I need some science fiction help

[DCR]

Hello, all. In my spare time I enjoy writing short stories in various themes. The one I'm currently working on is in the Science Fiction genre—a fairly standard "starships and space exploration" job. I've devised some extensive background for this particular storyverse (I intended these stories to be episodic in nature, revisiting the same crew on their various adventures and misadventures) but there's one aspect of it that's really been a stitch in my side, and I can't seem to get it ironed out: time.

It makes no sense to me that in other fictional universes where intra-galactic travel is commonplace, that we'd still be measuring time in the old years/days/hours/minutes/seconds, seemingly across hundreds of races and in all corners of the galaxy. So, for my stories, I wanted a "galactic standard time."

Now, of course, it would have been super easy for me to just... make some junk up. Lots of authors make stuff up—it's fiction. There's no obligation to be factually accurate. But I wanted something more than that for this one. I wanted a timekeeping system that actually maybe sort of kinda a little bit made sense. And something that locked into other aspects of the story as well. I wanted to tie it into the lore for the navigational process.

The galaxy in my story has been expanded just slightly, such that if I draw a point at one degree increments around the circumference, each dot is exactly one thousand parsecs apart. So essentially, what I have is a giant circle divided into three-hundred sixty slices each one degree apart. When I was trying to develop a new timekeeping system, this came to the forefront of my mind.

What I wanted to do was use the rotational velocity of the galaxy (as a whole), in comparison to this central circular navigational plane and somehow come up with a system for keeping time based upon that. Several problems with this arise, though. One, the rotational velocity of various different parts of the galaxy varies, though not as greatly as one might expect. To fix that, I just averaged a bunch of different velocities that I scrounged up on the Internet and used that number.

My second problem, it turns out that the galaxy is really, really big. It would take tens of thousands of years for this "galactic clock" to "tick" just one degree along the circumference. I thought I'd solve this by some quick division, but as near as I could figure, I'd have to divide by something on the order of 10^12 just to get the numbers down to a manageable level.

After staring at numbers for long enough to make myself dizzy, I decided to enlist the aid of... anyone who'd listen to my longwinded verbal vomiting. Heh.

Does anyone have any suggestions on how to iron this out? Has some brilliant mind already put thought into this and devised some genius system for telling time across the galaxy that I don't know about?

My head is spinning at this point, so I'd gladly listen to anything anyone has to offer. I'd really appreciate the help.

Thanks in advance,
-DCR

 

[mfb]

Galaxies do not have well-defined circumferences. The star density just goes down gradually.
The length of a parsec depends on the orbital parameters of Earth. Do you really want to use that?

I'd have to divide by something on the order of 10^12 just to get the numbers down to a manageable level.

So what? Our current second is defined as the duration of 9,192,631,770 periods of a radiation from a specific quantum-mechanical process. How annoying is that? Not at all, most people don't even know that definition because it does not matter outside precision science.

You can use any definition you want, it is advisable to have a definition that depends on physics only, not on objects in the universe (those can change). Just make sure to have suitable units that are handy for everyday timespans.

 

[DaveC426913]

Not that I want to short-circuit your creative solution but, surely a universal time-keeping system would not be one based on something as nebulous and slow as galactic rotation.

A really useful time-keeping system would be one that you could calibrate anywhere, anytime. Ship comes out of warp-stato-flogiston in Quadrant Nowheresville and needs to calibrate its clocks without access to external readings.

Maybe something like the number of vibrations of an energy level of a certain kind of atom...

Wait, we already have that. Well, it's a good system. More to the point, it's a logical one.

[ Derp. MFB is a faster typist. ]

 

[DaveC426913]

An idea doesn't have to be new to make for good reading. If you explained, as above (ships need to calibrate as quickly as possible), readers will go "Aw yeah. That's cool."

 

[DCR]

Now that you guys mention it, basing a timekeeping system on inconsistent rotational velocity probably isn't the best idea. I was caught up on the similarity between my navigational system and a clock face. Constant radioactive decay, as we use now, does seem more reliable. I had forgotten the caesium definition of the second—I was thinking of our time as solely based upon the various cyclic rates of neighboring celestial objects. It is that viewpoint that I found unbelievable as a universal measure of time.

As far as the parsec was concerned, I was under the impression that it was a consistent independent measurement. Unforeseeable events led to an early interruption in my college education—I didn't get a chance to attend any of the various physics courses that my majors required. Consequent to that, this is one of my weak areas. Heh.

I'm correct in assuming that the light-year is a more consistent measure? I've read that the speed of light can be affected by certain phenomenon, but then again I'm sure they take that into account when they calculate the distance.

 

[meBigGuy]

You can pick anything you want for a second, hopefully a nice round number of some physical phenomena. But, it doesn't need to be a round decimal number. Maybe hex or some other base?
Pick any number of days to be a month, any number of months to be a year. No reason to tie it to any planetary system.

How about 19 months of 19 days with 4 days leftover for partying? (that makes 365 though)

But, in reality, I personally don't like it when books use new or even metric time systems (like accelerando or others). All your readers are on Earth, so just translate it to Earth numbers.

