Time. A clock on a wall, a calendar, numbers on the top (or bottom) of your computer screen, ticking off the days of our lives. (Gee, that’d be a good title for a show or something, wouldn’t it?)

This morning on Facebook I read a couple of discussions about time keeping. One was about the decimal system, how everybody but the US seems to have taken up metric measurement. Which seems especially odd since they use the decimal system for their money. Somebody, in a fit of flippancy, remarked we could have a ten hour day, with one hundred minutes etc etc and then said, yes but that wouldn’t fit in with year. Which it wouldn’t if a minute was the same in duration as a minute is now.

The second discussion was about the pagan origins of the names of the days of the week, which I’m sure everybody knows are based on Norse God’s names, plus a day each for the sun and the moon. That can be extrapolated into the pagan origins of the names of the months of the year. Although quite a few really are based on month number.

At the end of the day, we can’t go past the three overriding fundamentals of time measurement. On this planet, anyway.

- The time it takes for the planet to revolve on its axis (day)
- The time it takes for the Moon to orbit the Earth (month)
- The time it takes for the Earth to orbit the Sun (year)

And we need to reconcile them. In earlier times, these cycles were extraordinarily significant for survival, since they dictated the amount of sunlight (daylight hours and the seasons) and tides. It’s how the ancients decided when to plant, when to harvest and when to celebrate, finally, the lengthening of the days and the passing of winter.

It’s hardly surprising that the Babylonian calendars were lunar based, that is, 28 days. Our 7 day week is one quarter of a month. Our ancestors probably came up with a duodecimal (base 12) system because 12 is so easily divisible by 2, 3, 4, 6 and 12. Thus 12 months, a 24 hour day, made up of 60 minutes, made up of 60 seconds. This is fine at a micro level, but it doesn’t fit the length of the year, so the length of months had to be juggled so that the end result was 365 days. In fact, the lengths of months were juggled to fir the needs of the solstices and equinoxes. And later, every four years we add a day because the orbit actually takes 365 ¼ days.

All in all, it’s an arithmetic nightmare. Trust me on this. I used to be a computer programmer and date mathematics was awful. The only way to calculate date (a) minus date (b) is to convert the dates to the day (number) in the year. Thus 28 February is the 59^{th} day of the year.

A decimal time system would seem to be eminently sensible. The French tried it, back in 1793, without success and that experiment is discussed on io9. In this case, tradition had the weight of inertia behind it, and the French reverted to the old hours in 1795 and scrapped the revolutionary experiment in 1806. Frankly, I’m not surprised. This decimal time system is artificial. It’s interesting that the French still stuck to 30-day months and 12-month years, though.

We COULD try a lunar calendar, with 13 months made up of 28 days, with an extra day at the winter solstice (say) to bring the number of days to 365. I think that would work. The solstices and equinoxes would be predictable and fall on a given date. Feel free to correct me if I’m wrong. And there’s no reason why we couldn’t trade in the old 24-hour day for (say) 20 hours or 25 hours. We’d have to adjust seconds and minutes to suit. 100 seconds in a minute, 100 minutes in an hour. The length of a week isn’t so much of an issue, since we don’t use it for much except how many days we work. Plenty of people do nine days on/nine days off and the like.

What do you think? Stick with the monster we know, or create a new time elephant?

Allan Douglas (@AllanDouglasDgn)Excellent discussion, Greta. Our calendar-making efforts are further hampered by the fact that even a solar year is not a nice neat number, but 365 days 5 hours 48 minutes 46 seconds. This is the reason Caesar created the leap year: to get things caught up every so often. Although, I suspect Caesar didn’t CREATE this he just gets credit for some astronomers work. 🙂

I have often wondered how things would evolve if we move out into the galaxy and settle new planets. These will have a completely different timing for years, months and days from Earth. Synchronizing dates between multiple planets would be a programmers worst nightmare! I have trouble adjusting to traveling through a couple of time zones on this planet!

Greta van der RolOh it is, indeed, a can of worms and none of the numbers are neat. Therefore, the answer can’t be neat. It’s one of the problems of trying to make a precise mathematical model fit a natural phenomenon. Like weather. 🙂

Richard LeonardI see an open can lying on its side, straddling a huge pile of worms!

Little wonder nothing’s changed!

As a programmer you’d appreciate the leap year rule of “4 is, 100 is not, 400 is”, not that we had to write code that ran back in 1900, or plan ahead for 2100, but anyway…

I think the most obvious requirement is that any new units of time must have different names. You can’t have a 100 seconds in a minute because by definition a minute has 60 seconds. Also as a programmer you’d rather we were all born with 8 fingers on each hand. Decimal is great until you need to halve 5.

Oh, by the way you’ve been nominated for a blog Award!

To end the mystery about the type of award, follow this link: http://richardleonard.wordpress.com/2012/12/15/the-very-inspiring-blogger-award/

Greta van der RolThat is the problem with decimal (halving five). But then, there’s a problem every which way you look. There is no ‘simple’ solution. Thanks for the award.

juliabarrettI don’t mind the current way of measuring time. Twelve/twenty-four are good numbers. The Jewish calendar is also lunar, a 28 day calendar, which means our holidays change yearly. Some years you lose time, some years it seems as if you gain time. I think I’d rather have Base 12.

Greta van der RolYes, you make the point that time doesn’t change. Just the way we measure it.

Michael FormichelliI’ve been using the Julian Day Number system in my scifi writing. It has nothing to do with the Julian Calendar despite the name (not exactly), and it’s based on counting seconds without regard to years, months, days, etc. and is used in astronomical measurements (to adjust for the drift of stars, etc.) I figure any space faring culture, with colonies on multiple worlds is going to need something arbitrary to keep time between them (for timing arrivals of cargo at the very least), so the JDN system, being already in use, seemed a logical choice.

As for using it in practical, every-day life it’s a little abstract for most (myself included). They sell JDN watches on specialty sites like ThinkGeek.com, but I doubt it’s going to catch on until humans live on multiple worlds.

Greta van der RolYeah, if we ever get ourselves onto multiple worlds, we’ll need some sort of multi-planet equivalent of GMT, otherwise how do we coordinate meetings etc? It’s a complex business. Thanks for popping in.

Robin Helweg-LarsenYou raise a lot of issues and problems.

Real months aren’t easy to work with, and don’t last 28 days. They “range from about 29.18 to about 29.93 days. The long-term average duration is 29.530589 days (29 d 12 h 44 min 2.9 s)”. Muslims have 12 lunar months a year, giving them a totally useless “year” of 356 or so days. Everything happens 10 or 11 days earlier than it did the year before.

Equinoxes and solstices already fall on the same day every year (or near enough, and the exact date will always vary a little by location on the planet). No need to change for that.

The concept of the second probably needs to stay approximately as is, being natural and related to the heartbeat. But the minute and hour are artificial and can be changed.

When we go off-planet, or onto a new planet, then what? How will we choose to measure time when the planetary rotation isn’t 24 hours, the year isn’t 365 days, and there’s no Moon? I don’t know.

There’s no reason to stay with Base 10 for everything, anyway. Base 12 might be better. then you can *really* start messing with the calendar!

Greta van der RolThanks, Robin. It’s an intriguing notion. I didn’t know that about the second and the heartbeat – but it makes sense, It had to come from somewhere.