20181126 Where do you want to put time zone?

tahanson43206 · 2018-11-26 08:36:44

This is for Space Nut ... I'd be interested in hearing thoughts about time zones on Mars.

A search for timezone produced only references to Earth.

Louis's proposed Sagan City would be as good a place as any for the New Greenwich site for a Zero point for Mars time zones.

Related subtopics would be how to divide the Martian Day.

Humans probably would like to retain Earth standard time, but the experiences reported by members of the JPL Mars Rover teams suggest (to me at least) that there are definitely issues with trying to move back and forth between the two time systems.

(th)

louis · 2018-11-26 11:26:07

tahanson43206 wrote:

This is for Space Nut ... I'd be interested in hearing thoughts about time zones on Mars.
A search for timezone produced only references to Earth.
Louis's proposed Sagan City would be as good a place as any for the New Greenwich site for a Zero point for Mars time zones.
Related subtopics would be how to divide the Martian Day.
Humans probably would like to retain Earth standard time, but the experiences reported by members of the JPL Mars Rover teams suggest (to me at least) that there are definitely issues with trying to move back and forth between the two time systems.

(th)

louis · 2018-11-26 11:34:42

I am not sure how "they" fixed the 0 degree longitude line but fix it they did (probably at some astronomical conference or some such I imainge, or perhaps NASA arbitratily chose it), it seems and I imagine it is already too late to move it. From the point of view of Sagan City, it can get by without being on the 0 degree line of longitude. Everywhere on the same line of longitude gets the same time once every Sol.

Time zones do of course matter. It is said London benefits from being well placed to trade with both the USA and the Far East during its working day. Mars, with a single planet administration and no internal borders, could of course have "rational" time zones.

One of the interesting questions is how you split up the sol - I favour retaining Earth hours, so have 24 hours and the remainder which should probably be slotted in at around 3am - a "short" interlude.

Last edited by louis (2018-11-26 18:37:56)

IanM · 2018-11-26 13:26:56

Perhaps the remainder of each sol could be used to make a completely new sol every given number of years, to create leap years. According to Wikipedia the Martian year is about 686.98 Earth days, so every 50 or so years a day could be subtracted from the year.

louis · 2018-11-26 18:51:46

You could do but then of course you lose the natural rythm of the day/night cycle. Our circadian rythm system is v. close to that of Mars.

Artificial constructs like clock time on Mars should, as here on Earth, try and work harmoniously with our body rythms in my view.

The idea of saving up sols to allocate elsewhere is more useful I think when you try and parcel up the sol year.

I favour a tensol "week" - with a 7 sol work "week" followed by a 3 sol "weekend".

Then you could have a period of 4 tensols (= 40 sols) equivalent to the Earth month period. Maybe call it a Quarantine.

Then you have 16 Quarantines which you could group into four "Seasons" each composed of 4 Quarantines. That leaves over a remainder of 28 complete sols which you could divide into two 14 sol festive periods - one for winter and one for summer. These would be periods of reflection, celebration and rededication.

IanM wrote:

Perhaps the remainder of each sol could be used to make a completely new sol every given number of years, to create leap years. According to Wikipedia the Martian year is about 686.98 Earth days, so every 50 or so years a day could be subtracted from the year.

tahanson43206 · 2018-11-26 19:13:52

Thanks to IanM and Louis for considering the Time Zone topic.

This is not offered in judgement, but I'd like to point out that 3 AM at Longitude 0 is 2 AM one "Mars Hour" West ...

That said, the underlying concept (as I understand it) would be to add 37 minutes to the clock once a day.

If the residents on Mars set up a broadcast similar to the Universal Standard Time broadcast, then the longitude chosen for that service would allow the planet to catch up for 37 minutes once a Sol.

If residents set up their local times to match the Sun's apparent motion, then the 3 AM concept would work well, but in that case, the local time would be out of sync with the planet time.

Television broadcasts might be scheduled based upon "planet time", but that time would differ from local time by 37 minutes except in the broadcast time zone.

Edit: the radio broadcast service that announces "Universal Standard Time" is due for a name change, to "Planetary Standard Time", as the human race edges closer to being a multiplanet species.

