Birthdays, Anniversaries and Temporal Distortions

Birthdays, Anniversaries and Temporal Distortions

Making sense of year zero

This article has nothing to do with technology, and yet it's technical enough to make my wife's head explode. It has to do with how we number our years, and the difference between birthdays/anniversaries and annual events.

We see a lot of annual events in the presentation business, and it sometimes gets confusing which year it is. Does the 18th annual event happen on the 18th anniversary? Oh wait...what do you mean it's not?  So in trying to make sense of this, I launched the graphics program.

In Figure 1, on the right, in green, we see that the first annual event is event #1. The second is #2, and so on. An annual event marks the BEGINNING of the year before the next annual event.

But for birthdays and anniversaries, we don't count the event (date of birth, or wedding day) as #1, we instead count it as zero. Since the initiating event isn't numbered, the first birthday or anniversary marks the END of the first year, as well as the end of all subsequent years. It also marks the beginning of the next year. (See the blue numbers on Figure 1).

All this gets kind of crazy when it comes to celebrating the decades. For instance, if it's an annual event, the 10th annual event marks the end of the 9th year and the BEGINNING or the 10th year. But if it's an anniversary or birthday it marks the END of the 10th year, and the BEGINNING of the 11th year. This is kind of cool, actually, because if you're trying to promote your business, you can milk it for two years. The first year (after the 9th anniversary), you can say "In our 10th year," and after the anniversary, "Celebrating our 10th anniversary." You can't really do that when counting event numbers.

It's also wierd when you try to line up numbered events to actual years.  Anniverersaries are easier - for instance, if you started your business in the year 2000, your 10th anniversary would have been 2010. But if your first annual event was in 2000, your 10th annual event would have been in 2009. Time warpage at its finest.

It's interesting to note that our year numbers are annual events and not anniversaries. The Holy Roman Empire, when they decided to number the era based on what they assumed* was the birthday of Jesus Christ. They did not include a zero year. Overnight it went from 1 B.C. ("Before Christ" aka "BCE" – "Before Common Era") to 1 A.D. ("Annus Domini" Latin for "Year of our Lord," now referred to as "CE" for "Common Era").

So while I'm at it let's explain another temporal distortion that I've often pondered. Why is it the older you are the shorter the years seem to be? We all know time ticks along at the same rate (except, of course, if you're traveling very fast, thank you Mr. Einstein). So why this perception that everything happens faster as you age?

Well it has to do with what I call the "time slice," which is illustrated in this pie chart (Figure 2). We number our days, months and years based on the rotations of the earth, and the earth's rotation around the sun, and those durations haven't changed more than a few milliseconds in my lifetime. But our perception of the passage of time changes as our lifespan increases, because each year represents an increasingly smaller "slice" of total life experience.

 If you're two years old (beginning your 3rd year), a year represents half (50%) of your total life experience. But if you're 60 years old, on your birthday (starting your 61st year), a year represents 1/60th (~2%)  of your total life experience. While the pie chart shows a linear representation. It's actually logarithmic, which is illustrated in Figure 3.

From the perspective of your age, the older you get, the smaller the percentage of total life experience a year represents. Hence the years seem to go by faster. If you were of infinite age, a year would represent an infinitely small time slice, which is why in the Bible we read, "With the Lord a day is like a thousand years, and a thousand years are like a day. (2 Peter 2:8)

I've noticed that when taking a long trip. It sometimes seems like it takes a long time to get to your destination, but the trip back, over the same route at the same speed, seems to take less time. That's because each mile at the end of the trip is a smaller slice of the total trip experience.

So those are my musings on temporal distortions, birthdays and anniversaries. I'm still working on why, when a presenter has been droning on for two hours about the latest sales performance stats, the time passes more slowly the longer it takes...oh wait, we can fix that.

And if you need digital content for your next birthday, anniversary or annual event, let us know how we can help make the event more special!



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