Leaplings

February 29, 2024

The BBC news caried an online story today about an 84 year old man who was celebrating his 21st birthday.  Ronald Mustard, of Sunderland, England, is 84 years old but has only marked the exact day of birth every four years.  The staff at the dementia-friendly care home Archers Court in the city decided to throw Mustard a party to mark this milestone 21st birthday with a surprise celebration themed around 1961, or the year when he was actually 21, to help him remember his younger days as part of his care.  Ronald’s daughter Sharon said her father suffered through the pandemic, but since moving to the specialist care home last year he had “come out of his shell”.   Sharon helped arrange the surprise, which included residents and staff dressed up as hippies while dancing to music from that era.  Mustard was born in 1940, a leap year.  So-called “leaplings” are rare and there is about a one in 1,461 chance of being born on 29 February. 

When I looked online, I found a leap year, also called an intercalary year or bissextile year, is a calendar year that contains an additional day (or for a lunisolar calendar, a month) compared to a common year.  The 366th day is added to keep the calendar year synchronized with the astronomical or seasonal year.  Since astronomical events and seasons do not repeat in a whole number of days, calendars having a constant number of days each year unavoidably drift over time.  By inserting (intercalating) an additional day or month into some years, the drift between a culture’s dating system and the physical properties of the Solar System are corrected.  An astronomical year is slightly less than 365-1/4 days.  The historic Julian calendar has three common years of 365 days followed by a leap year of 366 days.  This is done by extending February to 29 days rather than the normal 28.  The Gregorian calendar is the world’s most widely used civil calendar and makes further adjustment for the Julian algorithm.  Each leap year has 366 days instead of 365, but this leap day occurs in each year that is a multiple of 4, except for years evenly divisible by 100 but not by 400.  That greatly restricts the number of times leaplings can celebrate on their actual birthday.

While the Julian and Georgian calendars are based on the time it takes for the earth to travel around the sun, other calendars are based on the phases of the moon.  Both Chinese and Hebrew calendars are lunisolar, so during a leap year there is an extra month, often called an embolismic month after the Greek word for it.  In the Chinese calendar, the leap month is added to ensure the 11th month always contains the northern winter solstice, and the intercalary month takes the same number as the preceding month i.e., if it follows the second month it is called “leap second month”.  In the Hebrew calendar this extra month is called Adar Rishon (first Adar) and is added before Adar, which then becomes Adar Sheini (second Adar).  According to the Metonic cycle, a period of almost exactly 19 years after which the lunar phases then repeat.  This is done to ensure that Passover (Pesah) is always in the spring as required by many verses in the Torah (Pentateuch).  Counting your age as leaplings appears to be the opposite of considering your pets age in “dog years”.

THOUGHTS:  Technically, leaplings will have fewer birthday anniversaries than their age in years.  This can be exploited for dramatic effect when a person declares themself only a quarter of their actual age by only counting their leap-year birthday anniversaries.  In Gilbert and Sullivan’s 1879 comic opera The Pirates of Penzance, Frederic (the pirate apprentice) discovers he is bound to serve the pirates until his “21st birthday” (i.e., 88 years old) rather than his 21st year.  For legal purposes, legal birthdays depend on how local laws count time intervals.  It seems like you need to be a little crazy to grasp how this all works.  Tracking the passage of time (not seasons) is one of the advances that occurs with the rise of human civilization.  Act for all.  Change is coming and it starts with you.