Learned Vol. 5, Issue 8
This week: Muons are allowing us to see inside previously hidden areas of the world. Which is not surprising given that they are the very model of a modern cosmic particle. Let’s talk about it.
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In 1895 Wilhelm Conrad Roentgen made a discovery that would change the course of science in general and medicine in specific for the better. He had found a new type of ray that would pass through soft tissue but not dense bone, allowing scientists to look into people’s bodies without having to cut them open. Within a year, the new rays were being used to locate bullets and broken bones on wounded soldiers. Over a century later x-rays have become a common part of everyday medical practices.
And now, it seems history has repeated itself, only on a grander scale. Scientists have been able to use a tiny, cosmic particle to look inside the Great Pyramid at Giza and the volcano at the heart of Mt. Vesuvius. Emily Conover, writing at Science News (dot org) states it beautifully:
Inside Egypt’s Great Pyramid of Giza lies a mysterious cavity, its void unseen by any living human, its surface untouched by modern hands. But luckily, scientists are no longer limited by human senses. To feel out the contours of the pyramid’s unexplored interior, scientists followed the paths of tiny subatomic particles called muons.
The entire story is well worth a read and details what secrets scientists have been uncovering deep inside both these man-made and natural structures. But, for us, word nerds that we are, let’s take an etymological look at the little particle making all this possible, the muon1.
Let’s start with the definition from Merriam-Webster:
an unstable lepton that is common in the cosmic radiation near the earth's surface, has a mass about 207 times the mass of the electron, and exists in negative and positive forms
And, because I suspect that I’m not the only one who needs it, here’s the definition of lepton:
any of a family of particles (such as electrons, muons, and neutrinos) that have spin quantum number ¹/₂ and that experience no strong forces
I’m not sure that helped. Let’s see if the Encyclopedia Brittanica can help us out:
that a muon is correctly assigned as a member of the lepton group of subatomic particles—i.e., it never reacts with nuclei or other particles through the strong interaction. A muon is relatively unstable, with a lifetime of only 2.2 microseconds before it decays by the weak force into an electron and two kinds of neutrinos.
Hmm2. Well, what’s important is that muons are everywhere. They cascade down and through every part of the Earth (including me and you) all the time. Because scientists have all the information listed in the definitions, they are able to both measure the rate of and area in which muons are passing, thereby giving them the x-ray like look into the pyramids and volcanoes. They’re incredibly cool and I’ve been kind of obsessed with them since reading the Science News article last month.
One of the fun things about science words is that because we often have a specific date and coinage, we can accurately track how it spreads into the culture. Think about x-ray. As I mentioned above, it was originally coined in 1895 but referred only to the actual beam itself. It wasn’t until 1899 that x-ray made the shift to its verb form; it took even longer to become a noun, not making the leap until 1934, and not becoming an everyday bit of vocabulary for another couple of decades after that.
The question then, is whether muon will do the same? In another decade or two, will we refer to a graphic representation of a space mapped with muon particles as a muon? Will I be able to buy a muon of the interior cavity of the Great Pyramid in the gift shop3?
Physicist Carl David Anderson certainly did not seem to have anything like that in mind when he coined the term in 1936. Well, actually, Anderson called his discovery the Mu-Meson, thinking he had found a different particle entirely, one we now know as the pion. Over the next few years after winning the Nobel prize for his discovery, the somewhat awkward mu-meson become contracted into muon, with that abbreviation first being recorded in 1951.
From there, the word slumbered in relative obscurity, being used by the scientists researching it and almost no one else. Until about ten years ago when the type of experiments described in the article began to be theorized and then methodologized4. Since then, it has achieved a notable upswing in usage and recognition5 so I live in hope of one day being able to buy my souvenir muon.
Science-Fiction, Double Feature
But the other reason I have been obsessing over this little particle is because I love science-fiction and because I’ve been reading it most of my life. Within science-fiction, there’s a distinct subset you can call “big idea” books. While all science-fiction, by definition, takes ideas from the real world and extrapolates them into more-or-less realistic scenarios, big idea books take a single, extraordinary idea, and build it out until it permeates every aspect of the world within the book.
For me, one of my all-time favorites in this sub-genre is The Light of Other Days by Arthur C. Clarke and Stephen Baxter in which technology to use tiny wormholes is rapidly developed and deployed. At first it’s a cool technology for exploring far-distant places. But people soon realize that a wormhole can be used for looking backwards in time, too. Suddenly all of history is laid bare, including the history of just now. There is no more privacy. Everything you have ever done or said is now available for all to see. Think about that for a bit.
Muons will not allow us that level of detail, nor that of living history, if I understand the science correctly. But think of the other questions that this technology will begin to answer…only think also of the pyramid at the heart of the news story - how many more questions do we have now? That, to me, is the real promise of the muon: it will make us re-examine the world anew and with each new examining we will find something that makes re-think and re-evaluate our perceptions thus far. I can’t wait to see what muon comes up next.
Down the Rabbit Hole:
In my vast and mysterious collection of bookmarks, I keep a folder called “Thinking Better.” This is where I keep all the advice, tips, tricks, and gentle recriminations designed to help me maintain my creativity and curiosity. Here are four of the sites I’m currently browsing, in no particular order:
The No-Surf Activities List: Just what the title says, a list of things you could be doing instead of mindlessly surfing the internet or scrolling social media.
Tools for Better Thinking: Again, the title gives you the story. The site provides several cognitive models in easy-to-follow diagrams.
25 Ways to Be More Creative: Guess what this one’s about? In all seriousness, this is a site I keep on hand as a reminder for when I’m feeling too burnt-out to function.
Continuous Improvement: James Clear has an idea and he’s willing to teach it to you. I’m not sure how I feel about it yet; I’m still working through the first few articles.
From the Archives:
This week, I’m pulling up three issues that talked about books, science-fiction, or both. Here you go:
Learned Volume 4, Issue 19: Scientifiction - about the history of the genre science fiction
Learned Volume 3, Issue 22: Utopia Station - about the idea of Utopia and how the hang-out comedy has become our modern version of it
Learned Volume 1, Issue 7: First Star on the Left… - about space, mythology, and books
I feel like every typed instance of muon ought to have a mandatory exclamation point appended. It just feels wrong to see such a jauntily-pronounced word without one.
This is your fair warning that math and I do not get along and the science described in this essay and the linked article are way beyond my normal level of comprehension. I think I got everything right, but I wouldn’t quote me on any of it.
Is there a gift shop at the pyramids? There has to be a gift shop, right?
It’s a word.
I’m basing this off a cursory search of several of the corpora available at English-corpora.org. The jump in frequency from the COCA to the iWeb and other web-based corpora is huge.