(th)

Last edited by tahanson43206 (2018-11-26 19:31:05)

tahanson43206 · 2018-11-26 19:51:36

louis wrote:

I am not sure how "they" fixed the 0 degree longitude line but fix it they did (probably at some astronomical conference or some such I imainge, or perhaps NASA arbitratily chose it), it seems and I imagine it is already too late to move it. From the point of view of Sagan City, it can get by without being on the 0 degree line of longitude. Everywhere on the same line of longitude gets the same time once every Sol.

Curious about the history of Longitude Zero on Mars, I learned it was set far earlier than I had imagined:

Begin Quotation:
https://www.esa.int/Our_Activities/Spac … de_on_Mars

19 August 2004
On Earth, the longitude of the Royal Observatory in Greenwich, England, is defined as the 'prime meridian,' or zero degrees longitude. Locations on Earth are measured in degrees east or west from this position, but where is the equivalent position on Mars?

Earth's prime meridian was defined by international agreement in 1884 as the position of the large 'transit circle', a telescope in the Royal Observatory's Meridian Building. The transit circle was built by Sir George Biddell Airy, the 7th Astronomer Royal, in 1850.

For Mars, the prime meridian was first defined by the German astronomers W. Beer and J. H. Mädler in 1830-32. They used a small circular feature on the surface, which they called 'A’, as a reference point to determine the rotation period of the planet.
End Quotation.

Edit #2: By convention, UTC is the abbreviation agreed upon for (in English) Coordinated Universal time:

As indicated above, I think it is time to change this to "Coordinated Planetary Time".

There is a web site where WWV time signals can be played from recordings:
https://swling.com/blog/2014/08/listeni … orado-usa/

Per Wikipedia:
Begin Quotation:
https://en.wikipedia.org/wiki/Coordinat … ersal_Time

Coordinated Universal Time (abbreviated to UTC) is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude,[1] and is not adjusted for daylight saving time. In some countries where English is spoken, the term Greenwich Mean Time (GMT) is often used as a synonym for UTC.[2]
End Quotation.

(th)

Last edited by tahanson43206 (2018-11-26 21:33:55)

SpaceNut · 2018-11-26 20:46:32

25 hrs 37/60 hr versus 24 hrs both at 360 degree would make mars roughly 14.4 degrees for each time zone area versus earth at 15 degrees. Also earth uses 60 cycle per second as the start of its time base. 365.26 days, a period known as an Earth year. A year on Mars is equal to 687 days on Earth. On May 5, 2017, the sun will cross the Mars equator as this planet passes solar longitude 0.

tahanson43206 · 2018-11-26 22:09:33

Louis,

I started out liking your preference for retaining the Earth "hour" of 60 minutes, but SpaceNut's discussion below leads me to wonder if it wouldn't be easier for everyone to simply adopt 15 degree time zones and settle for 24 Martian "hours" which are longer than Earth hours by 37/24 minutes >> 1.681818182.

But if we make that adjustment, it might be a reasonable extension to simply set the hour to 60 Martian minutes, or 61.541666667 Earth minutes.

My guess is that we humans would hardly know the difference, and coordination of activities around the planet would be greatly simplified.

The amount of time we call a second would (it seems to me) work as well on Mars as it does on Earth, so a minute on Mars would be 1.025695 Earth minutes. In that case, we would continue to use 60 minute "hours", and simply make microcode adjustment in digital clocks. In fact, digital clocks could be fitted with buttons to show Earth or Mars time.

Louis, there might be a novelty business opportunity in that thought, for Earth customers.

***

(I'll be happy to correct errors in any are found in this post).

