I'm developing a game that mostly takes place in a universe different from Earth's. In fact, the game has many other universes as well, each with different date/time systems (as opposed to Earth's hours, minutes, days, years etc.). The game takes place mostly on an artificial world that acts a bridge between Earth and all these other universes. While this world does have a sun of sorts, neither it nor the world move in relation to one another, leading to constant, endless daylight.

While I'd be happy to invent an entirely new date/time system for this bridge world, due to the nature of the game's mechanics, time management is an important aspect of the game. Additionally, I don't consider learning a new time system and making conversions between it and the hours/days etc. we're all used to to be a skill worth mastering for this game in particular. Because of this, I'd like to use a time system similar in structure to that of modern day Earth. While this choice is purely for the player's sake, I'd like to make it work in-universe as well, if at all possible.

So my question is, what reason, if any, would the inhabitants of this world have to adopt such a system?

Some additional notes/things I've already considered:

I'm not necessarily looking for a system that mirrors Earth's clock; that is to say, what year/day/hour it is currently on Earth does not matter. All that matters are the units used for keeping track of time (ie. hours, days etc.). Of course, a clock which is actually perfectly in sync with Earth's (or rather, one of Earth's timezones) is also acceptable.

The system does not need to match modern day Earth's perfectly. Specifically, it only needs to have minutes, hours, days and years. A lack of months can be remedied by having dates be expressed as, for example, 123rd day of year X, and subdivisions of minutes as well as grouping of years are not necessary.

The inhabitants of this bridge world regularly perform trades with the denizes of other universes. Trade would be a pretty solid reason to adopt matching clocks, but that would be true for the clocks of other universes as well, not just Earth's. I briefly considered actually creating the different time keeping systems for each universe and providing the player the ability to switch between each, but that would be a lot of work for not a lot of benefit, seeing as the player would likely just stick to the Earth clock for the entirety of the game. I should note that the player character is not human, and has never been to Earth, so there is no reason for them to prefer Earth's clock over any other.

One option would be to create some naturally occurring event in this world that repeats at a certain interval, and make this interval coincidentally match some human-relevant timespan (every 24 hours, for example). While there is one single naturally occurring, repeating event in this world, it is highly irregular in terms of when it repeats, so I would think building a system around it would be difficult. I'm not entirely opposed to creating additional natural events for the sake of solving this issue, but I'm curious as to whether there is a cleaner solution.

I'm happy to provide clarification/additional information if necessary. Thanks in advance!

EDIT: Thanks for all the answers and comments! I've decided to go for a combination of a few answers, specifically those that mention Founder Effect, but most importantly, Ángel's idea of Earth having literally gifted the bridge world a giant clock before anyone else.

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    $\begingroup$ Honestly, this sounds like a time to just employ Translation Convention. After all, your UI is (presumably) otherwise in English, why not just hand-wave the time units also? $\endgroup$
    – Matthew
    Sep 12, 2020 at 15:33
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    $\begingroup$ earth time keeping is a pile of ad-hoc rules that seek to codify the days and seasons on earth. it's complicated and hard to get right. it has very little utility on a space station. pick one unit and use multiples of that. $\endgroup$
    – Jasen
    Sep 12, 2020 at 23:44
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    $\begingroup$ Once you have an answer to this question, maybe you find out how to make the USA use SI units ;) $\endgroup$ Sep 13, 2020 at 20:34
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    $\begingroup$ I believe they wouldn't, since they probably had this problem way before including Earth in their ranks, and found a working solution. Hopefully that solution is way better than our time measuring systems, probably related to universe expansion speeds. What I would do is include two time systems, one for alien, and one for Earth and display them on the screen together in sync. In time players will develop a sense of time for alien measurement system, like US nurses who constantly convert between pounds and kgs. $\endgroup$
    – edokan
    Sep 14, 2020 at 10:56
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    $\begingroup$ This would be a great opportunity to introduce "Swatch Internet Time" (en.wikipedia.org/wiki/Swatch_Internet_Time) to your players. Maybe even get Swatch on as a sponsor. ;-) $\endgroup$
    – YetiCGN
    Sep 14, 2020 at 12:00

13 Answers 13


Earth was for some reason really influential on the beginnings of this artificial world.

