Testing, Testing: 12/12/12 12:12:12

This is a modified version of last year’s 11/11/11 article, in case you missed it.

Today is a special day — at least if you are fond of the number 12, and especially so if you’re willing to buy in to one of the oldest human pseudo-scientific pursuits: numerology. Oh, don’t get me wrong, I love numbers and I always have. When I was five years old I was mesmerized when my parents’ car reached 99,999.9 miles, and I think 12:34:56 on 7/8/90 is just a cool a time as anybody else does. But I do this with a sense of humor.

Unfortunately it happens that a few influential people attempt serious and consequential numerology involving the calendar — predicting disaster and convincing people to sell their homes and give away their belongings. Now that makes me mad. Outraged, in fact — because it’s often obvious from the way these predictions are generated that those who made them don’t understand much about the calendar, about time, about history and about astronomy or physics… and yet they speak with authority, an authority they haven’t earned and don’t deserve.

So as we celebrate this one-two-of-a-kind moment, let’s also remember, and enjoy, just how absurd it really is. Let us even count the ways.

Cycles and Compromise

Let’s look at our string of twelves: we are 12 years after the year 2000; 12 months and 12 days after the start of the year; 12 hours, 12 minutes and 12 seconds since midnight.

Each of the first three 12’s has something to do with astronomy — but if we look closely, something’s a little off.

First we need to count years, and a year is the time it takes the earth to orbit the sun. Almost. Not quite. An astronomical year is the time it takes the earth to orbit the sun. A calendar year? that’s something else.

Then we need to count months. A month, of course, is roughly a “moon”, the time between two full moons … and a full moon occurs at the moment that the sun is on one side of the earth and the moon is on the exact other side. In some calendars around the world and throughout history, a month is a moon — but not in ours.

Then there’s the day: the time it takes for the sun to go from overhead to setting and rising and back to overhead again.

The problem with all of these astronomical cycles is that they are not synchronized; there’s no reason why they should be, since they are separate accidents of nature. The number of moons in an astronomical year isn’t a nice number; nor is the number of days in an astronomical year, or in a moon.

The number of days in an astronomical year is close to 365 and a quarter, not 365 or 366. That’s why at some point it was decided (by whom? and when? and on whose authority? it turns out our democratic society keeps track of its dates under the decree of a Roman emperor) that we would have three years in a row of 365 days, and then a fourth year of 366 years — a “leap” year. That way, the number of days in four calendar years is just about 1461, which is just about four astronomical years. But even this isn’t exactly right, so thanks to Pope Gregory, 3 of every 400 years (most recently the years 1700, 1800, and 1900, but not 2000) we skip a leap year, to get back on track, and keep the astronomical and calendar years lined up. More or less. It’s still not perfect.

Of course this way of doing things is completely arbitrary! We could just as well have 19 years of 365 days, and then in the 20th year have an extra five days. Or we could go 99 years of 365 days, with an extra month of 25 days at the turn of the century. Indeed some calendar systems around the world do something just like that. If we’d decided to do either of those things, there wouldn’t have been a leap year in 2004 or 2008, and today wouldn’t be 12/12 at all! It would be 12/14.

Or if Pope Gregory had removed three leap years at the start of each 400 year cycle, eliminating them in 2000, 2004 and 2008 instead of in 2100, 2200 and 2300, again it would not be 12/12 today. And so forth.

So let’s celebrate 12/12 — an accident of the leap year decisions of a Roman emperor and a Roman pope.

We’ve hardly begun. Let’s talk about those months. The number of days in a moon is about 29 and a half, so a moon is neither 29 nor 30 days, which is sort of inconvenient. And worse, it also doesn’t divide 365 (or 366) very conveniently; a year is quite a bit more than 12 moons and quite a bit less than 13. So how did we end up with 12 months of 30 or 31 days (except for February)? Well, you can blame the Roman emperors for that too: we’ve inherited our calendar mainly from Julius Caesar (who got a month named after himself — a long one with 31 days) with adjustments by Augustus (who had the following month named after himself and made sure it too was one with 31 days). And so the days per month are all funny. Why not, you might ask, have 12 months alternating between 29 days and 30 days, and 1 extra mini-month of 11 days?