Begin Quotation:
https://www.universetoday.com/14717/how … y-on-mars/

On Earth, this takes exactly 23 hours, 56 minutes and 4.1 seconds. In comparison, on Mars, a sidereal day lasts 24 hours, 37 minutes, and 22 seconds.
End Quotation.
(th)

SpaceNut wrote:

25 hrs 37/60 hr versus 24 hrs both at 360 degree would make mars roughly 14.4 degrees for each time zone area versus earth at 15 degrees. Also earth uses 60 cycle per second as the start of its time base. 365.26 days, a period known as an Earth year. A year on Mars is equal to 687 days on Earth. On May 5, 2017, the sun will cross the Mars equator as this planet passes solar longitude 0.

louis · 2018-11-27 16:27:49

Not sure if I'm entirely following you here but are you saying that time zones on Earth are usually on the hour? That is true and that certainly has been useful in the past (but I remember being surprised once to discover that Pakistan used to have some time zone that differed at 45 mins or some such and there may still be some 30 mins zones.) Mars will be a hi tech place from the first humans arriving. We know our mobile (cell) phones update automatically so I don't think we'll have any probably coping with the 37 mins differential...your device, whatever it is, will simply automatically inform you what the time is at Olympus Mons even if you are thousands of kms away - the seconds will be synchronised.

How you would synchronise Mars UST and Earth UST is an interesting question which I certainly am not technically able to answer! I am sure that some sort of v ery exact synchronisation would be required. I imagine it would be quite difficult because any seismic activity on either planet will cause a v. small "wobble" which might interfere with any synchronised communication (we are probably talking nanosecond differences, but still, that can be important).

tahanson43206 wrote:

Thanks to IanM and Louis for considering the Time Zone topic.
This is not offered in judgement, but I'd like to point out that 3 AM at Longitude 0 is 2 AM one "Mars Hour" West ...
That said, the underlying concept (as I understand it) would be to add 37 minutes to the clock once a day.
If the residents on Mars set up a broadcast similar to the Universal Standard Time broadcast, then the longitude chosen for that service would allow the planet to catch up for 37 minutes once a Sol.
If residents set up their local times to match the Sun's apparent motion, then the 3 AM concept would work well, but in that case, the local time would be out of sync with the planet time.
Television broadcasts might be scheduled based upon "planet time", but that time would differ from local time by 37 minutes except in the broadcast time zone.
Edit: the radio broadcast service that announces "Universal Standard Time" is due for a name change, to "Planetary Standard Time", as the human race edges closer to being a multiplanet species.
(th)

louis · 2018-11-27 16:37:26

I don't deny there are pluses and minuses for both approaches.

Even if your device can switch easily between M Hours and E Hours there will still be difficulties (not least trusting humans not to get it wrong). There is certainly the scope for catasrophic errors (remember NASA lost an extremely expensive Mars probe because of a stupid failure to account for a US measures v metric measures conflict).

On a psychological level I doubt humans would notice the difference of the extra 1.7 minutes per hour and it would have the advantage of reassuring familiarity. But again when it comes to doing any science or anything requiring exactitude you are going to have to ensure you or your machines are converting M Hours to E Hours accurately and vice versa.

And then there's the question of, as we move out across the solar system, maybe taking up residence on far flung moons and so on, are we going to have a "multitude of minutes". That doesn't feel right to me, that we could end up with hundreds of local time values.

tahanson43206 wrote:

Louis,
I started out liking your preference for retaining the Earth "hour" of 60 minutes, but SpaceNut's discussion below leads me to wonder if it wouldn't be easier for everyone to simply adopt 15 degree time zones and settle for 24 Martian "hours" which are longer than Earth hours by 37/24 minutes >> 1.681818182.
But if we make that adjustment, it might be a reasonable extension to simply set the hour to 60 Martian minutes, or 61.541666667 Earth minutes.
My guess is that we humans would hardly know the difference, and coordination of activities around the planet would be greatly simplified.
The amount of time we call a second would (it seems to me) work as well on Mars as it does on Earth, so a minute on Mars would be 1.025695 Earth minutes. In that case, we would continue to use 60 minute "hours", and simply make microcode adjustment in digital clocks. In fact, digital clocks could be fitted with buttons to show Earth or Mars time.
Louis, there might be a novelty business opportunity in that thought, for Earth customers.
***
(I'll be happy to correct errors in any are found in this post).
Begin Quotation:
https://www.universetoday.com/14717/how … y-on-mars/
On Earth, this takes exactly 23 hours, 56 minutes and 4.1 seconds. In comparison, on Mars, a sidereal day lasts 24 hours, 37 minutes, and 22 seconds.
End Quotation.
(th)

SpaceNut wrote:
25 hrs 37/60 hr versus 24 hrs both at 360 degree would make mars roughly 14.4 degrees for each time zone area versus earth at 15 degrees. Also earth uses 60 cycle per second as the start of its time base. 365.26 days, a period known as an Earth year. A year on Mars is equal to 687 days on Earth. On May 5, 2017, the sun will cross the Mars equator as this planet passes solar longitude 0.

