|Posted: 07 May 2018 at 7:57pm | IP Logged | 2
The measure of time has been re-jiggered many times in this planet's history. Time hasn't changed, but our arbitrary measures of it have.
Who is to say that Starfleet didn't decide to use a single clock from Earth as a standard and base everything from there? Star ships would be sent a subspace feed from this master clock and be all synchronized.
What might be considered an hour or minute in Federation time could be very different from our hours and minutes. It's all arbitrary.
If you really want to get all nitty gritty about it you'd have two clocks... one master clock from earth and a secondary clock on the starship to measure time dilation effects. If the clocks are communicating via a subspace link then they will technically be in the same relative frame. The only time they would get out of sync is if the ship encountered something external that warped time.
Birthdays are also just as arbitrary as any standard definition of time. We don't actively count the extra days we arbitrarily add for leap years when we celebrate someone's birthday... we just round it to the nearest year and pick a day off the arbitrary lunar calendar.
Starfleet duty rosters probably keep a standard format for day/night so people's circadian rhythms don't go out of sync and impact their health. There have been many studies that show in the absence of light/dark cues that people will fall into their own patterns of night and day that are completely out of sync with everything else -- to the point where they either wildly over or under estimated the number of days that had actually passed. Most people without light cues sync to a 20 hour day, possibly because of the timing of some biological mechanisms in the absence of light. You'd probably want everyone to have a consistent day and night to keep a semblance of social cohesion on the ship.
My guess for aliens aboard Starfleet ships is they adjust the duty rosters to accommodate different lengths of day or they just learn to synchronize to human day/night cycles -- which probably makes for some interesting visits to their homeworld. Perhaps that's the future's version of jet lag?