How Do Stardates Work?

Gene Roddenberry created stardates to show that Star Trek took place in the future. He never intended it to stand up to close scrutiny, and as such there are many discrepancies. During the Original Series, a four-digit stardate was used, followed by one decimal place. Each episode was approximately 57 units apart, and one unit corresponded to 24 hours. A tenth of a unit was therefore a tenth of a 24-hour period.

Because the network didn't air the episodes in the order they were written, from the viewer's perspective, the stardate didn't continually increase as intended. Gene attempted to explain this as a side effect of relativistic time dilation. Though admittedly had no idea what he was talking about, what he said made a lot of sense.

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 USS Enterprise at different times may equal as little as three Earth hours. The stardates 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.

When the first six feature films were being made, the amount by which the stardate increased varied from film to film. Thus the viewer perceives that the stardate does not always increase at the same rate. By the time the sixth feature film was being made, the four-digit stardate would have rolled over to five digits, but it was deemed that viewers would perceive this as being too close to the Next Generation so the stardate was arbitrarily set at 9523.

For the Next Generation, Gene decided to distance it from the Original Series and the feature films by adding a fifth digit to the stardate. He chose 4 as the first digit to represent the 24th century, and designated the second digit as the current season. The last three digits increased sporadically from 000 to 999. As with the Original Series, the stardate was followed by one decimal place to indicate one tenth of a 24-hour period.

For years, fans have tried to devise a method of converting between stardates and Gregorian dates. A few ambitious people have even attempted to reconcile the two different systems. The end result is countless methods, none of which produce the same results. Is their logic flawed? Before we can examine closely how stardates work in the fictional Star Trek universe, we must first examine how they work (or not) in the real universe, after which we will shift our perspective to consider the purpose and mechanics of stardates if the Star Trek universe were real.

Doing the Math

Returning to the Original Series stardates, if one unit is equal to 24 hours, 365 units should be equal to one year. Following this logic, three years should be equal to 1095 units since that is the number of days in three years (assuming there is no leap year). Looking at the progression of stardates during the Original Series, three years actually works out to around 4416 units. This gives 1472 units per year, and just over four units per day. Instead of increasing one unit per day, the increase is now one unit every six hours. Instead of indicating a tenth of a 24-hour period, the number after the decimal now indicates a tenth of a 6-hour period, which is 36 minutes. A little more math shows that 9999 units would elapse in 6 years, 9 months, 15 days, 9 hours, 47 minutes, after which the stardate must either roll over to five digits or reset back to 0000. The resetting theory is a popular way of explaining the strange stardate interval between the feature films.

Another interesting Original Series stardate theory postulates that a stardate is a combination of the number of months and days since the ship left spacedock. For example, stardate 1312 in "Where No Man Has Gone Before" would take place 13 months and 12 days after the Enterprise left spacedock. Coincidentally, the last episode of the Original Series takes place on stardate 5928, which would be exactly 4 years, 11 months, and 12 days after leaving spacedock. This is one month and 18 days before the supposed end of the Enterprise's five-year mission. To accept this theory as true, we would also have to accept that five years has elapsed in the Star Trek universe while less than three have elapsed in our own universe. Unfortunately, stardates where the last two digits are larger than 31 defeat this theory.

Not to be outdone, stardates during the Next Generation and subsequent series have plenty of their own flaws as well. For the first digit to represent the 24th century, 10000 units would have to elapse in 100 years, a rate of 100 units per year. Unfortunately with the second digit representing the season, 1000 units are elapsing per year, causing the first digit to increment after only 10 years. Perceptively, the first digit no longer indicates the 24th century.

For 0.1 units to equal a tenth of a 24-hour period, one unit must equal one day. Doing similar math as before, 99999 units will elapse in 273 years, 11 months, 19 days, 3 hours, 37 minutes. For humans, more reasonable than a four-digit stardate since there will be no overlap in a person's lifetime, but remember that humans aren't the only ones using this system. Vulcans have a much greater lifespan.

Redux

The reason we are having so much difficulty is because we are using the same logic and principles as those who have attempted to produce a method of converting between stardates and Gregorian dates. First, the Gregorian calendar is based on the Earth's orbit of the sun. The amount of time it takes for a planet to orbit its star is dependant on the distance between the planet and the star, as well as the shape of the planet's orbit. As such, the length of a year on one planet is different than the length of a year on another planet. Second, the length of a day is dependant on a planet's rotational speed. Some planets rotate at different speeds, resulting in days of unequal lengths.

The first rule was that the first digit must represent the century. We'll keep that rule, but the second rule has to go which is the second digit representing the season of TNG. To prevent the first rule from breaking, every 10000 units must equal 100 years. With a bit of simple division, 1000 units equals 10 years, and 100 units equals one year. The next step is to divide the year into 100 units, which is messy business. One year contains 365.242199 days; therefore 100 units equals 365.242199 days and 10 units equals 36.5242199 days. Divide by ten again, and we have 1 unit equal to 3.65242199 days. That just leaves the decimal place to contend with. The original rule was that the decimal place represented one tenth of a 24-hour period, or 2.4 hours, but that isn't going to work. Divide by ten again, and the decimal place represents 0.365242199 days. One day contains 24 hours; therefore 0.1 units equals 8.765812776 hours. This works out to 8 hours and 45.94876656 minutes, or more precisely, 8 hours, 45 minutes, and 56.9259936 seconds. That's so close to 8 hours, 45 minutes, and 57 seconds that only Data would notice the difference.

Take a look at that 8 hours. What else is 8 hours? A normal working day. That leaves 45 minutes and 57 seconds for your lunch break. Extending this idea, every 0.1 stardate units could be a shift. One log entry per shift and you have a nice list of entries each with a unique stardate incrementing consecutively. Additional entries made during the same shift are called supplemental.

Before we pat ourselves on the back, there's still another problem with the TNG stardate system which deserves mentioning. The first episode of TNG aired on September 28, and took place in the year 2363. The stardate given in the pilot episode is 41153.7 which unfortunately doesn't match up to our improved system. The 24th century begins on January 1, 2301 (not 2300, which is the last year of the 23rd century); stardate 40000. Fast forward ten years to 41000 and it's now January 1, 2311. Fast forward one more year to 41100 and it's January 1, 2312. Stardate 41153.7 puts us 182.6210995 days into the year, which is July 1, 2312 at 2:54:23pm. September 28, 2363 would be stardate 46274.2 which under the TNG system is sometime during the 6th season (2368).

Conclusion

The revised system I just described is more practical for real-world use, but to keep track of time in the Star Trek universe we'll have to stick with the 1 unit equals 24 hours rule. In the Sandbox area on this web site you'll find a script that calculates the current Stardate in the Star Trek universe.