March 25, 2015 • 41 mins
How do scientists retrieve ice core samples? What can we learn from them? Joe McCormick joins the show to talk about really cool historical records.
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Speaker 1 (00:04):
Get in touch with technology with tex Stuff from Either
and Welcome to Tech Stuff. I'm Jonathan Strickland and I'm
joined in the studio once again by my buddy Joe McCormick,
UH co worker, a colleague, co host of Forward Thinking, Uh,
(00:25):
Poopy Food. How you doing, Joe? I'm great, Hi everybody.
So Joe you you know I always like to ask
my potential co hosts what they would like to cover
in any given episode. And Joe, you had a really
interesting idea that that honestly had not occurred to me
to cover before. Well, I didn't know if we would
make a good episode, and I guess at this moment
(00:48):
I still don't know, but I guess we will. In
exactly we'll figure it out. But it was an idea
that came to me because I like to think about
ancient time 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.
(01:09):
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
(01:32):
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,
(01:53):
all 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 mountains, Yeah, misty mountains. That What did
(02:13):
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 the 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,
(02:36):
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,
(02:58):
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
(03:19):
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 that there is layer upon layer of evidence of
(03:42):
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 all in
the lake to remain liquid. Oh I actually didn't know
(04:02):
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 were
(04:23):
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
(04:45):
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
(05:05):
point where the season's warm, the snow starts to uh
to 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
(05:26):
layer of snow. Right. 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 into
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 can start to draw some conclusions about
(05:49):
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
(06:10):
is a way of getting at this cross section of
geological time that we can see in the ice layers
of glaciers, right, and a lot of it's going to
be you know, in places 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
(06:33):
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
(06:54):
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 for you know, like like a month at
(07:14):
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
(07:36):
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 a volcanic eruption. You can see kim
(08:00):
iCal 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, and you can see like there
(08:21):
was heavy snowfall this year and light snowfall the next year,
and we'll talk more about that, get more into detail
and a little bit. 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
(08:42):
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
(09:03):
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 creepy 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
(09:25):
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,
(09:45):
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 gonna 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
(10:07):
the hole as it goes deeper in. It's just a
solid shaft. Yeah, it's not gonna 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 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
(10:30):
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
(10:51):
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
(11:12):
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
(11:33):
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
(11:56):
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 often these drills
(12:19):
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,
(12:40):
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
are the The simplest of these mechanical drills are the
hand powered augers. You actually move these by hand. It
(13:05):
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 in the right handle
like that 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
(13:25):
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
(13:48):
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 made up
of segments. So depending upon the drill you're using, your
segments maybe between one and six ms long, right, So
(14:09):
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
(14:31):
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
(14:51):
extenders will exceed the strength and flexibility of that device,
So you can't you can't indefinitely use a hand dogger.
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
(15:14):
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
(15:37):
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 to 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
(15:57):
around forty, so it's even further other 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 physical um turning mechanism that
(16:20):
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,
(16:41):
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
(17:04):
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 your drill bit that are
getting the shavings out of the wall, and the excase,
they're transporting the ice chips up along the length of
the drill. That's right. And so you would use this
(17:26):
the same way you would use your handogger, 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
(17:47):
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
(18:10):
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
(18:33):
are called something that I love, core dogs. It's like
it's like going to the county fair and get yourself
and a couple of core dogs. I like to go
to Polucaville 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
(18:55):
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
(19:16):
of the lip of the pipe 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.
(19:37):
I mean, come on, it's ice, let's use heat to
melt away down there. Yeah. That actually does seem like
it 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,
(19:58):
you wouldn't use that in older 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 situations,
it will still be really cold. Um And then if
(20:21):
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. So it's not like some only
used one and some only use the other. Most will
(20:42):
rely on whichever one is the best fit for that
particular set of conditions. 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
(21:02):
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. Yeah, you got to
remember this ice is under a lot of pressure. I mean,
just from Waight 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,
(21:25):
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 close,
we've pretty much bean collapse in on itself. Like closing
sounds pretty gentle, it's not a gentle thing. Well, whether
(21:46):
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 hole, 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,
(22:08):
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 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,
(22:29):
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.
