Star Trek: The Metric Voyage

By The Metric Maven

Bulldog Edition

It was when Star Trek The Original Series (TOS) was in reruns, that I first noticed its use of metric units. I was very pleased, and assumed they were used exclusively, but then completely disappointed when  one episode was metric and another used imperial and often they mixed both. The 22nd Century was not what I had hoped for, an all metric one. I can only hope the Erlenmeyer flask Spock is holding in this comic book cover is graduated in milliliters.

I began to wonder how much metric usage occurred in Star Trek. To find out, I decided to watch all 79 episodes and keep track of metric and imperial usage. This seemed like a simple task, just write down the units used and tally them up. What I realized, after a while, was that the undertaking  was more nuanced than it appeared on the surface. Sometimes measurement units were used as proverbial metaphors. For instance in Episode 77 – The Savage Curtain:

SCOTT: You’d never know anything had been out of order. I can’t fathom it.

I could not see claiming that Mr Scott had used an imperial measurement in this episode. Scotty was clearly using a metaphor, and fathom in this case is really a verb, and not a noun.

In the same episode, another exchange occurred that caused me interpretive difficulty:

The Savage Curtain Episode 77

KIRK: Yes, if I recall, your Union Army observation balloons were tendered six hundred or so feet high. We’re six hundred and forty three miles above the surface of this planet.

LINCOLN: You can measure great distances that closely?

SPOCK: We do, sir. Six hundred forty three miles, two thousand twenty one feet, two point zero four inches at this moment, using your old-style measurements.

LINCOLN: Bless me.

Did Captain Kirk convert metric units over to imperial for the benefit of President Lincoln? Spock indicated that the Units he used were “old-style,” and therefore implied they were not used in the 22nd Century. The usage of imperial units seemed to be employed only as a courtesy to the 19th century President. Miles, feet and inches with a decimal point?—oh my! One can only hope Spock was thinking to himself: “how utterly devoid of logic the old style system is.” We will also not explore how he could quote a distance to the planet with an accuracy of 1 mm (0.04″).

At the beginning of the episode Mr Spock relates:

SPOCK: An area of approximately one thousand square kilometers. It measures completely Earth-like.

Given the “weight” of the evidence, I judge The Savage Curtain to be an “all metric” episode, despite the appearance of imperial units. In one case as metaphor, and in the other, as a convenience to “President Lincoln.”

Another difficulty, was that in many episodes, temperature was quoted in degrees without specifying Fahrenheit or Celsius. Often the logical choice of unit could be inferred from context, but not always. In Episode 4 – The Naked Time one cannot be certain which are being used:

UHURA [OC]: Entering upper stratosphere, Captain. Skin temperature now twenty one hundred seventy degrees.

There are also units quoted in Star Trek episodes that are no longer in use. The Angstrom (100 picometers) is mentioned in Episode 16 – The Galileo Seven. In Episode 31 — Who Mourns for Adonais? we have:

SCOTT: External pressure building up, Captain. Eight hundred GSC and climbing.

GSC is grams-force/square centimeter, which was part of the old gram-centimeter-seconds system proposed by the British. It is no longer used. Grams-force is strictly forbidden in The International System of Units (SI).  Grams are mass. So does it count as a metric episode?—the units are metric even if the system isn’t SI.

The First Season had 29 episodes, here’s the measurement breakout:

Imperial Units 13
Imperial and Metric Units 5
Metric 0
No Measurement Units 7
Indeterminate 4

Imperial units completely dominated, there was not a single episode in Season One that had only metric units.

The Second Season had 26 episodes, here’s the measurement breakout:

Imperial Units 5
Imperial and Metric Units 8
Metric 8
No Measurement Units 5
Indeterminate 0

Metric usage finally increased, and eight all-metric episodes occurred. The number of “all imperial unit” episodes decreased, but the “imperial and metric” episodes unfortunately increased.  Still the Star Trek future was becoming more metric.

The Third Season had 24 Episodes, Here’s the measurement breakout:

Imperial Units 2
Imperial and Metric Units 3
Metric 8
No Measurement Units 11
Indeterminate 0

Metric has not increased, but the number of imperial episodes decreased. Unfortunately eleven episodes had no measurement units at all.

