Why It's Time For The Decimal Day

Australia gave up years ago on the prehistoric systems of gallons, miles and pounds. But like the rest of the world, we cling like apes to hours, minutes and seconds. What fundamental law of the universe says we must divide our days into 24 equal parts? And then why must we divide these parts by 60 and then 60 again?

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I hereby declare our anachronistic "diurnal" time system broken and in need of urgent repair. Life in the 21st century is complex enough without requiring awkward mental divisions for what should be simple calculations of everyday relevance.

At this stage I should probably point out that, as a senior lecturer in Environmental Engineering, I'm no expert in time, although it does dictate much of my life. And no, in case you're wondering, I don't own shares in an experimental watch factory.

So, with that cleared up, who can tell me, without the aid of a supercomputer, how much I will earn if I work for three hours and 50 minutes at an hourly rate of $10?

When you're done with that, let me know how much water I will waste in a day if my toilet leaks 2ml per minute. And how far will a rocket travel in one day if it's travelling at a speed of 16km/s?

To simplify these questions, I propose we update to a decimal time system.

In a decimal system, we could divide each day into ten "decidays". A deciday would comprise 10 "centidays" or 100 "millidays" – each milliday would be 1,000 "microdays", and so on.

A decimal day would reduce the mental gymnastics to simply sliding a decimal point. Future primary school graduates could answer the questions above in around 10 microdays flat.

They would tell you that 3.8 decidays work at $10 per deciday earns you $38. They would know almost intuitively that a toilet leaking 2ml a milliday is going to lose two litres every day.

At 16km per microday, they will patiently explain, the rocket is going to travel 16,000,000km in one day.

Digital watches would be reprogrammed to provide decimal times such as 8.7.2 – that is, eight decidays, seven centidays and two millidays (about 8:56pm in the old system). Mechanical clocks would run at half the current speed with the digits 0 to 9 evenly spaced around the clock face.

With few Australians conforming strictly to the traditional 9-5 working day, now is the time to recalibrate to a new system.

The working day could become three decidays with a centiday break for morning tea and four centidays for lunch. It would take about a milliday to boil the jug for coffee. The definition of a late train could be re-jigged without anyone noticing.

While we're at it, we should take the opportunity to abolish international time zones and simply accept the fact that people in different places work, sleep and play during different decidays according to their longitude.

Decimal time is not a recent concept. In fact it was briefly adopted during the French Revolution. Decimal clocks and watches were manufactured, but the French deciday was sadly revoked after less than two years of service.

As with previous conversions to decimal systems, the deciday will again have its detractors. I expect that older generations will continue to work with the old system and the middle generation will just learn to convert.

But younger generations will appreciate our efforts and wonder how we managed to live with the cumbersome old system for so long.

The final hour of the hour must surely be nigh. We could look to a future where a "minute" is but a record of meeting and a "second" is an electoral result with no prize (sorry Mr Romney!).

The natural enemies of high school physics students and home accountants could be a thing of the past. In my view, we should fix time before we let another nanoday slip by.

Stuart Khan is Senior Lecturer in Environmental Engineering and Water Quality Researcher at the University of New South Wales. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

The Conversation

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    Whilst I agree with the sentiment I don't see this ever happening unless we move to a different planet.

      If we moved to a different planet the metric time system proposed here would be pretty stupid as its fundamental unit is an Earth day.

      Why not just measure time in meters?

        perhaps light-meters. The time it takes light to travel a meter. A second would be be about 300,000 light-kilometers.

        I can't see why that wouldn't work ... NOT

          They considered making that the official definition for a while, but the definition is still:
          the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom

          While it certainly does have uses, I think naming them 'day' could backfire pretty fast. Earth revolving is not a static thing, but we need our units of time to be static - hence why we have occasional leap seconds, to cope with the fact the day is gradually lengthening but seconds are not.

          It's best chance of success is to be adopted by scientific and technical folk as a standard. if high-end equipment has to support both standards, it'll eventually filter down to the low end. A few decades on every device will support it and it'd be easier to make the switch.

