[mkraft]

ISO 8601 was designed as a standard format for conveying date/times from the Gregorian calendar. The Gregorian calendar divides time into days, months, years which are units chosen based on Earth rotation around its axis and its orbit around the star Sol.

I don’t see why it would make sense to include points outside of Earth in that system, as I think you’re proposing.

Regarding the other part of your proposal to include locations: ISO 8601 purposely excludes those because converting a location to a UTC offset is a political process that requires lookups for historical changes to that conversion.

[samwillis]

OK, so my moon landing example what slightly wrong, the Astronauts were using ET not UTC, and so we can infer that prodominatly used "human time" at that location on the moon was actually ET (what the astonougts used). And so it should be:

   1969-07-20T16:17:00!Moon/0.67416/23.47314

The point is that at that location that is the time system they were using. It's mostly a contrived example trying to make a point.

For other planetary bodies, or other locations in the universe the first part of the time stamp could use any other format that could be in use at that location. It doesn't have to be tied to an Earth centric system.

> ISO 8601 purposely excludes those because converting a location to a UTC offset is a political process that requires lookups for historical changes to that conversion

My point is we need a standardised interchange format what actually takes that into account as that is how humans actually operate.

[pmontra]

It makes sense that moon dates are in sync with Earth, after all its motion is in sync with Earth too. Mars days are slightly longer than Earth's ones but there are more of them in a Martian year. You want months and years to be local if there are seasons that affect life on that planet. I expect that Mars will have its own months and years but they'll know Earth date for quite a long time, at least until they'll have to depend on Earth for survival.