Instant Genius - Why is the magnetic north pole moving? - Ciaran Beggan

Episode Date: March 6, 2019

The Earth’s magnetic north pole is rocketing towards Siberia at 50 kilometres per year, making the maps of the magnetic field out of date faster than expected. Why is it moving, what does this mean for us, and what can we expect it to do in the future? Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough. Enough to get lost. Or you could book a stay with Hilton. Welcome to your ocean front room. Just steps from the water.

The Hilton sale is on now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton, for the stay. It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speed.

That's why I chose GoogleFi Wireless. My connections stay strong even when the hive is buzzing. Plus, unlimited plans started $35 a month. Now, that's a deal that doesn't stay. Explore Google Fi Wireless plans today. Plus taxes and government fees. GoogleFi Wireless is not subject to data traffic deprioritization during times of high network usage. No one goes to Hank's for his spreadsheets.

They go for a darn good pizza. Lately, though, the shop's been quiet. So Hank decides to bring back the $1 slice. He asks Copilot in Microsoft Excel to look at his sales and costs. Help him see if he can afford it. Co-pilot shows Hank where the money's going and which little extras make the dollar slice work. Now, Hanks has a line out the door.

Hank makes the pizza. Co-Pilot handles the spreadsheets. Learn more at M365Copilot.com slash work. This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name audio,

alongside French acoustic specialist focal, combine handcrafted tradition with cutting-edge innovation and high-end materials, delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. visit name audio.com to learn more. So we were a bit like sort of say forecast is where 100 years ago where we might have a general idea which way the wind is blowing at a few points

along the coast and so we could make a general prediction that the wind will probably still keep blowing that way tomorrow. But to make a detailed forecast of what will happen even a few days later it's just beyond our abilities at the moment because we cannot measure the magnetic field accurately enough at the edge of the outer core to understand exactly how the liquid's flowing. You're listening to the Science Focus podcast from the BBC Science Focus magazine team. With the UK's best-selling science and technology monthly,

available in print and in several digital formats throughout the world. Find out more at ScienceFocus.com or look out for us in your app store. Hello and welcome to the Science Focus podcast. I'm Daniel Bennett, the editor of BBC Science Focus magazine. The magnetic pole is not a fixed spot. Before 1990, the pole was wandering around northern Canada, moving at a relatively sedate pace of 5 kilometres per year. But then, suddenly, it began to accelerate.

Fast forward to today, and now the magnetic north pole is surging towards Siberia, at a blistering 50 kilometres per year. That's so fast that the map of the Earth's magnetic field produced by the British Geological Survey and the National Oceanic and Atmospheric Administration had to be updated this January a year earlier than anticipated. In this episode, Dr. Kieran Began,

cheer physicist at the British Geological Survey in Edinburgh, talks to our online assistant, Sarah Rigby, about why the Earth's magnetic field is changing, and what that means for you and me, and what we can expect in the future. But before we begin, I just want to let you know about a seismic shift of our own. Those of you listening closely might have noticed that we've changed the name of the magazine

from BBC Focus to BBC Science Focus. The magazine will still feature the same blend of new ideas and discoveries that you know and love. But we've also added a new section called Reality Check, which takes a deeper look at the science behind the headlines. So if you'd like to try out a free issue of the all-new BBC Science Focus, visit www. www.sciencefocus.com forward slash free issue podcast to view a copy online. And now over to Sarah, talking to Dr. Kieran Began.

So the magnetic North Pole has been moving and it's been accelerating. So why is it moving so quickly and why is it moving at all? So the magnetic field is created by the liquid outer core. and that starts about halfway to the centre of the earth. The liquid outer core is made mostly of iron and nickel. And although it's under a huge pressure from the rock above, it's actually very hot around about 3,000 degrees centigrade. So because of that, the liquid is actually very runny

and it's as liquidy as water is on the surface of the earth. So you've got this very large, convecting layer of liquid metal. And as it moves, creates the magnetic field, but also drags the magnetic field with it. So at the surface of the Earth, on average, the magnetic field moves maybe 20 kilometers or so per year, mostly in a westward direction. But that does vary across the world. Now, the reason the magnetic North Pole is moving is because we think just that there's very high latitudes up around northern Canada.

A very fast jet of liquid has formed sort of jet stream and it's pushing the magnetic field just in this area, particularly rapidly. If you look back at how the magnetic pole, the North Pole, has moved in the last 100 years or so, you'll see that during the 20th century, so from sort of 1900 to sort of 1990, the average rate of change at the pole's position was about 5 to 10 kilometres per year.

