Author Topic: Mars Timekeeping System  (Read 57909 times)

Offline mark_m

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Re: Mars Timekeeping System
« Reply #80 on: 11/07/2016 12:12 am »
[Edit - a suggestion: since the Mars minute of 59 seconds will cause clocks to drift by about 5 minutes per day relative to solar time, is there a point in sticking to having an integer number of seconds in the Mars minute? Because if you allow decimals and make one Mars Minute equal to 61.6494751 seconds then the Mars Sol of 24 Mars hours of 60 Mars minutes each will be in sync with local solar time. Or you can make it 59.1834961 seconds for 25 hours of 60 Mars minutes and again be in sync...]
You're right, I miscalculated, I thought I was a few seconds off per sol, but I'm over 4 1/2 minutes off.  :(

So it's not quite as clean as I'd hoped. Your non-integer number of seconds in a minute would certainly work, and although it seems strange, it might not be bad at all. Most people could just consider it 59 seconds per minute, and devices would know the exact value. Another similar adjustment would be to go back to 60 seconds in a minute, but have an hour be 59 minutes plus an additional 11 seconds at the end of each hour. Then the drift would be really slow, and could be made up for in leap seconds periodically. Or, following your lead, have each hour be 59 minutes plus 11.00976 seconds....
« Last Edit: 11/07/2016 12:17 am by mark_m »

Offline Lumina

Re: Mars Timekeeping System
« Reply #81 on: 11/07/2016 12:35 am »
Inspired by Mark_M, here's my complete proposal for Martian timekeeping and calendar:

1 Mars second    =    1               Earth second
1 Mars Minute    =  61.6494751  Earth seconds
1 Mars Hour       =  60               Mars minutes
1 Mars Sol         =  24               Mars hours
1 Mars Year       = 669              Mars sols

January = 50 sols
February = 48 sols (46 sols every 5 Mars years)
March = 54 sols (Spring Equinox: March 36th)
April = 66 sols
May = 67 sols
June = 64 sols (Summer Solstice: June 43rd)
July = 64 sols
August = 63 sols
September = 45 sols (Autumn Equinox: September 30th)
October = 45 sols
November = 44 sols
December = 59 sols (Winter Solstice: December 39th)

Offline Lumina

Re: Mars Timekeeping System
« Reply #82 on: 11/07/2016 12:59 am »
Just for fun, I was wondering how long it would take to change Mars' solar day length to 24 Earth hours by firing raptors due west from the top of the southern rim of Pavonis Mons (latitude: 1.48 deg N, altitude 14,000 metres), perhaps as part of a terraforming project.

If my math is right, you'd need about 1 million vacuum raptors firing non-stop for 8,600 Mars years.

It will probably be much easier to get used to 1 Mars minute being only approximately 60 seconds!
« Last Edit: 11/07/2016 01:21 am by Lumina »

Offline ChrisWilson68

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Re: Mars Timekeeping System
« Reply #83 on: 11/07/2016 05:49 am »
Just for fun, I was wondering how long it would take to change Mars' solar day length to 24 Earth hours by firing raptors due west from the top of the southern rim of Pavonis Mons (latitude: 1.48 deg N, altitude 14,000 metres), perhaps as part of a terraforming project.

If my math is right, you'd need about 1 million vacuum raptors firing non-stop for 8,600 Mars years.

Your calculation is a little off.  It will actually take 1 million vacuum raptors firing approximately infinity Mars years.

The problem is that the exhaust of the raptors stays in the atmosphere and it eventually imparts its momentum back to the planet.

Said another way, unless something is leaving the planet, conservation of angular momentum says the rotational speed won't be affected except by the distribution of mass.  Move more mass to the poles and the rotation will speed up.  But you'd have to move an impractically huge amount of mass to get a 24-hour day.

Offline AncientU

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Re: Mars Timekeeping System
« Reply #84 on: 11/07/2016 10:39 am »
What is interesting about a 24 hour day?
(Earth's random and continually changing rotation rate aside, that is...)

Note: When we start terraforming, polar ices will be more evenly distributed and rotation rate will actually get slower -- longer days, not shorter.
« Last Edit: 11/07/2016 10:43 am by AncientU »
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Offline Lumina

Re: Mars Timekeeping System
« Reply #85 on: 11/07/2016 11:20 am »
Just for fun, I was wondering how long it would take to change Mars' solar day length to 24 Earth hours by firing raptors due west from the top of the southern rim of Pavonis Mons (latitude: 1.48 deg N, altitude 14,000 metres), perhaps as part of a terraforming project.

