I worked in aerospace for about 8 years, and in commercial engineering for about 15 years. The last company I worked for was packed-up and divided between China and India. I found myself accidentally becoming an engineering consultant. I expected to do this for perhaps 2 or 3 years at most, and then take a full-time position. It has been 14 years. When I found myself setting up my lab, it was a bit like how Thomas Paine described the potential of the young United States: “We have it in our power to begin the world over again.”
I decided there must be a person or persons somewhere that had studied and investigated the best way to use the metric system. The person I found by internet search was Pat Naughtin. He had wisdom and experience, but I had provincial American certainty in my unexamined views. Fortunately, I had Sven, and also the ability to change my view when the information I have changes. I very soon understood the utility of millimeters, and the Olde English distraction of centimeters. Cultural inertia in the US provides a ready barrier to adopting intellectual change—even when it is clearly superior after dispassionate examination.
It has been decades since I last worked in aerospace. I know a couple of engineers who worked in commercial, and moved to aerospace after our commercial company off-shored. I had lunch with them, and when I mentioned a dimension in millimeters, one of the pair jokingly said “what’s a millimeter?” Thirty years after I had worked in aerospace, and had metric drawings rejected, aerospace still uses inches, foot-pounds, and other non-SI measures, when the non-US world uses metric.
As I’ve pointed out in the past, the use of Ye Olde English (Imperial is New English) measures has colored our view of how to most efficiently implement a measurement system. The compulsion to translate the new system into the same familiar measures seems irresistible. Inches are a familiar size of pre-metric measure, so we’ll have a centimeter. This does two things psychologically, it first validates the current measurement prejudice, and second it diminishes the importance of adopting the metric system at all. A number of European countries adopted the metric system in the 19th century, and adopted an “Imperialized” view of metric usage, embracing the centimeter, deciliters, and such. When I question the use of centimeters there is often a visceral reaction: “lots of people use centimeters, they’re perfectly fine.” This is very strange, as it is the same non-argument Americans use about inches, feet, and so on. It was only the later adoption of metric in places like Australia, New Zealand, South Africa and others that allowed for more introspection, and a more rational adoption of efficient metric practices.
The instinctive reaction is to look for the commonality in measures, and equate the Anglo-Saxon compromise inch with centimeters. This was certainly the case in aerospace. It was seldom that metric was used in a discussion, but when it was you can be sure it was with Olde English interpretation in mind. Thirty years have passed, and for the last 14 I’ve tried to implement as much simplified metric as possible. Has any measurement change occurred in aerospace since my absence?
This year, 2021, Andy Weir published his new novel Project Hail Mary. I almost never read fiction anymore, but the gushing over this novel caused me to purchase a copy. Before I say anymore, this novel is the best piece of science fiction I’ve seen in decades. This is hard science fiction. Science is constantly used to move the plot along. There are no large dog-fights between space ships. No buxom space women. If you like SCIENCE in your science fiction, this is the book for you. I highly recommend it. It is like a combination of Isaac Asimov’s The Gods Themselves, The Currents of Space, Micheal Creighton’s The Andromeda Strain, and well, many other classic works of science fiction. This book is truly unique in today’s science fiction zeitgeist. I’m going to do my best not to introduce any spoilers, so forgive some of the vague discussion that follows.
It appears Andy Weir worked in government labs, and commercial companies for much of his career as a computer programmer. The use of metric throughout Project Hail Mary is consistent with the same pidgin metric I recall from my days in aerospace, and much of my commercial experience. Amazingly, early in the novel, metric usage is important to the plot, which is refreshing, but it also would could have been more nuanced if the author had a more expanded view of metric usage. His usage is consistent with the same metric usage I experienced in aerospace 30 years ago—nothing appears to have changed. I find no fault with Andy Weir, he is offering me a touchstone of the metric ossification that exists in 2021.
Most readers will never notice.
Andy Weir uses the term imperial for pre-metric measures and does not make distinction between Ye Olde English, and New English measures. I don’t fault him for this, as it is part of the word-of-mouth tradition in the US, rather than education based on investigatory work. I suffered from it myself. Microns are constantly in use, but I don’t recall a single micrometer within the text. There is a constant back-and-forth of pre-metric and metric units. The book is a centimeter smorgasbord with millimeters seldom encountered. The irresistible cultural force to phase-lock onto a unit that preserves pre-metric usages is a powerful one. The separation of what could be all millimeters into centimeters and millimeters is seen as normal:
“The solar disc is 27 centimeters on-screen and the sunspots are 3 millimeters. And they moved half their width (1.5 millimeters) in ten minutes…..”
Andy Weir has an understanding of how non-metric use is detrimental for American engineers and scientists:
“The tunnel is about 20 feet long. Or 7 meters. Man, being an American scientist sucks sometimes. You think in random, unpredictable units based on what situation you’re in.”
There is a point in Project Hail Mary where the definition of units becomes of importance, and centimeters are chosen. There is a place where a measurement error is of great importance to the plot, but as I said—no spoilers. Finally there is this:
“Yes, inches. When I’m stressed out, I revert to imperial units. It’s hard to be an American, okay?”
It is a sort of echo of Naughtin’s 1st Law: Dual-Scale Instruments are Evil. One reverts back to what one has used since grade-school. The educational system decides what “comfortable” measurement units are when you are young, and it makes it more difficult to “get a feel” for new units in an ocean of “imperial.”
Project Hail Mary gave me a touchstone into how metric is used in industry. Andy Weir has a very, very, promising future as a science fiction writer. I’m very hopeful that with all the use of measurement found in his novel, that he takes some time to look into modern metric usage, and perhaps integrate it into future work.
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 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.