And then the 1990s has suddenly started accelerating up to about 50 kilometres per year. And at the moment it's moving between 50 or 60 kilometres per year. So that's quite a lot. So how is that going to, affect the average person? So the average person uses the magnetic field in their mobile phone

in their smart map application or in their in-car navigation system. And they use maps that the British Geological Survey and NOAA, the National Oceanographic Administration, make in the US. And the maps we make every five years make a prediction about how the field

will change in the following five years. So the last one was released in 2015. The next one would be, which had been released in 2020. But because the magnetic North Pole had moved just a bit further than we expected it to. By 2018, the map was sort of out of date. So we were asked to update the map, mainly because the North magnetic pole has moved so much more rapidly than we expected. Now, for the average user, unless you're planning to trips around the Arctic in Canada or Siberia,

you wouldn't really notice the difference because the magnetic field maps that would make for lower latitudes below sort of the latitude of Scotland, say, are actually fairly decent and they're not too much in error, but the ones and the high Arctic are out of error, basically, because the magnetic field moves much more rapidly than we expected. So the average user, you know, your digital compass in your smartphone is only really accurate to a degree or two, and the differences between our latest update of the map and the previous update of the map for most people will only be a fraction of a degree. Actually, this has not much impact on most users.

So I read that we used the position of the magnetic north on our smartphone to determine which way we're facing. So when you're on a smartphone app and it shows you you're facing this way down this road, it uses the magnetic north pole to determine that. Is that correct? Yeah. So when you open your smartphone map, it's orientated towards geographic north. But your phone uses it's a little digital compass. digital compass, a tiny little thing, a few millimeters across.

And that detects the direction of the magnetic north. And using the location of your phone from GPS or from the nearest mobile phone tower, the application uses the map that British Geological Survey have computed to work out what the difference between magnetic north and true north is at your location. and then it rotates the map without you knowing into the correct orientation. And then as you turn around, the map uses the digital compass to figure out what direction you're orientated in and then orientates the map as you're using it to the correct direction. So in the UK, the difference between true north and magnetic north that angle is about one degree

or two degrees, so it's not very much. But if you're in, say, California, it could be 15 degrees or if you're in South America, it can be up to 25 or 30 degrees in places. Okay, so the amount that the magnetic north is moving is not enough to really affect that. Is that right? Yeah, that's correct. So anywhere sort of south of Greenland, yeah, it's not really a big deal. Okay, so who does use these maps and who does need to keep up to date with it in high precision?

So one of the main users is people who fly aircraft over those regions. And so most aircraft maps are actually still oriented in magnetic coordinates for historical reasons. So these maps are quite important for aircrafts, say, flying from London and San Francisco, they fly quite high up over the northern Arctic. So the plane would be navigating on magnetic coordinates. So it makes a difference for those. I mean, what would happen is the plane would maybe drift from a few tens of kilometers out of where it should be. But, I mean, that would be corrected anyway by GPS.

So that would be kind of an economic saving. The people who mainly use it are the UK and the US military. So they use it for their navigation systems in submarines and aircraft and so on. And also for working out which way they're pointing and so on. I read that the names of certain airports is affected by this. Is that correct? Yeah. So again, this goes back to historically runways are always marked and magnetic coordinates.

So runways in the high Arctic, you know, if they're facing kind of east-west, they'll be labeled 90-270 because that's the kind of orientation and magnetic coordinates. But if as the magnetic field moves away from the high Arctic

rapidly, then those runways have to be repainted with the new coordinate system and that presumably costs them kind of money and that's confusion if they have to change it every five years rather than in the past it, already change it maybe every a couple of decades. Okay, so why would they use the magnetic coordinates as opposed to coordinates

in relation to the geographical? Well, again, it's historic. So it comes from the time, you know, before GPS was kind of common in the 1990s, that, you know, airplanes used to fly using dead reckoning. So, you know, you take off and you fly a certain distance on a certain compass bearing for a few hundred miles, and then you'd sort of take a left and fly another few hundred miles. a different compass bearing. So airplanes are set up to kind of fly in magnetic coordinates. But since the advent of GPS, of course, that's not necessary anymore, but it's sort of a historical hangover.