  • This may have been founded by Earthling. You can see how colonies copied the standards from their metropolis.
  • The Earth paid most for this place. As such, it had a say on which timekeeping units to use.
  • There was an auction for this. One world paid for the privilege of seting the time unit, other for the space one, another for the name of a street, and the next one for the currency name. This is just another way of getting funds. Creating a world is not cheap, so if a civilization is willing to pay $$$$ for us to use an arbitrary unit, we will happily oblige. At the right price.
  • One key designer was from Earth. The transparent dome was made by the Kurgh'gt, but the design of the motors rotating the planet, which causes the day and night, was from human source (maybe copying an existing design?). As such, they made it according to human standards.
  • Earth gave a big clock in the early days (maybe place a Big Ben in the main square?), to the pride of their inhabitants. However, in order for this clock to be of any use, they had to adopt human time units (not necessarily as a decision from the beginning, but if their town council starts when the clock makes most sounds, you meet your friends when both hands of our mighty clock are 45 degrees, and it is patriot to mention your clock every time describing time... you are essentially using Earth units).

PS: I don't think that showing the time on different clock modes would really be a lot of work. It's unlikely to be used much, but being able between time units from 50 galaxies might make for an amusing feature.


Let's see:

  1. They don't. You tell the people playing the game that the time units have all been translated for gameplay.
  2. They don't. The characters use in-game translation systems that make translation seamless.
  3. Earth reached the bridge world first. Founder effect ensures that everyone uses their system, just as the USA speaks English even though people of English descent are a minority.
  4. Why this system arises so uniformly among the worlds is a great mystery. Especially given that it's not unique in any world -- they just converge on it. Of course, this introduces a great mystery into the world-building, and raises the specter of precursors. This can be limited by limiting it. Perhaps it's merely the most common. That could even be a minority -- a third of all worlds use this system, it's just that all the rest use unique or less popular ones.
  • 2
    $\begingroup$ The last solution reminds me of how the aliens from The Simpsons just happen to speak a language which independently evolved to completely resemble English. Much more hilariously improbable there of course, but it's a nice solution to make the hand-waving part of the in-game lore, rather than seeming like a lack of worldbuilding effort. +1. $\endgroup$
    – Lou
    Sep 13, 2020 at 15:51
  • $\begingroup$ 2 is probably what I'd go with personally, but particularly inquisitive players may wonder why these aliens working in alien systems keep telling them they have exactly a nice round number of Earth time units to accomplish something... $\endgroup$
    – Tin Wizard
    Sep 14, 2020 at 18:13
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    $\begingroup$ @TinWizard you could just add random (or random-looking) fractions to times, e.g. "Please come see me in 3.637 Earth hours". $\endgroup$ Sep 14, 2020 at 19:39

Funny Story...

I can think of several reasons, but in most stories/games, it's not a big deal. How does GMT (Greenwich Mean Time) come to be the time for the universe?

  1. Earth won the lottery that settled time. All the groups represented entered a randomized lottery to determine who's time was used. Earth won. Now the universe runs on GMT.
  2. Earth history was influenced by otherworldly visitors. When time was being set on Earth, time-obsessed aliens tampered with the decisions we made to assure that the final accepted time for Earth closely matched Karrelian New Mean time.
  3. Your character was given a time translator by a human, and follows the time for sentimental reasons. Their mentor was human, and gave the character a Rolex that tracks time in all worlds and automatically translates it into GMT. Sentiment and an expensive watch caused them to adopt that time.
  4. Quirk of founding: The first founder of this society was a human who accidentally arrived well before Earth was admitted. The society they helped found adopted GMT because it was a neutral (at the time) measure not in use by any of the significant factions.
  5. Earth is, or once had, significant influence on this world. Today, we still refer to a universal language as a lingua Franca even though France no longer has an empire. At some point, Earth wielded greater influence here and helped establish GMT as universal time.
  6. Quirk of voting: At one critical point, elections were held about who would control the system. Earth was a minority player, but the election was so close, Earth's vote became critical. The election was swayed by offering Earth the choice of universal time.
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    $\begingroup$ 7. Aliens are total Earth culture aficionados and found human culture much more rich and rewarding than what they had before. They copy us wholesale across their empire including time keeping. Many other aspects of human culture are also copied but the aliens are not too fastidious about region or time period, and the result is a grand jumbled gemische. $\endgroup$
    – Willk
    Sep 12, 2020 at 16:55
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    $\begingroup$ nit: UTC (or one of its variants) are more likely than GMT, especially if time synchronization for computers is happening. $\endgroup$ Sep 12, 2020 at 17:06
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    $\begingroup$ Some variant of 3/4/5: Earth supplied a lot of the technology they use. The early devices were still only configurable to use Earth time (you can only set the current time and the Earth time zone). There were lots of different time standards on that planet before then and plenty of arguments about which one should replace the others. They ultimately decided on Earth time as an acceptable compromise, in that everyone can rest easy knowing that it's not really what anyone else wanted either. $\endgroup$
    – NotThatGuy
    Sep 12, 2020 at 23:20
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    $\begingroup$ @Clockwork-Muse in any realistic sci-fi setting, all timezones are measured as an offset of UTC. (by humans anyway) Because when first contact was made, and the diplomats/legislators were busy, hackers on both sides worked tirelessly to connect up their two internets, and get an alien-quake LAN-party going. $\endgroup$
    – bobsburner
    Sep 13, 2020 at 8:11
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    $\begingroup$ A minor point-of-order: a lingua franca is not a "universal language", but rather a language used by two people to communicate, even though it's not the native language of either party. For example, if a French and a Dutch speaker were to communicate, neither of them knowing Dutch and French respectively, they could use English as a lingua franca. $\endgroup$
    – Lou
    Sep 13, 2020 at 15:54

