And again, we wish you an excellent New Year!
This first article of 2014 continues our last article of 2013 which tried to explain how humankind got to name and organize time cycles based on astronomical facts such as Earth spinning around itself and Earth’s voyage around the Sun.
But humankind had to also devise some complementary elements to this system (in addition to the objective, astronomic ones) which we can call « the needed arbitraries » because they are objectively required although they aren’t objectively determined.
When year 2013 ended and year 2014 started, where exactly on Earth did it happen first and why?
Well, the short and theoretical answer would be: it happened on the Eastern-most meridian of the Earth, of course.
But theoretical answers aren’t what you, folks, expect from this blog so let’s continue up to the real answer: the Eastern-most meridian is determined by « meridian zero« , the reference meridian, the one from where counting starts, the one referred to as « the prime meridian« .
Think of the Earth as if it were an orange: the equator line it is the biggest imaginary circle between the North and South poles, equidistant from them and is objectively determined by the physical reality of our planet’s shape, poles and axis of rotation.
Earth’s equator divides it into Northern and Southern hemispheres and latitude counting (0 to 90 degrees towards both North and South poles) starts from it, describing smaller and smaller imaginary circles called « parallels« .
But when it comes to the segments of the orange, there’s a different situation: which of them should be « meridian zero » from which the counting of longitudes towards East and West should start?
Because there is no physical feature allowing to objectively establish an imaginary circle containing both poles (stem end and blossom end of the orange) that would be « the longitude zero » meridian.
This is the first example of needed arbitrary: there must be a starting place but where?
Well, before 1884 different (important) countries used different prime meridians on the maps they’ve issued and of course, each such prime meridian was crossing a key landmark for that country, like for example the Paris Observatory for France or the Royal Greenwich Observatory for Britain.
To solve the divergences, in October 1884 the International Meridian Conference was organized at Washington D.C. reuniting representatives of 25 countries which decided by a majority of 22 votes that the prime meridian should be the Greenwich one mainly because it was quite widely used already.
France, which abstained from voting, was not really excited with the decision and afterwards it continued to issue maps having Paris as prime meridian until about 1911.
So this is how Greenwich meridian officially became the prime meridian of the Earth, the one from which longitudes and time-zones are counted and the line where East and West separates…. or meets.
The subject is so much more complicated than our brief story it often becomes weird so, for example, if you want to know where is the New Year first celebrated we can only say that since 1 January 1995, it’s on the Caroline Island, part of the Republic of Kiribati which by making a local political decision changed the time-zone for its Line Islands (one of the islands being Caroline Island) just in order to be the first to see the first sunrise of the year 2000.
The decision moved the International Date Line more than 1,000 km. east of Kiribati Republic despite the protests of other Pacific nations but the goal was reached: the huge interest of people all over the world for year’s 2000 arrival translated into more than 1 billion TV viewers watching broadcasts from the Caroline Island (which since 1997 was re-baptised to « Millenium Island« ).
In conclusion, the eastern-most point of the Earth is currently the Caroline Island but nobody knows for sure for how long as some prognoses for this basically uninhabited atoll are it might be swallowed by the ocean by 2025.
Oh well, « sic transit gloria mundi » once said someone fluent in Latin, so passes away the glory of the world.
But getting back to needed arbitraries in time-keeping, other examples are the sub-units of the astronomically-based units.
Like for example months/weeks subdivisions of the year or hours/minutes/seconds subdivisions of the day.
Basically, any imaginable kind of partitions can be done as long as they fit the main (objective) measurement unit to which they subordinate so it’s hardly surprising that along history and across cultures hundreds of possibilities and combinations were developed and used.
In our previous article we told you how the 10 Roman calendar of Romulus months were succesively corrected in time to become the 12 months with the days distribution we currently use.
So now let’s tell you that the origin of the present 7-days week system can be traced back to the Jews during the Babylonian Captivity.
It seems that both religions used the 7-days week calendar but as Jews’ sacred 5 books of Torah contains clear provisions regarding the 7 days cycle determined by the day of rest and as Christian and Islamic religions are directly connected to Judaism, it’s not really an enigma how this system got widely spread and became part of the international administrative calendar used today.
Day partitioning into 24 units we call « hours » seems to date back to the Sumerian then Babylonian civilizations but despite evidences found so far, it is mainstream that Hipparchus, one of the greatest astronomers and mathematicians (he is regarded as the founder of trigonometry) in antiquity was the one who devised or at least prioritized the 24-equal-hours division of the day based on equinox-days measurements.
The 60-base (sexagesimal) calculations were used by Babylonians which inherited them from Sumerians but the reason why Sumerians prefered sexagesimal calculations is still a mystery.
One theory asserts they might have been attracted by the high divisibility of 60 (which can be divided by 1,2,3,4,5,6,10, 12,15, 20 and 30) but regardless, fact is Babylonians inherited this too.
Greek astronomer Eratosthenes (inventor of the geography and chief-librarian of the Library of Alexandria, among others) used this sexagesimal system to divide a circle into 60 parts.
Just few decades later, Hipparchus devised longitudinal lines that encompassed 360 degrees and some 200 more years later, the Greek Claudius Ptolemy who lived in Alexandria too (when Egypt was a Roman province) went on further by dividing each of Hipparcus’ 360 degrees into 60 equal parts and even further, by subdividing each of the resulted parts into 60 smaller equal parts.
Being under Roman occupation, he named his 60-fold fractions in Latin: parts resulted from his first division were “partes minutiae primae” (« first small parts« ) and the parts resulted from his second division were named “partes minutiae secundae” (« second small parts« ).
So yes, as you’ve figured out already, these are the etymological origins of the words « minute » and « second » we are using today.
But lacking usability, these too small for their time subdivisions sunk into oblivion for the next centuries and re-surfaced once sciences and technology became advanced enough to require more and more accurate measuring of time.
Atomic clocks today provide unbelievable levels of time-measuring accuracy, for example a NIST Cesium clock is capable of keeping time to about 30 billionths of a second per year but just few months ago NIST announced that their ytterbium clock ticks are stable to within less than two parts in 1 quintillion (1 followed by 18 zeros), making it the most stable atomic clock ever.
Seems that our capabilities of measuring time greatly exceeds our capabilities of understanding it.
Well, here ends our cruising around time-measuring and calendars.
But before the final word let’s just mention that, according to our own internal calendar, there’s an event coming up really soon.
So hang on with us to see the outstanding new app we’re going to release shortly.
Sorry boss, it just slipped out!
Er….bye folks, see you next week!