Or why not have the last month of the year be the short one, making February a month of 30 days and December a month of 29, instead of our current odd arrangement? That would be more sensible — and if we did that, then today would be 12/11, not 12/12.

Or how about this? What about 13 months of 28 days each, with the last month being 29? That’s 365 days. Wouldn’t that be simpler? Each month would be four weeks, with just one extra day tacked on at the end of the year. No muss, no fuss, no having to remember which months have 30 days and which have 31. Ah, but that would mean 13 (ooooooooo! scary!) months… which we all know would be terrible. (And today would be 13/11, not 12/12.)

So let’s celebrate 12/12 — an accident of how a Roman military dictator chose the days of our calendar’s months, and perhaps also a consequence of the fear of the number 13.

I’ll get back to years, months and days in a minute and a second, but first let’s talk about 12:12:12 as a time.

An Ancient Obsession with Twelve

How did we end up dividing our day into 24 hours, each of which has 60 minutes, each of which has 60 seconds? Well, not everybody has counted on their ten fingers the way we do; some have counted the joints on their fingers (not including the thumb), of which we have 3 × 4 = 12 on each hand. Probably some have counted in other ways, but the fact that 12 was a special number for the Sumerians, Babylonians and Egyptians has resulted (through what appears to be a rather torturous history that I don’t claim to understand at all) in our having 12 hours for daytime and 12 for night, with 60 (which is 12 times 5) being the number of minutes in an hour and the number of seconds in a minute.

Our western culture does not share this obsession with 12. Our obsessions are with 10, and indeed that’s why Europeans worked to convince most of the world (except for the stubborn United States) to go over to a metric system, which is all based on 10s, 100s, 1000s, etc., in analogy to the way we in Europe and its former colonies (and many other human cultures) count. There are 1000 meters in a kilometer, 100 centimeters in a meter, 10 millimeters in a centimeter, and so forth. So how did we avoid ending up with a metric clock, and find ourselves stuck with timekeeping that harkens back to numerical preferences over 4000 years old?

The French actually tried a metric clock after their revolution, and indeed it would have worked rather well. With 24 hours, 60 minutes and 60 seconds, our day has a total of 86,400 seconds and 1440 minutes. If instead we made the second just about 15 percent shorter and the minute just about 15 percent longer, we could have 100,000 seconds per day, organized as 10 hours of 100 minutes, each with 100 seconds. Now wouldn’t that make more sense? No more having to figure out that a 140 minute movie is two hours and twenty minutes. No more making that silly mistake that we’ve all made, forgetting that 1 minute and 30 seconds is shorter than 100 seconds. Noon occurs at 5:00, Midnight at 10:00. All very simple.

Sadly, with that arrangement, no time during the day would be 12:12:12. So much for that. You’d have to reserve your excitement for 9:99:99. (Which actually sounds just as exciting to me — the last second before midnight.)

Of course we’d have to give up many other things. Those beautiful European clock towers would become anachronistic (pardon the pun.) No more “eleventh-hour solutions,” or “clock striking twelve” either. And we’d have to get used to the fact that a quarter of an hour — 0.25 hours — would be a sensible 25 minutes, not 15. Well, it’s certainly a little late for this change, reasonable as it would have been; we should have done it before the digital age.

So let’s enjoy 12:12:12 by honoring the Sumerians and Babylonians who made it all possible, and celebrating those who successfully defeated the French Revolution and prevented the metric system from taking over timekeeping.

By the way, this raises another issue: how we get ’12 from 2012. It happens we count years by 10s. 2012 is two thousand plus zero hundred plus ten plus two years. And when we write the year using two digits, we just strip off the “20”. But of course that’s arbitrary: we don’t count hours, minutes or seconds by 10s, and we don’t write the 1012th minute of the day by stripping off the 10. Instead, the 1012th minute of the day is what we call 4:52 in the afternoon, or 16:52 on a 24-hour clock. And we could have done the same thing with years: we could count 60 years as a cycle, and then 2012 would be the 32st year in the 34th cycle, which would then make today more naturally 12/12/32. In fact, that’s exactly what the Chinese do. However, their calendar doesn’t share our year 1; their last 60 year cycle started in 1984, so they refer to this year not as ’12 or ’32, but as ’29.

