Author Topic: Mars Timekeeping System  (Read 17279 times)

Offline Russel

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Re: Mars Timekeeping System
« Reply #180 on: 04/02/2017 11:46 AM »
The question is, why have an Earth-like calendar at all? Ie with months and days of the month?

I didn't say have an "Earth-like calendar", I suggested using just the actual (Earth) calendar on Mars and ignore the Martian year.

Prior to that, I've always pushed against creating an Earth like calendar for the Martian year. If you want to track the Martian year, you just count Sols. Nothing else makes sense.

Ok well at the risk of getting further out of synch, let me ask.

Are you proposing months and days of months to be formal elements in an official Martian calendar?

Or are you actually proposing what amounts to a quite separate lookup table? A calendar structured around Martian sols with the corresponding Earth calendar entry marked for each sol?

I'm in favour of the latter.
« Last Edit: 04/02/2017 11:50 AM by Russel »

Offline Paul451

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Re: Mars Timekeeping System
« Reply #181 on: 04/02/2017 12:41 PM »
The question is, why have an Earth-like calendar at all? Ie with months and days of the month?
I didn't say have an "Earth-like calendar", I suggested using just the actual (Earth) calendar on Mars and ignore the Martian year.
Are you proposing months and days of months to be formal elements in an official Martian calendar?

No.

Or are you actually proposing what amounts to a quite separate lookup table? A calendar structured around Martian sols with the corresponding Earth calendar entry marked for each sol?

No, and also no.

I'm saying you buy a calendar on Earth before you travel to Mars and that's the calendar you use on Mars.

But if you mark off days/dates on the calendar one-per-Sol then after about 36 Sols, you'll be a full day out of sync with the date on Earth. So you mark off two days/dates in order to get back in sync with Earth.

Formally then, I suggest getting everyone on Mars to skip the same specific days/dates on their respective calendars, in order to save confusion amongst themselves.

Dao Angkan suggests the same basic thing (at least for his "Business calendar"). We differ in when to skip over a day/date. Dao wants it to be when it's actually necessary, at 36 Sols, which is the 37th day on Earth. By skipping over the 37th day on the calendar, the next day is the 38th day on both planets.

Me, I think people would prefer a system that has a more convoluted pattern, but is easier for humans to remember. I suggested a specific day every fifth week, requiring a correction of roughly one day per (Earth) year. Then I suggested another pattern, such as the first Monday of every month, except in June and December, with further single-day corrections at memorable years (divisible by 10 and/or 25, etc). (I haven't bothered to fully map the latter pattern, so I'm not sure what the "further" corrections actually need to be.)

In Summary:

There is no such thing as a "Mars Calendar". There is only the Earth calendar.

But: The Sol is roughly 37/36ths longer than an Earth day.

Therefore in order to use a normal, unaltered Earth calendar on Mars, and mark off Sols as if they were days, and stay in sync with someone using the same calendar on Earth, you need to occasionally skip over a date. Annoying, but the reward for doing so means that you are never more that 12 hours out of sync with UTC-Earth.
« Last Edit: 04/02/2017 02:57 PM by Paul451 »

Offline Paul451

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Re: Mars Timekeeping System
« Reply #182 on: 04/02/2017 02:54 PM »
I think you're advocating a timekeeping system based on sols and then decimal fractions of sols.

Yes.

I'm not exactly clear as to what the argument in your first paragraph actually is. My point is that given an "official" timekeeping system that is in fact sols.fractions, people will look for more familiar/convenient methods and use those as a matter of practical day to day activity.

I don't think it'll be that common. Using Australian metrication as an example, people almost universally use metric and typically only use Imperial units in colloquialisms and approximate measure ("move it a couple of feet to the left"). And it didn't take long for people to get a feel for what a kilogram of sugar was, or a litre of milk, or a hundred km/h.

(Come to think of it, other than feet and inches and a few figures of speech involving miles, the others have faded almost completely out of use. I can't remember the last time I heard someone in Australia refer to "half a gallon" or "a couple of pounds", and certainly no-one born post-metrication.)

Indeed, its possible that people will have three clocks. The "official" one (sols.fraction), a local time 24 hour clock (with stretched seconds) and also a clock based on some time zone on Earth.

I really can't see that combination happening.

If there's an official time-keeping system, people will use that most of the time simply by necessity and quickly adapt to it. After a generation, young people will need a special app to understand Earth time because it will seem weird and counter-intuitive.

OTOH, if there's no official system, people might start using a stretched-second 24hr clock. Simply because it's relatively easy to modify time-keeping circuits to slow them by 3%, and initially every single time-keeping device will come from Earth. That might end up becoming official, simply because it's become too engrained by the time anyone has enough authority to make something official.

But I can't see both an official decimal-sol system being adopted and a common use of slow-second devices. If the latter hasn't become cultural-habit by the time the former is declared, then it won't become common. If the latter has become common, there'll be no sense of need to adopt the former.

Personally I thought scientists/engineers would have been the last people to mess with the length of the second, so this surprised me. But if scientists at JPL are doing it, then there's obviously not a huge resistance to it. I dislike it, but I can see it just happening.

No other proposed time system, including your suggestion, makes any sense. (IMO) They are terrible for official timekeeping, and they wouldn't arise naturally because they are terrible for people.

[People will need to know the time on Earth whenever they have a reason, obviously, but that has nothing to do with the local time-keeping system. However, I know plenty of migrants, and I don't know a single one who has a clock in their home set to that time-zone. It's more a business thing. So I can't see that becoming common on Mars.]

I've no problems in making the claim that technology will, quite definitely, be looking after all the boring detail.

A system has to be usable by humans. People need to be able to work out in their head what current_time+time_interval equals. I'm posting this at just after of 12:20. Thirty minutes ago, it was just after 11:50. A Mars clock needs to be that usable.

Your 3,698.968506125 seconds in a "Mars hour" is not usable. (Unless we're talking post-Singularity augmentation directly in the brain.)

Offline Dao Angkan

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Re: Mars Timekeeping System
« Reply #183 on: 04/02/2017 10:21 PM »
Example of Mars-Earth business calender;

There's a pretty major flaw in this calender. UTC-12:00 is essentially the same time as UTC+12:00, so really only 36 x 40 minute time zones. Still, that might be useful for the ~95 sol +40 minutes period. I'll rework it and also do a couple of variations such as the 5 week interval suggested by Paul. Also, if you do it at a higher frequency than 36 sols/ 37 days then maybe it would be more intuitive to just skip the last day of the month (which we already do with February every 3 out of 4 years ... although admittedly we don't actually skip the day of the week).

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