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Apr 26, 2023

How we measure the world with our bodies, and hunting critical minerals

First up this week, we hear about the advantages of using the body to measure

First up this week, we hear about the advantages of using the body to measure the world around you. Producer Meagan Cantwell talks with Roope Kaaronen, a postdoctoral researcher at the University of Helsinki, about how and why cultures use body-based measurements, such as arm lengths and hand spans. Read the related commentary.

Also on this week's show, the United States starts a big hunt for useful minerals. Staff Writer Paul Voosen joins me to discuss the country's Earth Mapping Resources Initiative, which seeks to locate rare earth elements and other minerals critical to sustainable energy and technology within its borders.

This week's episode was produced with help from Podigy.

About the Science Podcast

TRANSCRIPT

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0:00:05.7 Sarah Crespi: This is The Science Podcast for June 2nd, 2023. I'm Sarah Crespi. First up this week we hear about the advantages of using your body to measure the world around you. Producer Meagan Cantwell talks with researcher Roope Kaaronen about how and why different cultures use body-based measurements like arm lengths and hand spans. Also on this week's show, news writer Paul Voosen joins me to discuss the Earth MRI project. This large scale effort seeks to locate rare earth elements and other minerals critical to sustainable energy and technology within the United States.

0:00:45.6 Meagan Cantwell: When I was in the marching band in high school, we would use our stride as a form of measurement. We did have some standard lines that we could reference, which were on the football field, so that was a line every 10 yards. But besides that, we had to use our steps to figure out exactly where we would be placed. So if we had a paper telling us where to move, it would say you're two steps off of the yard line, and then we would march those two steps and stand there. So ideally, we were trying to aim to have the exact same stride length. I'm sure there were some variations, but this way of measuring things was definitely a lot faster than carrying around a meter stick and figuring out where we were supposed to stand. I'm here with Roope Kaaronen who published a paper this week that discusses how cultures around the world used their body to measure all sorts of things. Thank you so much for joining me.

0:01:40.1 Roope Kaaronen: Nice to be here. Thank you.

0:01:41.9 MC: Previous to your paper, there wasn't a lot of research specifically focused on body-based measurements. Why do you think this wasn't as delved into?

0:01:51.2 RK: It's possibly because I think especially the early anthropologists and historians of measurement wrote off the phenomenon of body-based measurement. If you look at the history of measurement, many of the early standards quite clearly evolved from body-based units. So for instance, in Ancient Egypt, you have the royal cubit, the cubit being the length of the forearm. And perhaps because of that, people had this idea, especially in the past, that you first had these simple body-based units and then standards emerge from blows and largely replaced standards. I think our paper shows that that isn't the right way to perceive this.

0:02:27.9 MC: In order to look at this evolution, you first needed, of course, to find a bunch of different forms of body-based measurements. What sort of data sets did you look into to figure out this out?

0:02:37.4 RK: First of all, we looked at the Human Relations Area Files, HRAF. It's a database commonly used by anthropologists. Basically, it's a dataset that's been gathered for, I don't know, at least 50 years, and it spans cultures across the world. It's always this goldmine to look at. So we started looking for evidence of body-based measurement over there and then later on we started filling the gaps of the less represented areas, and we ended up with this mixture of digital and physical manuscripts basically.

0:03:08.7 MC: After looking through all these data sets, how many instances of body-based measurements did you find?

0:03:14.4 RK: We looked at 186 cultures. So we found evidence from 186 cultures and about, I think, 300 plus references. I don't recall how many instances specifically, but that'll give you a general idea.

0:03:27.5 MC: So some cultures definitely had more than one form of body-based measurement?

0:03:32.1 RK: Right. So many cultures actually have a very elaborate system where they might have some conception that these body-based units might have a relation to each other as well. So there were several cultures that had a very complex, generalizable system of body-based measuring.

0:03:45.8 MC: What were the most common types of measurements that you found across all cultures?