The Arbitrary Starting Points

And why is it 2012 anyway? That’s 2012 years from when? Of course it is from when the Christian (or “Common”) Era began, ostensibly from the year of the date of birth of Jesus of Nazareth. But Jesus was born during or just after the reign of Herod the Great (so say two of the Gospels rather clearly). Herod is well-known from other non-religious historical sources, too. These sources also have dates, and it is clear, comparing them, that Herod died in what we now call 4 B.C. In other words, our calendar is wrong; it starts at the wrong year. (Even the Pope agrees, now.) The original estimate of when to set the year 1, made around the year 525, was simply mistaken; the historical knowledge available back then was not sufficient to make a correct estimate. And we can’t precisely fix the mistake now, because even today the historical data doesn’t make it clear exactly which year is the right one. So. Is it 2012? Or 2016? Or 2017? Or 2018?

Of course there are other cultures out there who might not agree that it is anywhere close to 2012. The Jewish calendar says it is 5773. The Chinese calendar says it is 4710. There are Buddhist calendars used in large portions of Asia that put the year at 2556; in Tibet the year is 2139. From the astronomical or the philosophical point of view, the setting of year 1 is arbitrary, and throughout human history there have been many calendars setting the starting year in different ways.

Ok, that’s one 12 down; now what about the fact that December is the 12th month? Hmm. “December.” What does that mean? Well, let’s see. September, October, November, December… oh, right! Seventh-month, Eight-month, Ninth-month, Tenth-month… wait a second! How did December end up with this name when it is the 12th month in our calendar?

Well, go back to early Roman republican times, and you’ll find December was the tenth month — the year started in the spring, in March. There was a change made for political convenience during the Roman republic, back in what we now call 153 B.C.E. (of course they didn’t call it that), putting January at the start of the year. Were it not for this change, today would be 10/12, and we’d be waiting til February, then the twelfth month (which is why it is the short month!) to celebrate today’s numerical excitement.

Then there is still a question of which day is to be denoted the first of the year: the first day of the first month. Why is the first day of January the day when we start the year? It’s not the solstice (December 21st or 22nd typically) — the shortest day of the year in the northern hemisphere and the longest in the southern — which would seem to be a natural day on which to mark the beginning of the year. And it’s not the equinox, the start of spring in the northern hemisphere, when day and night are of equal length across the globe. It’s a completely arbitrary day, and the position of the earth in its orbit on what we call January 1st has even shifted as adjustments have been made to our calendar. If we had put the start of the year on the solstice, but kept the months laid out the same way, we’d be at 12/23 by now, not 12/12.

Indeed, the arbitrariness of the date has been noticed before. For many centuries, different parts of Europe celebrated the new year on various days other than January 1st. And today many other cultures around the world start the year on another day. The Chinese start the year toward the end of February; for them we are not in the 12th month yet. The Jewish calendar has its New Year sometime in September; we’re not even into the 4th month. And so on. In short, there’s nothing intrinsically special about starting the year where we do, and so only for societies using Pope Gregory’s calendar (a minority of the world’s population) is today the twelfth day of the twelfth month.

So a toast to the Roman republic, without which we’d be in the wrong month. And also to Pope Gregory, who from the Vatican in Rome repaired Julius Caesar’s legacy with a one-time removal of 10 days from the calendar; without him we’d be on the wrong day. And finally to the Roman monk Dionysius Exiguus, who was perhaps worshiping Dionysus when he calculated the year 1; without him, it wouldn’t be ’12. We should definitely be drinking these toasts with Italian wine.

Time After Time

Let’s set the date aside again and go back to the time. 12:12:12 — 12 hours, 12 minutes, 12 seconds — after what? After midnight of course. Ah. Which midnight?

There’s astronomical midnight — the moment when your particular point on earth is exactly opposite the sun. And then there’s clock midnight — the moment when your time zone celebrates the start of a new day. These aren’t, generally, the same. In fact, astronomical midnight occurs about an hour earlier at the east edge of a time zone that it does at the west edge.

