We have Julius Caesar to thank for the existence of 29 February 2020, a.k.a. Leap Day 2020.
“During the Late [Roman] Republic, social disorder, political strife and an ongoing series of civil wars left the maintenance of the calendar in complete disarray. By the time Julius Caesar consolidated his power in 46 BC, the calendar months were off by as much as several months in comparison to the seasons.” – United Nations of Roma Victrix
“On the advice of Sosigenes, a learned astronomer from Alexandria, Caesar adds ninety days to the year 46 BC and starts a new calendar on 1 January 45. Sosigenes advises Caesar that the length of the solar year is 365 days and six hours. The natural solution is to add a day every fourth year – introducing the concept of the leap year. The extra day is added to February, the shortest of the Roman months.” – HistoryWorld
As it turned out, the year length determined by Sosigenes was approximate but not precise.
“The true length of a year on Earth is 365.2422 days.” – Evan M. Manning, California Institute of Technology
That length equals 365 days 5 hours 48 minutes 46 seconds (Source: Encyclopedia Britannica).
“By the 16th century, people noticed that the first day of spring had drifted 10 days ahead of the intended 20th of March. Basically, history had used a leap-day year 10 more times than was useful. Pope Gregory XIII had a scholar named Aloysius Liliusa devise a new system that would keep the calendar in sync with the seasons and keep Easter as close to the spring equinox as possible.”– Robert Coolman, Live Science
Under the new system, a year ending with 2 or more zeroes is not a Leap Year unless it is divisible by 400.
“So, 1900 was not a leap year, because it is not evenly divisible by 400. The next 4-year cycle not being a leap year will be the year 2100.”– National Geographic
“Despite Lilius’ ingenious method for syncing the calendar with the seasons, his system is still off by 26 seconds. As a result, in the years since Gregory introduced his calendar in 1582, a discrepancy of several hours has arisen. By the year 4909, the Gregorian calendar will be a full day ahead of the solar year.” – Jennie Cohen, History.com
Frog in Featured Image is from clipart.email.
REFERENCES
Cohen, J. (2018, August 22). 6 Things You May Not Know About the Gregorian Calendar. History.com. Retrieved from https://www.history.com/news/6-things-you-may-not-know-about-the-gregorian-calendar
Coolman, R. (2014, May 16). Keeping Time: Months and the Modern Calendar. Live Science. Retrieved from https://www.livescience.com/45650-calendar-history.html
Feb 24, 1582 CE: Gregorian Calendar Introduced. National Geographic. Retrieved from https://www.nationalgeographic.org/thisday/feb24/gregorian-calendar-introduced/
Gascoigne, B. (n.d.). History of the Calendar. HistoryWorld. Retrieved from http://www.historyworld.net/wrldhis/PlainTextHistories.asp?ParagraphID=bvt
Manning, E.M. (1997). “How Many Days Are in a Year?” The PUMAS Collection. California Institute of Technology. Retrieved from https://pumas.jpl.nasa.gov/files/04_21_97_1.pdf
The Roman Calendar. United Nations of Roma Victrix. Retrieved from https://www.unrv.com/culture/roman-calendar.php
Year. Encyclopedia Britannica. Retrieved from https://www.britannica.com/science/year#ref120288
The “Wanted” posters say the following about David: “Wanted: A refugee from planet Melmac masquerading as a human. Loves cats. If seen, contact the Alien Task Force.”