I guess in the next few decades, I'll probably disappear entirely, the use of magnetic coordinates. So how do we know that the magnetic north is changing? How do we measure this? So in the past, up until the kind of 1990s, early noughties, there were around. around about 200 observatories, geomagnetic observatories around the world, and they were mostly in the northern hemisphere, mostly kind of around Europe, and then a few kind of scatter around the world. These are places where we just measured the magnetic field continuously. But since 2000,

there have been a number of satellites that been launched into low Earth orbit, so they go up to about 400 kilometers, and they just fly around, just continuously measuring the magnetic field in its direction. And the latest bunch is a trio of satellites from the European Space Agency called Swarm. and they're very, very high precision, very, very accurate satellites, and they're built specifically just to measure the magnetic field of the Earth. Because there's three of them, we're getting huge volume of data over the last five years or so. And that allows us to, first of all, make better maps in the magnetic field. And also we can now, with the kind of advances in computing and disk storage,

we can now make these maps every six months or so, and we can see how the field is changing much more rapidly than we used to be able to do in the past. So it's really this volume of data from, satellite missions, along with improved computing and more disk space and the internet and so on, that allows data to be transferred much more rapidly. That's allowed us to make these maps much better and also to kind of find that the magnetic north pole is actually moving more rapidly than we expected. It sounds like there's also a lot of historical data about this as well. So, you know, before we started mapping the magnetic field so much, how, you know, historically did we

measure this? So it's been used for ship navigation for hundreds of years, and we've got ships, records, logs and logbooks going back to the 1590s or maybe even a bit earlier. And you can use those to work out where the magnetic north was by looking at all the measurements back in the past. It gets a bit more blurry as you go back further in time because there are fewer measurements and then they're sort of not as widely distributed around the world as, say, satellite data are. But that tells us that from the 1500s onwards, actually the magnetic fields, more North Pole,

particularly, kind of wandered around Canada more or less in a sort of erratic zigzaggy manner. And it really wasn't until the 1900s that it actually started moving westwards towards Siberia and sort of accelerating that way the last 30 years or so. Okay, so we can look at how people used to use compass coordinates and figure out where they were trying to get to and where they were pointing. Yeah, so the idea originally was from Edmont Halley of Comet fame. They were looking for a way to sort of solve the so-called longitude problems, where they knew how to measure latitude, which is your sort of position on the

sun, a position on the earth between, say, the equator and the north pole by looking at the height of the sun, the sky. But to measure longitude, which is sort of your position east or west of, say, Greenwich, that was much more difficult. So one of the ways I thought what they could do was looking at the variation in the angle of the magnetic field between true north and magnetic north. That's called declination. So in 1699, Edmund Halley went out in the ship and surveyed the Atlantic Ocean. And he came back and then drew up these maps, the original kind of maps on the magnetic field.

And they went back out again. He looked again and he realized that actually the angle had changed and it changed so quickly that his maps were basically out of date after five or ten. years. They couldn't be used for determining longitude. So he made the most amazing leap, which is that he thought, how is that the magnetic field is changing? And he suggested there must be a layer of liquid somewhere within the earth that was causing the magnetic field to move. So he was the first person to assume or dream of the idea of an outer core. And that wasn't confirmed until the 1906, actually, by seismological data. Did Edmund Halley have a good grasp of where magnetism comes from? No. No. No.

At the time, they still assumed that magnetism was fixed into the rocks or sort of liquid layer. They assumed it was just like magnets you get in your fridge or little compass needles. So, no, he didn't know that there was a liquid layer, but he suggests it was the most kind of an obvious way to solve the problem of the fact that the magnet field changed continuously. Oh, I see. Looking forwards into the future, what can we explain? in terms of this magnetic north movement, do we think it's going to carry on accelerating or do we think it might sort of steady out? We have no idea.

So if you look at longer records and it gets kind of less certain as you go back in the past, so you can look at archaeological records or you can look at records from muds in the bottom of the seafloor. So as a particle, a general magnetic particle piece of iron or something, it falls through the water and lands on the seafloor and, say, the deeper part of the ocean, it actually sort of aligns itself with the magnetic field of the earth. So you can sort of drill a borehole and sort of pull out these cores of mud and sort of sand and dirt. And you can actually measure the direction the magnetic field going back tens of thousands of years quite accurately. So it just looks like the natural behavior of the field. It just sort of moves back and forward all the time over the

course of centuries. Sometimes it stops for a while, sometimes it keeps going back and forward. And because it's to do with the flow of the outer core and because the outer core is so far away, we can't really sort of figure out exactly what the detailed flow of the outer core is. So we're a bit like sort of say, forecasters where 100 years ago where we might have a general idea which way the wind is blowing at a few points, you know, along the coast. And so we could make a general prediction that, you know, the wind will probably still keep blowing that way to But to make a detailed forecast of what will happen even a few days later is just a bit's beyond our abilities at the moment. Because we cannot measure the magnetic field accurately enough at the edge of the outer core to understand exactly how the liquid's flowing.