0:03:50.5 RK: So by far, the most common ones were the fathom, which is the arm span. Imagine spreading your arms way out and measuring it from fingertip to fingertip. Then you have the cubit or L, which is the length of the forearm from elbow to fingertips, and then variations of the hand span, basically measuring your extended hand from thumb tip to each of the fingers.

0:04:12.8 MC: Were these measurements used in similar contexts across cultures or were they used for very different purposes?

0:04:19.1 RK: I would say they are used in similar context, but some of them definitely had more of a specialized feel to them. So for instance, the fathom seems to be related quite often to the measurement of slack items. So you might see the fathom being used to measure, for instance, fish lines or nets or rope or cloth perhaps. Which of course makes sense because if you consider the act of measuring these slack items, it makes motoric sense to extend your arms and then bit by bit measure this long item. You always carry your body with you, so it makes sense to use that when and nothing else is available. In that sense, it's very reliable even if it isn't the most precise measurement tool.

0:04:54.4 MC: These are specifically for measuring length, distance. Did you find other forms of measurements that weren't related to this?

0:05:02.0 RK: Sure. So there's also units of volume; handfuls, double handfuls, handfuls, and temperature as well. Too hot to touch or the warmth of the human body perhaps. And, well, of course, the linear units are also often used to measure area. So that's specific case.

0:05:18.6 MC: I think my favorites were definitely the activity-based ones since they're so specific to the context of the culture for how long a hike might be, how many times you have to rest, things like that. What other examples did you find in that domain?

0:05:29.8 RK: Yeah, so we also collected units of measure that are related to bodily activity. I think there you'll find maybe the most peculiar ones, at least to us as external observers, but quite often they make very good local sense. So for instance, the Nicobarese have used this unit of length called basically young coconuts drinks that are drunk, which is used in seafaring in the Indian Ocean. And it might sound strange if you're not accustomed to seafaring in the Indian Ocean, perhaps with a canoe or a small sailboat. But if you think of it, it actually makes a lot of sense. So if your typical frame of reference is something like miles or nautical miles, that doesn't really account for the important variable of hydration. So if you're traveling in salt waters and you need to drink, of course, you'll want to measure distance as hydration units required for traversing that distance. Your mileage may vary in the sense that if you're against strong headwinds perhaps or strong currents, miles make less sense.

0:06:28.3 MC: You mentioned that the activity-based ones are probably the most out there. Do you have a favorite one that you discovered out of all of the different domains of measurements?

0:06:37.2 RK: There's also a peculiar one in Northern Finland that we didn't record in the data set because I think it's a bit of a rural myth perhaps. It's called the distance of the reindeer's urination basically.

0:06:49.6 MC: Interesting.

0:06:51.1 RK: The jury's still out there, but we haven't found very old traditional use of this unit.

0:06:55.9 MC: After you gathered all of these different forms of measurement, you then looked at the evolution of things. What did you find about the timeline of how these body-based measurements related to standardized measures, and how they either persisted or stopped at similar or different times?

0:07:12.7 RK: We're looking at the evolution of measurement on a regional scale. So on the level of cultural regions, you'd find quite often body-based units appearing maybe a couple of thousand years ago, maybe 500 years ago in the earliest cases, or something like 4500 years ago. But still, even in some of those regions, for instance in Northern Africa or the Middle East where some of the first standards emerged close to 5000 years ago basically, you would still find people using body-based units as recently as 20th century. It's hard to say when they emerged specifically 'cause we don't have the kind of evidence. At least we have evidence of the use of body-based units centuries or even millennia after the first emergence of standards.

0:07:52.1 MC: What did you find was maybe the advantage of these body-based units since they did coexist at the same time in many places?

