Timekeeping on Mars or other worlds

[TMac3000]

And this is just on Mars, where the days are relatively the same...imagine timekeeping on Mercury or Pluto

 

[Andy44]

Mercury or Pluto are like the moon: you just use UTC and ignore the local solar time.

I think maybe it would be best to just divide Mars into 24 martian hours and represent this with a second hour hand. The rest of the watch or clock would be a standard Earth clock and dial.

All you really need Mars time for is to estimate how much time you have before sunrise, noon, or sunset. A Mars hour hand allows you to estimate local time to the nearest half or quarter martian hour. For really precise stuff you can use UTC with SI units.

 

[flaugher]

Uhhhh ...

I've been thinking alot lately about what it will be like when we really do move out into the solar system. One thing we will probably need fairly quickly is a GPS constellation on any planet or moon we plan to spend much time on (even on the Moon if we really wanted to spend much time there). Anyway, I can't think that GPS and other navigation aids we establish (beacons, etc) would work properly unless we adopt a standard time standard for all worlds.

My though is that once space breaks open for humans, it will REALLY break open. Tourist and merchant ships will be as common as they are in the Caribbean today. We will also probably have Space Traffic Controllers who will track vessels, and they will have to have a common time system to know when things are supposed to be where.

We'll have to see how things develop (and I hope we will if we can get ion engines and supercapacitors moving along) but I'm guessing that zulu time (GMT) will remain the standard. We'll just have to accept that other worlds have daylight and darkness longer or shorter than we're used to.

 

[tblaxland]

We'll have to see how things develop (and I hope we will if we can get ion engines and supercapacitors moving along) but I'm guessing that zulu time (GMT) will remain the standard. We'll just have to accept that other worlds have daylight and darkness longer or shorter than we're used to.

Well, GMT has pretty much been deprecated in favour of UTC these days.

General relativity pretty much rules out a truly universal time standard since clocks will tick faster further out in the solar system. You would want your second to still be tied to local atomic time so that time-related physics constants would remain the same. Occasional clock updates (leap seconds) would be required if you wanted to retain synchronisity with Earth clocks.

 

[Linguofreak]

General relativity pretty much rules out a truly universal time standard since clocks will tick faster further out in the solar system. You would want your second to still be tied to local atomic time so that time-related physics constants would remain the same. Occasional clock updates (leap seconds) would be required if you wanted to retain synchronisity with Earth clocks.

Special relativity already does that. GR just extends it by telling us how gravity works into the whole thing. But relativity *can* tell us what our spacetime interval from a given point is, which can be used to track both location and time, and it can also tell us the time that will elapse between any two points on any trajectory we take through the universe, so you could probably work out a fairly good relativistic clock.

 

[tblaxland]

Special relativity already does that. GR just extends it by telling us how gravity works into the whole thing. But relativity *can* tell us what our spacetime interval from a given point is, which can be used to track both location and time, and it can also tell us the time that will elapse between any two points on any trajectory we take through the universe, so you could probably work out a fairly good relativistic clock.

I agree. We already keep Terrestrial Time, Geocentric Coordinate Time and Barycentric Coordinate Time.

 

[Suzy]

Humans (and other animals) have evolved to live with a 24-hour day on Earth, so living on other worlds would wreak havoc with your circadian rhythm - wonder how that would be catered for?

 

[tl8]

Humans (and other animals) have evolved to live with a 24-hour day on Earth, so living on other worlds would wreak havoc with your circadian rhythm - wonder how that would be catered for?

Evolution

 

[tblaxland]

Humans (and other animals) have evolved to live with a 24-hour day on Earth, so living on other worlds would wreak havoc with your circadian rhythm - wonder how that would be catered for?

The circadian rhythm is only rough and would adapt readily to a Mars day. Living on Mercury would be somewhat more of a challenge but adequate control of lighting would be sufficient. It is done regularly on the ISS for example.

 

[agentgonzo]

The circadian rhythm is only rough and would adapt readily to a Mars day. Living on Mercury would be somewhat more of a challenge but adequate control of lighting would be sufficient. It is done regularly on the ISS for example.

Most people don't have an exact 24 hour internal clock. I have noticed that without external timekeeping, my body-clock seems to revert to somewhere between a 25- and a 27-hour day. When I was revising for my finals, I quickly got out of synch with the rest of the country and at one point was having breakfast at 6pm with everyone else's evening meals, revising from about midnight until 8am, going to 'breakfast' and then going to sleep.

I've always wanted to spend a week completely away from any form of external timekeeping device and just use the sun (whilst camping or away from civilisation) but have yet to get the time and location to do it.

 

[tblaxland]

I've always wanted to spend a week completely away from any form of external timekeeping device and just use the sun (whilst camping or away from civilisation) but have yet to get the time and location to do it.