SpaceNut · 2018-11-27 21:11:51

24 hours multiply 687 days all divided by the real mars day 25 37/60 gives the real year on mars days.or 643 mars days and change due to the longer day for its calendar period as compared to earth 365 days.
A day is still sun rise until the next

tahanson43206 · 2018-11-27 22:22:17

For Louis ...

Your understandable concern about scientific measurement of time led me to the speed of light. The Wikipedia entry below is encouraging, because it suggests (to me at least) that the second can be a truly universal time interval, usable in any setting.

For SpaceNut ... your observation that a day (on any celestial body that rotates with respect to its local sun) would logically be defined for that body by the regular appearance of the local sun at the local zenith seems (to me) to support the argument for letting go of Earth time. Ship time would (probably) be set to match the time of the planet of origin. I am speculating here, but perhaps it would be common practice to maintain a clock with Earth time on all vessels, but even that is problematic if relativistic effects become significant.

(th)

Begin Quotation:
https://en.wikipedia.org/wiki/Speed_of_light

The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its exact value is 299,792,458 metres per second (approximately 300,000 km/s (186,000 mi/s)[Note 3]). It is exact because by international agreement a metre is defined to be the length of the path travelled by light in vacuum during a time interval of 1/299792458 second.
End Quotation.

Edit: Per the citation below, definition of the second has been separated from its astronomical origin:
Begin Quotation:
https://physics.nist.gov/cuu/Units/second.html

The second is 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 cesium 133 atom.

End Quotation.

Last edited by tahanson43206 (2018-11-27 22:42:09)

louis · 2018-11-28 05:23:02

Interesting piece here:

https://en.wikipedia.org/wiki/Timekeeping_on_Mars

I wasn't aware NASA actually use a local time system on Mars, with longer "minutes",rather than Earth time. So it doesn't appear to have been a problem. But it might be if that approach was adopted all over the solar system and you had a multiplicity of local "minutes" of varying length. I suppose for NASA, it makes it easier to design autonomous machines if they use a local time system - so they can operate on a day-night cycle without having to adjust times every day to take account of Earth time.

SpaceNut wrote:

24 hours multiply 687 days all divided by the real mars day 25 37/60 gives the real year on mars days.or 643 mars days and change due to the longer day for its calendar period as compared to earth 365 days.
A day is still sun rise until the next

Last edited by louis (2018-11-28 05:25:57)

tahanson43206 · 2018-11-28 09:05:37

For Louis ...

Thanks for the link to that Wikipedia article about JPL/NASA decisions regarding time measurement on Mars. I was with them all the way, until I read that they decided to change the second too. I suppose that makes sense for overall consistency, but it eliminates the possibility of having a "universal" second.

As founder of a city on Mars, you have the option of adopting the JPL/NASA precedent or advocating for something else. However, the strength of the community which has actually landed and operated vehicles on Mars is significant.

One thing I noticed was that (according to the article) time zones have not yet been defined, but it seems to me humans will want them. Also, there will surely be an incentive for humans on Mars to maintain an Earth standard time tracking system in order to be able to tune into broadcasts of entertainment and news programs which (I am confident) will be sent on to Mars.

(th)

louis · 2018-11-28 10:46:48

I'm delegating all Temporal Unit issues to you TA! though I do like my proposal for Mars year division: sol, tensol (10 sols), quarantine (4 tensols, 40 sols) and season (4 quarantines, 160 sols) arrangement with two festival period of 14 sols each in mid-winter and mid-summer. Pyschologically a 600 plus sol year on Mars will I think feel somewhat odd and possibly oppressive to humans from Earth, so dividing it up in this way will, I think, help

I agree time zones will be needed. You could have "rational time zones" - divided by longitudinal lines. But how do time zones work in the extreme north of Canada? They must change every hundred miles and then every ten miles or so as you get closer to the pole...