So if this continues to shift around or even continues to accelerate, is there any point at which the general public need to start worrying about this? Well, I mean, there have been reversals of the field in the past many, many times. And that's where the magnetic north pole and the magnetic south pole sort of switch over. But again, you have to look back at the last one of these reversals was about 780,000 years ago. And so there are no modern records of these kind of reversals. So you have to look at lava flows because as a volcano erupts, it just sort of traps a record of the magnetic field within the lava flows. when they cool down. So you can look at piles of lava flows

and see how the magnetic field has changed. And again, it's very uncertain as to exactly how the magnetic field reverses. But it looks like mostly it takes between 3 to 5,000 years, sometimes less, sometimes more. But what happens is the magnetic north and magnetic south pole disappear for maybe a few thousand years. And what happens is you get lots of small little magnetic poles appearing across the surface of the earth,

sort of like spots on the face. And all that happened is your composite point to the nearest one of those rather than pointing north or south. But again, it takes so long that, you know, in any one person's lifetime, they wouldn't really see too much change in the magnetic fields that would affect them. And things like satellites and so on that are susceptible to magnetic storms, for example, would have to be more heavily shielded, for example. But again, because this would change over, you know, hundreds of thousands of years, I'm sure technology would evolve to keep pace with it. So when that happened, when we lost our northern and south magnetic poles, how would that affect our ability to navigate? Well, I mean, it would be the case that, yes, you'd need more people like me to make your maps up to date more and more often. So you wouldn't, your compass wouldn't point north, basically.

It would point to some particular direction and that direction vary in where we went on the world. So actually, it makes navigation very hard, maybe just using a compass alone. But you'd assume that GPS would be more or less unaffected by these kind of changes because they don't rely on magnetic fields. GPS relies on radio waves to give you your location on the surface of the Earth. So the auroras, they also tend to gravitate towards the magnetic northern south poles, don't they? Yeah, that's correct. So if as the north magnetic pole moves, yes,

the aurora, position of the auroras will move with it. The aurora tends to form a sort of large ring around the north and a south magnetic poles. So, yeah, the aurora will move as well. And if the field reversed entirely, then yes, what you'd have is probably lots of local aurora and kind of middle attitudes and sort of low latitudes, wherever there was a sort of local magnetic pole. You'd probably get a ring of aurora around us, you know, when the magnetic field got active. because that's driven by the sun's magnetic field. I know there are certain animals that navigate by,

or that we seem to think they navigate based on the Earth's magnetic field. Is the moving magnetic north going to affect then? Well, presumably they'll be able to sense it. But again, the changes are so slow, I think over the lifetime of any given animal, they'd be able to adapt. Because it's, you know, so things like whales, I believe, are, you know, navigate by magnetic field. But, you know, if they swim back and forward to the same place every year, the magnetic field will only have moved a small amount compared to where it was

the last time around. So I think they would, they would realize that and adapt their kind of mental map, I guess, to account for the change in the magnetic fields. Because, I mean, as I say, it changes all the time anyway, so the animals will have to do this one way or another. Okay, so this, even 50 or 60 kilometers in a year won't make much of a difference for most animals? I don't think so. I mean, because this would be right at the polar regions, so I doubt many whales actually swim under the ice cap. Not that I know. But I think things like birds and so on, you know, if they got slightly lost, they navigate using landmarks, you know, hills and mountains and coastline as well as the magnetic field. So the magnetic field gets the most of the way there

and then they recognise a spot that they've seen before and they go, oh, I'm slightly up. So they would correct for that the next time, I'm sure. Do we know of any particular significance about why it's moving in the particular direction that it's moving, or is it just random? I think it's just random. It's just natural variation. I mean, you know, in a few decades' time, they start moving back the way it came. Or could have gone in a large loop around the north's geographic pole, for example. I don't really know.

