I'm working on a science fiction story. it takes place in the late 25th century. Humans have colonized and created alliances with other species. How would time and date keeping work in such a civilization?
You should look up how we humans define time. The year is defined by Earth's rotation around the sun, and a day is defined by Earth's rotation about its axis. So one idea would be to follow the same logic we use to define a time/date keeping system for another civilization.
Yes I know that. But it would there be a sort of central timekeeping for the galaxy. Out of a fictional point of view.
How about... Each galaxy is a defined area. The center of it, or the closest planet, would become the standardized time depending on its rotations. Each planet and culture would have their own time keeping but star military and the common time would be decided by this standard.
If they needed time keeping between solar systems, they would likely just develop some kind of standard time and they'd probably refer to local time and galactic standard time. You could pick any standard you wanted. What is more complex is if you are traveling between these planets at anything faster than light, time would pass at a different rate for the travelers as opposed to the planet bound individuals.
Realistically, there would be no way of actually keeping an "objective" "central timekeeping" because time is...well, it's not an actual objective category, because it is co-dependent on variables of... ...you are writing from a "fictional point-of-view"? Make up a fictional timekeeping system. Or just use whatever your characters would bw most familiar with. Year of Our Lord 2608? Sounds about right
What @GingerCoffee and @A.M.P. said. In addition to specific planets using their own calendars for non-interstellar matters, maybe there could also be a second calendar based on the rotation of the galaxy itself for interstellar co-ordination? Space-farers would not use such a calendar when they are actually traveling at relativistic speeds, but it would certainly help for planning departures and predicting arrivals. And of course, wormholes make all kinds of communication easier Does your novel use any of those?
That time passes faster for travellers in FTL speed. No my novel does not use wormholes for travel. Thought about it, but I like realism. Since there is so little information on that hypothetical phenomenon, I decided to go with FTL-travel instead. Sort of like the Alcubierre drive. But with my own fictional spit to it. But as I said, I don't want to go too far outside of realistic frames and standards. I might post some information about my novel in the near-future.
There's an inherent problem in a universal galactic time - according to Special Relativity, two observers in different reference frames cannot agree on simultaneity of events, and any attempt to synchronize time between reference frames will introduce paradoxes. Setting that aside, though, Isaac Asimov used the "conventional" measurements of a day, month, and year, in the later books in his Foundation series (after the original three) to help identify the long-lost original single homeworld of the human race. These periods did not correspond to the orbital and rotational periods of any of the major worlds of the Galactic Empire, even allowing for changes in those properties over the long age of the Empire. So these values were used to help rule out or verify worlds considered for other reasons in the search for the first world.
The easy answer is to invent a fictional system for measuring the duration of a specific period of time. Call them something new, just off the top of my head, something like microtans for the base unit, 10 microtans in a millitan, 10 millitans in a centan, 10 centans in a dekitan, 10 dekitans in a soltan, etc. Estimated voyage time 3,942 Soltans, 8.32 dekitans, ...approximately. Take the standard 8.5 centans for lunch. You've been waiting here, in the rain, for dekitans it seems...and you're getting tired of waiting. Okay buddy, you got 5 microtans to start talking. Depending on how you use it in dialog, it can work and nobody would even have to know just how long a millitan would last in duration.