 

[Hornbein]

It makes no sense to me that in other fictional universes where intra-galactic travel is commonplace, that we'd still be measuring time in the old years/days/hours/minutes/seconds, seemingly across hundreds of races and in all corners of the galaxy. So, for my stories, I wanted a "galactic standard time."

Sense or not, years/days/hours/minutes/seconds is what people would use. It's a deeply embedded tradition.

Why has English become the standard language of Earth? It's hard to learn. It was purely because of political/traditional/pragmatic reasons. It's an arbitrary standard. That's the way people do things.

On the other hand, most of the world has gone to decimal coinage. Invented by Thomas Jefferson, by the way. Is the UK the only holdout? Europe went to the metric system, though they had to cut off the head of the king to do it.

 

[mfb]

Constant radioactive decay, as we use now, does seem more reliable.

We do not use radioactive decays. We use the microwave radiation related to a specific hyperfine transition of atoms of caesium. A moderately more advanced society would probably use transitions with a higher transition energy (and therefore shorter period of the radiation). This is in discussion on Earth already ("optical clocks").

I'm correct in assuming that the light-year is a more consistent measure?

If the definition of a year is done properly (e. g. via atomic clocks), this is fine. The speed of light in vacuum is a constant. Don't use a year, however - roughly 31556736 seconds/year is an odd value. 100 million light-seconds are 3.17 light years or 0.97 parsec, and you can reach 10⁸ seconds with units like "1 second", "1.5 minutes", "3 hours", "4 months", "3 years", all separated by a factor of 100. The base 10 is arbitrary, of course, base 12 would have some advantages (e.g. 1/3 is much easier).

People would still use some local clocks because the concept of days is just too important to miss, but you would also have some universal time then.

 

[Khashishi]

I think you need to separate the concept of date and time intervals. Dates specify when events occur, and should be the same for everybody. Time intervals can be based on atomic clocks just like we do now, but the caveat is that everyone measures a different time interval between two dates. So, for dates, it's reasonable to use the rotation of some arbitrary star around the center of the galaxy. For a particular locale, you will have an approximate conversion between date and time, but you will probably have to throw in a leap-second here and there, just to synch things up.

 

[Michaelhall2007]

Have you considered planetary rotations? For example. '3-364.5.25 would be 3rd rock from the Sun so Earth and the time would be 12:15 pm New Years Eve.
A Mars rotation is longer but its just a simple maths equation. If its 12:15 on Earth it would be 4-68698.5.25 on Mars (ish).
As long as you know which system you are in, a computer can figure out the time.

 

[Khashishi]

Do you have FTL communication? If yes, the simplest thing would be for the capital of the empire or some arbitrary station broadcast a standard date over FTL lines.
If you don't have FTL, keep in mind that the Milky way is some 100000 light years across. If you are basing your clock on some regular event, like a pulsar, it needs to stay regular over several 100000s of years to be any use for someone across the galaxy. There aren't many good candidates. Probably your best bet for a "universal" time is the cosmic microwave background temperature. It is slowly decreasing as the universe expands. But the precision of the date measurements is probably far too low for any sort of practical use (e.g. I was born in 1900AD +- 100000 years). So, neighboring star systems will have to use their own local date definitions. Maybe it's better off to simply use time displacement measurements and keep careful records of your motion through the galaxy, so the date can be reconstructed. But you will still accumulate errors over 100000 years due to uncertainties in your inertial motion measurements and local gravitational field.

If you don't have FTL, how could a galactic civilization even form? What use would a galactic date serve?

 

[Noisy Rhysling]

Why not have a galactic GPS that tells time as well? It's been in place as long as anyone can remember and the "current" date is equivalent to ~8,000,000,000 Earth years.

 

[Noisy Rhysling]

Further thoughts on #12:

A culture could have sprung up selling "special" coordinates based on that Old Timer GPS system. Most of them would be fake, of course, but enough have been the key to amazing discoveries to make the purchase of "pig in the poke" coordinates a risk worth taking for some people.

And, of course, there's one set that legend says makes investigators go away, forever.

Sounds like a job for Flinx to me.

 

[newjerseyrunner]

If you don't have FTL, how could a galactic civilization even form? What use would a galactic date serve?

This would be a concern, civilizations can really only grow to the point where their influence can remain cohesive. Rome, Egypt, Persia... they all extended themselves so far that they fractured. At the speed of light, we have a nice little global civilization now, and that can probably extend to the Moon and probably Mars and stations deeper in the solar system, but no further. Colonies would likely be completely autonomous with only the most important information communicated between them.

 

[tobyr65]

As a reader of Sci-Fi, I'll accept whatever you tell me works in your faux reality. BUT I should be comfortable in your faux reality. Every time your star cruiser leaves the time saving worm hole that takes you from Planet A to Planet B or Galaxy C to Galaxy D, I don't want to have to have it explained to me. KISS. If there are 24 hours on one planet and 39 at the next, I should only know that as it is important for your plot, not as a gimmick to show me how much thought you have put into it. It is like learning to lie. The best lie is the truth with juuuuust enough tweaking to save your ass. Good luck and if you're ever published I want to know so I can read it.