Welcome to tech Stuff, a production from I Heart Radio. Hey there, and welcome to tech Stuff. I'm your host, Jonathan Strickland. I'm an executive producer with I Heart Radio and How the Tech Are Young. We are about to listen to a classic episode of tech Stuff. This episode originally published in March. It is called ice core Drilling. Pretty cool if you asked me, enjoy. I like to think about ancient times, so when I come on other shows, I like to be able to look to the past sometimes. So Jonathan, I want to talk to you about Lake Vostock. All right, So what is Lake Vostock. You've never heard of it. I know Lake Lanier. Is it near Lake Lanier? It's pretty close. No, it's a lake in Antarctica. But it's not just any kind of lake. It's a sub glacial lake, the biggest one in the world actually. So it is a lake that is under a glacier, a giant sheet of ice, and that glacier is really thick. I've seen estimates from about two miles thick to about four thousand meters of glacial ice over the lake, which would be like two and a half miles. I guess they're probably different segments where the ice is a different thickness, and it's been buried in ice for millions of years, al right, So in recent decades, scientists have been drilling samples of the ice above this lake to study what's down there. Um And whenever I picture this lake in my mind, this lake buried under ancient ice, it makes me think of Gollum's Lake under the mountain in the Hobbit in the misty Mountains. Yeah, misty mountains. What did the lake have a name or was it just where the yummy fishes. I don't think it had a specific name. If it did, it would have been a Goblin name, so I would be, you know, unpronounceable for a mere mortal that I am. Oh, I assume you speak Goblin. I know grish Nacht is fire. That's the only thing I can I can rattle off off the top of my head. Well, anyway, when scientists drill down into this deep, deep Antarctic golem lake below the ice, one of the craziest things is that they've found d n A and evidence of microbial life. And I remember there were stories about how some ice samples indicated there might even be more complex life like fish and arthropods in that water. Um. Now, I know that was highly controversial at the time. I just recently looked it up again to see if there were there were any developments on that. I found a piece of coverage from Nature News at the time throwing some serious doubts on the on the live fish and arthropods claim. So that's I'm sure not all that widely accepted, but just the idea of it is so cool that you have this completely sealed off ancient alien life in this lake below a mountain of ice, and things like that make me think about deep time, Like how ice is a cross section of geological time on Earth right, Like there is layer upon layer of evidence of what has happened in the past. Yeah. And and just in case people are curious, like how could a subglacial lake remain Why would you call that a lake? Why would that not just be another part of the glacier. Why wouldn't that just be ice? Geothermal heat actually counteracts the freezing action of the ice above it, allowing the lake to remain liquid. Oh, I actually didn't know why it was liquid. Oh yeah, it's because of geothermal geothermal vents that continue to keep the temperature of the lake above freezing. So yeah, that's why, uh there can be a lake, a sub glacial lake, because otherwise you would say, like, well, wait a minute, how could it still remain how could it remain unfrozen unless there are some other chemicals in the lake that would uh lower its freezing point below that of water. That's fascinating. Yeah, well, okay, you might be wondering, wait a minute, what does this have to do with technology. Well, we're getting get there in just a second. So when you think about glaciers, I guess at the polar regions. How do things like that form? It's actually a pretty simple process. Every year it snows, it'll it'll snow, and you get heavier snows in the winter and lighter snows in the summer. Right, But in some places in the world, unlike probably wherever you live, if it snows around your house or your yard, eventually that snow melts, right, right, you get to a point where the season's warm, the snow starts to uh to melt away, and then eventually you have no more snow. But there's some regions where either the snow accumulation is so great that it never completely melts or the temperature never rises above freezing and therefore it just continues to accumulate. So every season you get a new layer of snow. What happens when a new layer of snow goes on top of the old layer of snow, Well, eventually it gets kind of heavy. Yeah, it compresses in to the point where the lower layers of snow are compressed into ice. So then you get layers of ice. And if you were able to look at these layers of ice collectively, you could start to draw some conclusions about what had happened the years when that snow first accumulated. And this is what leads us to the practice of drilling down into ice sheets and glaciers to retrieve samples to kind of get a look back into the geological past of the Earth. Yeah, exactly, So ice core drilling is a way of getting at this cross section of geological time that we can see in the ice layers of glaciers, and a lot of it's going to be you know and play like Greenland or in Antarctica. Those are the two chief sites for ice core drilling, where people have to come up with these huge vertical samples of ice that might be miles thick, right, And what I wanted to know was, how on earth do they do that? It can't be all that easy, can it is? It's well easy, It is not simple. It is similar than I would have expected, actually it is. It is a simple method in the sense that it doesn't require tons of complex machinery or techniques. But it is not easy to do because it is difficult to reach to access the areas, and the methodology can often require people to essentially live on an ice sheet for a very you know, like like a month at a time, depending on how deep they want to drill. Right. So, uh, Within each of those layers of snow that have turned into ice, there are records of things of the past, like the you know, ice can trap chemicals, for example, precipitation can trap chemicals, and as that precipitation, in this case, snow hits the ground, then you have a record of what the chemical composition was at that given time. And then other layers will pack on top of it and they will have their own kind of you know, unique chemical fingerprint, if you will. The layers don't just show you a cross section of time. Each layer has data from the time it comes from. It might even have like ash from volcanic eruption. You can see chemical data like you were just talking about the concentrations of different gases in the atmosphere that become dissolved in little bubbles in these layers, or you can see exactly ash from volcanic eruptions. You can even discern things about the local weather patterns where the glacier was at certain times in the past. We'll be back with more about ice core drilling in just a moment, but first let's take a quick break. Another thing that I think is kind of cool with the volcanic ash layers is that it lets you compare one sample against another sample that was gathered somewhere else and not necessarily justin ice. There are other core uh coreing methods like that, going through peat bogs, for example, And if you find a layer of ash that corresponds to another layer of ash and a completely different sample, you can say, oh, well, these both came from that same eruption. That allows us to to corus correlate these two dates together by the chemical composition of the ash and the two layers, because the chemical composition is going to be unique each eruption, So that way you can actually start to build a global view of what had happened during any given you know, uh year or span of years in Earth's past, which is really interesting. I think. Yeah, it's way cooler and more full of creep be ancient power than you would have imagined ice drilling to be. But I want to hear about the drilling itself. How do they get these cores out of the glacier? Okay, Well, there are two basic categories of drills, and then there are are of you know, different examples of each category. So the first big one are mechanical drills. Now, these are drills that drilled down into the ice through mechanical action, essentially rotating. Right. But normally when you think of a drill that's making a hole in something, you are not removing any section of that substrate intact. You're just making a hole. I'm drilling in the wall. Well, it's going to be this sort of like you know, cylindrical object that's got screw thread kind of things on the outside to move the shavings out of the hole as it goes deeper in. It's just a solid knot. Yeah, it's not going to give you a cross section of the wood. So how do you get that? So in order to do that, you have to have a drill bit that is is an actual hollow cylinder right the middle of this. Instead of it being a solid shaft, it's a cylinder that has cutting teeth on one end of it, so that when it rotates, it creates this the the the actual drill itself rotates around a column of ice, it creates a column of ice cuts away so that you know the center of the drill bit starts to accumulate this ice. It goes straight down until you get to the length of the drill