If humans one day conquer all of our solar system we might have settlements not just on Mars and Earth, but also in orbit of Venus or Mercury, and on the moons of the gas planets, like Jupiter’s Europa. Each of those has a different length of day and year.
How would an interplanetary civilization find a common date and time system?
I assume each planet gets it’s own local time, but I think a common date-time system would be usefull.
Also I don’t like to just say, earth is human kinds origin, so it’s time is the standard. Feels lazy.
Common presentation of time doesn’t really help if the datum isn’t set in some way. I can present today as 1448/03/23 since today is 22 Rabi’ al-Awwal 1448 AH. The presentation of YYYY/MM/DD is kept standard, but it uses a different calendar with a different year zero and a different year length.
If two places can’t standardize time, why should they strive to present it uniformly? Also, it makes recording how time is kept important to the time’s recording as you’ve now brought in the wrinkle of how to handle relativistic time.