I have done that before and can highly recommend the health benefits. There may be other factors influencing that though, other than the timekeeping ones

 

[ar81]

We have GMT and local time.
My bet is martians will use martian local time.
GMT would be used for interplanetary travel only or any ops that require coordination between planets.

 

[Eagle]

Now would it be better for the martians to use a calendar year that synchs with Earth's so it would only be 340ish days long, but it might be October 30th on Earth while its October 20th on Mars.(I'm way to lazy to figure out the exact ratios).

Or an unrelated one consistent Martian seasons(/orbit) so the day and year are completely independent, but might reduce confusion. The Martian year will now not match an Earth year either.

Because if a Martian day isn't the same length as on on Earth, the dates are gonna get messed up.

 

[n122vu]

I never really thought of the problem of keeping time in space until I was watching a rerun of ST:TNG last week. I think it was called "Data's Day." Anyway, twice in the episode as the "shift" was over, Worf or Data gave report of the goings-on on the ship, then was relieved of duty and the other officer had the bridge and stated, "Begin Night Watch."

I thought, "How do they decide when it's "night" on the Enterprise? They have to have a universal timekeeping system. SFT, (StarFleet Time), maybe?

Anyway, back to the topic, I think the main thing causing the problem is you are insisting on being tied to SI measurements while on Mars. But SI measurements are based on Earth time. Mars takes longer to travel around the sun. It takes longer to make one rotation on its axis. To me, the solution is this (I'm not a mathemetician by any means, so if this won't work, please let me know). 24-hour days, 60-minute hours, and 60-second minutes. Mars seconds take longer than Earth seconds, thus the second hand, if you insist on having one, should move more slowly around the face of the watch such that it takes the correct amount of time to display one hour of Mars time passing. Base the yearly calendar on how many days it takes Mars to travel around the sun, using leap days to correct for imprecision every x years, just as on Earth, and coordinate with Earth to keep track of calendars on both worlds. I know that's messy, but until StarFleet implements their universal time system it's the best I can come up with. And it solves the problem of how to tell time on Mars.

 

[2552]

Humans (and other animals) have evolved to live with a 24-hour day on Earth, so living on other worlds would wreak havoc with your circadian rhythm - wonder how that would be catered for?

People living at the South Pole get 6 months of continuous daylight, then 6 months of continuous night, and can adapt to that.

 

[T.Neo]

Humans (and other animals) have evolved to live with a 24-hour day on Earth, so living on other worlds would wreak havoc with your circadian rhythm - wonder how that would be catered for?

The circadian rhythm is only rough and would adapt readily to a Mars day. Living on Mercury would be somewhat more of a challenge but adequate control of lighting would be sufficient. It is done regularly on the ISS for example.

tblaxland's answer pretty sums it up for humans, but what about animals and plants? How will they cope with different day lengths and/or lower light conditions what are present on Mars?

 

[Salamander]

a second has to be a second, regardless of where you are. adjusting minutes to local time is a prescription for errors, too.
i'd go with the stop the clock at midnight (or 3 am or somesuch) till syncronisation. an addiational hand may show how much of the leap period has gone by already.

as a side not, how would humans handle, say, life on a planet with a 14 hour day?

 

[agentgonzo]

tblaxland's answer pretty sums it up for humans, but what about animals and plants? How will they cope with different day lengths and/or lower light conditions what are present on Mars?

Plants don't really need to have a day/night cycle. Plants will grow when there is light, and don't really grow if there isn't. So day/night cycles don't make much of a difference unless they are sufficiently long to make the plant think it's winter/summer.

As for the lower light levels, it would be similar to taking the plant to a different latitude on Earth

 

[dougkeenan]

Plants don't really need to have a day/night cycle. Plants will grow when there is light, and don't really grow if there isn't. So day/night cycles don't make much of a difference unless they are sufficiently long to make the plant think it's winter/summer.

As for the lower light levels, it would be similar to taking the plant to a different latitude on Earth

To what extent is light level effected by latitude?

 

[flaugher]

Someone mentioned the barycenter a couple of posts ago. I imagine that the barycenter will eventually play a part in navigation and thereby timekeeping. Relativistic clocks? Sure. Human bio-cycles? I think we'll just have to get out there and see how things go.

Again, I think that once we actually get out there, space travel and space commerce will literally explode. We'll probably have a good chunk of population that lives on ships a lot, and others who will stay on certain planets. Who's to say which planets will develop though? How many different siderial "days" will we have? Any of the near 1-G gravity worlds has potential for permanent habitation.

Keeping human time will probably depend more on work-related topics. How many (your local time segments here) will we work in a stretch on Titan? How many (your local time segments here) will we sleep?

Navaids and travel times will have to be based on (your universal time system here).