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Future time measurement units for a tidal locked exoplanet

  1. Aug 3, 2015 #1
    Lets assume that a human colony wants to reform time measurement units for more practical.

    -circadian rhythm a bit exceeds 24h, so perfect day would be around 24h and 10 minutes ( http://www.circadiansleepdisorders.org/info/cycle_length.php )
    -readjusting year zero, somewhere around landing - no problem
    - it would be really nice to keep some units similar (like year for the same length to allow easier understanding of past history)
    -it would be nice to keep second unchanged not to have readjust measurement units
    -decimal division would be really nice


    1) Day 24h 21 min - so there would be a year of 360 days. (not round, second not preserved...)
    2) 10 000 seconds day (27h 46 minutes day would be somewhat too long)
    (yes, I've seen: http://www.projectrho.com/public_html/rocket/futuremeasure.php and I'm not convinced)

    (honestly speking I dislike both such ideas that suggested and hope someone sees something better)
  2. jcsd
  3. Aug 4, 2015 #2


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    Hanging onto "the second" and "rationalizing" other units are mutually exclusive goals; it's highly unlikely that anyone is going to stumble across a tidally locked body that revolves in a period (or precessional sequence) that is synchronous to a very precise one second time base brought from elsewhere in the universe. I suspect you'll be stuck with some sort of year-end festival/calends.
  4. Aug 4, 2015 #3
    Stretched second is already used on Mars.
  5. Aug 4, 2015 #4
    I hoped that someone could come one with some brilliant close approximation in line... dunno... kibibyte... (just I don't see any)

    The problem is that second is a base SI unit, so touching it would immediately cause problems with all units based on it.
  6. Aug 5, 2015 #5


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    I'd keep the second as the standard unit for all appropriate technical matters, but create a new unit you can base 'everyday' time on. Hell, you could just call this new unit a "second" and call the old one a "standard second".
  7. Aug 5, 2015 #6


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    Surely it's going to depend on the realities on the ground i.e. how many seconds long is a day on this planet? From there you can divide things up as best as possible in a way that allows for consistent subdivisions that are easy to understand.

    For example, if this planet has a day length of 27 hours 36 minutes 21 seconds (made up completely from the top of my head as typing) that adds up to 99,381 seconds. Using a spreadsheet there's a couple of subdivisions that are pretty clean (i.e. not much need for leap seconds or extra half hours or whatever.

    Working with that the day is divided into three equal periods of 33,127 seconds exactly. Let's call them a Triad, specifically Morn, After and Eve.

    Triads don't divide easily, the closest is 25 which gives you 1,325.08. If we timed these periods 1,325 seconds then every Triad we'd lose exactly two seconds. Not a problem, make the first and last of these periods one second longer. Let's call these Segments, the first and last segment of each Triad being one second longer.

    Segments also don't divide easily but they come close at 265 periods of 5.000302 seconds. Due to this you loose a second every 44 days, which is pretty easy to insert a leap second into. Let's call these sections Quins.

    So given a completely random day cycle it can be fairly easily broken up into three Triads of twenty-five Segments each lasting 265 Quins. Might seem confusing at first but it would be pretty easy to get used to a clock that read A:12:132(2) and realise it was midday.

    EDIT: Re Circadian cycle the link you provide doesn't confirm a cycle of 24 hours 10 minutes, it reports on a study that showed (with a fair amount of range) that on average isolated from external cues the cycle was measured at 24 hours 11 minutes but it reset to 24 when exposed externally with not problem. Provided the planet day length is not drastically different to Earth's this resetting could mean there isn't much problem and the body adjusts.
    Last edited: Aug 5, 2015
  8. Aug 5, 2015 #7
    Tidal lock. Which theoretically should increase the amount of freedom.
  9. Aug 5, 2015 #8


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    To the Sun?
  10. Aug 5, 2015 #9
    To their red dwarf.
  11. Aug 5, 2015 #10


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    Then why not just keep using the regular 24 hour clock and have public/domestic lighting tuned to emit light as appropriate given a healthy circadian cycle? Alternatively just go full SI. Have the second as the basis for their time measurement and use Kiloseconds, Megaseconds, Gigaseconds etcetera to denote larger units of time.
  12. Aug 5, 2015 #11
    I would think whoever is in control of your government would dictate how time is defined. Do you have a government controlled by the working population, or a group of plutocrats? If you have a plutocratic government (which is more likely) time will be broken up based on what's most efficient for business, it would force a world wide standard and base it's timescale on what's cheapest. How long does it take a human to take lunch? How long can they work without a break?

    If you have the workers in charge of the government, you'll have a little more chaos and timescale will probably be based on leisure activities. How long can we run without getting tired? How long can we watch something before getting bored?
  13. Aug 5, 2015 #12
    I thought about keeping population in 3 shifts, just to utilize the infrastructure better and provide a nice perk, that one ends his job and everything is open. There would be natural light all the time so no shift would be worse off.

    What would you think about calendar adjustment? 364 day year? (52*7) 360 day year? Not worthy?

    Honestly I don't see here how it is form of gov related, unless ideology prescribe for some special adjustment. The question related to time measurement, no to working hours as such.
  14. Aug 5, 2015 #13


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    You can have shifts in a 24 hour clock, we do it IRL all the time. Just this evening my flatmate said he was doing the two til ten shift. The real question is how many more workers you need if you plan on keeping every service open 24 hours a day.
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