What calendar or clock will be used once other planets are colonized?

Hell I don’t know – I’m still trying to figure out the time scale in Stephenson’s Anathem.

The Martian day (Sol) is 39.5 minutes longer than it is on Earth, so in Kim Stanley Robinson’s excellent Mars Trilogy he used a system in which the clocks worked the same as those on Earth but at midnight for 39½ minutes the clock would freeze and then start up again to begin a new Martian day.

Boy, those little calendars insurance agents give you will have to be a whole lot bigger on planets with many more than 365 days!!!

I think the atomic clock should serve us nicely wherever man should boldly go!

In the solar system the Earth calendar will be used as well, because of frequent communication. It’ll be a bit like making a call between time zones on Earth.

Outside the solar system? Just the new calendar that fits the main planet’s behavior. One problem will be

http://en.wikipedia.org/wiki/Chronobiology

Also, I remember in his trilogy, KSR used a system where there were 24 months in a year (668.6 sols in a Martian year) and the calendar went like this:
1 January, 2 January, 1 February, 2 February, 1 March, and so on, all the way through 2 December.

(GST) Galaxy Standard Time ^.^; perhaps we will set up a standardized system that is synchronized by a network of data beacons.

They will use stardates of course.

As long as Earth is the “mother country” they would likely use two. A local clock and calender using the local day and year. Interactions with Earth would likely be based on the Gregorian Calender and GMT (Zulu).

Clocks will be designed according to the time taken for one single rotation of the planet around it’s axis.In case of Mars, a day would comprise of 25 hours and so the clock.
Now about the calender.700 days,phew!!.Now it’s not about the number of days taken by the planets to revolve around the sun determine the months in a year.It’s the total distance covered around the sun and divided into small slots and each slot is of same distance,not the displacement.
For example:
In case of earth, there are 12 slots which are equidistant .In Feb, earth takes 28 days to cover the same distance that it takes to cover in December in 31 days.
The question remains,what results in such variation.Why not equal number of days in each month.The answer to that,is earth’s speed or revolution around the sun.
The equation of time period says T^2 is directly propertional to R^3.Where T is the time taken for orbital motion while R is the distance between the centres of earth and sun.
Now,how’s that related to earth’s revolution.As i have earlier said,earth’s orbit is not completely circular.It’s somewhat elliptical and at some places the value of R is less so is the value of T and hence the variation in number of days in a month.
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Similarly in Mars, the number of days in a month and the number of months would be decided by chopping off Mar’s axis into a number of equidistant arcs and record the time taken to cover those distance.The time taken for each slot in number of days(each day of 25 hours) would be considered as a month on Mars.
It could be 24 months with around 30 days each or 12 months with 60 days each.Won’t make much difference as long as the orbital calculations are made with precision

What is the point of time keeping? It allows the trains to run on time. The only reason we need clocks is so that people can meet each other at the time they designate.

This is not a problem between planets. Interplanetary travel will be an extremely rare event for a long time, and even if it becomes more common, people will easily be able to use local time conventions.

I think every planet will keep its own time that is relevant to how life goes on that planet. Mars can still have a 24 hour day, but it’s “hours” will be slightly longer than Earth hours. Maybe one and a half minutes longer.

The real problem will be adjusting human biological rhythms to local periodicities. I don’t know how NASA does it. Do they try to keep a 24 hour day for astronauts? What happens in the areas where winter and summer become permanent darkness or sunlight? Do people try to keep to regular working hours?

I don’t know. What I do know is that time was invented for our convenience, not to make things complicated.

@wundayatta- NASA astronauts use a 24 hour day based in Central Time.

@engineeristerminatorisWOLV pardon my derp, derp, derp moment here, but:

“In case of earth, there are 12 slots which are equidistant. In Feb, earth takes 28 days to cover the same distance that it takes to cover in December in 31 days.”

If the slots are equidistant how do you explain a constantly accelerating earth moving along one segment in 28 days and 31 the next? For that matter what about Februarys that have 29 days? The earths velocity does not speed up or slow down to account for this.

I was under the impression that months were arbitrary measures of time derived from lunar motion. Months really have no significance to time measured past an epoch.

I suppose that all the universe might eventually use a method similar to that used to synchronize the global time network which measures the number of seconds past a date in the past and then to apply some location specific algorithm to get local time. Though I do not know how it would be possible to keep a interplanetary/intergalactic time network in sync given relativity.