Anyway, you decide.

tahanson43206 wrote:

For Louis ...
Thanks for the link to that Wikipedia article about JPL/NASA decisions regarding time measurement on Mars. I was with them all the way, until I read that they decided to change the second too. I suppose that makes sense for overall consistency, but it eliminates the possibility of having a "universal" second.
As founder of a city on Mars, you have the option of adopting the JPL/NASA precedent or advocating for something else. However, the strength of the community which has actually landed and operated vehicles on Mars is significant.
One thing I noticed was that (according to the article) time zones have not yet been defined, but it seems to me humans will want them. Also, there will surely be an incentive for humans on Mars to maintain an Earth standard time tracking system in order to be able to tune into broadcasts of entertainment and news programs which (I am confident) will be sent on to Mars.
(th)

SpaceNut · 2018-11-28 18:24:31

Seasonal image for mars as they relate to earth

louis · 2018-11-28 19:19:47

Great image - thanks for that...I'm still trying to follow all of it...

My calendar "seasons" wouldn't necessarily reflect the true Sun-Mars relation any more than our variable "seasons" (school, weather, TV channels, sport etc) do back on Earth.

SpaceNut wrote:

Seasonal image for mars as they relate to earth
https://upload.wikimedia.org/wikipedia/ … it.svg.png

Mars_B4_Moon · 2023-11-24 07:32:49

Tahanson, this might be more your area of knowledge since you post on supply and time keeping a lot. On Earth the electricity is sold to consumers typically in an Earth based unit of kilowatt-hours, the unit price of electricity charged by utility companies in the USA may depend on the customer's consumption profile over time, the local Prices vary by State taxation or change considerably by locality so United States prices in different states can vary by a factor of three. I could not find a thread on this power supply and paying commercially by credits or coin, I guess this kind of relates to your topic since discussion of power, the Capacity of Battery and the idea for electric commercial providers and Nuclear energy planets on Mars was discussed with Timekeeping and ideas for Coordinated Mars Time.

We know on Mars there is an idea for a 28 day month and thinking by RobertDyck maybe upon which I believe the Mars Calendar topic is based, outside of Mars Ganymede divides time into longer increments with an orbital period of roughly four times Io’s, or 7.1 Earth days and another time keeping solution is to divide the Titanian solar day into 16 circads and the circad measurement of Titan would therefore be 23 hours, 57 minutes, 13.11 seconds, or 0.998068439 days, hardly distinguishable from either the terrestrial day or the Martian sol. Offworld colonies and their Moons might have their own ratio or 1:2:4 or 3:4 or 7:6 or 3:1 resonance which are comparable to units of time keeping measurement on Earth.

On Earth we have electricity meter they are in the USA, in France, in Japan, in China, Australia, located in Canada. Since Mars is thinking of using new numbers for days maybe new months a different form of time keeping might also exist on Titan or Europa. Will there be a new standard or will we continue to measure electric supply use the Kilowatt-hour or will we instead make new units of measurement suitable for the locals living on Europe or Titan or Mars?

The Earth Kilowatt-hour can also be described by other units such as Joules or Electronvolts or even 'Calorie' the Battery life is often described in Ampere-hour. How would the power company price payment for electricity on Mars, would it be a chaotic frontier or would it have a standard price system?

Each separate nation or space flight corporation might come up with their own measurement if the land people on Mars and currently no standard exists, numerous calendars and other timekeeping and energy measuring approaches for a local community have been proposed. The sol, or Martian day, is not too different from an Earth day but it is longer, the Mars solar day on average is only about 2.75% longer than Earth's measuring how much something was used in a day will not be a big difference but any difference in counting will increase greatly over time, but the Mars year is almost twice as long as an Earth year. NASA is not supplying Nuclear electricity to colonies of people living on Mars but it has lots of experience driving Robots and operations teams often have worked on "Mars time", with a work schedule synchronized to the local time.

There are also 2 upcoming missions to Jupiter's Moons by the USA and Europe, and a Dragonfly mission by NASA which can be seen on the jhuapl website.

Will these worlds also start using their local time?

