Once every four years (with the exception of century years that are not easily divisible by 400), a miraculous event takes place— we are afforded an extra day at the end of February (and by “we, us, our, etc.”, I mean Western Civilization).

We call this phenomenon “leap year”, and this year of our Lord, 2012, is one of them. Since this extra day— February 29^th— only occurs once every four years, we probably don’t spend much time thinking about its significance. If we find ourselves curious enough to question the purpose of a leap day, we might find a seemingly simple scientific explanation like:

“A year is really a little more than 365 days. In order to keep our calendar year in synch with our astronomical surroundings (or, our months in synch with their associated seasons), we add an extra day every four years.”

 

But Wait…There’s More!

Sounds simple enough, right? But what is a year? The basic standard our science propagates (and our culture accepts) is that a year is the period of time the Earth takes to revolve around the Sun— about 365 ¼, 24-hour days. However, this was not always the case.

The Romans— from whom the Gregorian imperial civil calendar (and most of our Western Civilization ideals) stemmed— had different numbers of days in a year at different times. They also divided daylight hours into only two parts: before midday (ante meridian, or A.M.) and after midday (post meridian, or P.M.), up until the 4^th century B.C.

Perhaps this was a throwback to the Egyptians, who divided a day (as early as 1300 B.C.) into two parts: 12 equal daytime hours from sunrise to sunset, and 12 equal nighttime hours from sunset to sunrise. The Egyptians borrowed this system from the Mesopotamians, who in turn probably borrowed it from the ancient Babylonians, who counted in units of 60, as opposed to tens. It just so happened that 12 was a convenient factor of 60.

Historians are not sure when, exactly, the day was divided into 24 equal hours, but it was at a decidedly later date that the hour was divided into minutes, and the minutes into seconds. The important thing to remember is that these divisions were arbitrary. The day could have easily been divided into 10 hours, and the hour into 100 minutes (or any other number that was convenient).

When In Rome

Another example of how time was handled in an arbitrary manner in the not-so-distant past lies in the question, “Why does February only have 28 days, when all of the other months have 30 or 31? And why did they decide to add the leap day to February?” According to Cecil Adams (the world’s most intelligent human being), the Romans skipped from December to March on their calendar up until the 8^th century B.C., when King Numa Pompilius decided it “would look stupid of Romans to give the world a calendar that overlooks 1/6^th of a year.”

As Mr. Adams so succinctly states, the fact of skipping those months “seems like a casual approach to timekeeping to us,” but back then, the main purpose of keeping a calendar was for agricultural purposes (to oversee the cycle of planting and harvesting), and not much happened in the way of gardening during the time between December and March.

 

There is a Season ( Turn, Turn, Turn)

When the Romans got the notion to give world domination a try, they added the months February and March to the calendar. With 12 months in a calendar year, it was necessary to make seven of the months 29 days long, and four of the months 31 days long, because even numbers were thought to be “unlucky.”

Unfortunately, Numa needed one short, even numbered month to make the number of days in a calendar year work out to 355 (which was the approximate length of a lunar calendar), and February was chosen because no one liked it (being that it was the last month of the newly reorganized year and in the middle of winter). When the future came calling and expressed its need for an extra day every few years, it seemed logical to add a day to the end of the calendar, which, at that time, was February 28^th.

A Giant Leap for Mankind

That future (and the imperfection of the Roman calendar) was realized when the Roman calendar dates became out of synch with the “seasons”. So, in 46 B.C., Julius Caesar decreed a year of 445 days to catch up, and defined a new calendar, the Julian, to be more accurate for future purposes. This calendar had years that were 365 days in length, with an extra day inserted every fourth year in order to bring the average year to 365 ¼ days in length. Hence, the leap year.

However, there were still problems with this calendar. The actual solar year is shorter than 365 ¼ days (and Julius was counting inclusively, meaning he counted both years one and four as “leaps”) and by 1582 A.D., the calendar was, again, out of phase with seasonal changes by about 10 days.

To remedy this, Pope Gregory XIII dropped 10 days from that year (many citizens objected to the loss of time) and a new calendar, the Gregorian, emerged. The new calendar deemed leap years as “any year whose date is exactly divisible by four, except those which are divisible by 100, but not 400.” But how did the Western world know that the seasons were becoming out of synch with the calendar? The answer, of course, is Jesus.

Finding Time to Find the Time

At this point, it is worth pointing out the way in which we came to orient ourselves in history by establishing the eras of B.C. (Before Christ) and A.D. (Anno Domini). Dinonysius Exiguus (an obscure Syrain monk living in Rome during the 6^th century A.D.), aka “Dennis the Little,” was tasked by the Pope to extend the timetable for calculating the correct date of Easter. Church officials relied on the Roman solar calendar for the “date” of Easter, but the “actual anniversary” of Christ’s death and resurrection were supposed to take place after the Passover festival, which was grounded on the Jewish lunar calendar (which measures months in terms of the time between two identical moon phases, new or full, as opposed to the Earth‘s revolution around the Sun).

While Dennis the Little was figuring out the chronological details for his Easter table, he counted backwards and established what he thought was the year of birth or “incarnation” of Christ (and he was off by at least four years, but we have yet to reconcile this in our historical timelines). The Pope then labeled the current year “Anno Domini Nostri Jesu Christi, 532” (literally, “In the Year of our Lord Jesus Christ, 532”) and we have been living with this system ever since.