itself, and obviously then you can't go any further because you hit the cap, like the top of the drill, and that's where you would have to stop and try and retrieve the ice that you've just drilled. Right, So you might think about it kind of like this. Imagine like a tin can or like a pipe, and then the lip of that pipe is sort of like a circular saw blade. It's got the blade is parallel to the length of the pipe obviously, so it can screw down in right, and it's also the teeth are usually adjustable, like you can either uh extend them or attract them a little bit, depending upon the nature of the ice that you're cutting into. So, for example, if they are if the if the teeth are retracted too far, it's gonna be really hard to get purchase on the ice. It's gonna kind of skitter around. Anyone who's had any experience with ice, nos, it's slippery, and so you'd have to have the teeth be a little bit longer. If they're too long, then they're going to get caught in the ice. So it'll make it more difficult to turn the drill and drill down into the ice. So you have to find that that sweet spot. And that's usually why the the teeth are adjustable, so that you can make it the perfect length for whatever conditions you encounter. You when you turn the drill the proper way, it cuts into the ice and it and it pulls in that cylinder like we were talking about. Now, there's also gonna be some waste product from this drilling in there. Yeah, chips of ice obviously are going to accumulate, so uh often these drills have treads on the outside of them, which will put push chips up to the surface. Some of them have chambers that will hold chips to keep it away from the ice core sample, because obviously, if you're looking at at creating a sample for you to study in the lab, you don't want to end up mixing that material all up, because then you don't have an accurate representation of what happened over any given length of time. Right, You've you've corrupted your sample. So most of these have a method of funneling chips up into a chamber. Uh. And you know, are the the simplest of these mechanical drills are the hand powered augers. You actually move these by hand. It looks like a kind of like a very long can, right, and the top of it has like a t junction handle, and like in cartoons when people have a dynamite box and they push it right or like a jackhammer, you know that kind of thing, And except of course, instead of going up and down, you're twisting this in order to create the rotational force. This translated into lateral force because the drill is kind of like a the inversion of a screw, right, So you're you're drilling down that way. And you might think, well, you were talking earlier about how some of the UM the core samples. We look at our our kilometers long. How could you possibly get a sample that's that long using a handogger? Well, first of all, you can't, but secondly, uh, when we talk about these core samples, Yeah, the entire sample might be several kilometers long, but that's made up of segments. So depending upon the drill you're using, your segments maybe between one and six meters long, right, so uh, that's between like, uh, you know, around three ft two around twenty ft long roughly, um And in order for you to create a full uh core sample, than what you would have to do is lower the drill back down into the borehole that you've started until it reaches the bottom, and you have to use extenders to come up out of the borehole so you can continue to drill downward. That sounds like you pretty quickly reach a sort of maximum depth. For these hand operated versions, you absolutely do, yeah, because eventually you're not going to the the amount of rotational force you'll have to create to rotate the entire thing, the the drill and all the extenders will exceed the strength and flexibility of that device, So you can't you can't indefinitely use a handogger. It would also just seem to be that that combined with whatever you have to hang it on to get it deeper and deeper, would get really heavy. Yeah. Yeah, you know, you keep in mind like you're talking about lifting up six meters of ice. Uh, And of course the diameter of this depends upon the drill to write the drill, the drills diameter will determine the diameter of the core sample. But you're still talking about lifting all that ice, which is heavy lifting the drill itself, which is heavy lifting all the extenders, which are heavy. So eventually you get to a point where you know you're just not gonna have the integrity to keep that all together, which is when you need to look at possibly switching to something else. So your typical handoggers can go pretty darn deep. I mean, we're talking twenty to thirty meters, that's like sixty six ft. That's deeper than I would have expected. Yeah, me too, And according to some of the things I read, it's more like fortys is the maximum. Twenty to thirty tends to be what people limit themselves to. But I think the record was somewhere around forty so it's even further than that. Um. So what do you do when you reach that that limit where you can't use the handoggers anymore? Well, that's when you try try kind of. You're using the electro mechanical drills. These are suspended on a cable, so instead of it having like a physic cool um turning mechanism that extends all the way up to the surface there, they they are actually suspended by cable lowered into a borehole and they consist typically of two barrels. You have an external barrel that remains uh motionless, it is, it does not turn all right, So the external barrel is uh just a stationary holding device. Then the inner barrel is the one that can rotate, all right. So the cable that suspends an electro mechanical drill, the cable doesn't move at all either. It's just there to supply the suspension mechanism and the power. So it's it's got the power lines that go down to power the drill. The inner barrel will rotate in the proper direction to continue drilling down. And the inner barrel also has treads on the external side of it, right, So those are going to be like the threads on your drill little bit that are getting the shavings out of the wall and the expa they're transporting the ice chips up along the length of the drill. That's right, and so you would use this the same way you would use your handdogger, except of course, in this case it's an electrical uh action, electro mechanical action that is causing it. So it's you know, it's a it's a little bit easier on the people who are operating it. They just have to make sure that they're lowering it properly, and then it's at the correct depth all of that kind of stuff, and and that the teeth are at the right length. It's just like the handdoggers. You've got to make sure that those those teeth are are proper so that they can cut into the material to ice properly. Uh So, usually you also have another cool mechanism literally to hold the ice in place. Once you've reached the point where you're ready to lift up the next segment. They have spring loaded lever arms inside that inner barrel that think of it like little pincers that come in and hold that core in place. Because you want it to be really steady. When you're lifting that drill up. You know, you're talking forty or more up a borehole. You don't want to lose the grip on that ice core sample because that would be bad. So the spring loaded lever arms hold them and they are called something that I love, core dogs. It's like it's like going to the county fair. You get yourself and a couple of core dogs. I like to go to Pelucaville to get my core dogs. Local establishment here in Atlanta. Now there is another type of drill that I love. Yeah, I think this is excellent. I love looking at the picture. I was looking at a picture of this before I read about what it was, and I was like, I don't understand how it cuts because it just looked like a pipe with kind of a strange lip. It didn't have any teeth, right, And then I read about it and I was like, oh, I see it doesn't thermal drill. Yeah, so it's using heat. Yeah, So imagine sort of a pipe that on the end of the lip at the pie ape has a heating element and it gets hot, melts straight through the ice and just sinks on down there. Yeah. Yeah, until you get to again to the end of the capacity of the drill, and then you have to lift it back up again. So yeah, it's really I love that idea, the idea of of of let's just use heat to work our way. I mean, come on, it's ice, let's use heat to melt away down there. Yeah. That actually does seem like you would have some limitations though, and it does. In fact, you are you're more likely to use that when you're using ice that is above minus ten degrees celsius for example, you don't know, which is fourteen degrees fahrenheit. By the way, you wouldn't use that in colder areas because the melt off the water that you would be creating as the heating element melts, the ice would likely start to refreeze and that would become a problem. So you are more likely to use it in uh in quote unquote warmer since you waitions it will still be really cold. Um. And then if you were to encounter those colder situations, you would use electro mechanical drill. And in fact, there are plenty of ice core drilling projects that that will switch out the drills based upon whatever the current conditions happen to be as they are drilling. You've got a little bit more show to