Anyways some news on Daylight saving time (DST)

Time is running out for House to pass permanent daylight saving bill
https://news.yahoo.com/time-running-hou … 00444.html

Daylight savings time is detrimental to our health
https://ucsdguardian.org/2023/11/20/day … ur-health/
most of the United States, barring Arizona and Hawaii, set their clocks back

Letters: Daylight saving time is pointless
https://www.nola.com/opinions/letters-d … 855ac.html

Daylight saving time: When we fall back in Melbourne, Florida, Australians spring forward
https://news.yahoo.com/daylight-saving- … 47537.html

Last edited by Mars_B4_Moon (2023-11-24 07:50:33)

tahanson43206 · 2023-11-24 08:02:32

For Mars_B4_Moon re Post #19

Thanks for bringing this topic from 2018 back into view, and for providing all the links and comments.

After re-reading the topic, I realized I have quietly decided to change (elongate) the "second" on Mars. It appears that NASA has chosen to elongate the minute. The benefit of either practice is to allow humans to retain the familiar structure of 24 hours in a planetary rotation, divided into 60 minutes each.

Your mention of Daylight Savings (on Earth) reminds me that there may not be much need for such a practice on Mars, because most folks will be living underground most of the time, until a way to block radiation becomes available on a planetary scale, or lightweight radiation blockers become available for individual atmosphere suits.

This is a good time to remind everyone (in the forum active membership at least) that RobertDyck has proposed the 3-5-8 rule for habitat atmosphere on Mars. This rule is simple enough a child can learn it, and it provides for 3 parts oxygen, 5 parts neutral gas, and 8 PSI inside the habitat. As RobertDyck has pointed out countless times, this allows a Mars resident to don an atmosphere suits and set it to 3 PSI for excursions outside the habitat without having to waste time pre-breathing.

Anticipating the predictable objection of RobertDyck that his actual recommendation is some decimal number that has an impossible to remember configuration, I'll simply concede that I have rounded his decimal numbers to the simplest whole number so a child can memorize it.

***
For Mars_B4_Moon ... I think that your interest in the kilowatt hour is interesting ... I expect that on Mars, if the longer hour is taken into account, then the kilowatt hour will measure a slightly greater amount of current flow. If ** that ** is the case, then I can foresee confusion in space craft that ply the solar system. It seems possible (since you brought this up and I've not thought about it before) that the Earth standards might persist since so much of the electric industry depends upon standard units.

In any case, I don't think the question is settled, but there is certainly a lot of momentum build up in industry, academia and the military.

(th)

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#1 2018-11-26 08:36:44

20181126 Where do you want to put time zone?

#2 2018-11-26 11:26:07

Re: 20181126 Where do you want to put time zone?

#3 2018-11-26 11:34:42

Re: 20181126 Where do you want to put time zone?

#4 2018-11-26 13:26:56

Re: 20181126 Where do you want to put time zone?

#5 2018-11-26 18:51:46

Re: 20181126 Where do you want to put time zone?

#6 2018-11-26 19:13:52

Re: 20181126 Where do you want to put time zone?

#7 2018-11-26 19:51:36

Re: 20181126 Where do you want to put time zone?

#8 2018-11-26 20:46:32

Re: 20181126 Where do you want to put time zone?

#9 2018-11-26 22:09:33

Re: 20181126 Where do you want to put time zone?

#10 2018-11-27 16:27:49

Re: 20181126 Where do you want to put time zone?

#11 2018-11-27 16:37:26

Re: 20181126 Where do you want to put time zone?

#12 2018-11-27 21:11:51

Re: 20181126 Where do you want to put time zone?

#13 2018-11-27 22:22:17

Re: 20181126 Where do you want to put time zone?

#14 2018-11-28 05:23:02

Re: 20181126 Where do you want to put time zone?

#15 2018-11-28 09:05:37

Re: 20181126 Where do you want to put time zone?

#16 2018-11-28 10:46:48

Re: 20181126 Where do you want to put time zone?

#17 2018-11-28 18:24:31

Re: 20181126 Where do you want to put time zone?

#18 2018-11-28 19:19:47

Re: 20181126 Where do you want to put time zone?

#19 2023-11-24 07:32:49

Re: 20181126 Where do you want to put time zone?

#20 2023-11-24 08:02:32

Re: 20181126 Where do you want to put time zone?

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