The Third season finally explicitly used metric temperature. In Episode 72 — That Which Survives we encounter this dialog:

KIRK: My phaser didn’t cut through it.
MCCOY: Whatever it is, it has a mighty high melting point.
KIRK: Eight thousand degrees centigrade. It looks like igneous rock, but infinitely denser.

Well, it’s centigrade instead of Celsius, but at least there was not a complete metric shut-out concerning temperature. Fortunately SI enforced Naughtin’s Fourth Law and eschewed a name with centi as a prefix, but there are still 100 graduations.. Perhaps SI should have created milligrade, but that’s another blog.

The First Star Trek Episode — The Man Trap was all imperial, but the last, Episode 79 — Turnabout Intruder was all metric, so there may be some hope for the future.

Dual Spocks and Dual Scales, both bad

I may be experiencing false hope however. I have concerns that even in the 22nd Century we might still have imperial units around. I think I know why it’s possible this could happen. It is because of Naughtin’s First Law which states that Dual-Scale Instruments are Evil. This law appears to be constantly violated in Star Trek. It’s clear from the program, that Spock can apparently set his sensor for miles and/or kilometers when measuring. He schizophrenically changes his mind from week to week. Not very Vulcan if you ask me. It was Pat Naughtin that noted, with surprise, that the use of dual unit measurement devices delays metric implementation by at least hundreds of years, and probably indefinitely.  The Star Trek world appears consistent with Pat Naughtin’s assertion. I can only hope it’s not a portent for us in the future.

Miranda in her metric sensor dress

In Episode 60 — Is There In Truth No Beauty?, we see an example of a violation of Naugtin’s 3rd Law, Don’t Change Units in Midstream and Naughtin’s 4th Law, No centimeters. Here’s the dialog after Kirk finds out Miranda is blind and uses a sensor net to observe the world:

MIRANDA: Pity, which I hate. Do you think you can gather more information with your eyes than I can with my sensors? I could play tennis with you, Captain Kirk. I might even beat you. I am standing exactly one meter, four centimeters from the door. Can you judge distance that accurately? I can even tell you how fast your heart is beating.

One should only use millimeters, meters, or kilometers with no mixing. What I mean is, don’t use metric like imperial, where a distance might be described with 5 meters, 35 centimeters and 2 millimeters. It just defeats the utility of metric adoption and complicates measurement for no reason.  It would be best if Miranda said she was 1040 millimeters from the door, or 1.04 meters.

Star Trek has predicted many technical innovations which have been realized since the 1960s. The communicator was the original flip phone. Electronic clipboards could be seen as early Ipads or Blackberrys. Flat screen monitors were everywhere. The wireless earpieces, Uhura, Spock, Chekhov, and others  used are so similar to modern Bluetooth type earpieces, that the first time I saw one in a coffee house, I was not sure if it was real or a “fashion statement” of some kind. Video conferences with Star Fleet command, Klingons, Romulans, and aliens were ubiquitous, and also are today for those who use Skype and other teleconferencing methods. Doors which sense your approach, and open automatically were novel in the 1960s, now they exist at the entrance of most grocery stores.

I deeply hope Star Trek is as wrong about future of the metric system in the 22nd Century, as they were at predicting we would still be using magnetic tape. The best way to intervene in the culture of the 22nd Century is to switch the US to metric in the 21st—with actual mandatory weights and measures legislation.


If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is not of direct importance to metric education. It is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

11 thoughts on “Star Trek: The Metric Voyage

  1. > What I mean is, don’t use metric like imperial, where a distance might be described with 5 meters, 35 centimeters and 2 millimeters. It just defeats the utility of metric adoption and complicates measurement for no reason.

    Brazil has been next to fully metric (save for some agricultural mass units that came in disuse post-1960s) since the get-go, but we speak of a person’s height in meters and centimeters. Either “1 meter and 70 centimeters”, abbreviated “1m70”, or just “1 and 70” (much like six-two tall is understood to be 6ft+2in)

  2. Damn it Maven!!!
    You didnt explain ‘warp speed’, no doubt it exceeds 186,000 mps…

    • It exceeds 300,000,000 meters per second. Actually, the true value is 299,792,458 m/s, now by definition. A really strange coincidence in the history of metric is that the chosen length for the meter would later be found to give a speed of light so close to three with eight zeros, that even today’s microwave engineers generally don’t bother to key in the exact value: 3 E 8, three keystrokes, is good enough, less than a tenth of a percent off.