          The question is: does it offer the scientists anything they don't already get from kiloseconds? http://en.wikipedia.org/wiki/Orders_of_magnitude_(time)

        If we moved to a different planet, we would divide their day into 10 equal parts, and call it the Standard Golgafrincham Time zone.
        Although, by the time we do that I'm pretty sure that we would have genetically modified the human race so that we each have 2 heads. If we can do that, then we could also genetically modify ourselves to have six fingers on each hand. Then we simply trash the decimal system! That would allow us to keep our current time measuring system.
        Problem solved!

        Last edited 20/11/12 12:35 pm

          We can already count to 12 on one hand, and 60 using both hands - the Babylonians used this counting system for purposes of trading. Using your thumb, count the segments of each of the remaining four fingers on the same hand - if your hand is whole and complete, you should have 4 by 3 segments. Keep track of each group of twelve using thumb and fingers on the other hand in the way you would normally count 1 through 10 - 5 by 12 gives you 60.

          So yeah, 12 into 24/60 isn't actually so arbitrary afterall.

          EDIT: Oh, I see you brought this up yourself further down the page. Does that mean we'll evolve to a base90 counting system?

          Last edited 20/11/12 3:41 pm

        it sort of already is. though the duration of a second is officially described by the rotating caesium atoms thing mentioned below, a metre is defined as the distance light moves in a vacuum in 1/299,792,458 th of a second, so a second could be defined as how long it takes light to travel 299,792,458 metres.

        Actually the fundamental unit is second. It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. The day can be measured in 3 different ways - sidereal, stellar and mean solar.

      Screw the clock.
      Someone please divide the year into thirteen equal months of twenty eight days around the luna cycle.
      "Thirty days has September...." got old centuries ago.

    I was thinking about this a couple of weeks ago. It should also work in with our current measurements.
    As in a 1 cm cube is 1 ml which is 1 gram of water and 1 Cal is the energy required to heat 1 ml by 1 degree maybe the base time unit should be the time it takes to heat the water by 1 degree. and then multiply by ten.

      But Calorie isn't metric. It was replaced by Joule. Joule is 1 Newton for 1 metre, or 1 Amp through 1 Ohm.

        The calorie is metric, it just isn't SI. http://en.wikipedia.org/wiki/Calorie

    Not really possible unless it happens globaly, as too many computer systems (and non-computer systems for that matter) rely on the current system of time, and decimal time would require new time lengths, making every computer system that uses the second useless, as they rely on the second for many functions. While things could be reprogrammed, it would be prohibitively expensive to do so, especially for things like GPS, as some of the older satellites may not be able to be reprogrammed, so they would have to become yet another piece of space junk, as it would be far to resource intensive to recover every satellite that cannot be remotely updated.

    So yeah, the opportunity to have a relatively pain free switchover to metric time ended when timing became critical for the continued operation of complex computer systems.

      Most computer systems use a mechanism of measuring intervals since an epoch. Quite a lot will be milliseconds since 1970/01/01 (Unix Epoch), various other systems use other epochs, but most will have a concept of a day/time "0". These kind of systems actually allow themselves to work in parallel with something like a decimal time very well.

      Computers could easily run both systems and convert as needed, phasing out the old system slowly. They already represent time in a bunch of formats anyway. For the computer, the only time that actually matters is the clock frequency.

    What's so special about 10. It would be far smarter to use a number like 8 or 16, given our predeliction for all things digital.

      It's decimal, makes it easier to do calculations in your head.

      Last edited 20/11/12 11:45 am

        It's decimal.

        And Pedant is really talking binary

      We are stuck with a base ten number system. Unless you want to try convert people to hexadecimal.

      Humans are good at base 10. Switching to octal or hex doesn't make any of the problems in the article any easier for us to solve. And why make maths easier for computers when they're several orders of magnitude faster at it than us?

      Because we have ten fingers. That's the reason we represent numbers in base 10. You can represent them on any base and it would be the same number, but ten is natural.

    It's not April Fools Day is it?

    So what would replace the "One Mississippi..." measure of counting?

    I'd be keen to do it, but I just can't wrap my head around it at the moment. Sure it makes sense on paper (I had an "uhh duh!" moment when you asked how much money you'd get on the decimal system) but I'd need to live it for a while to see how it goes..