They don't use our measurements at all.

However, the clever, ubiquitous translation machines convert seamlessly and perfectly every time, so that humans don't miss their appointments with alien dentists (nor show up too early, which is arguably worse).


Earth's humans may not have been the first to reach the game world. But they were the first that brought a system of timekeeping that worked reliably anywhere in the universes and could be reproduced with commonly available materials and even the most primitive electronics, to wit:

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 caesium-133 atom

Thus, virtually all other species eventually adopted this definition of a second, and most also adopted Earth's definitions for minute, hour, day and year as a universal reference for inter-species and inter-universe communication and commerce, and even those who didn't officially adopt it are still familiar enough with it to be able to convert units when communicating with others who do.

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    $\begingroup$ There are probably aliens who write about the mystical significance of the number 9,192,631,770 to humans. $\endgroup$
    – Mary
    Sep 13, 2020 at 17:15
  • $\begingroup$ Makes no sense that space-faring races wouldn't have invented precision timing before. It's basically a necessity to get to that stage. $\endgroup$
    – Tom
    Sep 19, 2020 at 11:34

It was the year 72 of the great galactic war. Or 128 by K'rel standards. 91 by Ogroch counting, 21 by Flipkak calendar and... well, the Tilhahfgloh year is 626 K'rel years, so it was year 5 like almost everything else.

The factions had agreed to meet for peace talks in neutral space. The talks were to begin at AK hour, though the K'rel were late because that's 19:5/21 their time and that's an unlucky number. The Ogroch almost left because AK rounds down to a&5aX and that's almost an hour early! The Flipkak didn't show up at all because 00551 isn't a meaningful time to them, and let's not get into the problem with the Zrotkli...

When, after 3 days of time confusion, everyone finally met in the great conference room, the first, hastily added item on the agenda was to ensure that no further organisational hickups would get in the way of a peace accord. Everyone, of course, suggested that their time and date system should be used and nobody was willing to adapt to the counting of one of their mortal enemies.

Finally, exasperated, the moderating AI proposed to take the time system of a lesser race, one not involved in the conflict at all. Best, one that didn't even know about the conflict. It could not be more neutral, it argued, and everyone agreed.

So the AI digged through its database and found six local civilizations advanced enough to have proper timekeeping, but backwards enough to not know about the galaxy and its civilizations (and wars). Of those six, three were discarded because their systems were too similar to one of the warring factions. Two more were thrown out because their timekeeping systems were irregular, changing based on moon cycle or season. One was left that had a nice, easy, constant system everyone could easily translate into and out of and that had never even heard of the galactic war, despite its cute little attempts at communication using incredibly primitive technology.

Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.

(Douglas Adams)

...and so, the peculiar time and date system of one of the most insignificant species in the galaxy became the galactic standard time.

As to why it remained standard time after humans became space travellers? Well, everyone was used to it, but the actual reason is that Quisly runs on standard time, and nobody wants to miss Quisly.

(can be a sport, TV show, space racing, whatever your story requires)

  • 1
    $\begingroup$ This would lead to great confusion amongst the first human delegates to the wider galaxy... It’s lovely. $\endgroup$
    – Joe Bloggs
    Sep 15, 2020 at 18:32

they could have been forced. maybe there are many worlds like this for every other universe. a sort of bridge to the rest of the universes to get people to understand that time will be different in other universes. so maybe they were forced to do so in order to help the earth universe understand. although that's a little assumptive of what your world is like.

maybe, what about the infinite universes theory? because then there is GOING to be a universe where they HAPPEN to have the same words but different amounts of time.