(22:51):
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,
(23:13):
which is a recent effort by the United States in
which an ice core that was three thousand, four d
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
(23:35):
obviously more than um uh 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 project workers per shift, so nine people working
for six days a week and drilling is going on
(23:59):
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 cores 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
(24:20):
want to see that person ever again. Right 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. That
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
(24:41):
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, right,
(25:06):
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,
(25:27):
you know. Now, to be fair, if you're getting them
from Greenland, I think the oldest we've looked at it
is a hundred thirty 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
(25:49):
running rampant. Probably not, but at any rate, they would
that be detectable from the ice we see dissolved particulates
of I don't know. Yeah, just like there's there's one
of the chemical constituents of the old one, right, you
can 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
(26:12):
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
(26:34):
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 thousand, five fifty 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
(26:57):
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 storage facilities. It
(27:17):
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, just just an ancient on the rocks, right, yeah,
(27:38):
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 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
(27:58):
stoner comedy of 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 planet. There's money in this, Joe, I
think we need to develop it. But before that we
(28:18):
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.
(28:41):
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.
(29:01):
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 represent a year's
passage of time. Right, You've got the summer and winter there,
(29:21):
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
backwards 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
(29:41):
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 lay or should represent,
testing the chemical composition of that particular layer of the ice,
(30:06):
and comparing it to data that we have from other means,
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,
(30:29):
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
(30:50):
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 solid form of
a fluid, but it still has some fluid mechanics to it, right,
It's not 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
(31:12):
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
(31:34):
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
(31:56):
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
(32:17):
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
(32:40):
can make things a little more complicated. Uh, having those
numerical flow models, which essimpially 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 would we consider
(33:01):
like how how far down would we go before we
hit I don't know, two years for example. This is
the kind of I'm just throwing that out there 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
(33:23):
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
(33:43):
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
(34:06):
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
(34:28):
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
(34:51):
year where there was very light precipitation. Then you could
go and start doing more studies to see, like, while
there are other elements inside this ice core 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,
(35:12):
I see, So maybe you could just for example, look
at concentrations 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 up, that's not
(35:34):
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 doox i can get
dissolved in water and sometimes they're they're also melting layers.
Melting layers are where, uh, you know, the temperature got
high enough so that some snow had melted. The water
(35:55):
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 be 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
(36:17):
you a false positive that there was more common carbon
dioxide in a layer than there really was. Fortunately scientists
are aware of this. 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,
(36:38):
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
(36:58):
by uh, 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 conflate the two. Right, climate influences weather, right,
(37:20):
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,
(37:44):
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's
said this morning? Yeah? Well, put so. Uh. By looking
(38:07):
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
(38:29):
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
(38:51):
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,
(39:15):
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
teary 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,
(39:40):
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. You know, it's really kind
of interesting. And again, shuck ups. So well, Jonathan, thanks
(40:01):
for helping me look into this totally random question. This
was this was interesting. I'm curious too because we have
love listeners who have done a lot of different things
and including people who have worked on really interesting scientific projects.
So if any of you out there have ever worked
on something like this. If you've ever used like an
ice drill an auger in that sense, I would love
(40:22):
to hear about your experience and what it was like. Um.
I mean, I know a lot of you guys out
there and probably used augers in one way or another.
Buzz specifically talking about ice drills in this case. Uh.
If so, you should let me know, send me an
email message, and if you want to hear a podcast
about a specific topic something else about technology, whether it's
how something works or a bigger picture on a particular
(40:45):
company or personality, let me know. That email address is
tech Stuff at how stuff works dot com, or you
can drop me a line on Facebook, Tumbler, or Twitter.
The handle at all three is tech Stuff H s W.