go before we get to that. We're gonna take one more quick break now. I would imagine that once you get down to a certain depth, the whole enterprise sort of changes. I mean, once you're getting two thousands of feet down, you're going to start dealing with the ways that ice behaves kind of like a plastic and yeah, do you know what I mean. You gotta remember this ice is under a lot of pressure. I mean, just from wait alone, it's under a ton of pressure. But there's also there are other elements there too. There's glacial flow, right, glaciers move, they don't move very quickly, but there is this pressure from glacial flow where the glacier is potentially moving in a specific direction, which means that's putting pressure on the borehole too. And if the pressure is too great, that borehole can close, and by clothes, we've pretty much mean collapse in on itself. Like closing sounds pretty gentle, it's not a gentle thing. Well, whether it's gentle or not, it's a big problem for your research project exactly. So, Uh, there are times where you will have these these projects where they will start pumping liquid down the whole, and there's a couple of different reasons for this. Some will pump anti freeze liquid down the whole in order to make sure that any melted runoff, for example, if you're using a thermal drill doesn't refreeze, but then you may need to put down a different type of liquid, another one that would be less likely to freeze, in order to equalize the pressure from inside the hole to what what is outside the hole. Yeah, I read somewhere that the drill fluid that they would normally use can be something like kerosene, like a petroleum derived fluid. Uh, And it just basically has to have the right freezing point. And they wanted to be of a certain thickness right right because they have to you know, if it's if it's too thin, then it's not going to create the pressure that they need in order to keep the whole stable. And if the freezing point is too is too high, then it's going to just end up mucking everything up anyway. So it is a delicate balance. There's one project in particular I wanted to talk about the kind of give an idea of what it's like to work on one of these. Again, it all depends upon how deeply you need to go when you're retrieving the ice core sample. You know, how far back are you going to be looking. Uh. There's one called the West Antarctic Ice Sheet Divide Project. There's a recent effort by the United States and which an ice core that was three thousand, four hundred five meters long, so three point four kilometers long, was retrieved over the course of six field seasons. Now, they defined a field season as approximately forty days of drilling. The actual drilling took place six days a week, so obviously more than um. Since you're not drilling seven days a week. Forty days of drilling is you know, you've got to divide that up properly. But twenty four hours a day, three shifts UH for drilling per day, with three UH project workers per shift, so nine people working for six days a week and drilling is going on twenty four hours a day. I'm sure that's not an easy job, but I would kind of like that job just to be able to say I drilled course of ancient ice at one of my past jobs. But you might you might have some interesting stories to tell about the the the quirks of the two shift workers you shared all that time with and whether or not you ever want to see that person ever again. To the two am to ten am shift is kind of rough in Antarctica. You can also just be like, I will never not hear the sound of ice being drilled. It is just gonna go through my head through the rest of my days. But anyway, Yeah, it's it's a really serious endeavor and it's very important scientific work. And so because it's important, and because this is something that you know, once you once you have retrieved the ice core sample, you've only just started, you have to make sure that you can store them properly so that you have the chance to actually examine them later. Right, So you've got these cylindrical segments of you know, essentially priceless scientific data that are just in containers. And yeah, and it's perishable. It's perishable. There's something that's beautiful about this to me, the fleeting nous of it. How you know, this is something that could be millions of years old, but it's frozen bran. It could melt if the power goes off. You know, now, to be fair, if you're getting them from Greenland. I think the oldest we've looked at is a hundred thirty thousand, and Antarctica it's more like eight thousand, so not quite millions, but still well before human history was ever recorded or potentially even possible to record. You know, we're talking way back, we're talking back when Cathulu was running rampant. Probably not, but at any rate, they would that be detectable from the highest we see dissolved particulates of I don't know, yeah, just like there's there's one of the chemical constituents of the old ones, right, you could be like, well, there was a frozen sugar right that right around this level. So we're pretty sure it was around this time at any rate. So we have to we have to store these things obviously until they can be examined by various scientists, and a lot of the ice cores when they are stored, like, there are a lot of different research facilities that want to have a chance to to examine this stuff, so they have to go to a special facility to do that. One of those is the National Ice Core Laboratory, which stores more than seventeen thousand meters of ice that's incredible. And its main archive freezer is fifty five thousand cubic feet in size, that's one thofty seven cubic meters, And so incoming ice has to first reach a thermal equilibrium with the temperature inside the freezer, which is minus thirty six degrees celsius or minus thirty two point eight fahrenheit. And the reason for that is obviously you don't want to start handling the ice before it's reached thermal equal equilibrium for fear of damaging the sample. Right, So once it's reached that thermal equilibrium, that's that only then can you actually unpack it and then label it and and racket categorize it. I've seen pictures of these two ridge facilities. It looks like kind of like a National Film Archive or something that's got these silver cans and the shelves going to the ceiling. Though I do wonder that if there's a temptation for people working in these places every now and then to get a little cheeky and make themselves a highball, it's just just an ancient on the rocks, right, Yeah, on the ancient rocks. I guess. Then again, you may be unleashing microbes into your into your body that you have no natural defenses. Again, Yeah that that. Yeah, I see that. We're kind of starting to mix up movie genres too, because this is kind of a rolling emeric, you know, kind of into the world derivative, right, and then and then Judd Apatel where you get like the kind of stoner comedy. So you get like the stoner character who's just trying to make a drink. And then unleash is the terrible super flu Hey this this this, this particular bacteria or virus or whatever has been in suspended animation for hundreds of thousands of years now has been unleashed on the plant. There's money in this, Joe, I think we need to develop it. But before that we have to finish this podcast. So wait a second. Okay, So once they've got the ice, Yeah, you have this priceless repository of ancient data. How do you analyze it and what can you learn? Well, the first thing you can do is look at it. I know that sounds silly. You are a man of many insights using your eyeballs, so uh. The interesting thing about an ice core sample is you can actually see the passage of time just by looking closely at the ice core sample. Yeah, you should look up an image of this if you're listening on a computer or device where you can have internet access. It's cool. It's got stripes, yeah, and those stripes represent summers and winters, right. So winters are darker because you usually have much greater snow accumulation during the winter. Summers are lighter because you have less snow accumulation. So you get these dark bands separated by light bands, and together those represents a year's passage of time. Right, You've got the summer and winter there, and so you just start counting backwards. It's like rings on a tree, except you'd be counting vertical stripes rather than the concentric circle exactly. Yeah, So you count that backward and you can actually say, oh, well, this particular year is such and such because it's so many far back from the surface. And then you can start or at least you can estimate, like within a reasonable degree of certainty, what year that represents. And in fact, uh, they have done tests, they being scientists, have done tests to make sure that this is the case by looking at various layers identifying what year that layers should represent testing the chemical composition of that particular layer of the ice and comparing it to data that we have from others other means, like and we're talking like around the nineteen fifties, like looking at the nineteen fifties, so counting back until you hit to nineteen fifty on the ice core sample and then testing it to see if it actually matches the other records we have, and they match, so it shows that this actually does work. Now, however, that being said, when you start