The bridge world has eternal daylight. To still make sense of it all, a form of timekeeping is freat to take with you. Culturally this can have transferred from the Earth to the bridge world. This can be done:

  • Either because they were the first settlers, taking the time with them, to keep some track of it.
  • because they were the first traders with the bridge world people. Trading on Earth time became very important for the bridge world, so they use Earth time.
  • Or Earth was the most influential in the last so many centuries.

The time can be adapted to suit bridge world, but still having hours, minutes and possibly a few others.

Culture can have incredible lasting effects. As a real world example, you can look at how the metric system has influenced practically the whole world, showing culture can change. And 3 countries still cling to other forms, showing this deep cultural rooting can stay even if it can harm trade. These two combined give you the freedom to make your story nearly anything you want. Earth can be insignificant in bridge world now, but the time can still be from Earth as it's ingrained culturally by some events in the past.


In the absence of all external references (astronomical events etc.): at one point humans were dominant, and the dominant timing is based on the human heartbeat at an assumed rate of one beat per second when relaxed and contented. With a nod to Vernor Vinge, all other timing is based on multiples of this, i.e. kilosecs, megasecs and gigasecs, and where an epoch is needed (i.e. the zero point of a calendar system) it is close to the time at which humans landed on their moon (the offset of roughly 14.183 megasecs has never been adequately explained).


The technology that manages the gate system between universes was originally developed by Terrans and the internal clock systems are all hard coded to Earth time.

Although it would be possible to rebuild the systems to run on some other time system, it would be expensive to do so and would return extremely limited benefit - so no one has bothered.


Backwards Compatibility

Long ago, when the bridge was first established in a collaboration between several species, it was found that the computing substrates (optical, biological, quantum, etc.) of most of these species was unsuitable for this environment; perhaps due to solar interference or slight changes in how this specific universe operates. It was found that human electronics, while less efficient than some of the other aliens' technologies, was less susceptible to this issue. As such, the initial computing infrastructure of the bridge was built around human technologies as a placeholder until the issues could be sorted out.

Unfortunately, as is the case in the real world, there is nothing more permanent than a temporary solution. As more and more systems were built into this infrastructure, it became increasingly costly and difficult to replace all of them with a fundamentally different technology. Eventually, it became an outright financial impossibility; the cost of replacing the system became vastly greater than just dealing with and maintaining the core infrastructure and retaining backwards compatibility. While adapters were eventually built to interface with other alien technologies, the central core and most of its systems was built around not only human technologies, but also a specific human operating system. In fact, this operating system itself was built to be backwards compatible with even older human operating systems (for similar reasons).

Since most of the original inhabitants were the engineers that built everything, it made sense to use the same concepts of time as the systems they were building. It thus became the de facto standard, which was eventually carried over past the completion of the bridge world and became official.

And that's how the human time units became a inter-universal standard: by accident and the financial necessity of backwards compatibility.


The Culture will have his orgins on a Planet. They will have days and years. You can translate this in a other language or not. Months exists, beccouse we have a Moon. Do they have one too? or a Gasgiant between there Planete and the sund who is orbiting the Sun 10 times faster and ist very bright in the nightsky?

And hours and Minutes... That is just random :(


One option is to just define a unit that is close to a second, then work your way up using powers of 10, e.g. multiples of 100 seconds rather than talk in minutes, a ks is roughly 30 minutes, 10^5 sec is almost one day (27h), a megasecond Ms 10^6 is 11.5 days, so a long week, and 30 Ms is almost a year 347 days.

Put an origin on your calendar (a few gigaseconds ago), and there you are, all dates in seconds.

If you want to more closely match the duration say of a day counted as 10^5 secs to normal 24h, you could make the second a tad shorter.

Anyway, a culture neutral way of counting time is to keep a time unit (seconds), then just go for powers of ten, not aligned with any cosmic stuff such as the earth revolution. We can hope different alien cultures could agree on a time unit at least, and every space faring civ must have math for powers of ten.

  • $\begingroup$ "every space faring civ must have math for powers of ten". Why would they? An octopus would find natural to count in base 8, a starfish in base 5, and those would be their natural powers. $\endgroup$
    – L.Dutch
    Sep 15, 2020 at 8:55
  • $\begingroup$ well at some point we have to make allowances so the player can fit it to known things. But I'd be fine with replacing 10^3 (a ksec) by 1024 secs (a kibisec ?) i.e. just use powers of 2. That could be more "universal". Also, the second is the only standard shared with octopi, then octopi of course use 64 instead of 100 to make an octopi-minute but that's irrelevant, conversions can be done precisely and without loss between the two systems. $\endgroup$
    – Yann TM
    Sep 15, 2020 at 9:02

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