We'll talk to you again really soon for more on
(41:09):
this and thousands of other topics because at how stuff
works dot com
Get in touch with technology with tex Stuff from Either
and Welcome to Tech Stuff. I'm Jonathan Strickland and I'm
joined in the studio once again by my buddy Joe McCormick,
UH co worker, a colleague, co host of Forward Thinking, Uh,
(00:25):
Poopy Food. How you doing, Joe? I'm great, Hi everybody.
So Joe you you know I always like to ask
my potential co hosts what they would like to cover
in any given episode. And Joe, you had a really
interesting idea that that honestly had not occurred to me
to cover before. Well, I didn't know if we would
make a good episode, and I guess at this moment
(00:48):
I still don't know, but I guess we will. In
exactly we'll figure it out. But it was an idea
that came to me because I like to think about
ancient time 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.
(01:09):
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
(01:32):
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,
(01:53):
all 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 mountains, Yeah, misty mountains. That What did
(02:13):
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 the 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,
(02:36):
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,
(02:58):
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
(03:19):
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 that there is layer upon layer of evidence of
(03:42):
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 all in
the lake to remain liquid. Oh I actually didn't know
(04:02):
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 were
(04:23):
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
(04:45):
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
(05:05):
point where the season's warm, the snow starts to uh
to 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
(05:26):
layer of snow. Right. 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 into
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 can start to draw some conclusions about
(05:49):
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
(06:10):
is a way of getting at this cross section of
geological time that we can see in the ice layers
of glaciers, right, and a lot of it's going to
be you know, in places 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
(06:33):
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
(06:54):
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 for you know, like like a month at
(07:14):
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
(07:36):
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 a volcanic eruption. You can see kim
(08:00):
iCal 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, and you can see like there
(08:21):
was heavy snowfall this year and light snowfall the next year,
and we'll talk more about that, get more into detail
and a little bit. 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
(08:42):
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
(09:03):
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 creepy 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
(09:25):
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,
(09:45):
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 gonna 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
(10:07):
the hole as it goes deeper in. It's just a
solid shaft. Yeah, it's not gonna 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 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
(10:30):
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
(10:51):
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
(11:12):
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
(11:33):
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
(11:56):
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 often these drills
(12:19):
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,
(12:40):
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
are the The simplest of these mechanical drills are the
hand powered augers. You actually move these by hand. It
(13:05):
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 in the right handle
like that 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
(13:25):
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
(13:48):
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 made up
of segments. So depending upon the drill you're using, your
segments maybe between one and six ms long, right, So
(14:09):
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
(14:31):
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
(14:51):
extenders will exceed the strength and flexibility of that device,
So you can't you can't indefinitely use a hand dogger.
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
(15:14):
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
(15:37):
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 to 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
(15:57):
around forty, so it's even further other 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 physical um turning mechanism that
(16:20):
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,
(16:41):
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
(17:04):
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 your drill bit that are
getting the shavings out of the wall, and the excase,
they're transporting the ice chips up along the length of
the drill. That's right. And so you would use this
(17:26):
the same way you would use your handogger, 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
(17:47):
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
(18:10):
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
(18:33):
are called something that I love, core dogs. It's like
it's like going to the county fair and get yourself
and a couple of core dogs. I like to go
to Polucaville 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
(18:55):
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
(19:16):
of the lip of the pipe 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.
(19:37):
I mean, come on, it's ice, let's use heat to
melt away down there. Yeah. That actually does seem like
it 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,
(19:58):
you wouldn't use that in older 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 situations,
it will still be really cold. Um And then if
(20:21):
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. So it's not like some only
used one and some only use the other. Most will
(20:42):
rely on whichever one is the best fit for that
particular set of conditions. 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
(21:02):
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. Yeah, you got to
remember this ice is under a lot of pressure. I mean,
just from Waight 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,
(21:25):
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 close,
we've pretty much bean collapse in on itself. Like closing
sounds pretty gentle, it's not a gentle thing. Well, whether
(21:46):
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 hole, 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,
(22:08):
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 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,
(22:29):
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.
