February 29, 2020
Since it’s 2020, this year is a leap year.
I decided to cheat a little bit and use a term that is very pertinent to this year: leap year. While looking up the history of this term, I learned some interesting facts about the Gregorian calendar and the Earth’s revolution around the sun.
What Is a ‘Leap Year’?
Of course, a normal year according to the Gregorian calendar is one that lasts 365 days. A leap year has an extra day and generally comes every four years. The extra day, called a leap day, is February 29.
Our calendar year does not perfectly match up with the tropical year, which is the time it takes the Earth to make a full revolution around the sun. The Tropical year is also referred to as the solar year astronomical year, or an equinoctial year. We need to add a leap year every four years so that our calendar can line up with the Earth’s revolution around the sun, otherwise, we would lose about six hours every year and a total of 24 days in a century (“When Is the Next”).
How Did We Get the Leap Year?
We have the leap year thanks to Julius Caesar, who introduced it with the Julian calendar.
Before the Julian calendar, many societies used lunar calendars to track seasons and time in general. However, lunar calendars had about 354 regular days. Other ancient societies adopted calendars that had twelve months of 30 days each, but that meant that each year was short about five days. To address this discrepancy, Egypt added extra days at the end of the year and devoted those days to festivals.
Julius Caesar adopted the Egyptians’ 365-day year, but he made some tweaks and started the shift by decreeing the 445-day-long Year of Confusion (46 B.C.). This year was used to correct the Roman calendar, which had drifted from the seasons by about three months. After the Year of Confusion, Rome was to follow a calendar that had a leap year every fourth year. However, this system was imperfect, because Caesar’s 365.25-day year was 11 minutes shorter than the solar year and the former would be ahead of the latter by a full day every 128 years (Handwerk).
Pope Gregory XIII adopted the Gregorian calendar for use by the Catholic Church on February 24, 1582 CE (“Gregorian Calendar”). The Gregorian calendar to address the flaws in the Julian calendar while ensuring that Easter would be observed around the same time each year (“The True Story”). The Gregorian calendar dropped ten days from October. Also, the calendar required that all years divisible by 4 are leap years with some exceptions ().
What Are Exceptions to the Leap Year Rule?
Above, I said that leap years “generally” come every four years because there are some notable exceptions. Leap years are skipped at the turn of the century when those years are not divisible by 400. That means the years 1600 and 2000 were leap years and the year 2400 will be a leap year. However, the years 1700, 1800, and 1900 were not leap years and the years 2100, 2200, and 2300 will not be leap years (Various).
This sounds simple, but this system has some flaws, as well.
What Are the Flaws of the Gregorian Calendar?
The Earth takes approximately 365.242189 days (365 days, 5 hours, 48 minutes, and 45 seconds) to revolve around the sun (“10 Interesting”). That’s about 26 seconds shorter than a calendar year (“The True Story”). Also, the Gregorian calendar adds a few extra seconds each leap year. We will be ahead of the solar year by a day in about 3,300 years (Handwerk). This will add up to about three extra days every 10,000 years (Boeckmann). Additionally, the Earth’s orbit is slowing. To compensate for this disparity, we add leap seconds throughout the calendar year (“The True Story”).
Were You Born in a Leap Year?
If you were born on February 29, you’re a “leapling,” so you don’t get to celebrate regular birthdays each year. Still, I wish you a happy birthday.
“10 Interesting Facts You Didn’t Know About Leap Day.” WorldTimeServer.com, https://www.worldtimeserver.com/learn/10-facts-about-leap-day/. Retrieved 29 February 2020.
Boeckmann, Catherine. “Why Is 2020 a Leap Year?” Almanac.com, 4 February 2020, https://www.almanac.com/content/when-next-leap-year. Accessed 29 February 2020.
Caryl-Sue. “Gregorian Calendar Introduced.” National Geographic. National Geographic Society, Last Updated 6 February 2014, https://www.nationalgeographic.org/thisday/feb24/gregorian-calendar-introduced/. Accessed 29 February 2020.
Handwerk, Brian. “Leap year saved our societies from chaos—for now, at least.” National Geographic. National Geographic Society, Published 26 February 2016, Updated 21 February 2020, https://www.nationalgeographic.com/news/2016/02/160226-leap-year-science-time-world-cultures-february/. Retrieved 29 February 2020.
Specktor, Brandon. “February 29th: 9 Quirky Leap Year Facts You Probably Didn’t Know.” Reader’s Digest, https://www.rd.com/culture/february-29th-leap-year-facts/. Accessed 29 February 2020.
“The True Story Behind Leap Year Proves We’re Just Making Up Time As We Go Along.” All That’s Interesting, 29 Feb 2016, Updated 22 January 2018, https://allthatsinteresting.com/leap-year-facts. Accessed 29 February 2020.
Various Authors. “Leap year.” Wikipedia, Updated 29 February 2020, https://en.wikipedia.org/wiki/Leap_year. Retrieved 29 February 2020.
“When Is the Next Leap Year?” Timeanddate.com, https://www.timeanddate.com/date/leap-day.html. Accessed 29 February 2020.