“I don’t understand it,” said Father. “Leopold’s birthday should be here, and it’s not.”
Mother agreed. “The calendars can’t be wrong. They’re official.”
from Leopold’s Long Awaited Birthday
written by Dawn Desjardins
illustrated by C. E. Locander
Artistic Ventures Publications, 2008
February 28th is a very special date every year. It’s the date I became a grandma! Of course we celebrate my grandson’s birthday, too, because he’s also very special. But if he had waited one more day… then again he was not born in a leap year.
I’ve written about the Atomic Clock, the Doomsday Clock, Daylight Savings Time, Time Zones, and Circadian Rhythms. I surprised myself when I realized I haven’t tackled Leap Year, until now.
I started wondering. When did it start? Who figured out we needed it? Do all calendars have leap years? I rolled up my sleeves, so to speak, to find out.
Yesterday, National Public Radio (NPR) broadcast Rachel Treisman’s story from its affiliate in Oregon. She explained Leap Year and had me at the first sentence: “Nearly every four years, the Gregorian calendar—-which is used in the majority of countries around the world—gets an extra day: February 29.”
Wait! What? NEARLY every four years? So I kept reading.
Even though most people know that a year has 365-1/4 days, leap year is just a little more complicated than adding up those 1/4s every year till we have 4 and add one day.
Alexander Boxer wrote a whole book about how different civilizations used each other’s explanations to create different calendars, some more successful than others to come up with “[a] great undertaking of trying to understand time.”
At first, it was enough to know when the longest and shortest days were. Planting crops, harvesting them, and predicting weather patterns depended on that information.
Julius Caesar introduced a calendar in 45 BCE, based on an Egyptian idea. Caesar added an extra day every year, over-estimating the solar year by about 11 minutes. By the 16th century holidays were out of whack. Easter wasn’t in the Spring anymore. Passover was, but I’m jumping ahead.
Pope Gregory XIII presented the world with his fix: the Gregorian Calendar. He added a day in years that were divisible by four, unless it is also divisible by 100, except when the year is also divisible by 400! Yikes! Accordingly, 1900 was not a leap year, but 2000 was, and 2024 is.
Here’s a chart.
Astronomers have since determined our Earth orbits the sun every 365.242190 days, so our year is just a tiny bit less than 365-1/4 days. We leap every fourth year, usually. There is still a margin of error of about 27 seconds per year. But one day in 3,236 years does not make my list of things to worry about.
When Pope Gregory XIII created his calendar, he added two months and divided the year into 12 instead of the original ten. We’re still using his calendar.
Most names come from ancient Greek or Latin. Some are named after gods, January for Janus, and March for Mars. July is named for Julius Caesar and fittingly August is for his successor, Augustus. Some, September through December are archaic forms of ordinal numbers.
The number of days per month reflects their importance to the Ancients. Note July and August have the most days and February, named for a month-long purification ceremony that took place at that time of the year, has the least.
Since February was the shortest month, that’s where the leap day landed.
A week is 23% of a lunar cycle. Seven is an awkward amount of days, but has been a standard for almost 4000 years. Its use is traced back to a 2300 BCE decree of King Sargon I of Akkad. It was a spiritually important number for the king and his people. With their naked eyes, they observed seven celestial bodies: the Sun, the Moon, and five planets (Mercury, Venus, Mars, Jupiter, and Saturn).
The Gregorian calendar is not the only calendar used in modern times. The Hebrew calendar, the Islamic calendar, and the Chinese calendar are all based on the lunar cycles and begin each of their twelve months with a new moon.
Each month of the Hebrew calendar is 29 or 30 days long. To compensate for the shorter year, a leap month is added seven times during a 19-year cycle. This adjustment ensures the holidays fall during the same season each year. They are later or earlier compared to the Gregorian calendar depending on when in the 19-year cycle a leap month is added.
Like the Hebrew calendar, the traditional Islamic calendar uses 29- and 30-day months. Without the use of mathematical mechanisms like leap days and leap months to synchronize the lunar calendar with the solar one, Muslim holidays occur earlier and earlier in each solar year. But a month is as long as a month is. Holidays occur in their appropriate month, no matter what the season.
Chinese New Year begins on the first new moon after the Winter Solstice. Like the Hebrew and Islamic calendars, the traditional Chinese calendar uses a twelve-month cycle of 29- or 30-day months and compensates by adding a whole month when needed to keep the months in their traditional seasons.
Other cultures use their own calendars, too. Bahá’ís, Ethiopians, Hindis, Persians, and Buddhists all have calendars. You can discover how they all work by clicking these links.
So, 2024 is Leap Year. We all have twenty-four extra hours. How will you celebrate Thursday’s precious gift?
I’m reading The Ballad of Songbirds and Snakes by Suzanne Collins (Scholastic Press, 2020). It’s the prequel to The Hunger Games. The stage is set for the 10th annual Games and tensions and emotions are high. Collins creates a seamless transition to what have become Young Adult classics. If you pick this one up, set aside plenty of time. It’s hard to put down.