@tekn0lust : You came back with an intelligent debate.First of all I applaude you for putting forth this question.
Earth’s acceleration around the axis is not constant.It does accelerate faster in closer distances to sun.
The time period is given by T^2 is directly propertional to R^3.The time taken to cover a particular segment is less if the R values i.e the distance between the earth and the sun is less and the month of feb lies in that zone where the R value is less.This is because in closer distances the Gravitarional pull is more which is counterbalaced by earth’s orbital speed or centrifugal force.Hence the acceleration boosts up at lower distances.
This theory of acceleration is used in deep space explorations of rover missions.If you are aiming to send a rover to Saturn,you have to make it go around Mars and Jupiter to give it an extra boost.Simply launching it from space and directing towards saturn won’t be sufficient

Yes,we have 29 days once every 4 years in the month of feb.That’s because of ¼th of a day that earth covers up every year that is not considered in 365 days.Those ¼ days add up to give 1 more day on the 4th year.
The lunar theory of yours is widely accepted in astrological calculations,but this is an old concept given by kepler in one of his studies and Space scientists can’t discard it due to accuracy of calculations achieved by it.
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Regarding keeping the time universal all overr the universe,it’s a difficult thing to do.Beginning and end are human perceptions.When you consider universe,there’s nothing like beginning and nothing like end(putting aside all theories regarding the birth of universe)
When we are in our solar system,Sun is our time keeper and when we consider our motion in our Spiral galaxy milky way,the center of the galaxy which is believed to be a black hole,is the time keeper as every thing is in a relative motion and finally merges into the centre of the galaxy which is fixed.Now when you consider the motion of our galaxy and other galaxies,we have to take another reference point to arrive on a conclusion.

The relativity of time reminds me of one of Einstein’s jokes.Once when he was asked by a media person,“How time is relative?”,he replied,“You sit on a red hot iron for a minute and i sit with a pretty girl for a minute.For you that 1 minute would be like a year,but for me, my one minute would vanish like a fraction of second”.

On Mars, an extra half-hour to the day will hardly be noticed. Just add stretch out the length of a second by a tiny amount, and then continue to use the same 24-hour clock we use on earth.

As for planets with much longer or shorter days, I think it’s qustionable that we could colonize such a planet because crops wouldn’t grow in a day/night cycle much longer or shorter than 24 hours.

As for a year being much longer or shorter than 365 days, I don’t think that will matter much at all, except to stretch yearly holidays and anniversaries closer or farther apart.

I’m with @stranger_in_a_strange_land On this one, using both earth time and local time, however earth time would die out with the first generation.

Earth seconds, minutes, and hours will not change in lenght, but there will be an additional 35 minute period at the end of the day.
People living on Mars will use Earth years for their ages. So, if they are on Mars for 3 Martian years, they will still age 6 years.

I would imagine those celebrating religious holidays on another world would continue to observe a traditional Earth calendar when necessary.

@AstroChuck – If we’ve colonized other worlds, and Jesus/Mohammed/Buddha still hasn’t returned by then to rule the Earth, well, er, uhm…..

@engineeristerminatorisWOLV – You are correct that the earth’s velocity is faster at perhelion, and slower at aphelion, but the distribution of the days in the months defy your explanation fo the months filling “equal size” slots in Earth’s orbit. As you know, the months have tghe following number of days:

January 31
February 28/29
March 31
April 30
May 31
June 30
July 31
August 31
September 30
October 31
November 30
December 31

If your conjecture were true, the months would be more like this:

January 30
February 30
March 30
April 30
May 30/31
June 31
July 31
August 31
September 31
October 31
November 30
December 30

@HungryGuy : The later on is close to the calender given by one of the Astrophysicist of ancient ages who gave this slot theory.Till now, no one did prove him wrong,but his ideas are not accepted due to other overwhelming theories.

At least we think we know what ‘time’ is based on, as a measurement, I would argue, of a perceived element of—change? Aging as defined by decomposition, a degrading of elemental properties?
Because I am really not sure that time exists the same ‘everywhere’ since it seems to be a matter of perception, significance, and therefore ‘subjective’ (I would take the poet’s side and argue time is ‘perceived’ measurement based on a value that depends on another ‘value’—inception, change over time and ‘death’—but do you think a tiger views ‘time’ as a human? Probably not. Which makes it ‘relative’ to me—not like a ROCK, which a tiger or human would think: HARD, or a thorn in their paw, ‘SHARP=PAIN.”
Time? Who’s to say lives elsewhere in the ‘known’ galaxy a) perceive the passage of time in the same units as us; b) due to the laws of physics applied in other atmospheres—say aliens don’t age, so ‘time’ causes no ‘emotion’ for them like it does to a human—
that is why I think we ‘feel’ time and need to document it at all. So, Mayan, Roman, Chinese—I’ll bet they use all of them in an overlay. Time-Space-continuum may take on a very different face where the chemical interplay of elements creates different ‘consciousnesses…’ if losing time is not an issue then its value becomes reduced.
very esoteric, crazy metaphorical poetic pov, I admit, not trying to be scientific one bit!
maybe no numbers just sounds!
to annotate the changing light patterns of a day—‘dawn’ – noon – sunset—midnight
why do we need to count days anyway?? to keep track of how long it takes to ‘do’ things that ensure our survival, like grow food, or how long a resource sustains the tribe or group.
if ‘abundance’ were a constant, always replenished (like our air to us) and we had no need for ‘accounting’—who’s to say where our consciousness could lead us?
great question! you really spurred my imagination on this one, thank you!

Internal clocks.
Or the 24 hour clock.