Handling time in space

[LukeLee]

I’m sure this has been covered before, but I can’t find but apologies if I’m rehashing.

My WIP is based in space, but different parts of the galaxy. I’m struggling with how I handle time - not as some abstract concept but as how long before things happen or what time is it? etc...

My hang up is that if you are on a planet, days, months and years are okay, but what about on the next planet, or off-planet? What about smaller increments equivalent to hours, minutes and seconds? What about at a space port outside of a star system?

The time needs to also be an equivalent measure for different species.

I think have an idea how to handle this but wondered if the Chron hive had any thoughts?

 

[goldhawk]

You don't need equivalent units of measure; you need to convert one system to another. Think about the imperial and metric systems. If you measure something in both systems, you get different amounts but you can convert one to the other by applying the appropriate conversion factor.

 

[Venusian Broon]

I’m sure this has been covered before, but I can’t find but apologies if I’m rehashing.

My WIP is based in space, but different parts of the galaxy. I’m struggling with how I handle time - not as some abstract concept but as how long before things happen or what time is it? etc...

My hang up is that if you are on a planet, days, months and years are okay, but what about on the next planet, or off-planet? What about smaller increments equivalent to hours, minutes and seconds? What about at a space port outside of a star system?

The time needs to also be an equivalent measure for different species.

I think have an idea how to handle this but wondered if the Chron hive had any thoughts?

Do it the way you want to do it. I don't think there is any standard scientific way of defining it as we haven't really gone anywhere else.

But we have very firmly defined the second as humans, so I'd guess we'd use that as a building block. Or at least you could translate whatever you've arrived at into human friendly units.

I use seconds/minutes/hours/'days/months/years (as I don't have any aliens) then morph them into 'local' times based on the system (planetary spin and orbit) but also 'natural' times (i.e. based on human biology ~24 hour days) and other standard times (based on political hegemony). But I don't really plan on discussing this, just throwing it in without explanation. And I mess around with time periods so come up with different sorts of 'hours' that are not 60 'earth' minutes - but instead time periods that I think people might come up with given the different day lengths on different planets.

So I'm going for complexity

As for real aliens, or at least the aliens in your WiP. Well, that gets a bit tricky. What sort of aliens? Aliens like us, in development, might well use their own system to generate their own time measurements...but you can really go crazy with all sorts of methods. Remember there's big variations in what we humans used ourselves - look at the Mayan/Central American long & short count system. So they (quite accurately) could measure a solar year, but placed a simple 365 'year', so 18 months of 20 days and one month of 5 days, and all as part of a long count that would last ~7885 solar years. Why? Why not?

But what if aliens were of Kardeshev 2.0 civilisations - so that they had been divorced from their planet for hundreds of thousands or even millions of years and had been floating about in Dyson swarm, say, and had evolved away from living on a planet and had no need to pay heed to their original natural dinurnal rhythms. Or what about AI's with lifetimes potentially of tens of millions of years? Would they perhaps make a measurement based on something closer to their lifetimes - say the revolution of the milky way?

If I was doing something with aliens, I think I'd see what sort of interactions my aliens would have. A being who, say, lives for 100 million years may not even bother to interact with gadflies like humans and therefore there would be no need to tie together either sides calenders and conceptions of times.

 

[Cathbad]

Time is a concept only - it doesn't really exist. So, however you want to judge 'how long' something takes, go for it!

 

[LukeLee]

Do it the way you want to do it. I don't think there is any standard scientific way of defining it as we haven't really gone anywhere else.

But we have very firmly defined the second as humans, so I'd guess we'd use that as a building block. Or at least you could translate whatever you've arrived at into human friendly units.

I use seconds/minutes/hours/'days/months/years (as I don't have any aliens) then morph them into 'local' times based on the system (planetary spin and orbit) but also 'natural' times (i.e. based on human biology ~24 hour days) and other standard times (based on political hegemony). But I don't really plan on discussing this, just throwing it in without explanation. And I mess around with time periods so come up with different sorts of 'hours' that are not 60 'earth' minutes - but instead time periods that I think people might come up with given the different day lengths on different planets.

So I'm going for complexity

As for real aliens, or at least the aliens in your WiP. Well, that gets a bit tricky. What sort of aliens? Aliens like us, in development, might well use their own system to generate their own time measurements...but you can really go crazy with all sorts of methods. Remember there's big variations in what we humans used ourselves - look at the Mayan/Central American long & short count system. So they (quite accurately) could measure a solar year, but placed a simple 365 'year', so 18 months of 20 days and one month of 5 days, and all as part of a long count that would last ~7885 solar years. Why? Why not?