I say “about an hour earlier” because the time zones that we use around the world aren’t exact divisions of the earth into 24 equal slices, like an orange cut into equal wedges. In principle they should be, but they’re adjusted for a very non-astronomical reason — political concerns and societal convenience. It was judged inconvenient for the US state of Texas to be in two time zones, so the time zone dividing line was adjusted to put the entire state in the same zone. The union of Europe has led most of western and central continental Europe, from Spain to Poland, to join a single time zone; the United Kingdom, due north of France, remains in a different zone, even though, as Paris is almost due south of London, astronomical time in London and Paris are only about 10 minutes apart. In some parts of Europe, 12:12:12 occurs well before astronomical 11 o’clock! And then there’s China, a country the width of the continental United States. China uses a single time zone, while the continental US uses four. The time 12:12:12 occurs all at once across China, while it happens at four different hours across the United States.

There’s even more arbitrariness hidden here. Astronomical midnight in Washington D.C. occurs fifteen minutes or so after astronomical midnight in New York, but then again, neither city’s astronomical midnight is the same as clock midnight within their shared time zone. In a given time zone, whose astronomical midnight determines the clock midnight? Due to a historical accident, the time zones were set in the 1880s as follows: astronomical midnight in the English town of Greenwich is set as clock midnight in the London time zone, and then all other time zones worldwide differ by one hour, two hours, three hours, and so on. (There are exceptions, where the shift involves an additional half hour [e.g., all of India], or an additional fifteen minutes.) If human history had played out a little differently, and astronomical midnight in the London time zone had been set by astronomical midnight in the Swiss city of Geneva, then what we call 12:12:12 in New York would instead be called 11:55:32, or something like that. (I didn’t actually calculate the precise time shift; that’s an exercise for the reader.)

In short, if we want to measure 12:12:12 from astronomical midnight, the problem is that it doesn’t occur when the clock says 12:12:12; it may happen when the clock says 11:58:34, or 12:24:06, depending on exactly where we are located within our time zone. And if instead we do want to use clock time, we should remember that if it weren’t for the historical progression that set the London time zone on Greenwich astronomical time, then again our clocks would be shifted away from where we find them today.

So let’s celebrate 12:12:12 — a time that, but for the grace of history and the strength and scientific prowess of the British Empire, might easily have been shifted by as much as half an hour in either direction — and in some countries with extended time zones, by as much as two or three hours!

Today and Tomorrow

We have one more great accident to thank for today being 12/12/12 here in North and South America. I refer to the location of the International Date Line. It’s one thing to set all the time zones — starting from midnight in one time zone, around through noon, and back to midnight as you go round the world — so that they give roughly the same clock time as astronomical time. But you still have to decide what day it is. And it can’t be the same day everywhere on the earth at the same time! For instance, if it is midnight in London, it is after midnight in Moscow and before midnight in New York… so if London’s calendar says it is July 2nd, then so does Moscow’s, while in New York you would think it is July 1st. But then in San Francisco it is a few hours earlier on July 1st, and in Tokyo it is even earlier on July 1st; still earlier in Beijing and in New Delhi on July 1st; and back we come to Moscow very early on … July 1st??? Whoops! A contradiction. Somewhere around the earth we have to make the day jump. And that’s what the International Date Line is for. When you cross that line, the calendar day has to jump by one. That line is completely arbitrary too. It was placed at a convenient value of longitude, right down the middle of the Pacific Ocean, where it intersects no continents except for a corner of Siberia, and affects rather few people, mainly on small islands. So when it is before midnight on July 1st in New York and San Francisco, it is midday on July 2nd in Tokyo. And when it is 12/12/12 at 12:12 in the morning in New York, it is 12/13/12 in Tokyo already; Tokyo is not 11 hours behind New York, it is 24 – 11 = 13 hours ahead.

Well, there’s another place where the International Date Line could have been conveniently placed: down the middle of the Atlantic. There’s just enough room between the continents to squeeze it in. And if that were the case, instead of New York being 5 hours behind London time, it would be 24 – 5 = 19 hours ahead of London time. In other words, it would already be 12/13/12 here in North and South America.

Thus we celebrate 12/12/12 here in New York today because of the location and shapes of the continents and the oceans, and because of the arbitrary choice to locate the International Date Line on the ocean between the Americas and Asia, and not on the ocean that separates the Americas from Europe and Africa.


