Goodreads Sci-Fi/Fantasy Authors discussion

I got a science question for everyone: how will we tell time and keep a calendar in space? Once we colonize other worlds, keeping to the Earth calendar and clock will be pointless. New planets will have different years (orbit of star), months (lunar orbit), and days (full rotation). All three measurements will have to be thrown out. Even hours might not make a lot of sense.

Do we keep hours, minutes, and seconds? If we change measurements of time, then we will need conversions from one planet to another. Hardly practical. A new universal measurement of time will be needed like Stardate from Star Trek.

Any thoughts? Does one already exist and I just haven't heard of it?

Yes, I had to look this up once. There is a method which would be used. I think its called solar time. Having to do with the sun's rotation? I forget the details. Anyway its what is used for satellites and the like.

Anyway its all kind of moot, isn't it. I don't know what you're talking about with regard to colonization; that's strictly science fantasy. We're never getting off this speck of frozen mud. We can't even keep our keep computers running without an army of babbling helpdesk staffers located in Bangladesh.

Just looked it up. Solar time is measurement based on sun's position in the sky, which is only relevant to Earth. Its basically what we use now.

Sure it wasn't called something else?

I've taken on that question in one of the books I'm writing. I just make the people readjust using their new sun. The cycle between rising suns is a day. And a calculated orbit around the sun is a year. You just decide bow many days that makes.
For planets with more than 1 sun? Ask George Lucas ;-)

One universal constant, which can be measured from anywhere, is the rate of expansion of the Universe. A clock could be derived from a function of that speed. However, the expansion is slowing down, and one day the universe will start to contract, but that rate is so slow it would not affect the creation of a universal clock, which could take it into account rather like our leap years.

Stephen Hawking will probably tell me there are flaws in this suggestion, but hey - we're talking about fiction.

Neven wrote: "I've taken on that question in one of the books I'm writing. I just make the people readjust using their new sun. The cycle between rising suns is a day. And a calculated orbit around the sun is..."

Yes, that makes sense. I can't see why you wouldn't make a day whatever number of hours it is on your planet. Out in space, you'd have to have it in shifts, depending on whether you're sleeping it out or doing a Star Trek thing, with the crew awake and working. In the latter case, yes, you'd need a Stardate, but I would think also a clock set to, say, Greenwich? Just so you know what's happening on Earth...

Sue wrote: " I would think also a clock set to, say, Greenwich? Just so you know what's happening on Earth...."

Except time is relative - the faster you flew away from Earth, the greater the real time difference would be...

And then there are the issues of, say, werewolves and vampires out in space...;-) yes, I know, fantasy, but it might be fun. I vaguely recall that A.Bertram Chandler wrote a book with a werewolf out in space, can't recall the details. I would think it might be easier for a vampire, though, no sunlight, so he/she could get up and go to bed same time as everyone else.

Pete wrote: "Sue wrote: " I would think also a clock set to, say, Greenwich? Just so you know what's happening on Earth...."

Except time is relative - the faster you flew away from Earth, the greater the real ..."

True. Stardates it is. :-)

The reality is that when mankind reaches the stars, there will be no real-time communication between them. So a coordinated timeclock is irrelevant.

Obviously the question is a hypothetical based on a few assumptions. It assumes FTL travel and maybe communication. Whether you consider the hypothetical realistic or fantasy is irrelevant. I pose the question because it is something I've bumped up against in my FICTION-writing.

Universal constant makes most sense. It is something that whole universe is experiencing together, not distinct to each planet. I'll need to look into that.

The Greenwich and other time ideas are not practical in the long term. Days, Hours, Months, and Years will vary planet to planet. With each having their own time and calendar system, you'd need a converter just to understand what others off-planet are saying about schedules. Sure we have computers to deal with that but human conversation would be hampered.

If communication is too slow or impossible between stars than yes each planet can devise its own calendar and time system with no regard to any other.

I read somewhere the stardate idea is an arbitrary time system. There's no theory underneath it unlike many other Star Trek ideas.

Wesley wrote: "Obviously the question is a hypothetical based on a few assumptions. It assumes FTL travel and maybe communication. Whether you consider the hypothetical realistic or fantasy is irrelevant. I pose ..."

So, what IS your story about, Wesley? What assumptions does it make? Is it a generation ship? A FTL ship? A sleeper ship? One that goes through wormholes? If you assume FTL is possible, then you can do almost whatever you want, including star dates and real time communication. If it's one of the others, you go from there.

I read a YA novel recently that was about a generation ship and got most of the possibilities to make sense... then had real time communication and a raid of one ship on another... Whatever you decide, it has to be consistent.

Seems to me that there's two extreme possibilities. Either there is some form of real time, or near real time, communications between planets, or there isn't.

In the latter case, any kind of co-ordination is probably irrelevant as Pete says.