But what if aliens were of Kardeshev 2.0 civilisations - so that they had been divorced from their planet for hundreds of thousands or even millions of years and had been floating about in Dyson swarm, say, and had evolved away from living on a planet and had no need to pay heed to their original natural dinurnal rhythms. Or what about AI's with lifetimes potentially of tens of millions of years? Would they perhaps make a measurement based on something closer to their lifetimes - say the revolution of the milky way?

If I was doing something with aliens, I think I'd see what sort of interactions my aliens would have. A being who, say, lives for 100 million years may not even bother to interact with gadflies like humans and therefore there would be no need to tie together either sides calenders and conceptions of times.

Thanks VB. That’s a good answer. All my species have been ‘assisted’ to become interstellar by ‘Ancients’ who no longer exist, as far as anyone knows. I know this is a time-honoured plot mechanism (trope?), but it isn’t hugely germane to the story itself. Because of this though, and because there are multiple species, I wanted them to have left behind a method of measurement that would be common across the board.
All my background research leads to almost everything referring back to something human-based, which I want to avoid. As you said, I’ve just made something up because I don’t have to (and won’t) explain it as long as the basis for it is clear in my own mind.

 

[Teresa Edgerton]

This is actually something that is relevant to a situation I am going through right now.

I live in California but spend a lot of time online communicating with people on the east coast and, of course, in Great Britain and Australia. So being in California I am completely accustomed to everyone being some hours ahead of me, to my afternoon being their night, to my evening being early morning. But for the last month I have been on the east coast, and I have to say that it continually freaks me out that, in terms of communicating with my family back at home, it is now the other way around. It's not jet lag, because it doesn't interfere with my sleep, or make me more tired. And I never forget the time difference. It just ... disorients me. It even freaks me out that when it is dark here it isn't yet dark there. (Rotation of the planet, I tell myself, which is of course something I have known about and accepted since I was a wee tot. But that very familiar fact seems ... spooky .... to me now that everything is backward.) Although when it is the other way around with the people farther east it has never bothered me at all.

This probably doesn't happen to people who are used to traveling outside their time zone, which I almost never, ever do. But if you have a character for whom it's all new, they might react the way that I am reacting now.

So what I am saying is that time may be an imaginary construct, but when you have to undergo a sudden and unaccustomed change in how you measure it against time for other people in other places, it can really play with your mind.

 

[CTRandall]

On the other hand...

Ask yourself why we our current divisions of time are structured in multiples of 12==60 seconds, 60 minutes, 24 hours. There is no physical, astronomical or biological reason for this; it is entirely because in the cuneiform system of writing in ancient Sumeria, it was easy to calculate in 12s. (That's also why there are 360 degrees in a circle.) We've stuck with that system for 4000 years for no reason other than it is familiar. I suspect we'll stick with it for another 4000 years for the same reason.

 

[Venusian Broon]

On the other hand...

Ask yourself why we our current divisions of time are structured in multiples of 12==60 seconds, 60 minutes, 24 hours. There is no physical, astronomical or biological reason for this; it is entirely because in the cuneiform system of writing in ancient Sumeria, it was easy to calculate in 12s. (That's also why there are 360 degrees in a circle.) We've stuck with that system for 4000 years for no reason other than it is familiar. I suspect we'll stick with it for another 4000 years for the same reason.

Actually I think you could argue that there were 'reasonable' reasons for it. Namely that the Sumerians/Akkadians and their descendent civilisations were comfortable with their mix of base-60 and base-10 numerals and arithmetic....namely, I think that 60 is a fantastic composite number with a lot of numbers (also a lot of them very nice composites) in its list of composites. Therefore dividing 60 by a large number of it's composites makes it reasonably easy to partition etc... (and therefore generate nice fractions etc...) So it makes me think that they really were getting to grips with some simple number theory and finding out stuff, something that the Greeks would later inherit.

But that's the mathematician in me. Maybe it's a neurological reasons too - that it's a mathematical thing that our human brains recognise?

12 is one of the lovely composite numbers of 60 so I'd include it with that. But why it was included as part of the day as hours....apparently the Egyptians (who I'm pretty sure weren't sexagesimal) originally divided the day into 10, then added one hour for dawn and one for twilight, then divided the night into 12, observing 36 star specific groups that rose 40 minutes after each other to accurately chart it through the night. Probably because they wanted to match the hours of the day....but actually it got pretty complicated because the day-time and night-time hour length would have varied over the seasons the way they observed it.

But why the Mesoamerians used a mixed base-20/base-18 system for their long count - other than it was the way of dividing up their short count year - no idea. And I believe we don't know how they divided up the day.

Therefore yes, despite some nice reasoning for having the Sumerian system, there's a degree of randomness on how we got todays formally defined second. And everything else.

 

[J Riff]

The decay of a pi-meson, or ome other particle, same everywhere. There's no change in 'time' till you reach C, wot's the problem ,everyone has writ around it a thousand times already, just spout some Hawking references...