 

Waiting for the…Moon?

The scientific explanation (“leap years are added to keep us in synch with our astronomical surroundings”) may be valid, but it doesn’t account for the thousands of years of human history that occurred to make it so. When scientists and historians explain that our previous calendars went out of fashion because of discrepancies between the observed season and the calendar dates, they are really referring to a similar conundrum Dennis the Little encountered while calculating his Easter table in 532 A.D; the date of Easter is fixed by an approximation of lunar cycles used in the Jewish lunar calendar. Easter is, and has always been, celebrated on the Sunday after the 14^th day of the full moon that falls on or after the vernal equinox. So, when the Julian calendar “date” for Easter began drifting away from the vernal equinox in 1582 A.D., Pope Gregory XIII set it to rights.

The Science of History

So what is a vernal equinox? Simply put, an “equinox” occurs twice a year when the tilt of the Earth’s axis is inclined neither from nor towards the sun. The center of the sun is in the same place as the equator. We have come to think of an equinox as a day in which daylight hours are equal to darkness hours, but this is not strictly true. It is a point in time, not a day.

The vernal equinox (ver meaning “Spring” in Latin) is wont to occur (most often) on March 21. The autumnal equinox (autumnus meaning “Autumn” in Latin) happens (usually) on September 22. It’s worth noting that “March” and “September” are slowly becoming the de rigueur titles for the equinoxes by technical writers because the terms “vernal” and “autumnal” pose a certain bias, in that they only apply to the Northern hemisphere. Although the months of March and September occur at the same time all over the world (theoretically), the actual seasons associated with those months differ in the Southern hemisphere.

Science Fiction

It is true that we observe leap year in an effort to keep the astronomical occurrences of equinoxes on (or very near to) the calendar dates they are traditionally associated with, but considering science’s propensity to discredit the ideas of creation, immaculate conception, and resurrection from the dead (basically, God and Jesus Christ altogether), it’s ironic  that the whole reason we cared about these “astronomical occurrences” and “seasonal changes”in the first place is simply because the Roman Catholic Church found the moving of the “date” of Easter to be undesirable.

What is even more ironic is that this is a perpetual cycle. Science (the successor of religion) attempts to discredit Christianity with scientific facts, while Christianity attempts to discredit its successor (Paganism) with biblical facts. Historians note that Pagan celebrations by Germanic tribes were the original reason for the date of the Easter celebration. When Christianity came to town, the powers that were (and still be) changed most of the Pagan holidays and celebrations into events that would focus the lamb’s (or sheep’s) minds on how best to glorify their new Lord, rather than on the original Pagan occasion.

 

It’s all the Same Day, Man

So, our “scientific” explanation for leap years (and essentially time itself) is really rooted in the history of Western Civilization, Christianity, and Paganism. For example, other forms of measuring time do exist (see List of Calendars).

“Our” years are measured by Earth and Sun relationships, but some cultures operate on a totally different system for measuring something as basic as a “day.” For example, in Islam, a “day” begins at sunset, and the first day of the month begins with the first sighting of the crescent moon shortly after sunset. If the crescent moon is not observed after the 29^th day of a month, that day (at sunset) begins at 30.

Another example of a difference in “cultural” time is that of the Jewish lunar calendar, which measures its years in moon cycles, with a year consisting of 355 “days.” Even scientists have other methods of tracking time; “star time” (aka sidereal time) is measured by noticing the positions of the stars as the sky turns around the Earth. A sidereal day is about four minutes shorter than a solar day.

What’s more, even our idealized Gregorian calendar and our scientific approach to “leap years” doesn’t account for the “actual” length of a year. We are still losing .0003 days a year, which means that in 8,000 years, the calendar will be about one day behind where it is now. But in 8,000 years, the length of the vernal equinox year will have changed by some unpredictable amount anyway.

A Better Tomorrow

So, how is a “leap year” purely scientific? A better question: How can time itself be considered scientific? Scientists can’t even agree whether time is a fundamental feature of the Universe or simply an intellectual structure— a concept by which we measure sequences and compare events.

We often take for granted how long it took homo sapiens to invent the things that we now can’t live without (language, writing, time, science, etc.) and we continue to assume that we have it all figured out. But the truth is that even our precise scientific measurements and our injected leap years can’t account for the changing positions of heavenly bodies, and we’ll end up getting a day away from Easter anyway.

Perhaps by that time, Western Civilization will have crumbled, a new God will have taken over, and it won’t matter anymore. Future humans will find something else to orient their time by, or they’ll have a better understanding of what time really means. Maybe global warming will have switched the seasons themselves and we’ll have to devise a new calendar to accommodate the changes anyway, or, as Stephen Hawking hopes, we will have colonized space and will need to consider time from a totally different perspective.

So, on the off chance that this year of our Lord, 2012, is indeed, “The End,” make sure you really enjoy those “extra” 24 hours on February 29^ththat have been allotted to you. Try not to be too disappointed if the world lasts to see another leap year; considering the nature of time and calendars, there is a good chance the Mayans—or those who interpreted them—were mistaken.