It could just wander back and forward. It's currently unpredictable. We don't know. And if humans wanted to do something about this, if we wanted to try and sort of stop it and make it steady just to make our lives easier for whatever reason, would we be able to do that? No. So the outer core is about the size of Mars and it's sort of, it's very large. It contains a vast amount of energy. You can imagine how much energy it requires to keep a bowl of that liquid. and nickel kind of molten.

So the energy is left over from the formation of the Earth. So the Earth is still slowly cooling down from its formation four and a half billion years ago. To try and affect it is just, we just, you know, we don't have enough energy available as a human race to kind of do that, despite what films like the core from years ago I suggest. Nuclear weapons would be just sort of like firecrackers, you know, in a hurricane, just, you know, pointless. So am I correct in thinking that the Earth's magnetic field is weakening? Yes, it's been weakening for the past couple of hundred years.

So if you look back over 10,000 years, it's sort of going back to the average strength that has been over the last 10,000 years. So the last 3,000 years has been actually kind of anomalously strong. And then sort of a few thousand years before that, it was kind of a bit weaker than it is nowadays. So again, it's just natural variation. It strengthens and weakens all the time. time. Again, just due to the flow of the liquid outer core and how the magnetic field is generated within the core. So it's just a function of that.

Okay. How does the flow of the core make it stronger or weaker? So we're getting more technical detail there. So the actual magnetic field is created by there's a very large loop of electric current. So a magnetic field is generated by an electric by flowing electricity in the same way that we make it energy for the grid. So an energy, a generator is a magnet spinning, a spinning magnet creates an electric field. But then the opposite is true that an electric field creates a magnetic field. So within the core, there's a very large electric field going kind of, you can imagine, just sort of around the equatorial region.

And that generates the magnetic field. but the fluid flow in a very complicated way modifies the electric current and then the electric current will get weaker or stronger, particularly the bit we sort of detect on the surface because there's a large amount of magnetic field in the core itself that we just can't detect because it never leaks out. So as the Earth's magnetic field gets gradually weaker, well, the Earth's magnetic field provides us with a lot of protection from space, isn't it? So at what point would we need to start worrying, has it gradually got weaker? Well, again, I think this is a sort of a bit of a myth. The magnetic field protects the Earth's atmosphere over long periods of time, over millions and billions of years.

And it stops the sun's magnetic field essentially eroding off to the upper bits of the atmosphere. Because that's what's happened in Mars. So Mars has no magnetic field, which is why its atmosphere was kind of mostly blown away. And of course, gravity is weaker, so that that's two combined effects. But on the Earth, because the magnetic field,

when it reverses, doesn't actually disappear as such. It just gets a lot weaker than it currently is. There's still a magnetic field so that it still does deflect the solar wind and stops eroding our atmosphere. But in terms of cosmic rays and stuff like that,

it's mostly the atmosphere that protects people on the ground, certainly at sea level from getting, say, a large dose of radiation. If you live somewhere high in a mountain like the Himalayas or in say Colorado or somewhere like that, you are exposed to more cosmic radiation anyway. And I presume a weakly magnetic field will probably give you a larger annual dose of cosmic rays than you get under strong field conditions.

But overall, there seems to be no relation between the changing and reversing a magnetic field and say mass extinctions and so on. They related to different effects. That was Dr. Kieran Beggen, talking about the Earth's magnetic North Pole. In the latest issue of BBC Science Focus, the first featuring our brand new design, we explore the hidden power of the brain. We also look at what the oldest galaxies in the universe can teach us.

We examine how leaders seem to fail upwards and introduce a new section called reality check. And as always, there's much, much more inside. And remember, if you like what you hear, then please rate a review and share with anybody who's think might enjoy our podcast. You can also subscribe and leave us a review on your favourite podcast apps. Also, if there's anybody you'd like us to speak to or a topic you want us to cover, then let us know on Twitter at Science Focus. Thank you for listening to the Science Focus podcast from the BBC Science Focus magazine team. With the UK's bestselling science and technology monthly, available in print and in several digital formats throughout the world. Find out more

at ScienceFocus.com or look out for us. in your app store. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analog warmth. Alongside French acoustic specialist focal,

Name creates high-end audio systems combining innovation with craftsmanship so you can listen to music, just as the artist intended. Discover more at Name Audio.com. Home. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building. Fit for your ambition for Citizens Bank. Some follow the noise. Bloomberg follows the money, whether it's the funds fueling AI or crypto's trillion dollar swings.

There's a money side to every story. Get the money side of the story. Subscribe now at Bloomberg.com.