going to deeper levels, it starts getting more and more difficult to differentiate. Yeah, I think I was seeing various concerns about how factors in the physics of the glacier can change what happens to these levels. I mean, number one, you just have that more pressure, but I think the glacier flow can also change how the levels are represented, right, Yeah, yeah, I mean, if you if you think about like, these glaciers don't necessarily all move. It's like one big solid unit. Keep in mind that this is this is a a solid form of a fluid, but it still has some fluid mechanics to it, right, It's not not all of the glacier is necessarily moving. As in concert with itself, right, So you could have sections of the glacier that are moving that could end up changing a little bit of what you would expect to find as you're counting back to a certain depth. And so it's one of those things where, uh, you know, you have to after at some point you have to start looking at alternative means of dating that particular part of the ice core sample, and that could involve doing something like performing some geochemistry on it. So you look to see what materials are in that layer and how does that correspond with the records we have about our geological history. So it's usually mass spectrometry that we use where we try and see what chemicals are represented within that layer and kind of map that to what else we know about our history. Um, there's also that layers of ash. So if we find layers of ash, then we know that this is uh, you know, a mark of a volcanic eruption and based upon our records, we can kind of date it from that point. Or it could be just another emergence of hexus. Could be could be likely a volcanic eruption, but could be electrical conductivity because again depending on what the what materials are dissolved within that ice, it's going to be either more or less conductive, and so by doing that we can make determinations of what materials are in there and thus kind of get an idea of how where in the the timeline that particular part of the ice core sample falls. Numerical flow models which help us correlate age to depth. This is what we were talking about just a second ago, Joe, the idea of the glacial flow and how that can can make things a little more complicated. Uh, having those numerical flow models, which essentially that's a simulation of what must have happened within a particular body of ice over a given amount of time, and by modeling it and trying to get that as accurate as possible, we can try and correlate, all, right, at what depth would we consider, like, how how far down would we go before we hit I don't know, two thousand years for example. This is a kind of I'm just throwing that out there as as a off the top of my head example. And also radiometric dating dating, which is a not away for nuclear physicists to know, hang out and find that special someone. They use tender just like everybody else. It's more about actually looking at um radioactive decay. Not every layer of ice has anything in it like that, but some layers of ice do have trace amounts of uranium dust, and that would might be a way that we could date certain types. This is pretty deep in the Antarctic ice usually. Um As for what we can learn, we can learn lots of stuff, right, I mean, like it's really important information that tells us about the way our world has changed over huge expanses of time. Right. Well, I know one of the main things that scientists are looking at ice cores for these days is to help understand what past climate systems look like and to help predict what changes will be brought about by the current climate change we're observing right right, And of course you know, uh, you can't really make predictions without necessarily understanding what has happened in the past, right. You need to have that model there so that you can have something to base your predictions upon. So one thing you can easily see, and by easily I mean I described looking at those layers and seeing the summer and winter. You can easily see the general precipitation trends year over year by the thickness of those layers. Right, So if one summer winter layer is very thin compared to the next one below it, you could say, well, there was a year where there was a relatively heavy amount of precipitation followed by a year where there was very light precipitation. Then you could go and start doing more studies to see, like, while all, there are other elements inside this ice core that could indicate why that might have been the case. What what was going on in the atmosphere that would have made one year particularly heavy with precipitation and the following year light. Oh I see, So maybe you could just, for example, look at concentrate of different atmospheric chemicals in the layers preceding the layers that have more precipitation, so like, oh, wow, it's strange there was more nitrogen in the atmosphere the past three seasons before we had these heavy precipitation seasons. Or it might be look here, that's not a real result. And then you can also look and say, oh, look at the concentration of carbon dioxide for example. Now you've gotta be a little careful with this, particularly with the green Land examples, because carbon diox i can get dissolved in water, and sometimes they're they're also melting layers. Melting layers are where uh, you know, the temperaturey got high enough so that some snow had melted. The water can trickle down into the snowpack and you get these kind of bubble free areas of ice. That's a melt layer, which can still have a lot of useful information in it. But it also means that sometimes water that has carbon dioxide dissolved in it can set down into older layers and thus change the composition of them, giving you a false positive that there was more common carbon dioxide in a layer than there really was. Fortunately, scientists are aware of this. You know what to look for and uh and like I said, that's more prevalent in Greenland and Antarctica. You don't tend to see that same issue. But uh, you know, you can also look at things like, um, the chemical composition, which will tell you more about the concentration of greenhouse gases uh in any given year, and you can look for trends. Right, you can actually look and see like it may not be uh, this love layer was thick and that layer was thin. It maybe we're seeing a gradual decrease in layers over a really long time, followed by a period where they were very very thin layers for a long time, and then very thick layers as another ice age started coming on. You could actually see these big trends, because that's really what we're talking about with climate. Right, Climate isn't weather. We often, like the people often will conflay the two. Right, climate influences weather, right, and and climate is like you know, a weather is this is this localized, regional, temporal thing. Like it's happening in a very small time span. You're talking like, while the weather is terrible today, climate is long reaching. It can it's a global thing. It's not or at least a much larger regional thing. Um and it it is not. Uh, it's not as mercurial you could say, as weather would be, because weather can change dramatically day to day. Climate are these long trends. Describing climate would be like describing Jonathan's personality. Describing weather would be like can you believe what Jonathan said this morning? Yeah, we'll put so. Uh. By looking at this, we can say, all right, during this period of time where we know there was a greater concentration of greenhouse gasses because it was trapped in the ice. We have we have, uh, we've analyzed the ice. We know what the concentrations are. We can see from the following layers how that affected climate over a great span of time. So because our records don't stretch back that far, heck, our our weather records don't stretch back far at all. We're talking like a century or so, and otherwise we're we're relying upon things like the recollections that people had written down and either letters or or you know, just the general language used by people who are writing at the time what the weather might have been. Like. This is an actual way for us to look back and say, here's what the climate was a hundred thousand years ago, and here's what here's how the climate changed over a twenty thousand years span. I mean, it's a big picture look at something that otherwise we would just be making wild guesses about. And that's really interesting to me. Yeah, it's obviously incredibly useful. I have to say again, how much. Maybe it's just me, but anything that's that old gives me this very cool, mysterious feeling. I get a little try about it. Yeah, yeah, I mean, it's it's neat to know that there there exists a record where by applying careful scientific, careful scientific approach to analyzing that material, we can draw very very uh, very interesting conclusions about what the Earth was like well before humans were walking around and being human ish. I hope you enjoyed that classic episode about ice core drilling. If you have suggestions for topics I should cover in future episodes of tech Stuff, please reach out to me and let me know. The handle for the show on Twitter is text stuff hs W and I'll talk to you again really soon. Tech Stuff is an I Heart Radio production. 