Who standardized Stardate throughout the galaxy?

Question

In Delphic Expanse, Degra sent a coded message to Enterprise NX-01 containing a stardate for when Enterprise should rendezvous with Degra's ship. T'Pol was able to calculate that the given stardate was three days away. It means that Vulcans did know about stardate.

Vulcans didn't have any contact with any race of Delphic Expanse, which includes Xindi too. Who did set the standards of stardate among two fully disconnected races? Is this something to do with trans-dimensional beings? Or, the race which seeded the life throughout the galaxy (its unlikely, however)? Or, someone else?

AFAIK, this has never been mentioned in TV series, comics & movies. So, answer from novels is welcome.

Answer 1

When Gene Roddenberry came up with Stardates, he had this to say (bolding mine):

In answering these questions, I came up with the statement that "this time system adjusts for shifts in relative time which occur due to the vessel's speed and space warp capability. It has little relationship to Earth's time as we know it. One hour aboard the U.S.S. Enterprise at different times may equal as little as three Earth hours. The star dates specified in the log entry must be computed against the speed of the vessel, the space warp, and its position within our galaxy, in order to give a meaningful reading." Therefore star date would be one thing at one point in the galaxy and something else again at another point in the galaxy.

This is actually sort of similar to how we track time here on Earth. If I go across the time zones quickly enough, I can end up in the "past" or the "future" according to the date/time. The part I bolded implies that there's some sort of similar natural breakdown you can make on the galaxy itself (which, presumably, is only known to spacefaring cultures within Star Trek).

Now, if instead of a 24-hour day, think about if we used percentages: Midnight is 0.0, noon is 0.5, 6pm is 0.75, etc. The concept of percentages is easily translatable across cultures, but whether 0.0 occurs at sunrise, sunset, or (in our case) sometime else entirely is culture-dependent.

Likewise, we can't really know when Stardate 12345.44 is, unless there are other things we know. If one culture says "now" is that Stardate, and we're currently on Stardate 23456.67, then it's just like someone from the US talking to someone in France. The difference between ".44" and ".67" would be equivalent to the difference between times in different time zones. The difference between the "12345" and "23456" parts is just the difference between calendars that started at different points.

Now, there's another reallife factor we can add in: Email, which automatically includes a "Sent at" date. If Degra's message had both an automatic "sent at" date and the rendezvous date in the message, then it would be possible (but not simple) to use those galactic conditions to calculate the time from "now" to "then", and then convert to human time spans.

Note that I'm not really saying they were ever synchronized across cultures, but that it's possible for T'Pol to convert between them despite the Vulcans not having had prior contact with the Xindi.

Answer 2

There isn't really a standard for stardates as it varied across the various tv series and episodes. In TOS it wasn't even consistent from episode to episode with numerous episodes having a stardate that was actually smaller than a previous episode. Usually the only consistency was across the days of a single episode.

The Next Gen updated that to make it somewhat more consistant as the dates all started with 41 for the first season, 42 for the second and the last three numbers progressed so that dates of one episode would actually occur after the dates of the previous episodes. In the original Star Trek writer's guidelines for TNG the 4 designated 24th century and the 1 designated 1st season, 2 for 2nd season, etc. This scheme was followed somewhat consistently across DS9, VOY and the TNG movies with dates progressing by year from the 41 that TNG first season started with.

However, stardate in general is a Starfleet measurement of time. It is not the standard of time for other races across the galaxy and alien measurements of time are assumed to be translated by the universal translator into Starfleet units of measurement when receiving communications, though that has often been somewhat nebulous in practice across episodes.