0:08:00.7 RK: Quite often, I think, when people think of measurement, they think of something like abstraction or abstract representation of length. Whereas if you really look at these ethnographies, you'll find that body-based units are used basically to solve everyday problems. And if you think of the everyday problems of the past, perhaps it was to design a kayak for yourself, a paddle for that kayak, or a bow, or a spear, or a fishing line, or clothes, or any of these everyday items. Typically, they were made, if not by you, then by someone close to you, and then they could actually take your body-based units of measure and design these things. So perhaps the surprising thing there for the uninitiated is that quite often body-based units were used to design these ergonomic everyday technologies. So if you design a bow using your own body-based units, for instance, the fathom to design your kayak pedal, you'll end up with a pedal that's perfectly fit for your own personal use.

0:08:56.9 MC: Some of these ways of measuring still persist today, right? There are still some people who create kayaks specifically form fitted to their body as well?

0:09:04.8 RK: Yeah, yeah. I am one of those people. I suppose I'm a kayaker. I make my own kayak pedals and I use my own body-based units for that. So that's actually one of the roots that I gained interest in this topic.

0:09:15.9 MC: How are you building them?

0:09:17.0 RK: Basically, there's a couple kinds of kayak pedals around. There's the European paddle that you'll commonly see, which has these wider cup blades, and that's the one you'll probably encounter in your local kayak rental. And then you have a traditional kayaking pedal, which often goes by the name of the Greenland pedal. It has a much thinner profile, so the blades aren't as wide and they're much longer. So I designed my own kayaking pedals with my own fathom and cubit. And of course, the loom or the center part of the kayak you're actually gripping, has to be the girth of your fingers pinched. So basically if you think of the okay gesture, that's the girth of the pedal at that part. So you have this complex system of the kayak and the paddle and the user are all having interrelated measures.

0:10:02.4 MC: Have you done any time tests to see how much more efficient you are at traveling with this paddle versus the standard paddle that you would just buy from a store?

0:10:11.1 RK: No, I haven't. At first, it took me a while to get used to these traditional pedals, but I'm faster now than before, so it's definitely not slower. I've also done very long distances with these, so we did this cross Baltic Sea expedition with one of my own pedals.

0:10:26.6 MC: Oh wow!

0:10:27.2 RK: They work really, really well. I took much inspiration from ethnographies in designing these pedals myself.

0:10:32.6 MC: I really like the example of different ways that cultures use the measurements to create skis too. I feel like there were some very specific small measurements that they would take into account in order to create the most form-fitting efficient ones.

0:10:45.6 RK: Yeah, and it all depends on context as well. So we have evidence of the Khanty designing skis basically using their own height as a unit of reference, which is also something that's been used by other Finno-Ugric peoples. But there's also these ecological variables that you have to design skis that don't carry too much snow perhaps, so in more snow heavy regions, you'll have to account for that as well. So it's really, it gets quite complex when you look at the details.

0:11:13.1 MC: Besides using it to build tools or specific custom built for people items, were there other uses that you found where they used it all for building larger things?

0:11:24.3 RK: Yeah, definitely. It's not rare to find these body-based units used in even large scale construction projects. Large scale in the context of small scale societies. You'd have maybe the construction leader defining their body-based units first and then everyone else would use those. This way you revert this problem of having several different units floating around with one construction project. But also, you'd find body-based units used surprisingly often in trade. You can imagine how this might lead to some issues with some people being taller than others, for instance. But still, surprisingly, often, body-based units were still used in trade not so long ago.

0:12:00.8 MC: You found a lot of advantages to using these, and that's part of the reason that they even still persist today. Based off everything that you found, what kind of avenues are you hoping to further pursue, with better understanding, the evolution or persistence of these measurements?

0:12:15.7 RK: Well, maybe the lingering question that we touch upon in the discussion section of our paper is whether or not this replacement of body-based units by standard units was really a practical reason or does the transition to standardization have more to do perhaps with needs of governance? So we have this idiom by James C. Scott, "seeing like a state." So the idea being there that to control people, to tax them, to measure land that's taxed and so on, you'll actually need standards more than in these very practical tasks of, for instance, designing skis.

