valley of the Kings, Egypt, Public Domain, https://commons.wikimedia.org/w/index.php?curid=33527052