NEW YORK (AP) — It’s a leap year. This is a treat for the calendar and math geeks among us. So how did it all start and why?
Take a look at some of the numbers, history and information behind the phenomenon that adds (not exactly) a 29th day to February every four years.
BY THE NUMBERS
The math is mind-boggling to the average person and comes down to fractions of days and minutes. There are even leap seconds occasionally, but when this happens there is no chaos.
What’s important to know is that a leap year exists largely to keep the months in sync with annual events, including the equinoxes and solstices, according to the Jet Propulsion Laboratory at the California Institute of Technology.
This is a correction that eliminates the fact that the Earth’s orbit does not have exactly 365 days a year. NASA says the journey took about six hours longer than that.
But contrary to what some believe, a jump doesn’t occur every four years. Adding a leap day every four years would extend the calendar by more than 44 minutes, according to the National Air and Space Museum.
JPL stated that later, in a future calendar (more on that), it was decided that years divisible by 100 do not comply with the four-year leap day rule unless they are also divisible by 400. In the past 500 years, while there was no leap day in 1700, 1800 and 1900, there was a leap day in 2000. If the practice continues in the next 500 years, there will be no leap days in 2100, 2200, 2300 and 2500.
Are you still with us?
The next leap years are 2028, 2032 and 2036.
Who invented leap year?
Short answer: It evolved.
Ancient civilizations used the cosmos to plan their lives, and there are calendars dating back to the Bronze Age. Like various calendars today, they were based on the phases of the moon or sun. They were generally “lunar-sun” using both.
Now jump to the Roman Empire and Julius Caesar. He was dealing with major seasonal deviations in the calendars used in his neck of the woods. They coped poorly with the drift, adding months. He was also navigating a wide variety of calendars, starting with a wide variety of routes across the vast Roman Empire.
He introduced the Julian calendar in 46 BC. It was entirely solar powered and counted a year as 365.25 days, so an extra day was added every four years. Before this, the Romans counted a year as 355 days, at least for a time.
But there was still a drift under Julius. There were so many leap years! The solar year is not exactly 365.25 days! That’s 365,242 days, said Nick Eakes, an astronomy educator at the Morehead Planetarium and Science Center at the University of North Carolina at Chapel Hill.
Adding time zones to a year to reflect changes in lunar and solar cycles was done by ancient people, said Thomas Palaima, a classics professor at the University of Texas at Austin. He said the Athenian calendar was used in the fourth, fifth and sixth centuries with 12 lunar months.
This did not work for seasonal religious observances. The drift problem causes an extra moon to be periodically “interleaved” to realign with the lunar and solar cycles, Palaima said.
The Julian calendar was 0.0078 days (11 minutes and 14 seconds) longer than the tropical year, so errors in timekeeping were gradually accumulating, according to NASA. But stability has increased, Palaima said.
The Julian calendar was the model the Western world used for hundreds of years. Enter Pope Gregory XIII, who calibrated further. The Gregorian calendar came into force in the late 16th century. It is still in use today and is clearly not perfect, otherwise there would be no need for a leap year. But this was a major improvement, reducing drifting to mere seconds.
Why did he step in? Well, Easter. It would eventually come later in the year, and he was concerned that Easter-related events such as Pentecost might clash with pagan festivals. The Pope wanted Easter to remain in the spring.
He eliminated the extra days accumulated in the Julian calendar and changed the rules of leap days. It was Pope Gregory and his advisors who came up with some really complicated math about when a leap year should or shouldn’t happen.
“If the solar year was a perfect 365.25 then we wouldn’t have to worry about complicated math,” Eakes said.
What does leap year and marriage have to do with it?
Strangely, leap day comes with information that women are asking men about marriage. It was mostly good-natured fun, but it came with a bite that reinforced gender roles.
There is a distant European folklore. According to an article by historian Katherine Parkin published in the Journal of Family History in 2012, the idea of women proposing in one of the stories dates back to fifth-century Ireland; According to historian Katherine Parkin, St. Bridget came to St. Louis to give women the chance to ask men to marry them. He appeals to Patrick.
Nobody actually knows where it all started.
In 1904, columnist Elizabeth Meriwether Gilmer, a.k.a. Dorothy Dix, summed up the tradition this way: “Of course people will say that a woman’s leap year privilege, like most of her liberties, is merely a shining mockery.”
The pre-Sadie Hawkins tradition, no matter how serious or playful, might have empowered women, but it only perpetuated stereotypes. Proposals would take place via postcard, but most such cards turned the tables and teased women instead.
Advertisements continued the leap year marriage game. A 1916 advertisement for the American Industrial Bank and Trust Co. stated: “This Leap Year day, we advise every girl to propose to her father.”
Because of the leap day, women had no breath of independence left.
Should we feel sorry for those who jump?
Being born in a leap year, on a leap day, is certainly a controversial topic. But from a paperwork perspective, this can be a bit of a pain. Some governments and others have stepped in to declare which date jumpers use for things like driver’s licenses (February 28 or March 1), requiring forms to be filled out and birthdays specified.
Technology has made it much easier for bounce babies to note their milestones on February 29; however, there may be disruptions to healthcare systems, insurance policies, and other businesses and organizations where this date is not established.
Worldwide, there are now approximately 5 million people who share a birthday among the approximately 8 billion people on the planet. Shelley Dean, a 23-year-old from Seattle, Washington, chooses a cheerful attitude about making the leap. Growing up, She threw regular birthday parties every year, but when the leap years rolled around, she would throw an extra special party. Because as an adult, he marks the jump-free period between February 28 and March 1 with a simple “wow.”
This year is different.
“This will be my first birthday to celebrate with my family in eight years, which is very exciting because on the last leap day I was halfway across the country to New York for college,” he said. “This is a huge year.”
What would happen if there were no leap days?
After all, there’s nothing good about when big events happen, when farmers plant, and how the seasons align with the sun and moon.
“Without leap years, we will have summer in November in a few hundred years,” said Younas Khan, a physics instructor at the University of Alabama at Birmingham. “Christmas will be in the summer. There will be no snow. There will be no Christmas feeling.”