 

[Max Egorov]

I think it depends on what kind of sci-fi you’re writing. If you’re going for hard sci-fi where the science takes center stage and the plausibility of it is integral to the plot then how you handle time may be very important. In this case it helps to do some research on how time flows and what affects that flow and your characters perception of it.

Of course if you’re going for more of a character or plot driven spec fiction/fantasy piece along the lines of Star Wars or Babylon 5 then I wouldn’t worry too much about it. As long as you have an interesting hook and characters your readers are invested in I think they’ll forgive scientific implausibility.

 

[LukeLee]

I think it depends on what kind of sci-fi you’re writing. If you’re going for hard sci-fi where the science takes center stage and the plausibility of it is integral to the plot then how you handle time may be very important. In this case it helps to do some research on how time flows and what affects that flow and your characters perception of it.

Of course if you’re going for more of a character or plot driven spec fiction/fantasy piece along the lines of Star Wars or Babylon 5 then I wouldn’t worry too much about it. As long as you have an interesting hook and characters your readers are invested in I think they’ll forgive scientific implausibility.

Thanks @Max Egorov I think the story is the latter, but I'm the former. I wouldn't notice it in someone else's story but it would irritate me in my own if it wasn't at least partially correct. Also, it is relevant to the background of how the species come to be at the same level of development at roughly the same time.

 

[CupofJoe]

I read that time in space is officially UTC [which is roughly equivalent to GMT on Earth].
I could see that for humans in space would still use UTC and then make any relativity corrections from time to time.
The first thing a ship's computer would have to do on entering a system or interacting with other systems is to find out what the local time is and make any corrections necessary. Maybe the larger crew/ship takes the lead when to ships meet in deep space. As for aliens... the process would be more complex but basically the same.
One thing I never really got was the time in ST: DS9. The Bajoran 26 hour day. Where there 26 earth hours in a day on Bajor, or was a Bajoran day divided into 26 periods. It didn't really matter but it has always niggled with me.

 

[Dave]

I think there is a little more to this question than the answers already given. There are some biological reasons why we measure things in days, sleep being the main reason - you know the song... How many more "sleeps" 'til Christmas? So, unless we find some way to control our sleeping patterns in the future, then we will still sleep once a day for 5-8 hours, and that is the notch on the wall that we will use to mark time passing, whether we are on a planet with 36 hour "days" or on a spacecraft with no "days."

The time needs to also be an equivalent measure for different species.

Another species, with a different biology, living on a planet with a different length of day, then it stands to reason that, if they sleep, then their sleep pattern will not be the same as us. How you deal with that? I don't know. I've never seen a book, TV show or film that has dealt with that. It is easier just to have everyone awake at the same time. On spacecraft and in starports, it would make more sense to have three shifts per "day" with different staff, but we never see that in popular TV shows, rather we see the same staff on duty all the time.

 

[Venusian Broon]

Another species, with a different biology, living on a planet with a different length of day, then it stands to reason that, if they sleep, then their sleep pattern will not be the same as us. How you deal with that? I don't know. I've never seen a book, TV show or film that has dealt with that. It is easier just to have everyone awake at the same time. On spacecraft and in starports, it would make more sense to have three shifts per "day" with different staff, but we never see that in popular TV shows, rather we see the same staff on duty all the time.

Even species on this planet have quite different sleep arrangements. Dolphins use unihemispheric sleep where half the brain sleeps, the other keeps going. Aliens may have sleep like this. Or perhaps if they are an old species they have worked out how to 'remove' sleep and use other methods to stop going crazy. Or perhaps they have evolved brains that just don't require sleep at all.

As for nightshifts - well, I assume we are watching a TV show or film for the actual characters of the story. It would be a bit strange to have an hour about a random nightshift manager, rather than the protagonists

Pretty sure Star Trek talks/hints about different watches on their ships, and I'm sure Battlestar Galatica did it too.

 

[Elckerlyc]

My WIP is based in space, but different parts of the galaxy. I’m struggling with how I handle time - not as some abstract concept but as how long before things happen or what time is it? etc...

I am not a physicist, but on a pure practical point of view:
It would depend how you have structured your galaxy. How do the different planets interact? Is there FTL, instant-communication?
I would imagine every planet has it's own time-structure, based on the orbit and rotation of the planet and the solar-orbit. It wouldn't work otherwise for the planetary population. This would be planet-wide.
For communications purposes between planets (assuming it's near-instantaneous, because anything else would render communication nonexistent) there would have to be a time-structure completely independent from the time-structures used on the planets, a time-structure that is used also in space and on spacecraft. This should be based on something astronomical on a galactic scale that's observable by anyone, other species included. The nature of this time-structure is something you can structure anyway you like, without pre-asumptions, because it should be totally disconnected from anyplace or any species,