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Welcome to tech Stuff, a production from I Heart Radio. Hey there, and welcome to tech Stuff. I'm your host, Jonathan Strickland. I'm an executive producer with I Heart Radio and How the Tech Are Young. We are about to listen to a classic episode of tech Stuff. This episode originally published in March. It is called ice core Drilling. Pretty cool if you asked me, enjoy. I like to think about ancient times, so when I come on other shows, I like to be able to look to the past sometimes. So Jonathan, I want to talk to you about Lake Vostock. All right, So what is Lake Vostock. You've never heard of it. I know Lake Lanier. Is it near Lake Lanier? It's pretty close. No, it's a lake in Antarctica. But it's not just any kind of lake. It's a sub glacial lake, the biggest one in the world actually. So it is a lake that is under a glacier, a giant sheet of ice, and that glacier is really thick. I've seen estimates from about two miles thick to about four thousand meters of glacial ice over the lake, which would be like two and a half miles. I guess they're probably different segments where the ice is a different thickness, and it's been buried in ice for millions of years, al right, So in recent decades, scientists have been drilling samples of the ice above this lake to study what's down there. Um And whenever I picture this lake in my mind, this lake buried under ancient ice, it makes me think of Gollum's Lake under the mountain in the Hobbit in the misty Mountains. Yeah, misty mountains. What did the lake have a name or was it just where the yummy fishes. I don't think it had a specific name. If it did, it would have been a Goblin name, so I would be, you know, unpronounceable for a mere mortal that I am. Oh, I assume you speak Goblin. I know grish Nacht is fire. That's the only thing I can I can rattle off off the top of my head. Well, anyway, when scientists drill down into this deep, deep Antarctic golem lake below the ice, one of the craziest things is that they've found d n A and evidence of microbial life. And I remember there were stories about how some ice samples indicated there might even be more complex life like fish and arthropods in that water. Um. Now, I know that was highly controversial at the time. I just recently looked it up again to see if there were there were any developments on that. I found a piece of coverage from Nature News at the time throwing some serious doubts on the on the live fish and arthropods claim. So that's I'm sure not all that widely accepted, but just the idea of it is so cool that you have this completely sealed off ancient alien life in this lake below a mountain of ice, and things like that make me think about deep time, Like how ice is a cross section of geological time on Earth right, Like there is layer upon layer of evidence of what has happened in the past. Yeah. And and just in case people are curious, like how could a subglacial lake remain Why would you call that a lake? Why would that not just be another part of the glacier. Why wouldn't that just be ice? Geothermal heat actually counteracts the freezing action of the ice above it, allowing the lake to remain liquid. Oh, I actually didn't know why it was liquid. Oh yeah, it's because of geothermal geothermal vents that continue to keep the temperature of the lake above freezing. So yeah, that's why, uh there can be a lake, a sub glacial lake, because otherwise you would say, like, well, wait a minute, how could it still remain how could it remain unfrozen unless there are some other chemicals in the lake that would uh lower its freezing point below that of water. That's fascinating. Yeah, well, okay, you might be wondering, wait a minute, what does this have to do with technology. Well, we're getting get there in just a second. So when you think about glaciers, I guess at the polar regions. How do things like that form? It's actually a pretty simple process. Every year it snows, it'll it'll snow, and you get heavier snows in the winter and lighter snows in the summer. Right, But in some places in the world, unlike probably wherever you live, if it snows around your house or your yard, eventually that snow melts, right, right, you get to a point where the season's warm, the snow starts to uh to melt away, and then eventually you have no more snow. But there's some regions where either the snow accumulation is so great that it never completely melts or the temperature never rises above freezing and therefore it just continues to accumulate. So every season you get a new layer of snow. What happens when a new layer of snow goes on top of the old layer of snow, Well, eventually it gets kind of heavy. Yeah, it compresses in to the point where the lower layers of snow are compressed into ice. So then you get layers of ice. And if you were able to look at these layers of ice collectively, you could start to draw some conclusions about what had happened the years when that snow first accumulated. And this is what leads us to the practice of drilling down into ice sheets and glaciers to retrieve samples to kind of get a look back into the geological past of the Earth. Yeah, exactly, So ice core drilling is a way of getting at this cross section of geological time that we can see in the ice layers of glaciers, and a lot of it's going to be you know and play like Greenland or in Antarctica. Those are the two chief sites for ice core drilling, where people have to come up with these huge vertical samples of ice that might be miles thick, right, And what I wanted to know was, how on earth do they do that? It can't be all that easy, can it is? It's well easy, It is not simple. It is similar than I would have expected, actually it is. It is a simple method in the sense that it doesn't require tons of complex machinery or techniques. But it is not easy to do because it is difficult to reach to access the areas, and the methodology can often require people to essentially live on an ice sheet for a very you know, like like a month at a time, depending on how deep they want to drill. Right. So, uh, Within each of those layers of snow that have turned into ice, there are records of things of the past, like the you know, ice can trap chemicals, for example, precipitation can trap chemicals, and as that precipitation, in this case, snow hits the ground, then you have a record of what the chemical composition was at that given time. And then other layers will pack on top of it and they will have their own kind of you know, unique chemical fingerprint, if you will. The layers don't just show you a cross section of time. Each layer has data from the time it comes from. It might even have like ash from volcanic eruption. You can see chemical data like you were just talking about the concentrations of different gases in the atmosphere that become dissolved in little bubbles in these layers, or you can see exactly ash from volcanic eruptions. You can even discern things about the local weather patterns where the glacier was at certain times in the past. We'll be back with more about ice core drilling in just a moment, but first let's take a quick break. Another thing that I think is kind of cool with the volcanic ash layers is that it lets you compare one sample against another sample that was gathered somewhere else and not necessarily justin ice. There are other core uh coreing methods like that, going through peat bogs, for example, And if you find a layer of ash that corresponds to another layer of ash and a completely different sample, you can say, oh, well, these both came from that same eruption. That allows us to to corus correlate these two dates together by the chemical composition of the ash and the two layers, because the chemical composition is going to be unique each eruption, So that way you can actually start to build a global view of what had happened during any given you know, uh year or span of years in Earth's past, which is really interesting. I think. Yeah, it's way cooler and more full of creep be ancient power than you would have imagined ice drilling to be. But I want to hear about the drilling itself. How do they get these cores out of the glacier? Okay, Well, there are two basic categories of drills, and then there are are of you know, different examples of each category. So the first big one are mechanical drills. Now, these are drills that drilled down into the ice through mechanical action, essentially rotating. Right. But normally when you think of a drill that's making a hole in something, you are not removing any section of that substrate intact. You're just making a hole. I'm drilling in the wall. Well, it's going to be this sort of like you know, cylindrical object that's got screw thread kind of things on the outside to move the shavings out of the hole as it goes deeper in. It's just a solid knot. Yeah, it's not going to give you a cross section of the wood. So how do you get that? So in order to do that, you have to have a drill bit that is is an actual hollow cylinder right the middle of this. Instead of it being a solid shaft, it's a cylinder that has cutting teeth on one end of it, so that when it rotates, it creates this the the the actual drill itself rotates around a column of ice, it creates a column of ice cuts away so that you know the center of the drill bit starts to accumulate this ice. It goes straight down until you get to the length of the drill