If my math is right, you'd need about 1 million vacuum raptors firing non-stop for 8,600 Mars years.

Your calculation is a little off.  It will actually take 1 million vacuum raptors firing approximately infinity Mars years.

The problem is that the exhaust of the raptors stays in the atmosphere and it eventually imparts its momentum back to the planet.

Said another way, unless something is leaving the planet, conservation of angular momentum says the rotational speed won't be affected except by the distribution of mass.  Move more mass to the poles and the rotation will speed up.  But you'd have to move an impractically huge amount of mass to get a 24-hour day.

I think you are right that this fun idea is theoretically as well as practically infeasible. I didn't geek out all the way with the math of atmospheric pressure at that altitude, the resulting momentum exchange with the plume, the exhaust velocity relative to the escape velocity of a particle launched westwards from 14,000m / 28,000m up on Mars, the angle of the plume to the horizontal and whether all that's enough to get a plume to punch through the 30 pascals of pressure at Olympus Mons and to escape into space (I changed to Pavonis at the last minute for its equatorial location). Even if I did go through all that, you're probably right about the infinity thing, but never let the math stand in the way of a good laugh!
« Last Edit: 11/07/2016 11:24 am by Lumina »

Offline Paul451

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Re: Mars Timekeeping System
« Reply #86 on: 11/07/2016 11:35 am »
Inspired by Mark_M, here's my complete proposal for Martian timekeeping and calendar:
1 Mars second    =    1               Earth second
1 Mars Minute    =  61.6494751  Earth seconds
1 Mars Hour       =  60               Mars minutes
1 Mars Sol         =  24               Mars hours
1 Mars Year       = 669              Mars sols
January = 50 sols
February = 48 sols (46 sols every 5 Mars years)
March = 54 sols (Spring Equinox: March 36th)
April = 66 sols
May = 67 sols
June = 64 sols (Summer Solstice: June 43rd)
July = 64 sols
August = 63 sols
September = 45 sols (Autumn Equinox: September 30th)
October = 45 sols
November = 44 sols
December = 59 sols (Winter Solstice: December 39th)

Do you really not see how incredibly annoying that would be to actually live with? Fractional seconds per minute? "Months" ranging from 44 to 67 days in a random pattern? Why? What possible advantage could there be to having such a system?

Offline mark_m

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Re: Mars Timekeeping System
« Reply #87 on: 11/07/2016 01:12 pm »
Do you really not see how incredibly annoying that would be to actually live with? Fractional seconds per minute? "Months" ranging from 44 to 67 days in a random pattern? Why? What possible advantage could there be to having such a system?
Unfortunately 88,775 (the integer number of seconds in a sol) doesn't divide up nicely, so if you're keeping seconds as they are and want time periods at all roughly analogous to minutes and hours, it seems like you have 3 choices: a few "leap" seconds per hour,  almost 5 "leap" minutes per day, or Lumina's suggestion of non-integer seconds per minute (which conveniently also takes care of the fractional number of seconds in a sol). With digital devices keeping and calculating time, which is really the least intrusive?

I'm assuming the variable length months is related to orbital mechanics and Martian seasons. I could see 56 day months except for February, which would be 52 or 53 days. The equinoxes and solstices might shift a bit, but I think they'd be close enough to feel comfortable.

Offline Oersted

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Re: Mars Timekeeping System
« Reply #88 on: 11/07/2016 06:03 pm »
I really hope they will use a logical regular calendar, such as the proposed International Fixed Calendar that we OUGHT to use here on Earth...
- Every day of the month falls on the same weekday in each month—the 17th always falls on a Tuesday, for example."

I can't think of anything more horrendous! This is a perfect example of calendar design that exalts logic over humanity. Calendars are meant to be used by people. People who have, for instance, birthdays; and we all know we prefer to celebrate our birthday on some days of the week more than others - those where we don't have to go to work the next day, for instance. Such a fixed calendar means that if you're unlucky enough to be born on a day that's a bad day for a birthday party, it will be a bad day for a birthday party your entire life. The Gregorian calendar rotates the dates through the days of the week giving everyone a shot at good and bad days.

