In the movie Star Trek: First Contact the Enterprise enters the past through a temporal vortex created by the Borg. Upon arriving there is the following exchange:

PICARD: A missile complex? ...The date? Mister Data, I need to know the exact date.
DATA: April fourth, two thousand sixty-three.

Surely when the Earth converted to using stardates they converted all past dates into stardates as well. It isn't as if we refer to things in the Olympiad dating system.

  • 1
    Because April 4th, 2063 sounds better than IV.IV.MMLXIII B.S? – Major Stackings Jan 3 '13 at 5:07
  • 10
    Because the writer needed to inform the viewer of the current date, and not many viewers can convert stardates in their head ;) – Martin Jan 3 '13 at 11:53
  • 3
    @MajorStackings, A Roman would call our date of "4/4/2063" as "the day before the Nonis of April, 2817 AUC". This book goes into more details on calendars than you probably want to know: amazon.com/Standard-Date-Time-Library-Programming/dp/0879304960 – Tangurena Jan 3 '13 at 15:56
  • Jack B Nimble - Your question is flawed in assuming that a date of "April fourth, two thousand sixty-three" must be a date in the Gregorian calendar as we know it. It would be quite easy for a group - the United Earth government, or a national government, for example - to modify the Gregorian calendar by using a different starting year commemorating a different event years, decades, or centuries earlier or later than year 1 AD. And various episodes show the use of several different Earth calendars when giving the dates of Earth events. – M. A. Golding Dec 17 '17 at 19:47

This is perhaps circular, or at best, descriptive rather than explanatory, as it uses your very question as its reference point, but from Memory Alpha:

Stardates ... do not apply retroactively instead of Gregorian or Julian calendars either: for example, the first contact with Vulcans still took place on April 5, 2063, not on a stardate.

  • 3
    I wonder if they have a Y2K equivalent problem in StarFleet – Silver Fox Feb 18 '13 at 16:32
  • 1
    @SilverFox Boy I hope there will variable length numeric data types by the 24th century. – cmc Mar 12 '14 at 19:00
  • @cms: I'm pretty sure your comment is missing a word or two. I don't know what you mean. – Flimzy Mar 12 '14 at 19:02
  • Stardates are a mathematical formula which varies depending on location in the galaxy, velocity of travel, and other factors, can vary widely from episode to episode. – user16696 Dec 20 '14 at 21:52

Data, being a pedantic sort, as artificial lifeforms often are, has actually answered Picard's question literally.

PICARD: A missile complex? ...The date? Mister Data, I need to know the exact date.

Note that Picard asks for the date and not the stardate. Data is simply answering the question with the information that he thinks Picard wants according to his internal logic/programming.

In addition it has been mentioned before that Data thinks at a much faster rate so he has probably had time to come to the conclusion that they are in the past and therefore that it will be more useful for him to give an old style date.

Data could instead have explained, at length, that the date was before stardates began but probably thought that it was unnecessary.

Wether or not it's an in joke, deliberate plot point, or simply good/bad script writing is open for debate.

  • 1
    Agreed; I doubt Picard would know how to (well, ok, not want to bother to) back-calculate the stardate and work out how far in the past it is. I'm sure Picard would be well aware of the historic Gregorian dates. As to whether it's deliberate or not: I'd say it's just to appease the non-Trekkie film viewers. Don't want to confuse them with negative star dates! – Nick Shaw Jan 3 '13 at 11:53
  • 1
    Not a bad theory, but the other answers here give a more accurate and canonical explanation. – Iszi Jan 3 '13 at 22:21
  • 1
    I don't think Gregorian dates were so much historical, as they were for Earth. I'm sure Picard, and every human (and several non-humans) were just as familiar with Gregorian dates as we are now. Surely Picard knew his own birthday, July 13, 2305, by the Gregorian date (perhaps by stardate as well). – Flimzy Jan 5 '13 at 7:27
  • 1
    @Iszi: But this answer does address the question of "Why did Data answer the way he did?"--the other answers, mine included, are more about the usage of stardates, which is still related to the question, but a little less directly. – Flimzy Jan 5 '13 at 7:29

In-universe, TOS/TNG versions of Stardates can't be applied that far in the past, and they were the only two versions of Stardates that existed at the time that movie was created.

  • TNG/DS9/VOY-style Stardate 0 is the year 2323
  • TOS-style Stardates ran from 1312.4 through 4731.3, so Stardate 0 can be roughly estimated to be somewhere around 2263
  • There's an argument that the movie stardates are a whole new system, as they seem to start low again and end high. – trlkly Aug 14 '14 at 5:50

Four possibilities occur to me, which haven't been said yet...

Local context

I think the simplest answer is that when you're dealing with time travel and your Captain asks for the "exact date", you give it to him in the context in which it makes the most sense. In this case, the Earth date, since they've traveled to a pre-stardate period.

Just like if we'd traveled to ancient Rome and you asked me "when is this," I might say, "the reign of Augustus Caesar." I'd be using local context to describe the time period.

