Imagine thinking that’ll be the biggest date-related computing problem for a galactic society.

If you really want to make programmers despair, point out:

• massive variations in day, month and year lengths on different worlds.
• some worlds may not have “months” (no moons, or many moons).
• ambiguous definition of “year” for multi-star systems.
• days may be longer than years (hello Venus).
• communication latency across interstellar distances.
• tine dilation.