itself, and obviously then you can't go any further because you hit the cap, like the top of the drill, and that's where you would have to stop and try and retrieve the ice that you've just drilled. Right, So you might think about it kind of like this. Imagine like a tin can or like a pipe, and then the lip of that pipe is sort of like a circular saw blade. It's got the blade is parallel to the length of the pipe obviously, so it can screw down in right, and it's also the teeth are usually adjustable, like you can either uh extend them or attract them a little bit, depending upon the nature of the ice that you're cutting into. So, for example, if they are if the if the teeth are retracted too far, it's gonna be really hard to get purchase on the ice. It's gonna kind of skitter around. Anyone who's had any experience with ice, nos, it's slippery, and so you'd have to have the teeth be a little bit longer. If they're too long, then they're going to get caught in the ice. So it'll make it more difficult to turn the drill and drill down into the ice. So you have to find that that sweet spot. And that's usually why the the teeth are adjustable, so that you can make it the perfect length for whatever conditions you encounter. You when you turn the drill the proper way, it cuts into the ice and it and it pulls in that cylinder like we were talking about. Now, there's also gonna be some waste product from this drilling in there. Yeah, chips of ice obviously are going to accumulate, so uh often these drills have treads on the outside of them, which will put push chips up to the surface. Some of them have chambers that will hold chips to keep it away from the ice core sample, because obviously, if you're looking at at creating a sample for you to study in the lab, you don't want to end up mixing that material all up, because then you don't have an accurate representation of what happened over any given length of time. Right, You've you've corrupted your sample. So most of these have a method of funneling chips up into a chamber. Uh. And you know, are the the simplest of these mechanical drills are the hand powered augers. You actually move these by hand. It looks like a kind of like a very long can, right, and the top of it has like a t junction handle, and like in cartoons when people have a dynamite box and they push it right or like a jackhammer, you know that kind of thing, And except of course, instead of going up and down, you're twisting this in order to create the rotational force. This translated into lateral force because the drill is kind of like a the inversion of a screw, right, So you're you're drilling down that way. And you might think, well, you were talking earlier about how some of the UM the core samples. We look at our our kilometers long. How could you possibly get a sample that's that long using a handogger? Well, first of all, you can't, but secondly, uh, when we talk about these core samples, Yeah, the entire sample might be several kilometers long, but that's made up of segments. So depending upon the drill you're using, your segments maybe between one and six meters long, right, so uh, that's between like, uh, you know, around three ft two around twenty ft long roughly, um And in order for you to create a full uh core sample, than what you would have to do is lower the drill back down into the borehole that you've started until it reaches the bottom, and you have to use extenders to come up out of the borehole so you can continue to drill downward. That sounds like you pretty quickly reach a sort of maximum depth. For these hand operated versions, you absolutely do, yeah, because eventually you're not going to the the amount of rotational force you'll have to create to rotate the entire thing, the the drill and all the extenders will exceed the strength and flexibility of that device, So you can't you can't indefinitely use a handogger. It would also just seem to be that that combined with whatever you have to hang it on to get it deeper and deeper, would get really heavy. Yeah. Yeah, you know, you keep in mind like you're talking about lifting up six meters of ice. Uh, And of course the diameter of this depends upon the drill to write the drill, the drills diameter will determine the diameter of the core sample. But you're still talking about lifting all that ice, which is heavy lifting the drill itself, which is heavy lifting all the extenders, which are heavy. So eventually you get to a point where you know you're just not gonna have the integrity to keep that all together, which is when you need to look at possibly switching to something else. So your typical handoggers can go pretty darn deep. I mean, we're talking twenty to thirty meters, that's like sixty six ft. That's deeper than I would have expected. Yeah, me too, And according to some of the things I read, it's more like fortys is the maximum. Twenty to thirty tends to be what people limit themselves to. But I think the record was somewhere around forty so it's even further than that. Um. So what do you do when you reach that that limit where you can't use the handoggers anymore? Well, that's when you try try kind of. You're using the electro mechanical drills. These are suspended on a cable, so instead of it having like a physic cool um turning mechanism that extends all the way up to the surface there, they they are actually suspended by cable lowered into a borehole and they consist typically of two barrels. You have an external barrel that remains uh motionless, it is, it does not turn all right, So the external barrel is uh just a stationary holding device. Then the inner barrel is the one that can rotate, all right. So the cable that suspends an electro mechanical drill, the cable doesn't move at all either. It's just there to supply the suspension mechanism and the power. So it's it's got the power lines that go down to power the drill. The inner barrel will rotate in the proper direction to continue drilling down. And the inner barrel also has treads on the external side of it, right, So those are going to be like the threads on your drill little bit that are getting the shavings out of the wall and the expa they're transporting the ice chips up along the length of the drill. That's right, and so you would use this the same way you would use your handdogger, except of course, in this case it's an electrical uh action, electro mechanical action that is causing it. So it's you know, it's a it's a little bit easier on the people who are operating it. They just have to make sure that they're lowering it properly, and then it's at the correct depth all of that kind of stuff, and and that the teeth are at the right length. It's just like the handdoggers. You've got to make sure that those those teeth are are proper so that they can cut into the material to ice properly. Uh So, usually you also have another cool mechanism literally to hold the ice in place. Once you've reached the point where you're ready to lift up the next segment. They have spring loaded lever arms inside that inner barrel that think of it like little pincers that come in and hold that core in place. Because you want it to be really steady. When you're lifting that drill up. You know, you're talking forty or more up a borehole. You don't want to lose the grip on that ice core sample because that would be bad. So the spring loaded lever arms hold them and they are called something that I love, core dogs. It's like it's like going to the county fair. You get yourself and a couple of core dogs. I like to go to Pelucaville to get my core dogs. Local establishment here in Atlanta. Now there is another type of drill that I love. Yeah, I think this is excellent. I love looking at the picture. I was looking at a picture of this before I read about what it was, and I was like, I don't understand how it cuts because it just looked like a pipe with kind of a strange lip. It didn't have any teeth, right, And then I read about it and I was like, oh, I see it doesn't thermal drill. Yeah, so it's using heat. Yeah, So imagine sort of a pipe that on the end of the lip at the pie ape has a heating element and it gets hot, melts straight through the ice and just sinks on down there. Yeah. Yeah, until you get to again to the end of the capacity of the drill, and then you have to lift it back up again. So yeah, it's really I love that idea, the idea of of of let's just use heat to work our way. I mean, come on, it's ice, let's use heat to melt away down there. Yeah. That actually does seem like you would have some limitations though, and it does. In fact, you are you're more likely to use that when you're using ice that is above minus ten degrees celsius for example, you don't know, which is fourteen degrees fahrenheit. By the way, you wouldn't use that in colder areas because the melt off the water that you would be creating as the heating element melts, the ice would likely start to refreeze and that would become a problem. So you are more likely to use it in uh in quote unquote warmer since you waitions it will still be really cold. Um. And then if you were to encounter those colder situations, you would use electro mechanical drill. And in fact, there are plenty of ice core drilling projects that that will switch out the drills based upon whatever the current conditions happen to be as they are drilling. You've got a little bit more show to