0:12:52.0 MC: That's really interesting. Well, I look forward to seeing that. Thank you so much for taking the time to speak with me.

0:12:56.7 RK: Thank you.

0:12:57.4 MC: Roope Kaaronen is a post-doctoral researcher at the University of Helsinki as part of the Past Present Sustainability research unit. You can find a link to his paper at science.org/podcasts. Also, keep an eye out on the Science Magazine YouTube channel in the coming weeks for a video about the paper.

0:13:16.2 SC: Stay with us for a look at the geologic history of the United States and how it can be linked with vital minerals important for sustainability and the latest technology.

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0:13:35.1 SC: Now we have Paul Voosen. He's a staff writer for Science, and this week he wrote about a large project that's basically gonna survey most of the United States for minerals critical to the economy and technology. Hi Paul.

0:13:49.1 Paul Voosen: Hello.

0:13:49.8 SC: So the big surprise for me here was that, this is an unknown thing. In the US, we really don't know what we have and where, whether we have a lot of lithium, a lot of other rare earth elements. Why don't we know this?

0:14:04.8 PV: We kind of know in broad strokes what rocks make up the country, but the last time there's been intense surveying of the country for mineral wealth, it's really the '70s and '80s, and that was searching for uranium especially. So there hasn't been a really comprehensive campaign to figure it out since then, until the past few years.

0:14:26.9 SC: So '70s and '80s, you're looking for uranium, I'm guessing, for something nuclear, either fuel or missiles or whatever. But what about the rest of mining? I know we do oil drilling and we do, there's some fracking going on, but what happened to the rest of mining? Why haven't we been digging up lithium or other minerals that are important for technologies that we use all the time?

0:14:48.6 PV: Yeah, well, mining is not a pretty thing. It is horrible for the environment and landscape.

0:14:57.0 SC: Yeah, we should mention coal mining also happens or has happened for extensive periods of our history.

0:15:01.8 PV: Yes, there's still a lot of that.

0:15:03.6 SC: Yeah.

0:15:04.1 PV: There is a lot of mining. I think there's still thousands of mines in the country. A lot of it is like getting stone, gravel or sand or whatever. There are less mines for things like precious metals or practical metals.

0:15:16.8 SC: We did have this little phase there was a lot of gold mining in the US.

0:15:21.5 PV: We did.

0:15:22.0 SC: We can't forget that, yeah.

0:15:23.4 PV: And traditionally, we've mined a lot. Lots of mining, industrial powerhouse. The fast few decades, as a country, we've decided to produce things not in the country and to mine things not in the country, and so moving things offshore. So that's prompted less interest in, if you're never gonna mine something here, why would you be exploring so much? So that has started to change with national security type concerns and the awareness that a lot of these minerals that weren't really valued back in the day are important for the move to renewable energy.

0:15:57.8 SC: Yeah. The survey project you talk about is called Earth MRI, and it's being run by USGS?

0:16:04.1 PV: So it's run by the US Geological Survey, which is one of the oldest scientific institutions in the US government, and it stands for the Earth Mapping Resources Initiative. And this started in the late last decade, building out this bipartisan agreement that we need more of these minerals. We shouldn't be relying on China, especially for these, and let's look for them in the US as well. You have lawmakers asking the USGS, "Where are these?" And they're like, "We don't know."

0:16:34.0 SC: And they call them the critical minerals. What falls in that category? I think you said it was about 50 different things?

0:16:39.8 PV: Yes. This is a list also assembled by USGS. So it's very country-dependent where if we have lots of supplies of copper, it's not on the list. There is a vibrant copper mining in the US. So you have, it's a wide range of things. It's things like lithium, things like the rare earth elements, which are 17 of the critical minerals. There are things like graphite, and it just goes on and on.

0:17:06.5 SC: But the idea is that they're key to technology, they're key to sustainable energy. There are things that are future-looking, the materials that we need for our society?