If the former, though, it should be possible to co-ordinate some kind of stardate and time as a universal reference. This would probably be arbitrary, or tied to some arbitrary point like Greenwich.

IMO it doesn't really matter because the only point of such a clock would be to co-ordinate things that need co-ordinating between worlds. For everyday practical purposes I think each planet would use its own calendar and clock based on local conditions.

Let me restate the question, since we are getting a little caught up in determining the plausibility of the hypothetical.

Assume humanity has an interstellar empire, with FTL capability and with it FTL communication via a mail service on starships. All planets have their own calendars and clocks but need a standardized time system for interstellar business.

Is there anything that can be used as a measurement of time that is constant or uniform across worlds, stars, and galaxies?

OK, with the scenario you've described, each world will have its own local timekeeping but, as you say, you need some standardized system for interstellar business. The key characteristics of this system are (a) it is agreed and understood by everyone, and (b) you have a way of keeping everyone in step over vast distances. The first is a political problem (so deal with it how your will), the second is practical.

I don't know of any universal measurement that is uniform everywhere. Even the expansion of the universe (which Pete mentioned) is problematic for me. Firstly, it is not truly uniform everywhere (and possibly not even in every direction). Cosmologists just treat it as if it were for simplicity because otherwise the calculations become intractable. Secondly, even if it were uniform in absolute terms, any measurement you make would give different results depending on your own motion. Thirdly, it doesn't seem to me to be a good thing to use. It's a bit like saying I'll set my stopwatch by the speed of that passing car. So how do you know its speed? By my stopwatch, of course!

If I were writing this, I would probably pick something like a bright pulsar that everyone can see and use that to beat time. The trickiest part would be to get everyone lined up to some arbitrary baseline - hour zero - then everyone can count beats from there. Even that has its problems. If one world is a thousand light years further away than another, they are counting beats a thousand years apart so you'd have to pick a pulsar whose heartbeat is steady over many millennia.

The thing is, this is a hard question to tackle, because perceptions of time will differ thanks to relativity. You might just have to accept that there will always be inaccuracies that have to be ironed out from time to time by worlds synchronizing clocks with each other. The question is, how accurate do you think an interstellar civilization needs to get?

You could duck the "universal measurement" problem altogether by having your universe set up with a timekeeping network that issues a standard but arbitrary "universal time", a bit like the network of atomic clocks here on Earth. Have you researched the time network in use today? That will give you an idea of the difficulty keeping accurate time just on one planet, let alone across interstellar distances.

I think this can be done, even with relativity. This is for shipping and travelers who need to know the situation upon arrival to a new planet. Their subjective time isn't important from a business standpoint, only what their clients or partners are experiencing on their respective worlds. As long as the clock or calendar is based on something external that all within the empire can observe, then two people in the same place can't claim it to be two different times or dates.

Another possibility is something having to do with the life cycle of the Sun or Sol. Humans will probably be biased in creating systems, preferring one that utilizes our home world and home star, even if it isn't an objective choice. For example, we count years from the supposed birth of Christ. Pretty arbitrary.

Unless a FTL or instantaneous communication system is ever discovered, we will look at time like our ancestors did in colonial time. We would know the news we receive from Great Britain is three months old and may be obsolete but everything reported up until that point the ship left happened.

Actually, that is exactly what it would be like. The sailors of the colonial era and before. Since transportation and communication are so slow, all you need is agreement on time and date upon arrival at a port.

Wesley wrote: "I think this can be done, even with relativity. This is for shipping and travelers who need to know the situation upon arrival to a new planet. Their subjective time isn't important from a business..."

Even on our own planet we have time differences. And as you say, people in colonial times knew their news was out of date. It seems to me that if you can assume FTL travel is possible and have an interstellar empire, presumably with some form of communication, you can decide on your own universal clock. Readers will accept it. "Be vague" is a piece of advice I read once in a book on writing SF while trying to decide what effect two or three moons would have on an Earthlike planet. So - be vague. If you try to get it scientifically exactly right, you'll only have a LOT of arguments. If no one is arguing with you about FTL flight, be glad!

You would have to have a standard across all worlds. some have mentioned business and legal purposes. Imagine a world with a three month year and a child from that world comes to Earth and tries to buy alcohol. If the laws set the age limits in terms of vague "21 years old," the kid could be five Earth years, but 21 according to his or her laws. Sure you could stipulate "21 earth years," but if each world had their own system of time keeping, it would become confusing for bar owners and liquor stores to sort out someone's age.

Since we've already standardized all other measurements under the metric system in most places on earth, why not create a similar system for time? a minute equals 100 seconds, an hour equals a hundred minutes, a week equals a hundred hours. Instead of measuring time in terms of a planet's rotation and revolution, the rotation and revolution would be measured in terms of time.