go before we get to that. We're gonna take one more quick break now. I would imagine that once you get down to a certain depth, the whole enterprise sort of changes. I mean, once you're getting two thousands of feet down, you're going to start dealing with the ways that ice behaves kind of like a plastic and yeah, do you know what I mean. You gotta remember this ice is under a lot of pressure. I mean, just from wait alone, it's under a ton of pressure. But there's also there are other elements there too. There's glacial flow, right, glaciers move, they don't move very quickly, but there is this pressure from glacial flow where the glacier is potentially moving in a specific direction, which means that's putting pressure on the borehole too. And if the pressure is too great, that borehole can close, and by clothes, we've pretty much mean collapse in on itself. Like closing sounds pretty gentle, it's not a gentle thing. Well, whether it's gentle or not, it's a big problem for your research project exactly. So, Uh, there are times where you will have these these projects where they will start pumping liquid down the whole, and there's a couple of different reasons for this. Some will pump anti freeze liquid down the whole in order to make sure that any melted runoff, for example, if you're using a thermal drill doesn't refreeze, but then you may need to put down a different type of liquid, another one that would be less likely to freeze, in order to equalize the pressure from inside the hole to what what is outside the hole. Yeah, I read somewhere that the drill fluid that they would normally use can be something like kerosene, like a petroleum derived fluid. Uh, And it just basically has to have the right freezing point. And they wanted to be of a certain thickness right right because they have to you know, if it's if it's too thin, then it's not going to create the pressure that they need in order to keep the whole stable. And if the freezing point is too is too high, then it's going to just end up mucking everything up anyway. So it is a delicate balance. There's one project in particular I wanted to talk about the kind of give an idea of what it's like to work on one of these. Again, it all depends upon how deeply you need to go when you're retrieving the ice core sample. You know, how far back are you going to be looking. Uh. There's one called the West Antarctic Ice Sheet Divide Project. There's a recent effort by the United States and which an ice core that was three thousand, four hundred five meters long, so three point four kilometers long, was retrieved over the course of six field seasons. Now, they defined a field season as approximately forty days of drilling. The actual drilling took place six days a week, so obviously more than um. Since you're not drilling seven days a week. Forty days of drilling is you know, you've got to divide that up properly. But twenty four hours a day, three shifts UH for drilling per day, with three UH project workers per shift, so nine people working for six days a week and drilling is going on twenty four hours a day. I'm sure that's not an easy job, but I would kind of like that job just to be able to say I drilled course of ancient ice at one of my past jobs. But you might you might have some interesting stories to tell about the the the quirks of the two shift workers you shared all that time with and whether or not you ever want to see that person ever again. To the two am to ten am shift is kind of rough in Antarctica. You can also just be like, I will never not hear the sound of ice being drilled. It is just gonna go through my head through the rest of my days. But anyway, Yeah, it's it's a really serious endeavor and it's very important scientific work. And so because it's important, and because this is something that you know, once you once you have retrieved the ice core sample, you've only just started, you have to make sure that you can store them properly so that you have the chance to actually examine them later. Right, So you've got these cylindrical segments of you know, essentially priceless scientific data that are just in containers. And yeah, and it's perishable. It's perishable. There's something that's beautiful about this to me, the fleeting nous of it. How you know, this is something that could be millions of years old, but it's frozen bran. It could melt if the power goes off. You know, now, to be fair, if you're getting them from Greenland. I think the oldest we've looked at is a hundred thirty thousand, and Antarctica it's more like eight thousand, so not quite millions, but still well before human history was ever recorded or potentially even possible to record. You know, we're talking way back, we're talking back when Cathulu was running rampant. Probably not, but at any rate, they would that be detectable from the highest we see dissolved particulates of I don't know, yeah, just like there's there's one of the chemical constituents of the old ones, right, you could be like, well, there was a frozen sugar right that right around this level. So we're pretty sure it was around this time at any rate. So we have to we have to store these things obviously until they can be examined by various scientists, and a lot of the ice cores when they are stored, like, there are a lot of different research facilities that want to have a chance to to examine this stuff, so they have to go to a special facility to do that. One of those is the National Ice Core Laboratory, which stores more than seventeen thousand meters of ice that's incredible. And its main archive freezer is fifty five thousand cubic feet in size, that's one thofty seven cubic meters, And so incoming ice has to first reach a thermal equilibrium with the temperature inside the freezer, which is minus thirty six degrees celsius or minus thirty two point eight fahrenheit. And the reason for that is obviously you don't want to start handling the ice before it's reached thermal equal equilibrium for fear of damaging the sample. Right, So once it's reached that thermal equilibrium, that's that only then can you actually unpack it and then label it and and racket categorize it. I've seen pictures of these two ridge facilities. It looks like kind of like a National Film Archive or something that's got these silver cans and the shelves going to the ceiling. Though I do wonder that if there's a temptation for people working in these places every now and then to get a little cheeky and make themselves a highball, it's just just an ancient on the rocks, right, Yeah, on the ancient rocks. I guess. Then again, you may be unleashing microbes into your into your body that you have no natural defenses. Again, Yeah that that. Yeah, I see that. We're kind of starting to mix up movie genres too, because this is kind of a rolling emeric, you know, kind of into the world derivative, right, and then and then Judd Apatel where you get like the kind of stoner comedy. So you get like the stoner character who's just trying to make a drink. And then unleash is the terrible super flu Hey this this this, this particular bacteria or virus or whatever has been in suspended animation for hundreds of thousands of years now has been unleashed on the plant. There's money in this, Joe, I think we need to develop it. But before that we have to finish this podcast. So wait a second. Okay, So once they've got the ice, Yeah, you have this priceless repository of ancient data. How do you analyze it and what can you learn? Well, the first thing you can do is look at it. I know that sounds silly. You are a man of many insights using your eyeballs, so uh. The interesting thing about an ice core sample is you can actually see the passage of time just by looking closely at the ice core sample. Yeah, you should look up an image of this if you're listening on a computer or device where you can have internet access. It's cool. It's got stripes, yeah, and those stripes represent summers and winters, right. So winters are darker because you usually have much greater snow accumulation during the winter. Summers are lighter because you have less snow accumulation. So you get these dark bands separated by light bands, and together those represents a year's passage of time. Right, You've got the summer and winter there, and so you just start counting backwards. It's like rings on a tree, except you'd be counting vertical stripes rather than the concentric circle exactly. Yeah, So you count that backward and you can actually say, oh, well, this particular year is such and such because it's so many far back from the surface. And then you can start or at least you can estimate, like within a reasonable degree of certainty, what year that represents. And in fact, uh, they have done tests, they being scientists, have done tests to make sure that this is the case by looking at various layers identifying what year that layers should represent testing the chemical composition of that particular layer of the ice and comparing it to data that we have from others other means, like and we're talking like around the nineteen fifties, like looking at the nineteen fifties, so counting back until you hit to nineteen fifty on the ice core sample and then testing it to see if it actually matches the other records we have, and they match, so it shows that this actually does work. Now, however, that being said, when you start