    Perhaps when I get my Pebble smartwatch (whenever THOSE will ship!) I'll hook up a watch face that displays that..

    Last edited 20/11/12 11:37 am

      (FYI, it's slightly faster than a second. Possibly "One Mississip")


        Probably in this day and age being so fast-paced, we probably need something that is faster than a second anyway!

          Faster than a second?

          How about the CU? The Child Unit of time is the duration between asking a teenager why they did it, and the inevitable "But I didn't do it!".

          But then again, that could be too fast..

    Since when do apes cling to hours, minutes and seconds? I'd rather take advice from someone who can come up with less inappropriate similes.

    "but the French deciday was sadly revoked after less than two years of service."

    How unexpected.

    Yes, you're right, we should abandon a fundamental SI unit because the author can't do arithmetic.

    "as a senior lecturer in Environmental Engineering"

    IOW, an academic who doesn't have to interact with the real world?

    "What fundamental law of the universe says we must divide our days into 24 equal parts? And then why must we divide these parts by 60 and then 60 again?"

    Ummm, I was under the impression it was due to how quickly our planet orbits the sun (in about 365.25 days), how quickly the planet rotates (creating day/night cycles), and how many times that rotation happens.

    But hey, that's just me.

      Good guess, but not correct. The 12, 24, 36, 144 and 360 system of counting was first used by the Babylonians thousands of years ago. It evolved because they counted using the knuckled segments of the fingers to come up with 12, or a dozen. It was useful because 12 could be more easily divided by more useful numbers, to give halves, quarters, and eights.
      The Egyptians, on the other hand (see what I did there?) counted using only their fingers and thumbs, thus giving us the decimal system.
      Dozens are useful because it is easier to buy half a dozen eggs than it is to buy 5 eggs.
      It is only coincidental that the number 360 is close (but not close enough) to the number of days it takes for us to orbit the sun.

      Last edited 20/11/12 12:40 pm

      How exactly do you get 24 from how fast the planet rotates?
      You don't.

        You don't, but as Dave_lord said, 24 is a useful choice as it can be divided by 2, 3, 4, 6, 8 and 12. 10 can only be divided by 2 and 5.

      The Earth was rotating long before we decided to divide its rotation in 24 hours... a decimal system would just be changing this division into 10 decidays... So the Earth would rotate every 10 decidays... still once a day.

      We decided the measurement, the Earth's rotation didn't decide on the number 24.

      You are saying the day/night cycle is inherently split into 24 discrete parts?

      I can't see how 365.25 days in a year is relevant to how we split a day.

      It is based on the sexagesimal system which I think is originated from the babylonians. That is also why 360 degree make a full circle.
      For the question of calculating 3 hr 50 min for $10/hr, simple, raise your fee $12/hr to make your hourly charge sync with time or charge the full 4 hours :)

        Right. Most people would round up to the nearest half or quarter hour, making the problem - dare I say it - ACADEMIC, like the senior lecturer in env eng who proposed it.

    Who says the decimal system is any better? It might be easier, but I don't hear anyone else complaining about how we measure time. Anyway, it would make no sense just to change the measurement of hours, minutes and seconds - what about days, weeks, and months? Why is a week 7 days, and not 10? Or a year 12 months and not 10?

    This is where the ever-so rational argument for decimalisation starts to break down.

      Month is based on the lunar cycle but had to be skewed when more accurate measurements of the earths orbit where made along with roman emperors desperate to name months in their own honor. The week is meaningless and is based on the bible. And do you really need a reason on why we can't change the number of days in the year?

    Decimal time is complete gibberish, what we REALLY need is Cubic Time! http://www.timecube.com/

      What have you stumbled upon? I cannot even begin to comprehend what is happening on that website, I mean, I understand the words, but nothing more.

        To be honest, Timecube guy is one of the founding cranks(/nutjobs/provider-of-lulz) on the internet. He's never made any sense, and he's done nothing but add to his original website since day one.