By this point I hope you have a very healthy distrust of date-based and time-based numerology. Up to now it’s been fun, but I also want to remind you how this gets misused. For instance, let’s recall Harold Camping, former head of Family Radio Stations, whose ludicrous prophesies of the end of the world led many of his followers to give their money to his ministry and to dispense with all their worldly belongings. Yet it was completely obvious he was a solatic. (A lunatic is a person who becomes crazy when in the presence of the moon; but Camping was obviously nuts in broad daylight.) This became clear when not only did he predict a date — May 21, 2011 — of the earth’s destruction, but also a time: 6 p.m.

Ummm.. that’s 6 p.m. where? according to whose clock?

Camping’s answer: local time.

Is that astronomical time or clock time?

The answer wasn’t very sharp, but seemed to be: clock time.

Is that Standard Time or Daylight Savings Time? (A chunk of the Northern Hemisphere, heading into its summer, was on Daylight Savings time. The Southern Hemisphere, heading into its winter, was not.)

I don’t think we ever got an answer to that.

So: we were asked to believe that Camping was brilliant enough to carry out the numerology necessary to determine, from a document written down and unchanged for more than 1600 years, that divine forces would begin to destroy the earth on a particular date this year. And yet we learned, from his own predictions, that he was silly enough to infer from this ancient document that the destruction would start at the International Date Line (an arbitrary human convention that dates back only 125 years) and at 6 pm (using a method of timekeeping that is a human convention and did not exist even 200 years ago) working its way time zone by time zone (even though time zones are a human convention that dates back 125 years, and the time zones are heavily modified from astronomical time by political redrawings of their boundaries) and would perhaps even destroy the Southern and Northern hemispheres at slightly different rates because of the use of Daylight Savings Time in some northern regions.

In short, we learned Harold Camping doesn’t know too much about the real world.

It might be worth mentioning that when the New Testament was written down, the mistake of getting year 1 of the Christian era in the wrong place hadn’t happened yet. And of course Pope Gregory hadn’t removed his 10 days from the calendar yet either. I’m not sure, of course, but I’m willing to bet Camping didn’t know about these issues and probably didn’t correct for them.

So since Camping clearly didn’t understand some basic issues in timekeeping, why in heaven’s name did anyone give him the time of day, much less millions of dollars? And why couldn’t we have stopped him from damaging the lives of so many innocent people? It is too late for Camping’s followers, but perhaps we can be better prepared for the next round. At least, we should bring justifiable discredit on this type of numerology, pointing out its many logical flaws.

End of rant

There; I’m finally done. So glasses up, and let’s make a final toast to 12/12/12 12:12:12 — a consequence of misaligned astronomical orbital periods, calculation errors, ancient political decisions, Western hegemony, human physiology, historical anachronisms, religious doctrine, and Babylon. On the absurdity scale from one to ten, it surely scores a twelve.

[This article was posted on 12/12/12 at 12:12:12 … Atlantic Standard Time, Gregorian Calendar.]

31 responses to “Testing, Testing: 12/12/12 12:12:12

  1. Humanity is a very curious creature – you may say with serious shortcomings and child like in its beliefs.

    As you say some predict and execute bizarre occurrences – namely a man caused the red sea to split into two divides with a stick, another man caused a dead person to have life restored and for the majority of all the people on the planet to believe in God, and for countless people to be murdered in his name! Best just to ignore it…..and find the truth for oneself even if the body of mankind cannot do it as a group!