  3. I know countries that are far more metric than US do the m, cm thing. I’ve seen it in Japan also. Although I agree, it should not be that way.
    Starwars trivia: The death star was 160 km in diameter, the exhaust vent that Luke killed the death star with was 2 meters. (Source: Wookieepedia)

    • star Wars, now we are talking!!!
      “The target area is only two meters wide. It’s a small thermal exhaust port, right below the main port…”

  4. Centimeters vs. millimeters can be over emphasized, it is important to note that we are talking about educating people who are not only unfamiliar with the metric system but may not understand imperial either. We need to emphasize that metric makes things simple.

    • You, me, and I’m sure the Maven, are in violent agreement. But if simple is good, why not simpler? Why not a measurement system with only one conversion factor: 1000? This is ultimately why centimeters are an issue around here: they complicate things — without need. If we could have a metric USA tomorrow, but with centimeters still sticking out of odd cracks and corners, I’d say let’s go for it. The problem is that metrication doesn’t seem to happen this way. The metrication consultant Pat Naughtin wrote a fifty page paper on the question (he could be a bit obsessive-compulsive at times, but it’s well worth skimming). His principal contention:

      If you choose millimetres as your small unit for a metrication upgrade then the metric transition is smooth, rapid, and so economical that the companies involved save so much money that their net profits increase dramatically…. On the other hand, if you choose centimetres as your small unit (as chosen by Australian textile industries), then you should expect your metric transition to be painfully slow, bitterly fought and enormously expensive, not only in financial terms but also in terms of ongoing human conflict. It’s hard to know how long a metric transition using centimetres will take as no one has completed one yet….

      The point is not that informal and innumerate uses of centimeters, and centimeters mixed with meters, (and if you’re French, meters, centimeters, and millimeters all glommed together), won’t persist — but this is no excuse for not trying to encourage better up front. Then, if a hundred years from now, a somewhat spooky diplomat in an electronic dress still uses the centimeter to describe doors that make a really cool pneumatic whoosh, I would be willing to be broadminded.

      • Would the American health care industry be considered a crack or a corner? Next time you go to the hospital or Doctor, take note of the sizing (usually in cm) on the cuff of the sphygmomanometer (blood pressure monitor.) At least the reading is in millimeters of mercury. Last time I went to the Doc, I noticed the height rod on the scale was in inches and cm. Don’t forget the measurement of the birth canal when a woman is giving birth is stated in cm. (last time I watched emergency anyway) Many other things in the health care industry are scaled in cm.
        I’m not a big proponent of the cm, especially if its use only slows down the metrication of this country. Personally, I accept the cm as part of the metric system and don’t fret over its use.

        • No idea how we got here, but I think the short answer is…no. I have a number of epithets for the US health care industry, and some even more colorful ones for the US health insurance industry, but cracks and corners aren’t among them. On the other hand, a blood pressure cuff might well qualify as a crack or corner in the Grand Scheme of Things.

          If you see centimeters on a doctor’s scale as evidence of their preferability for the purpose, then you are welcome, but it’s just as possible they are an artifact of disorganized thinking, or of no thinking at all: an opportunity for improvement rather than a mandate.

  5. >One should only use millimeters, meters, or kilometers with no mixing. What I mean is, don’t use metric like imperial, where a distance might be described with 5 meters, 35 centimeters and 2 millimeters. It just defeats the utility of metric adoption and complicates measurement for no reason. It would be best if Miranda said she was 1040 millimeters from the door, or 1.04 meters.

    I lived in Sweden my whole life and I would never give that distance in millimeters. The distance is just to far to feel natural to measure in millimeters (unless their is a clear reason for doing so. Kind of like saying 1,010,000 millimeters instead of 1.01 km. Now when I think about, I (and most likely all of my friends) would probably not say 1.04 meters either. Would actually say either “one meter and four centimeters” or “104 centimeters”. (Saying 1.04 meters would just feel unnatural. I would totally use it in written language, but it somehow feels strange in spoken language. Maybe it’s the “0”, because it wouldn’t feel unnatural to say 1.4 meters.)

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