-—Be curious! (and mindful)
Mother agreed. “The calendars can’t be wrong. They’re official.”
from Leopold’s Long Awaited Birthday
written by Dawn Desjardins
illustrated by C. E. Locander
Artistic Ventures Publications, 2008
February 28th is a very special date every year. It’s the date I became a grandma! Of course we celebrate my grandson’s birthday, too, because he’s also very special. But if he had waited one more day… then again he was not born in a leap year.
I’ve written about the Atomic Clock, the Doomsday Clock, Daylight Savings Time, Time Zones, and Circadian Rhythms. I surprised myself when I realized I haven’t tackled Leap Year, until now.
I started wondering. When did it start? Who figured out we needed it? Do all calendars have leap years? I rolled up my sleeves, so to speak, to find out.
Yesterday, National Public Radio (NPR) broadcast Rachel Treisman’s story from its affiliate in Oregon. She explained Leap Year and had me at the first sentence: “Nearly every four years, the Gregorian calendar—-which is used in the majority of countries around the world—gets an extra day: February 29.”
Wait! What? NEARLY every four years? So I kept reading.
Even though most people know that a year has 365-1/4 days, leap year is just a little more complicated than adding up those 1/4s every year till we have 4 and add one day.
Alexander Boxer wrote a whole book about how different civilizations used each other’s explanations to create different calendars, some more successful than others to come up with “[a] great undertaking of trying to understand time.”
At first, it was enough to know when the longest and shortest days were. Planting crops, harvesting them, and predicting weather patterns depended on that information.
Julius Caesar introduced a calendar in 45 BCE, based on an Egyptian idea. Caesar added an extra day every year, over-estimating the solar year by about 11 minutes. By the 16th century holidays were out of whack. Easter wasn’t in the Spring anymore. Passover was, but I’m jumping ahead.
Pope Gregory XIII presented the world with his fix: the Gregorian Calendar. He added a day in years that were divisible by four, unless it is also divisible by 100, except when the year is also divisible by 400! Yikes! Accordingly, 1900 was not a leap year, but 2000 was, and 2024 is.
Here’s a chart.
Astronomers have since determined our Earth orbits the sun every 365.242190 days, so our year is just a tiny bit less than 365-1/4 days. We leap every fourth year, usually. There is still a margin of error of about 27 seconds per year. But one day in 3,236 years does not make my list of things to worry about.
When Pope Gregory XIII created his calendar, he added two months and divided the year into 12 instead of the original ten. We’re still using his calendar.
Most names come from ancient Greek or Latin. Some are named after gods, January for Janus, and March for Mars. July is named for Julius Caesar and fittingly August is for his successor, Augustus. Some, September through December are archaic forms of ordinal numbers.
The number of days per month reflects their importance to the Ancients. Note July and August have the most days and February, named for a month-long purification ceremony that took place at that time of the year, has the least.
Since February was the shortest month, that’s where the leap day landed.
A week is 23% of a lunar cycle. Seven is an awkward amount of days, but has been a standard for almost 4000 years. Its use is traced back to a 2300 BCE decree of King Sargon I of Akkad. It was a spiritually important number for the king and his people. With their naked eyes, they observed seven celestial bodies: the Sun, the Moon, and five planets (Mercury, Venus, Mars, Jupiter, and Saturn).
The Gregorian calendar is not the only calendar used in modern times. The Hebrew calendar, the Islamic calendar, and the Chinese calendar are all based on the lunar cycles and begin each of their twelve months with a new moon.
Each month of the Hebrew calendar is 29 or 30 days long. To compensate for the shorter year, a leap month is added seven times during a 19-year cycle. This adjustment ensures the holidays fall during the same season each year. They are later or earlier compared to the Gregorian calendar depending on when in the 19-year cycle a leap month is added.
Like the Hebrew calendar, the traditional Islamic calendar uses 29- and 30-day months. Without the use of mathematical mechanisms like leap days and leap months to synchronize the lunar calendar with the solar one, Muslim holidays occur earlier and earlier in each solar year. But a month is as long as a month is. Holidays occur in their appropriate month, no matter what the season.
Chinese New Year begins on the first new moon after the Winter Solstice. Like the Hebrew and Islamic calendars, the traditional Chinese calendar uses a twelve-month cycle of 29- or 30-day months and compensates by adding a whole month when needed to keep the months in their traditional seasons.
Other cultures use their own calendars, too. Bahá’ís, Ethiopians, Hindis, Persians, and Buddhists all have calendars. You can discover how they all work by clicking these links.
So, 2024 is Leap Year. We all have twenty-four extra hours. How will you celebrate Thursday’s precious gift?
I’m reading The Ballad of Songbirds and Snakes by Suzanne Collins (Scholastic Press, 2020). It’s the prequel to The Hunger Games. The stage is set for the 10th annual Games and tensions and emotions are high. Collins creates a seamless transition to what have become Young Adult classics. If you pick this one up, set aside plenty of time. It’s hard to put down.
-—Be curious! (and mindful)
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