  2. 5:52 is 17:52 in military time not 16:52; but whose counting. 🙂

  3. Still, you have to admit: it’s pretty cool that it was 12:12:12 12/12/12 just a few minutes ago.


  4. Well, rather long comments, with rather speculative thoughts. The new age is about to come. It will start with a huge scandal. Scientific scandal. The essential causes of that scandal are vanity, hubris, arrogance, self-love, greed, jealousy, snobbishness. One hundred years ago, the new, German-scientific elite decided to make a clean-slate, to start from scratch. In physics. In the way to make superficial all of the scientific achievements of their main competitors – France and Great Britain. The competitors were no better, they behaved in the same way – Newton-Leibniz dispute was an example of vanity fair. But, at the beginning of the 20th century, Germany took the lead. From then, the physics stopped to be the science. It became the mathematical mysticism. The most advanced, the most sophisticated kind of stupidity. Which lasts 100 years already. The physics elite feels pretty comfortable and safe behind the thorn-fence of highly abstract concepts and their killer-mathematics-models, dreaming about big-bangs, wormholes, black holes, multiverses, dark matter, dark energy, uncertainty, spontaneity, ambiguity and other whatnots. Mishmash, hotchpotch of physics branches, sub-branches, academic clans, black-holers, (super)stringers, braners, etc.
    They have made the mechanisms that within them, nothing that does not include their ideas, cannot pass. Outside that safe place, the army of crackpots is trying to make variations of official concepts. And the official scientists simply ignore them. Because they know that no one can know their concepts better than they do. But, internet is great. Take Wikileaks for example. Or, check out this, the first purely scientific paper since the explanation of photoelectric effect. The dawn of new age – age of reason ennobled with love, and love guided by reason:
    Welcome the reason and true science, true knowledge. Or don’t. Suit yourself.

    • This is trolling nonsense.

      • … said Millikan, and started the 10-years-long experiment program to disprove Einstein’s explanation of photoelectric effect.
        Talents hit the targets no one else can hit. And the guy who wrote this just hit the target no one else could see. And clearly showed that “Behind it all is surely an idea, so simple, so beautiful, …” (John Archibald Wheeler).
        After all, try and deny it. Or don’t – enjoy in your visions, while you still can. I replaced mine with reality and reason. And I feel better.

  5. … and that 12:34:56 7/8/90 was in July or August?

  6. Cheers, Dilaton 🙂

  7. Well, depending on the country and culture, we would express dates and times with different formats.

    Next year, we will not get the chance to have a date like 13/13/13, but on some countries there will be an interesting palindrome to enjoy, like say, 31/11/13 (that would be the 31st of November).

    Kind regards, GEN

  8. Rant:

    If you followed Camping you’re not just an innocent bystander. At some point you have to be responsible for what you do. If they had been deliberately deceived for fraud I could have understood the objections, but this was an issue of lack of critical thinking. (Notably why anyone didn’t bring up the bible verse stating that we know ‘neither the day nor the hour’, surely sound scriptural grounds for ignoring him?)

    I have my own weird little beliefs, and I like to think I have examined them critically rather than just accepting things I like the sound of. If they cost me, I shall not expect anyone to stand up for me as if I were some uninformed idealist led astray. What happened to Camping’s followers is unfortunate, but hopefully they and others will learn from it and think more critically next time.

    End rant

    I wonder if, as we move to a more global society, we will eventually use one single time zone? that would make a lot of sense, at least to me, since we don’t really need clock time to tie into a specific time of day. Midnight at 4:15 is fine, so long as an hour is an hour.

    I believe the Bad Astronomer (Phil Plait) had some fun designing a near perfect method of leap years. I still find it interesting that our year length is so very close to .25 days, the 4\400 year rule is simple, if arbitrary.

  9. “But Jesus was born during or just after the reign of Herod the Great (so say two of the Gospels rather clearly). ”
    Well, Prof. Strassler, this is not true: Jesus was born during or just after the reign of Herod the Great according to Matthew. According to Luke, he would have been born when Quirinius was sent to clear up the mess done by Herod’s son Archelaus, which is about ten years after Herod’s death…

    • Hmm… not sure now where I got my information, since I wrote that part last year. I also have not looked at what the Pope says in his new book, presumably based on scholarship. My understanding was that there were various clues that put his birth during Herod’s time, but I’m no expert (clearly!)

      • It doesn’t help that there are several Herods. Ironically we covered this recently in study group while going over the arbitrariness of the dates of Christmas and Easter. But this does little harm to your main point.

      • On the contrary, it does a lot of harm: there is only one Herod the Great, the other Herods being his sons…The two nativity stories are not only fictions, but they are completely different, and they give two dates for the birth of Jesus, with a time span of 10 years. But they have to be read with a critical mind. See for instance Alfred Loisy here: http://www.earlychristianwritings.com/loisy2/chapter1.html

  10. Mary was twelve years young on the very first Annunciation Day.

  11. Numerology might be a matter of opinion. I still do not believe that Prof. Gerald Rosen’s work on the masses of quarks and leptons is empirically irrelevant. Furthermore, my guess is that Breakstone’s work on the same subject is extremely important.
    Compare Breakstone’s formula (2) with Witten’s formulas (4.14) and (4.15).)
    http://arxiv.org/pdf/0706.3359v1.pdf “Three-Dimensional Gravity Revisited” by Edward Witten, 2007
    http://arxiv.org/pdf/physics/0602118v2.pdf “Empirical Relationships among Lepton and Quark Masses” by A. Breakstone, 2009 revision

  12. Dear Matt,

    Thanks for this tour de force and your lively wit about all this human nuttiness.

