What time is it out in space?
Time is a funny thing, you know? Something we’re acutely aware of, something we pay attention to, something we lament, but something that’s entirely of our own creation. Not the passage of time, but the language of the passage of time.
Days are reckoned by how long it takes the Earth to complete a rotation, and years by how long it takes Earth to traverse a path around its sun. That works great for the planetbound, but what about starfaring civilizations? After we’ve left, should we still consider ourselves bound by the tyranny of our homeworld? And what about other species, why should they care about how long it takes one planet to complete a solar rotation?
When dealing with a multiworld or multispecies society we need something better. Something more consistent and less arbitrary. A standardized day, at the very least. One solution:
The base unit of metric time is the second. A second is a second. We’ve defined it internationally in terms of atomic decay, and that’s universal enough for me.
Minutes? Hours? Arbitrary base-60 systems, convenient within human mathematics but irrelevant to alien species. We’ll stick with the decimal.
10 seconds is a decasecond. Not terribly useful.
100 seconds is a hectosecond. Close enough, perhaps, as a replacement for the minute.
1000 seconds is a kilosecond. This is, perhaps, the first truly useful period, equivalent to about 16 minutes. A quarter hour to us ancient earthlings. We can think of things in terms of “kilos”, and plus, calling things “kilos” is fun.
10,000 seconds is a myriasecond and about two and a half hours, which isn’t tremendously useful, but 100,000 seconds is close enough to our own reckoning to call it a metric day. Maybe a bit longer, but in space, where there are no natural day-night cycles, it’s still close enough for the sake of human physiology.
On other worlds, where rotational periods might span hours or years? Well, there’s the local day describing natural processes, and the Metric (or Galactic or whatever) day, which gives us a consistency.
1 Metric Day is divided up into 100 kilos. By convention, asking someone to meet you at Kilo 30 refers to 30 kilos after the metric day begins. Or, if you convert back to ol’ Earth time, 500 earth minutes gives us 8:30 am.
Next we have the Megasecond, our week replacement. 10 metric days. About 11 Earth days. Close enough… the seven day week is arbitrary and tied to Earth history.
And here a snag. We’re caught between 10,000,000 seconds (110 earth days) as our Metric “Year” or 100,000,000 (1100 earth days.) We must choose between years that are 1/3rd as long, or days that are three times as long. On earth you’re 30. In space you’re 10 or you’re 90.
Let’s go big. The “Metric Year” is 3 earth years long. A spacefaring society is going to be dealing with longevity issues anyway, right? Maybe 90 IS the new 30.
And our final human-relevant time period, the Gigasecond. A billion seconds. Ten Metric years, or about 30 Earth years.
One final consideration is formatting. We use an “hours:minutes” format to make it easy to tell the time at a glance. In our hypothetical future, we’ll use timecodes in terms of the most relevant, perhaps color coded to some standard.
For daily use the Kilo gives us a standard. There are 100 kilos in the day. Our hecto “minutes might be useful, too, so for a timepiece useful on a daily scale we’d see something like 035:9 to tell us that it’s Kilo 35, Hecto 9. In one Hecto it’ll be 036:0.
Something more like a calendar would focus on the metric year. 1000 Metric Days in the year, so each year’s calendar has 1000 days, maybe divided into 10 Metric Months.