Most people know that one day is a full rotation of the earth and a year is a cycle around the sun. Besides that, the common person doesn’t really know that much about the science that essentially rules our lives. Here’s a brief history about time that will make you think twice next time you look at your watch.
Ever notice that September, October, November and December all have prefixes for seven, eight, nine and ten, respectively, despite being the ninth, tenth, eleventh and twelfth months? Blame it on the Romans. The original Roman calendar consisted of 10 months, and began in March, with a 61-day period at the end of the year that was possibly unnamed, according to Owlcation. This was because the Romans mainly used their calendar to track agricultural seasons and major festivals, and it’s likely that they didn’t really need to name the winter months. The months of Quintilis and Sextilis — the former fifth and sixth months — were renamed after Julius and Augustus Cesar. Other months were named after Roman gods, festivals and seasonal happenings.
In 713 BC, King Numa Pompilius reformed the calendar and added two new months, Ianuarius and Februarius, into the wintertime period. All of the months were between 28 and 31 days, to match up with 12 lunar cycles, equalling 355 days.
However, an intercalary month consisting of 27 days, called Mercedonius, or sometimes Intercalaris, was added by a higher-up in Roman religion in order to realign the calendar with the months, according to Dictionary.com. However, sometimes Mercedonius was rumored to be inserted into a year for political motivations, in order to keep an official in power for longer.
Astronomer Sosigenes of Alexandria was commissioned in 46 BC to recreate the new calendar under the reign of Julius Cesar— which is when the name changes of Quintilis and Sextilis occurred, according to Owlcation. The intercalary month was abolished, and all months were set to 30 or 31 days, besides Februarius, which was given 28, and then 29 every fourth year.
In 1582, Pope Gregory XIII introduced the Greogrian Calendar we know and use today, as the Julian Calendar had been used up until that point, as stated by History.com. The Julian Calendar miscalculated the solar year by 11 minutes — still impressive for 46 BC — and thus the months had fallen out of sync with the season. As Pope, this concerned him, since that meant Easter, which was traditionally celebrated on March 21, was getting further and further away from the spring equinox.
In the Gregorian Calendar, leap years aren’t actually every 4 years, either. If the year is divisible by 4, but not by 100, a leap day is added. However, if the year is divisible by 400, a leap day is added anyway. This seems confusing to most, but it mostly solved Cesar’s lag in time.
According to Live Science, the Julian Calendar did put the new year as Jan. 1— but many European countries didn’t observe this, as they believed the celebration of New Year was a Pagan tradition. Therefore, the Christian Church declared Dec. 25 or March 25 the beginning of the year. Pope Gregory put an end to that, re-declaring Jan. 1 the beginning of the year.
Believe it or not, time wasn’t completely accurate after the Gregorian Calendar we still use today was implemented. The Coordinated Universal Time (UTC) has two parts— the International Atomic Time (TAI) and the Universal Time (UT1), according to Time and Date.com. When the UTC and the UT1 reach a difference of 0.9 seconds, a leap second is added to clocks around the world, essentially allowing an extra second for the Earth to catch up. In 1972, the time was approximately 10 seconds behind the true time, which is when the first leap second was added. Since then, there has been a total of 27, with the most recent being Dec. 31, 2016, and the next one being approximately June 30, 2020.
If all that is making your head spin around faster than hand on a clock, don’t fret. Leave it to the experts to figure out when we need some time to catch up. At least next time you check your planner, you’ll know — somewhat — why our calendar is the way it is.