Stardates may be more useful for ships than planets

According to the Star Trek Guide...

We invented "Stardate" to avoid continually mentioning Star Trek's century (actually, about two hundred years from now), and getting into arguments about whether this or that would have developed by then. Pick any combination of four numbers plus a percentage point, use it as your story's stardate. For example, 1313.5 is twelve o'clock noon of one day and 1314.5 would be noon of the next day. Each percentage point is roughly equivalent to one-tenth of one day. The progression of stardates in your script should remain constant but don't worry about whether or not there is a progression from other scripts. Stardates are a mathematical formula which varies depending on location in the galaxy, velocity of travel, and other factors, can vary widely from episode to episode.

According to that description, stardates sound like a naval tradition, but not necessarily one that would be associated with planets. On Earth you have no "velocity of travel" aside from the planet's natural movement, and your location in the galaxy is a given. Combined with their presence in the 21st century before the "stardate era" began, it might render the formula irrelevant, or even incomputable.

At the very least it probably renders the idea of a stardate less useful and important, since those other variables aren't in play. For example, a NASA scientist might say something is going "483 meters per second," but a cop on the highway would just say, "he's doing 95." In the latter example, the unit of measurement isn't stated because it's understood in context. Stardates might similarly be more useful for ships in transit than on planets, or on Earth specifically.

Stardates require computation

Even if stardates are seen in the canon being used on Earth (and I'm sure they are), it might be more useful to give the Gregorian date in a pinch: as stated in the above quote, stardates are the result of a complex formula.

Even if Picard is capable of back-tracking a negative stardate into a Gregorian date equivalent to the era in which they've arrived, Data may just be saving time by doing the calculations for him.

The information source could be local

When first estimating their arrival date, Data mentions taking measurements of the atmosphere, etc. However, when Picard demands to know the exact date, Data doesn't elaborate on his methods for deducing it. Given that the previous "natural scans" were accurate but imprecise, he could have accessed a computer on Earth or on a satellite, and pinged it for the current timestamp.

If this was so, it would likely have returned either a Unix timestamp, or a date/time string. Either way, the most natural and efficient way to relay that information would be in the parlance of the time, which would be the Gregorian calendar.


There are multiple universes with Star Trek Journeys occurring simultaneously.

My theory is that the 'master' analog timeline is based on Earth dates.

And the other timelines are more holographic in nature, threads if you want to analogize it to computer process, where each reality occurs in a in 'Matrix' of sorts, and the Stardate is based on processing 'cycles', much like any processor has.

  • 1
    Welcome to scifi.se! Usually I'd ask you if you have any evidence to support you theory. But I know Star Trek quite a bit and after some pondering I found literally nothing to support your theory in canon: Matrix? Holographic timelines? Stardate based on computer-cycles? No-one mentions any of that! Ever! I'm just saying because this community is really more about verifiable answers - as far as the genre permits. – Einer Jan 13 '15 at 14:12
  • Greetings, Einer. I accepted the multiple universe theory as fact about 3 years ago, and it's been enlightening in reviewing science fiction not as science fiction but instead as science fact. Or as the aliens in Galaxy Quest said "In reviewing your historical records, Oh those poor people" (about Gilligan's Island) Now what's been most interesting is understanding time in a nonlinear fashion which is simple fact when you accept this theory as fact, and the truly interlinking nature of reference material I'd previously deemed fiction. Now to your question, if you isolate Star Trek (more) – Q The First Timelord Jan 14 '15 at 18:48
  • (ctd) in a box like the Borg would do, then within that universe you'd only find evidence which can be subject to interpretation. Take for instance, the holodeck. This provides proof of a holographic universe, despite it's lack of direct acknowledgement. In the episode Parallels, there's the introduction of potentially infinite quantum realities. Now these quantum realities demonstrate some hellish characteristics, which suggests WIDE variances not just in events, but if you dont let the imagination run free - even time interpretations themselves can vary in these alternate realities. more – Q The First Timelord Jan 14 '15 at 18:55
  • Again, interpretation without direct evidence. But personally I think you'd be tough pressed to consider alternate realities int he show without considering the potential that the Mayans conquered the world and did not permit the development of western based calendars. But back to your question: The episode Parallels provides DIRECT evidence of Quantum timelines and alternate realities. Now whether you want to refer to these as holographic or not is irrelevant, but the sheer computer calculated nature of BOTH the star trek universe AND our universe,ie: Golden Mean Ratio and 'constant' values' – Q The First Timelord Jan 14 '15 at 18:57
  • Suggests that Stardates, like an Earth Date, are calculated constructs - labeling mechanisms - which MAY actually be used in simulations to simulate the development of culture, perception, and the cyclic nature of a mathematically organized construct. Referring to our own past - Mayan Calendars, Julian calendars, and more - suggest the same cyclic, mathematical nature. Now here's the problem: To assume there's a one for one correlation between universes and unlike timelines is a logical flaw - you can thank Einstein and relativity for that. And since Star Trek depicted alternate realities – Q The First Timelord Jan 14 '15 at 19:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.