(22:51):
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,
(23:13):
which is a recent effort by the United States in
which an ice core that was three thousand, four d
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
(23:35):
obviously more than um uh 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 project workers per shift, so nine people working
for six days a week and drilling is going on
(23:59):
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 cores 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
(24:20):
want to see that person ever again. Right 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. That
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
(24:41):
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, right,
(25:06):
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,
(25:27):
you know. Now, to be fair, if you're getting them
from Greenland, I think the oldest we've looked at it
is a hundred thirty 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
(25:49):
running rampant. Probably not, but at any rate, they would
that be detectable from the ice we see dissolved particulates
of I don't know. Yeah, just like there's there's one
of the chemical constituents of the old one, right, you
can 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
(26:12):
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
(26:34):
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 thousand, five fifty 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
(26:57):
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 storage facilities. It
(27:17):
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, just just an ancient on the rocks, right, yeah,
(27:38):
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 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
(27:58):
stoner comedy of 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 planet. There's money in this, Joe, I
think we need to develop it. But before that we
(28:18):
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.
(28:41):
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.
(29:01):
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 represent a year's
passage of time. Right, You've got the summer and winter there,
(29:21):
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
backwards 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
(29:41):
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 lay or should represent,
testing the chemical composition of that particular layer of the ice,
(30:06):
and comparing it to data that we have from other means,
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,
(30:29):
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
(30:50):
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 solid form of
a fluid, but it still has some fluid mechanics to it, right,
It's not 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
(31:12):
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
(31:34):
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
(31:56):
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
(32:17):
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
(32:40):
can make things a little more complicated. Uh, having those
numerical flow models, which essimpially 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 would we consider
(33:01):
like how how far down would we go before we
hit I don't know, two years for example. This is
the kind of I'm just throwing that out there 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
(33:23):
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
(33:43):
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
(34:06):
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
(34:28):
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
(34:51):
year where there was very light precipitation. Then you could
go and start doing more studies to see, like, while
there are other elements inside this ice core 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,
(35:12):
I see, So maybe you could just for example, look
at concentrations 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 up, that's not
(35:34):
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 doox i can get
dissolved in water and sometimes they're they're also melting layers.
Melting layers are where, uh, you know, the temperature got
high enough so that some snow had melted. The water
(35:55):
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 be 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
(36:17):
you a false positive that there was more common carbon
dioxide in a layer than there really was. Fortunately scientists
are aware of this. 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,
(36:38):
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
(36:58):
by uh, 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 conflate the two. Right, climate influences weather, right,
(37:20):
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,
(37:44):
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's
said this morning? Yeah? Well, put so. Uh. By looking
(38:07):
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
(38:29):
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
(38:51):
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,
(39:15):
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
teary 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,
(39:40):
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. You know, it's really kind
of interesting. And again, shuck ups. So well, Jonathan, thanks
(40:01):
for helping me look into this totally random question. This
was this was interesting. I'm curious too because we have
love listeners who have done a lot of different things
and including people who have worked on really interesting scientific projects.
So if any of you out there have ever worked
on something like this. If you've ever used like an
ice drill an auger in that sense, I would love
(40:22):
to hear about your experience and what it was like. Um.
I mean, I know a lot of you guys out
there and probably used augers in one way or another.
Buzz specifically talking about ice drills in this case. Uh.
If so, you should let me know, send me an
email message, and if you want to hear a podcast
about a specific topic something else about technology, whether it's
how something works or a bigger picture on a particular
(40:45):
company or personality, let me know. That email address is
tech Stuff at how stuff works dot com, or you
can drop me a line on Facebook, Tumbler, or Twitter.
The handle at all three is tech Stuff H s W.
We'll talk to you again really soon for more on
(41:09):
this and thousands of other topics because at how stuff
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