J.J. wrote: "You would have to have a standard across all worlds. some have mentioned business and legal purposes. Imagine a world with a three month year and a child from that world comes to Earth and tries to..."

Do I have to assume some form of instantaneous communication has been devised, so that worlds light years apart can keep in touch real-time? Without that, there is no need to keep synchronous time. eg: On planet Zarg, I place a pizza order with Earth, 300 light-years distant. I then write in my will that in 600 years my descendants should expect a pizza delivery. (What they will get is a message ' is that with anchovies?' instead.)

Legal documents between planets would have a dual date/time stamp - easily calculated, just as we check the time in New York or Paris - but only if instantaneous transmission were possible.

Okay, so Earth becomes the 'Greenwich Meridian' and all planets adopt an Earth-second base for time. But time is relative, and varies according to speed of travel. So a tourist travelling at 0.9C (speed of light) would say he's only taken 320 years to reach his holiday destination, but the clock at the arrivals lounge tells him it's taken 478 years. Which one does he believe?

I stick to my belief, J.J, that when distant solar systems are colonised, there will be no communication between them.

I've just had another thought.

Fact: Scientists are currently playing with this quarky dark matter particle thingy that is apparently paired with a sister particle which can be anywhere in the universe. When they change the state of one particle, the other instantly changes also, no matter how far away it is. (Can't be bothered to look it up right now, but that's the gist of it.)

So... the first colony starship takes clusters of these quarkies, and leaves a set on each planet. The quarkies are attuned to a master set on Earth, broadcasting the atomic clock. So irrespective of distance, each planet has an accurate real-time Earth clock. Another matched set could be used, akin to optical fibre, for instantaneous communication.

Whether or not this works out in reality, it's plausible enough for SF. Does this get you out of your fix, Wesley? (I have quarked this post back one year, so you will receive it one month before you think of the problem as outlined in your original post.)

Unless challenged I claim intellectual copyright on this idea. Send royalties to .... ;-)

Following on, as I am currently in lunatic mode, the quarkies could of course also be used as a speedometer on starships, my comparing relative time with real time. (How else, apart from wildly inaccurate calculations of thrust, do you measure the speed of an FTL spaceship?

Pete wrote: "J.J. wrote: "You would have to have a standard across all worlds. some have mentioned business and legal purposes. Imagine a world with a three month year and a child from that world comes to Earth..."

I think the ultimate answer would depend on the situation we're trying to define. Just checked to see how the original poster defines the situation and it sounds like they're looking at a real world scenario. If we were talking about a solution for scifi, there really would be no one way, because each fictional universe could use its own method based on the parameters of the universe established.

Even looking at it real world, the OP suggests we're colonizing other stars, in which case you'd be right. Standardized time keeping would be iffy. but if we're considering an ultra real scenario, and assuming we'll never actually go to another star, then we're looking at colonization involving Mars and maybe some of the more interesting moons within our own solar system in which case, an earth based time system would seem more practical.

On the other hand, if we are colonizing outside this system, the concept of day/night could get interesting if we place a colony within a binary system, and you have a second star providing something between a day and night state.

BTW, there was an episode of Stargate SG1 where two of the characters pilot a an experimental fighter meant to travel into space. borrowing alien technology, it's taken over by a rogue program that sends it on a slow course out of the solar system. Among other things, the episode deals with the time issue involving radio communications. The further out they get, the longer it takes for messages to go between earth and the fighter. Early on they get the idea to announce the time with each communication so the recipient knows how long ago a message was sent and they can use it to continually recalculate the distance of the craft from earth.

I agree. A complex subject and no definitive answers.

I have to admit this thread was the inspiration for the time-keeping conventions in my current WIP.

There are numerous options for telling time in space. What is required is a measurable physical constant. The speed of light comes to mind. Or it could be the frequency of vibration of a common crystal, like a diamond. What counts is the commonality across worlds. Once the choice is made, the physical details are arbitrary.

Wesley wrote: "I got a science question for everyone: how will we tell time and keep a calendar in space? Once we colonize other worlds, keeping to the Earth calendar and clock will be pointless. New planets will..."

Any number of possibilities would work, namely those relying on a universally available physical constant - e.g. the frequency of oscillation in a specific crystal, used in many places, from cheap watches to the atomic clock. After that, it is just a matter of picking a standard.

The rotation of a star, the orbit of a planet, and similar items clearly do not work, since there's too much variation (depending on the star or the planet).

In some stories, Einsteinian time dilation might mess things up, but if folks aren't going faster than light, then there's probably no space civilization anyway.

Sometimes one wonders whether fiction is close to truth than one realizes. The following is an example of that. I would be delighted if someone would criticize it . Meant this to be in permanentlink, but can't seem to get that in Goodreads.

https://drive.google.com/file/d/1ulah...