    Yeah yeah yeah, the rest of the world, blah, blah. We should do it anyway. There are hundreds of languages, units of measure and dozens of timezones and seasonal variations, and we all get along just fine. Technology has the answer to translating from one system/language/unit to the other, and I assume a 'global deciclock' could be instituted and conversions to and from the 24hr clock to the deciclock (localized per time zone) would be easy to produce. Let's do it!!

    Anyone remember Swatch "beat time"? I always thought that was rather nifty.


    Wouldn't it be easier to start with standardising planes and angles using decimal form. The maths for that already exists, and it works perfectly, except for those pesky non-integers that result in massively long chains of numbers for relatively simple measurements.

    Get the scientific and mathematical communities to go all-in with decimal in geometry, and you might have a chance here. Otherwise, I think your 250 millidays are up.

    Days, months and years are all based on astronomical phenomena. Dividing a day of roughly 24 hours into powers of ten can be made to work. Problems occur when working with periods greater than a day. Weeks are arbitary so a week could be ten days (a decaday) . However months and years will not fit easily into this system. Months would be roughly 2.8 decadays and years roughly 3.65 hectodays.
    Starting with a year as the base unit is even more confusing. You could divide a year up into ten "months" (a deciyear) of 36.5 days but they would have no relation to the orbit of the moon. In that case, you could start work in one month and after working 8 hours finish work in the next month! And trying to fit the time it takes for the earth to complete one rotation (a day) into this system just makes my head hurt (27.4 milliyears ??).
    As the author states, this is not a new idea. And the reason why we don't have decimal time is because no one has come up with a feasible way of making it work.

      Well working on less than a day and more than a year are easy, I mean we've got it right when we use decades, centuries and millenium as they are all factors of ten. Its trying to get 365.25 into a neat decimal quantity that's the trick. We are stuck with the Earth's rotation and revolution to come up with something that works for us.
      The thing is that a week as seven days just works for humans. Five days work and two days rest is how many disparate cultures have devided their calendar. In the same way that eight hours sleep just works. We have an average of 12 hours darkness, but sleep on average (life commitments permitting) two thirds of that.
      I say we don't try to make a year exactly decimal. How about seven days a week so that a fortnight (which will need a new name) is still ten working days; five weeks a month so that every month has the same number of days and two months is ten weeks; ten standard months a year (350 days) with an eleventh month of 15 days and 16 in leap years. This eleventh month could be considered the holiday/festival/feast month when most people take their annual holidays. Its length would have similar rules to those currntly used for February. Why is it that the SECOND month is taking up the leap year slack anyway?? While we're resetting the calendar we could start it right on a solstice rather than having it on the 22nd (WTF???)
      I do like the idea of decimal time, but since we usually work for eight hours and sleep for eight hours it would have to be a system that can be divided by three.

    Obviously your conversions have transformed today to APRIL FOOLS DAY
    This can be the only reason for this discussion

    i want a binary time system. day or night.

    What time is it?
    umm... daytime.
    oh shit! I'm late!

    So something like Star Trek's stardate system? According to that, today at 4:00pm (ie right now) is:

    Stardate: -310112.932604736

    Negative value since Stardate actually begins January 1, 2323 @ Stardate Zero.

    Btw, I used this conversion tool:

    I'm not THAT much of a nerd, that i'd have things like that embedded in my brain. hahaha

    As others have said, the problem isn't really around the counting of hours and minutes, but around time frames longer than days. We'll still need to count a year as 365 days, we can't change this to decimal unless we were to re-define a day as more (or less) than 1 rotation of the earth.

    You need a supercomputer to work out 3 x10 + ((5*10)/6)

    No wonder you are only earning $10 per hour!

    Just loving the debate on this one... good article get the masses talking.
    Oh and yeah vote 1 for Decidays!

    Any programmer/system designer has suffered through this anachronistic (no pun intended) nonsense since... well whenever they started in the profession

    Not only I'd like to see a 10 based date/time system, but one international standard to represent it.

    Quickly, which date is this: 03/12/2012. Is it March 12 or December 3rd? I can't tell you how many hours I have dedicated over my career to take care of this stupidity.

    Last edited 21/11/12 11:20 am

    I'm all for it.
    But... how can we stop SONY deciding to implement their own standard that's incompatible with everyone else's?

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