If that is the worst you can come up with about the International Fixed Calendar then I am tempted to take that as a ringing endorsement of the idea! Most people happily celebrate their birthday on the nearest practical weekend day or holiday. Or are you saying they only celebrate in the years where their birthdays happen to fall on a weekend? :-)

No worries, we can agree to disagree. What we think is not important anyway.
« Last Edit: 11/07/2016 06:03 pm by Oersted »

Offline ChrisWilson68

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Re: Mars Timekeeping System
« Reply #89 on: 11/07/2016 06:08 pm »
I really hope they will use a logical regular calendar, such as the proposed International Fixed Calendar that we OUGHT to use here on Earth...
- Every day of the month falls on the same weekday in each month—the 17th always falls on a Tuesday, for example."

I can't think of anything more horrendous! This is a perfect example of calendar design that exalts logic over humanity. Calendars are meant to be used by people. People who have, for instance, birthdays; and we all know we prefer to celebrate our birthday on some days of the week more than others - those where we don't have to go to work the next day, for instance. Such a fixed calendar means that if you're unlucky enough to be born on a day that's a bad day for a birthday party, it will be a bad day for a birthday party your entire life. The Gregorian calendar rotates the dates through the days of the week giving everyone a shot at good and bad days.

If that is the worst you can come up with about the International Fixed Calendar then I am tempted to take that as a ringing endorsement of the idea!

He didn't say that's the worst, just an example.

The International Fixed Calendar just trades some disadvantages of the Gregorian calendar for other disadvantages.  Which disadvantages are preferable is purely subjective.  I hope you can recognize that just because someone prefers the Gregorian calendar doesn't mean they're stupid or don't understand the IFC.  They just have different things they value.

Offline Robotbeat

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Re: Mars Timekeeping System
« Reply #90 on: 11/07/2016 06:23 pm »
Leave seconds, minutes, and hours alone, you insane people!  ;D
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Offline Hyperion5

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Re: Mars Timekeeping System
« Reply #91 on: 11/08/2016 01:42 am »
Quote
... it's just that 24-hour time makes a lot of sense.  Obviously it's going to need some adjusting however, since we need to stuff more seconds into each hour.  A Martian Hour would therefore consist 3,698.9675 seconds in 60 Martian Minutes.  Each Martian Minute would consist of 61.649 seconds, while the SI second would be left as is.  This would probably be a good compromise at doing an early Martian timekeeping system.

This is obviously a new usage of the phrase 'good compromise' that I've not previously come across before! Do you really think people are going to use 'minutes' consisting of 61.549 seconds?

People need to remember that a self-sustaining Mars colony is going to be big enough that a substantial fraction of the population won't have careers in any numerate discipline, let alone scientists and engineers (it will probably have the same proportion who are functionally innumerate!). Calendars and time-keeping have to work for everyone, not just scientists and engineers, or even just the well-educated.

Leave seconds, minutes, and hours alone, you insane people!  ;D

No need for exclamation marks or questioning of sanity, gentlemen.   8)  I think all of us realize that a substantial fraction of any population, be they in South Korea or South Africa, won't be very numerate.  That's not what the issue is about.  All of this boils down to how do you create proper Martian time zones using Earth-based measures of time?  Most of us have agreed that we should keep the SI second.  The problem is unless you then adjust the Martian Minute or Martian Hour, you wind up with the 39-minute long "Zero Hour", which ruins any attempt to create proper time zones.  Unless you can miraculously force Mars to have the same length day as Earth, this issue isn't going away.  The alternative is not to have any time zones at all, which I think is wildly unfeasible, but that's exactly what it appears you are proposing. 

Offline Lumina

Re: Mars Timekeeping System
« Reply #92 on: 11/08/2016 10:27 am »
Leave seconds, minutes, and hours alone, you insane people!  ;D

"No one pretends that democracy is perfect or all-wise. Indeed, it has been said that democracy is the worst form of Government except all those other forms that have been tried from time to time."

This is from a speech Winston Churchill gave to the House of Commons, November 11, 1947.

