Sundin column: Our complicated history of measuring time | PostIndependent.com

Sundin column: Our complicated history of measuring time

Hal Sundin

Hal Sundin

Starting with the months of the year, have you ever wondered where our crazy calendar came from, and how it got that way? It is obvious from the names of the last four months: September, October, November and December, meaning seventh, eighth, ninth and 10th in Latin, that Rome is the source of our calendar. But those are our ninth, 10th, 11th and 12th months. How did that happen? It is a long, complicated story.

Romulus, the legendary founder and first king of Rome, is credited with creating the first Roman calendar, consisting of 10 months. The first four were named for gods and goddesses — Marius, Aprilis, Maius and Junius — and the last six — Quintilis, Sextilis, September, October, November and December — were given numerical names.

The original calendar was a lunar calendar with each month consisting of a lunar cycle, which was dedicated to a phase of agricultural activity starting in early spring (covering a total of 285 days, which left an unnamed period of 80 days during which there was no agricultural activity).

Around 700 B.C., Romulus’s successor, Numa Pompilius, replaced this void by introducing two winter months, Januarius and Februarius, and moved the beginning of the year from Marius to Januarius. He also gave all the months except Februarius an odd number of days because odd numbers were considered to be lucky. There were seven 29-day months and four 31-day months, which with Februarius’s 28 days added up to only 355 days. It was therefore necessary to insert an intercalendar month of 20 days every other year to keep the calendar synchronized with the sun.

In 46 B.C., Julius Caesar reformed the calendar to a more orderly system based on a year of 365.25 days, adding an extra day to Februarius every fourth year, and it has since been known as the Julian Calendar. He also changed the name of the seventh month from Quintilis to Julius. Then his successor, Augustus, to have equal recognition, changed the name of Sextilis to Augustus.

However, the true length of a year is 365.242 days, which though a seemingly insignificant difference, by the beginning of the 15th century it had added up to a difference of 10 days between the calendar date and the solar date. Since this was creating a problem with setting the date for Easter, Pope Gregory XIII reset the calendar by adding 10 days in October 1582 and corrected the problem by decreeing that for years ending in 00, only those divisible by 400 would be leap years. This is now known as the Gregorian Calendar.

Thank goodness for the introduction of the Hindu-Arabic decimal numbering system (based on the concept of zero), which was promoted by Fibonacci, an Italian mathematician, in 1202, but not widely adopted until advent of the printing press in 1482. Otherwise our calendars would have dates like XIV and XVIII. Today Roman numerals are used only for old-fashioned-looking clocks and counting Super Bowls.

The Roman week originally had eight days, but with the ascendancy of Christianity, the current seven-day week was adopted. The days were named for Sol (the sun), Luna (the moon) and the five planets (Mars, Mercury, Jupiter, Venus and Saturn.) Only one of our days, Saturday, retains its Roman origin. The names of the other six days come from northern Europe. The days named for the Latin Sol and Luna became Sunday and Monday. Tuesday, Wednesday, Thursday and Friday are named for Norse-Teutonic divinities, Tiw, Woden, Thor and Freya.

We can thank the ancient Egyptians for our 24-hour day. They divided the day and the night into 12 segments each, and since they were based on the duration of daylight and darkness, daytime hours were longer and night hours were shorter in summer and the reverse in winter. The invention of the first clock (the water clock) made it possible to have 24 hours of equal duration throughout the year.

The Babylonians, who were remarkable for their astronomical skills — they were the first to be able to predict solar eclipses — adopted 60 instead of 10 as the base for their numerical system, presumably because 60 was divisible by the numbers 2, 3, 4, 5 and 6, whereas 10 is divisible by only 2 and 5. That is why we have 60 minutes in an hour and 60 seconds in a minute. And we now are able to measure time in units as small as milliseconds and nanoseconds.

Hal Sundin’s As I See It column runs on the first Thursday of each month.