going to deeper levels, it starts getting more and more difficult to differentiate. Yeah, I think I was seeing various concerns about how factors in the physics of the glacier can change what happens to these levels. I mean, number one, you just have that more pressure, but I think the glacier flow can also change how the levels are represented, right, Yeah, yeah, I mean, if you if you think about like, these glaciers don't necessarily all move. It's like one big solid unit. Keep in mind that this is this is a a solid form of a fluid, but it still has some fluid mechanics to it, right, It's not not all of the glacier is necessarily moving. As in concert with itself, right, So you could have sections of the glacier that are moving that could end up changing a little bit of what you would expect to find as you're counting back to a certain depth. And so it's one of those things where, uh, you know, you have to after at some point you have to start looking at alternative means of dating that particular part of the ice core sample, and that could involve doing something like performing some geochemistry on it. So you look to see what materials are in that layer and how does that correspond with the records we have about our geological history. So it's usually mass spectrometry that we use where we try and see what chemicals are represented within that layer and kind of map that to what else we know about our history. Um, there's also that layers of ash. So if we find layers of ash, then we know that this is uh, you know, a mark of a volcanic eruption and based upon our records, we can kind of date it from that point. Or it could be just another emergence of hexus. Could be could be likely a volcanic eruption, but could be electrical conductivity because again depending on what the what materials are dissolved within that ice, it's going to be either more or less conductive, and so by doing that we can make determinations of what materials are in there and thus kind of get an idea of how where in the the timeline that particular part of the ice core sample falls. Numerical flow models which help us correlate age to depth. This is what we were talking about just a second ago, Joe, the idea of the glacial flow and how that can can make things a little more complicated. Uh, having those numerical flow models, which essentially that's a simulation of what must have happened within a particular body of ice over a given amount of time, and by modeling it and trying to get that as accurate as possible, we can try and correlate, all, right, at what depth would we consider, like, how how far down would we go before we hit I don't know, two thousand years for example. This is a kind of I'm just throwing that out there as as a off the top of my head example. And also radiometric dating dating, which is a not away for nuclear physicists to know, hang out and find that special someone. They use tender just like everybody else. It's more about actually looking at um radioactive decay. Not every layer of ice has anything in it like that, but some layers of ice do have trace amounts of uranium dust, and that would might be a way that we could date certain types. This is pretty deep in the Antarctic ice usually. Um As for what we can learn, we can learn lots of stuff, right, I mean, like it's really important information that tells us about the way our world has changed over huge expanses of time. Right. Well, I know one of the main things that scientists are looking at ice cores for these days is to help understand what past climate systems look like and to help predict what changes will be brought about by the current climate change we're observing right right, And of course you know, uh, you can't really make predictions without necessarily understanding what has happened in the past, right. You need to have that model there so that you can have something to base your predictions upon. So one thing you can easily see, and by easily I mean I described looking at those layers and seeing the summer and winter. You can easily see the general precipitation trends year over year by the thickness of those layers. Right, So if one summer winter layer is very thin compared to the next one below it, you could say, well, there was a year where there was a relatively heavy amount of precipitation followed by a year where there was very light precipitation. Then you could go and start doing more studies to see, like, while all, there are other elements inside this ice core that could indicate why that might have been the case. What what was going on in the atmosphere that would have made one year particularly heavy with precipitation and the following year light. Oh I see, So maybe you could just, for example, look at concentrate of different atmospheric chemicals in the layers preceding the layers that have more precipitation, so like, oh, wow, it's strange there was more nitrogen in the atmosphere the past three seasons before we had these heavy precipitation seasons. Or it might be look here, that's not a real result. And then you can also look and say, oh, look at the concentration of carbon dioxide for example. Now you've gotta be a little careful with this, particularly with the green Land examples, because carbon diox i can get dissolved in water, and sometimes they're they're also melting layers. Melting layers are where uh, you know, the temperaturey got high enough so that some snow had melted. The water can trickle down into the snowpack and you get these kind of bubble free areas of ice. That's a melt layer, which can still have a lot of useful information in it. But it also means that sometimes water that has carbon dioxide dissolved in it can set down into older layers and thus change the composition of them, giving you a false positive that there was more common carbon dioxide in a layer than there really was. Fortunately, scientists are aware of this. You know what to look for and uh and like I said, that's more prevalent in Greenland and Antarctica. You don't tend to see that same issue. But uh, you know, you can also look at things like, um, the chemical composition, which will tell you more about the concentration of greenhouse gases uh in any given year, and you can look for trends. Right, you can actually look and see like it may not be uh, this love layer was thick and that layer was thin. It maybe we're seeing a gradual decrease in layers over a really long time, followed by a period where they were very very thin layers for a long time, and then very thick layers as another ice age started coming on. You could actually see these big trends, because that's really what we're talking about with climate. Right, Climate isn't weather. We often, like the people often will conflay the two. Right, climate influences weather, right, and and climate is like you know, a weather is this is this localized, regional, temporal thing. Like it's happening in a very small time span. You're talking like, while the weather is terrible today, climate is long reaching. It can it's a global thing. It's not or at least a much larger regional thing. Um and it it is not. Uh, it's not as mercurial you could say, as weather would be, because weather can change dramatically day to day. Climate are these long trends. Describing climate would be like describing Jonathan's personality. Describing weather would be like can you believe what Jonathan said this morning? Yeah, we'll put so. Uh. By looking at this, we can say, all right, during this period of time where we know there was a greater concentration of greenhouse gasses because it was trapped in the ice. We have we have, uh, we've analyzed the ice. We know what the concentrations are. We can see from the following layers how that affected climate over a great span of time. So because our records don't stretch back that far, heck, our our weather records don't stretch back far at all. We're talking like a century or so, and otherwise we're we're relying upon things like the recollections that people had written down and either letters or or you know, just the general language used by people who are writing at the time what the weather might have been. Like. This is an actual way for us to look back and say, here's what the climate was a hundred thousand years ago, and here's what here's how the climate changed over a twenty thousand years span. I mean, it's a big picture look at something that otherwise we would just be making wild guesses about. And that's really interesting to me. Yeah, it's obviously incredibly useful. I have to say again, how much. Maybe it's just me, but anything that's that old gives me this very cool, mysterious feeling. I get a little try about it. Yeah, yeah, I mean, it's it's neat to know that there there exists a record where by applying careful scientific, careful scientific approach to analyzing that material, we can draw very very uh, very interesting conclusions about what the Earth was like well before humans were walking around and being human ish. I hope you enjoyed that classic episode about ice core drilling. If you have suggestions for topics I should cover in future episodes of tech Stuff, please reach out to me and let me know. The handle for the show on Twitter is text stuff hs W and I'll talk to you again really soon. Tech Stuff is an I Heart Radio production. 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