0:17:15.8 PV: Yeah, they're often things that can alloy well with the different, more common metals and make improvements in magnetic performance, and just all these type of things you need for semiconductors.

0:17:27.5 SC: Okay. Well, let's look at this mapping effort. We're basically looking at ourselves with all these different techniques. There's basic stuff like collecting what's already been mapped, maps and records. But there's also a lot of survey flights planned. Can you talk about how those work and what they're looking for from the air?

0:17:46.8 PV: With airborne flights, essentially you have contractors who fly small airplanes carrying two primary instruments, a magnetometer and a essentially a Geiger counter. Very low-flying, just 100 meters up, mowing the lawn across our region and getting this high resolution data. We have this data in very kind of poor serves, '70s era data for the whole country. But we don't have this in the resolution you actually need to really better understand the histories of these systems that could have minerals in them. The magnetics let you, there's sensitive iron, magnetite and iron, and they can let you see underground really. And rock formations have different amount of these magnetic materials, so you can map out where one formation stops, another one comes up. And then the Geiger counter, essentially, certain of these critical minerals are known to form alongside Thorium, Uranium radioactive elements. And so, when those spike, you have a good chance something important down there.

0:18:46.8 SC: Right. So in the past, when we were mining for gold or some of these other minerals, it was like we went after the low-hanging fruit, as one of your sources says. This is much more technical. We're looking for these hints in magnetics and radiation. The other half of that is, well, you have to know what those mean. So you talk a little bit about looking into the history of the continent and how these minerals might be formed.

0:19:17.8 PV: There's been this move in economic geology to mineral systems approach. This has really been pioneered in places like Australia and Canada where these are kind of mining superpowers. But it really involves tracing the lifetime of this mineral from the volcanic eruption that might have taken it out of the mantle through the little interactions that might go through, precipitating out of water or getting bed on sea floor, or...

0:19:46.3 SC: It's so complicated, Paul. [laughter]

0:19:48.3 PV: Interacting with limestone or... Yeah, just endless possibilities of the Earth's crust.

0:19:53.9 SC: So, do we know what to look for because we know how these minerals form when we're looking deep in the earth and seeing different shapes of levels of magnetism bumping up against each other?

0:20:04.2 PV: The magnetism, it's really about taking these geologic maps and putting them down in three dimensions. But you can see structures in the middle of the continent, there's these failed rifts where the continent started to be torn apart 750 million years ago for one of them called the Reelfoot Rift. And this provided a route for then magma to go up through and create these later formations of a couple hundred million years later that end up being sources for these different minerals.

0:20:34.3 SC: One other thing we should mention is that when there was all this mining in the US in the past, they maybe just threw out some of this stuff or left it in big piles near the mine 'cause they didn't need it back then. So that's another effort that's part of this survey?

0:20:48.7 PV: Yeah. So there's this Bipartisan Infrastructure Law, threw a ton of money at this, which is why it's become such a big program. And part of that law specified also understanding our above ground reserves, and that's all these slag piles and things that are dumped out. And a lot of these minerals were not appreciated as anything. They were just waste. In places like Manville, New York, go to an old iron mine and you have rare earth popping out of the these slag piles. The question is, are they concentrated enough to be worth getting at? And also where are they?

0:21:23.3 SC: Yeah. So there are a number of bycatch benefits here. So maybe we can catalog the slag piles in the US, find old pipelines and that kind of thing. What other interesting phenomena are popping out as they do this?

0:21:38.6 PV: These are really gonna be a huge resource for scientists in the future, far beyond, looking for valuable minerals. A lot of this is just basic understanding of how the United States came together and stuff. Traditional science might not fund as much if it's not answering a big hypothesis. This is how the shorelines of the Carolinas assembled during the ice ages, or how this rifting worked, or in the West, you have interaction of the deep continent with the volcanic arcs that piled into it and created some of these reserves. But also people have been doing this work and they're they have better understanding how that happened. Also, using this magnetic data can show you the faults in the earth that are invisible. They don't manifest above ground at all you see in the west a lot, and they're too shallow to be seen with seismic. There aren't earthquakes to show that these exist. So they have done work showing these hidden faults beneath Charleston, which had a massive, maybe magnitude 7 earthquake 100 years ago, and no one really knows when that should happen again. There's a similar place in Southeastern Missouri. There are lots of other uses too.