After weighing the alternatives, and considering that all timekeeping is basically digital nowadays, I suggest that having a fractional number of seconds per Martian minute is the worst form of timekeeping except all those other forms that have been suggested from time to time :)
« Last Edit: 11/08/2016 10:28 am by Lumina »

Offline Lumina

Re: Mars Timekeeping System
« Reply #93 on: 11/08/2016 10:49 am »
Inspired by Mark_M, here's my complete proposal for Martian timekeeping and calendar:
1 Mars second    =    1               Earth second
1 Mars Minute    =  61.6494751  Earth seconds
1 Mars Hour       =  60               Mars minutes
1 Mars Sol         =  24               Mars hours
1 Mars Year       = 669              Mars sols
January = 50 sols
February = 48 sols (46 sols every 5 Mars years)
March = 54 sols (Spring Equinox: March 36th)
April = 66 sols
May = 67 sols
June = 64 sols (Summer Solstice: June 43rd)
July = 64 sols
August = 63 sols
September = 45 sols (Autumn Equinox: September 30th)
October = 45 sols
November = 44 sols
December = 59 sols (Winter Solstice: December 39th)

Do you really not see how incredibly annoying that would be to actually live with? Fractional seconds per minute? "Months" ranging from 44 to 67 days in a random pattern? Why? What possible advantage could there be to having such a system?

The lengh of the months is not random at all and it certainly isn't any more arbitrary than the length of months on Earth (see the children's rhyme below).

The intent of the concept is to keep the most important features of our calendar as close to being intact and familiar as possible while adapting to the orbital realities of Mars by making the fewest possible adjustments in the least worst places.

One important feature of a Mars calendar in my opinion is to have the familiar names of the months aligned with the familiar orbital seasons. I tried to do that by aiming to get all the solstices and equinoxes to occur two thirds of the way through their usual months. This then constrained somewhat the choices of how many days I could give to each month, and that was the source of the variance in month lengths. It's a loose constraint because you can take days from April and give them to May for instance without affecting the solstice/equinox dates, so there are many other ways to do this if you don't like the result. I do admit to putting my finger on the scales and giving extra days to December so that you can have a long one to two week end of year holiday without butchering the number of work days in that month.

"Thirty days hath September,
April, June, and November.
All the rest have thirty-one,
Except for February alone,
Which hath but twenty-eight days clear,
And twenty-nine in each leap year."
« Last Edit: 11/08/2016 10:56 am by Lumina »

Offline baldusi

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Re: Mars Timekeeping System
« Reply #94 on: 11/08/2016 03:38 pm »
Leave seconds, minutes, and hours alone, you insane people!  ;D

"No one pretends that democracy is perfect or all-wise. Indeed, it has been said that democracy is the worst form of Government except all those other forms that have been tried from time to time."

This is from a speech Winston Churchill gave to the House of Commons, November 11, 1947.

After weighing the alternatives, and considering that all timekeeping is basically digital nowadays, I suggest that having a fractional number of seconds per Martian minute is the worst form of timekeeping except all those other forms that have been suggested from time to time :)

I insist: 25 martian hour with 53 martian minutes of 67 seconds. leaves an error of .5 seconds/sol. Don't call them hour and minutes, put another name, and you are done.

Offline ThereIWas3

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Re: Mars Timekeeping System
« Reply #95 on: 11/08/2016 04:02 pm »
At a different level, what to choose as the origin for figuring years on Mars?  Many SF books take the "year of first manned landing" as the origin, and figure in Mars Years before and after that.  In Heinlein's "Podkayne of Mars" the heroine, who was born on Mars, describes herself as being a bit over 8 years old, or 15 in Earth Years.

Earth cultures have handled varying traditional calendars without much problem.  Ask someone in Japan what year it is and they are just as likely to answer "Heisei 28" as they are "2016".  You will even find dates written that way on public announcements.

Offline Duds

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Re: Mars Timekeeping System
« Reply #96 on: 11/08/2016 05:26 pm »
Those living on Mars would want a sunlight oriented system for sols like we have on Earth.  I think it's a bad idea to alter the second proportionately as some elsewhere have suggested.  Although not noticed by Mars residents it could complicate engineering calculations and be a source of error.

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.