    Good wishes for your continuing work in whatever year comes next — better yet, good wishes!!!

  13. One more little arbitrariness: the length of the second. For a very long time (pun intended) we thought that the celestial orbs were the perfect clocks, and used them as our standards for time keeping (in many varied ways, as you state, but still based on what we thought was going on in “the perfect heavens”). Toward the end of the 1800s, astronomers used their accumulated careful measurements to come up with the best measurements of the length of a day, and hence of the second (the so-called “Ephemeris Second”). Trouble is, neither the Earth’s orbit nor the Earth’s spin is all that regular. By the mid-1950s, using data from the 1800s gave incorrect positions and timing of astronomical events. And when atomic clocks started counting the “ticks” of things that really do occur in repeatably equal times, we discovered that the length of an astronomically-based “second” would have to change continuously! From the 1950s to the early 1970s, the time of day was already off from celestial time by over 32 seconds. Throw in a few relativistic effects, based on height above (or below) the geoid and relative speed differences, and things get really weird. Namely, almost all of our standards of measurement involve time, and hence the definition of the second. So, to maintain some degree of rationality, we now define the SI second in terms of the rate of transitions of atoms of Cesium under very specific conditions. But its duration was chosen to maintain compatibility with that previous (arbitrary and incorrect) “Ephemeris Second”.

    We now have standards bodies all around the earth with atomic clocks, and we have the BIPM (Bureau International des Poids et Measures) that correlates all those measurements, taking into account things like their elevation and latitude, to come up with a standard “atomic time” (“TAI”) based on the SI second. The International Earth Rotation Service also measures, models, and predicts Earth’s actual rotation and orbital motion, and issues corrections to “clock time” (“UTC”) to keep clocks in relatively close sync (within a second) of actual solar time – the time of high noon as the Sun crosses the Greenwich Meridian. (Actual astronomical observations use other relativistic time standards, but all are based on the SI atomic time standard.) Thus we get “Leap Seconds” every few years: at the end of June or December, we sometimes get minutes that are either 59 seconds (a negative leap second, never needed so far) or 61 seconds long. The last Leap Second, the 26th since 1972, was added on 30 June 2012: on that day, 23:59:60.0pm was a valid time! If we didn’t do that, “noon” would eventually start happening when the sun comes up rather than when it is directly overhead in Greenwich (or more accurately, a few miles from Greenwich, where the actual Meridian really is). But again, these leap seconds don’t happen on any regular schedule. The rate at which the Earth’s rotation is slowing down varies quite a bit (sometimes even speeding back up), affected by everything from earthquakes and the motion of its rotational axis and the poles to tides to weather. And like the weather, we can’t accurately predict when we will need another leap second (or not) for more than a few months in advance. So you really can’t know exactly when the next 12:12:12 will occur even a few years from now – there may have been multiple leap seconds added in in the mean time! How’s that for the Universe itself (not just us humans) being arbitrary? 🙂

  14. Well, the reason to add a leap second every now and then (this does not happen according to a precise and repetitive schedule, as it is based on detailed observations of the rate of spin of the Earth) is in fact that the Earth is slowing down its rate of spin over time, due to the work exerted by non conservative forces (friction forces) and other various effects that affect the rate of spin.

    Just to name a few: the friction caused by all bodies of water (seas, rivers, lakes, etc.). The friction caused by the air, the friction caused by all moving bodies in touch with the surface of the Earth (like ourselves!).

    Besides, the Moon is slowing spinning away from the Earth, and that also affects the rate of spin of the Earth.

    Kind regards, GEN

  15. I meant to write “is slowly spinning away from the Earth”

  16. Thanks for the fun date, you have quite some time at your hands !
    I just wanted to add that this was the last time in our live time that we have a date like that. There won’t be any 13/13/13 13:13:13 etc