0:22:46.7 SC: Also hidden volcanoes?

0:22:48.0 PV: Yes, in the Salton Sea in California, there's very new data I can point out there. There might be a couple varied volcanoes in there.

0:22:57.4 SC: Very cool. And last side effect, if you will, of the survey is finding other sources of energy.

0:23:04.0 PV: There's this very nascent push. My editor Eric Hand wrote a story a couple months ago about geologic hydrogen.

0:23:10.4 SC: We had that on the podcast.

0:23:11.8 PV: Yes. We know there's produced hydrogen. Can it actually be captured and stored and drilled into? If that is the case, these places like this rift in the mid continent has these volcanic rocks, that would be perfect for producing that. So using this data, you can better understand these potential source rocks.

0:23:32.0 SC: And hydrothermal too. If we can could find hot water underground, we can use that as well.

0:23:36.7 PV: Yeah. So Nevada is a big hotspot for understanding lithium formation, while the waters that might be forming or depositing lithium are also hydrothermal, sometimes even the same of water supply.

0:23:50.3 SC: What are the next steps? So say we find a really good source of lithium or some of these rare earth elements. We have this information. Does that mean that we have to mine it or do we have to do a bunch of careful study to make sure that we're not destroying our home?

0:24:05.4 PV: Yeah.

0:24:06.5 SC: It's just very worrying.

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0:24:09.4 PV: You certainly don't wanna go into it haphazard. We have some of the best environmental protections in the world in the United States, and that's one reason to want to do it here because we are getting sources from places that are just causing havoc for other people, and we should probably care about those people too. But it's difficult to move quickly. A lot of people will oppose this because it is doing harm. And the big question is, is there a way to do it responsibly where you're only harming at least what is in the area of the mine and nothing around it. There've been lots of problems in the past of water flowing, taking hazardous materials from mines elsewhere. The current administration wants this to happen. There's a bipartisan consensus of wanting it to happen, but it's not gonna happen quickly.

0:24:54.7 SC: Right. How green can we be as we try to make our energy sources more green in the process?

0:25:01.8 PV: Yeah. There's also, if these miners can lower their own emissions, move to more electric vehicles, heavy duty vehicles or other different future of mining type techniques. But there's a time issue here. We need to do this now, and there's a bit of a mismatch there that this is not gonna necessarily be coming in the next couple years. These mines are gonna take a bit to open.

0:25:25.2 SC: Oh yeah, for sure.

0:25:26.5 PV: But the demand's gonna keep going up and eventually, talking to people, we will get to a point where, so the value of this is, okay, you mine these minerals. You don't burn them into the atmosphere. You can recycle them. They can be reused, and you can eventually design it that you will think that we've gotten enough out that we can just keep reusing it and ramp the mining back down again. But that's our children's lifetime.

0:25:50.8 SC: Thank you so much, Paul.

0:25:52.0 PV: Yeah, my pleasure.

0:25:53.0 SC: Paul Voosen is a staff writer for Science. You can find a link to the story we discussed at science.org/podcast.

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0:26:01.1 SC: And that concludes this edition of the Science Podcast. If you have any comments or suggestions, write to us at [email protected] You can listen to the show on our website, science.org/podcast, or search for Science Magazine on any podcasting app. The show was edited by me, Sarah Crespi, Meagan Cantwell, and Kevin McLean, with production help from Podigy. Jeffrey Cook composed the music on behalf of Science and its publisher, AAAS. Thanks for joining us.

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