Conversions from one time-construct to the other would imho be impractical, or utter useless. The more planets and species are involved the more complicated this would become. So, everyone uses 2 time-structures. His own and a, literal, universal one.
Futhermore, I don't think people on planet A would be very concerned about what the local time would be on planet B or spacecraft C. Or the hundreds of other planets and spacecraft. You wouldn't.
* Hopes this makes sense*

 

[Elckerlyc]

Some additional thoughts.
Equivalents for hours, minutes etc. I would imagine this depends whoever colonized the planet first. They would 'invent' or fall-back to a system they are familiar and comfortable with. It will have no connection with any other time-structure on other planets, except perhaps their place of origin. Simply because every planet or craft or spaceport will be a world on its own.
Any spacecraft may have a base-port, a place of registration. For onboard purposes they would adhere to that place's time-construct, but for communications use the universal one.
More additional thoughts may follow....

 

[Dave]

Pretty sure Star Trek talks/hints about different watches on their ships, and I'm sure Battlestar Galatica did it too.

Yes, they did "talk" about it, as did Babylon 5. In Star Trek TNG it was usually Data's night-shift as he didn't sleep. I think there was also a night-shift command test which involved Troi having control of the Bridge and trashing it. I just don't think there would be any period that was less busy than another, so can't see that it would work like that. it would be a 24-hour round the clock environment, especially on a space station, or during a war. The nature of those shows is that nothing ever happens when the main characters are asleep, just as we don't see them doing crosswords during the very long voyages between planets, nor Kirk being caught on the toilet when the Klingons attack.

 

[Karn's Return]

I believe that, as has been said earlier, you would need an entirely different measurement of time up in space. The further you are from star systems, the more abstract measurement of time you would need. Hours, days, months, years, those are all based upon a planet's orbit around its parenting star, in our case, the Earth's orbit around the Sun, as well as the moon's orbit around the Earth, plus the Earth's own rotation. Take away those three types of celestial bodies, and you have no context for what would construe a day or a year. It would most likely have to be event based for most people, or even something so generic that everybody on board of said spaceship, plus any and all other starships, would be able to immediately recognize. Timekeeping technology would have to be absolutely crucial, however, as again, there's no light/dark cycle when you're fifteen light years from the nearest star system.

 

[Elckerlyc]

My WIP is based in space, but different parts of the galaxy. I’m struggling with how I handle time - not as some abstract concept but as how long before things happen or what time is it? etc...

The time needs to also be an equivalent measure for different species.

I've been thinking (yeah, I know, I shouldn't)
We on Earth have our clock and the aliens on their planets in the Vega and Alpha Eridani systems have their own, all totally unconnected.
That's not a problem, because these spheres of influence are lightyears apart. Nothing that happens on Vega world 3 at local time 34wrqut::56frut will affect is in any way anytime soon. If their star goes nova we will notice, eventually, but that's about it.
There is no way of communication or physical contact. The local time on Vega is a non-issue to us.

The speed of our local spacecraft within the solar system is best described as crawling. (perhaps the Vegans do better, but as I haven't seen them yet flying overhead I will assume they don't.) The onboard clock can still be based upon that of it's homebase: Earth, Vega etc. No problem as far as communications are concerned (delays notwithstanding.), but still limited to the local (is system) area.

So, there's no need as yet for universal time-structures, for dealing with totally different (alien) clocks.
You would only need anything like that if there was a connection, an immediate influence. Something that - with the knowledge we have today - seems impossible. A way to beat the time barrier, like, say, the Ansible for simultaneous communications.
And once you have that, you also have a means of utilizing an universal clock. Like we can now sync the clocks on our tablets or PC's via the internet with the Atomic Clock Worldservice.
And than we can go visit the Vegans with the Ansible in our backpack and say "Hey guys, listen. We have this thingy for simultaneous communications and we would like to setup a system for broadcasting an universal time for universal purposes. Cool, right? You're in? We only need to agree on a time-system that would fit and benefit us both. Any ideas?"
And the Vegans will say something totally unintelligible. They also reek a little. But that's beside the point.

On what concept should such an universal time-system be based? Perhaps use the pulses of a pulsar, which are picked up at a certain base, which in turn broadcasts the pulses over the Ansible and regulates your universal clock. The units to use for the minute and hours equivalents is more tricky. It also depends on the metabolism of the Vegans, that could be much faster than ours (and explain why they reek so much.)
But I'm sure the answer lies somewhere in the mathematical realm, which is universal (I reckon).

I'm done thinking for now.

 

[Dave]

On what concept should such an universal time-system be based?

You need to read Einstein's Theory of Special Relativity. (Seriously, it is accessible. I read it when I was 14.) Everything is relative, including length, mass, mass–energy equivalence, and time. The only constant is the speed of light in a vacuum. You cannot have a universal time system as the same event is different for every observer. (A Brief History of Time by Stephen Hawking is accessible too.)