Similar to Stanley Robinsons sci-fi Red Mars trilogy idea for martian time keeping

Offline guckyfan

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Re: Mars Timekeeping System
« Reply #97 on: 11/08/2016 05:42 pm »

My radical Mars quirky solution is to use normal Earth hours minutes and seconds but at midnight when all but the night shift and those wild & crazy late night Mars party animals are asleep, have the clocks go to Red Time where the extra 39 minutes 35.244 seconds are added and counted down before resuming at say 12:01.  Mars sols are preserved.  Everyone in the inner solar system is using standard seconds, etc.  And a party time is enshrined in unique Mars culture.

The perfect solution as long as there is just one major settlement. When people are spread all over Mars and people live in all time zones, there is a problem.

You can keep that part hour locally everywhere at midnight, that would make for odd jumps of time between time zones.

You can move that part hour around locally, so that it is everywhere at the same time, but that would have it during the day in many locations. Despite the disadvantage I like this option best.

Offline Paul451

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Re: Mars Timekeeping System
« Reply #98 on: 11/08/2016 06:40 pm »
The lengh of the months is not random at all and it certainly isn't any more arbitrary than the length of months on Earth

It really is.

Even Earth's arbitrary and centuries abused calendar is just:

31, 28*, 31, 30, 31, 30, 31,
31, 30, 31, 30, 31.

A fairly clear 31/30, 31/30 pattern, with just one odd month which is then the home of that single leap day (nicely signposted by its odd-man status). Though it would have better if the damn Romans hadn't messed with August... 31, 29/30, 31, 30, 31, 30, 31, 30, 31, 30, 31, 30. Even better if they'd kept the March start, 31, 30, 31, 30, 31, 30, 31, 30, 31, 30, 31, 29/30, so the odd-man is at the end.

(Thanks to this relative uniformity, the solstices and equinoxes are always somewhere around the 20th.)

For Mars, you've got a "pattern" of....

50, 48/46, 54, 66, 67, 64, 64, 63, 45, 45, 44, 59. (I actually ran out of colours that display well.)

(With equinoxes/solstices varying: 36, 43, 30, 39. And those dates will each vary by three days, drifting back and forth as they interact with the leap-year cycle, just as Earth's do.)

(see the children's rhyme below).
...
Thirty days hath September, April, June, and November.
All the rest have thirty-one,
Except for February ...

Yeah, just two repeated values, 30 & 31, and one thrown exception - and we consider it complex and arbitrary! Which is why so many nerdlings are attracted to the 13-month universal calender.

Now make up a rhyme for your system.

The intent of the concept is to keep the most important features of our calendar as close to being intact and familiar as possible

What's familiar except "twelve sort-of-months"?

One important feature of a Mars calendar in my opinion is to have the familiar names of the months

Which only serves to force people to specify which calendar they are talking about. Like having to specify which regional "foot" you are using in the various pre-metric systems, or ounce, or pound, or mile...

January or Mars-January?

This then constrained somewhat the choices of how many days I could give to each month, [etc etc]

So why not give up the whole thing? It doesn't work. It can't work. The Martian year is too different from the Earth year.

Just count Sols. They are going to do that anyway. And they would have to in order to understand your system, certainly no-one is going to remember it.

(And if you must insist on some kind of calendar, at least use a simple one like the Darian 7/4/24 variants.)

[edit: Plurals vs possessives.]
« Last Edit: 11/08/2016 07:27 pm by Paul451 »

Offline Paul451

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Re: Mars Timekeeping System
« Reply #99 on: 11/08/2016 07:12 pm »
At a different level, what to choose as the origin for figuring years on Mars?  Many SF books take the "year of first manned landing" as the origin, and figure in Mars Years before and after that.

You mean the same way it's currently Year 524 in the American Calendar?

[edit: Or 71 AE, if we're using the SF books I read as a kid. Still waiting for us to switch to the more sensible "Atomic Era" calendar.]

When people are spread all over Mars and people live in all time zones, there is a problem.
You can keep that part hour locally everywhere at midnight, that would make for odd jumps of time between time zones.

Sounds like the problem is in having time-zones. Universal Mars Time, FTW.

I insist: 25 martian hour with 53 martian minutes of 67 seconds. leaves an error of .5 seconds/sol. Don't call them hour and minutes, put another name, and you are done.

While I insist: if you aren't going to use hours and minutes, don't use pretend hours & minutes. Especially don't use weird numbering like 25/53/67. (At least it's integers, but still, two primes?)
« Last Edit: 11/08/2016 07:26 pm by Paul451 »

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