SIO449: The Northern Lights Went South for the Summer

Transcript

This transcript was generated automatically and may contain errors — the audio is the record.

0:00:16 Thomas: And welcome to Serious Inquiries Only. This is episode 449. I'm your host Thomas Smith, and today I've got astrophysicist Dr. Brian Gillis to explain what the hell happened to the sky the other day. Is important. Somehow the northern lights were no longer northern. They were very much lights, but they were not as much northern as they normally are. And Brian volunteered to explain that to us, and it's very complicated.

It is so much more complicated than you might think, a lot of really fascinating and complex science here that make sense for us, so that's pause for a brief break that you don't have to hear if you're a patron at patreon.com/seriespod. I also want to note that a Seriously Awful Movies or a Seriously Good Thing is on deck. Steve Propper is back, and he decided to give us a break and let us watch something good.

And we watched the pilot episode of Scrubs to talk about kind of the medical science involved there. And it was a very pleasant change from having to watch House. So that'll be on patreon.com/seriouspod very soon. Thanks much to those who support the show, you're the best, you make it happen, and I hope you enjoy the no ads and the goodies. All right, after this break, let's find out what in the world happened to the sky the other day. We're joined by Brian, everyone's favorite astrophysicist, to tell us what happened to the sky. It broke, I think. How's it going, Brian?

0:01:44 Bryan: Yes, hello, Thomas. Things are going well with me and how are things with you?

0:01:48 Thomas: I heard from the outside world that something happened in the sky, I've only, I haven't been chained to a rock in a podcast factory, but people tell me something happened.

0:01:57 Bryan: Oh, yeah. Yeah. I've heard you've been making a new podcast there. Congratulations. This is what, number six, something like that?

0:02:05 Thomas: Knows? Yeah, thank you.

0:02:07 Bryan: Okay. Yes. So for those who haven't heard, or are listening to this far in the future, just the last week, there was a phenomenal display of the Northern Lights, which was, is visible from much further south than is normal. Many people in the U.S. even were able to see them, which, outside of Alaska, almost never happens. So I thought that was a good time, had an open slot in the show, so I could come in and talk a bit about what exactly the Northern and Southern Lights are and why ridiculously magical -looking thing actually happens, well.

0:02:45 Thomas: I'm rooting, rooting for apocalypse. I'm hoping it means it's all over soon, but maybe there's just a more basic explanation. But yeah, it really was incredible. I, Lydia messaged me and was like, "Hey, you should go see the Northern Lights." I was like, what in the world does that mean? Like, is there, is this code for something? What are you talking about? I had no idea, because that, like in a normal day that, what does that mean? That means like, hey, I know it's like 9 p .m. and you're editing or whatever, it was like 10. But go to right now or something, you know? And then I just was too busy. And then, I saw people start to post stuff. I was like, oh, shit, really? And it was visible all the way where were, I think, or not far away from it, which is, you know, Sacramento is not the North Pole here. It's not, uh, it's not very North.

0:03:03 Bryan: Yeah.

0:03:38 Bryan: That, that was extremely unusual, and good news is that, uh, probably won't be the last time in the near future that there are going to be some good Northern Lights displays. It might not get as far south as Sacramento again, but, uh, from, from everything I've heard, we're kind of entering a part of like an 11 -year or so cycle of the sun's activity where seeing the Northern Lights becomes more and more common, if you're living a bit further north than that, in the regions that can normally see it. So the cutoff for that is roughly the UK, Northern Europe, Northern Russia, and mid to northern Canada. Canada.

0:04:21 Thomas: Hmm.

0:04:21 Bryan: So like if you're above the southern strip of Canadian cities where they're all clustered, if you'RE a bit above that, you can often see the northern lights. So that's the region that can normally see them. And then of course, the southern lights too. Physically, they're exactly the same phenomenon just on the other side of the planet. Yeah, they'll be active too if youRE in Australia or New Zealand. You should have some good chances to see them again if you miss them this time.

0:04:46 Thomas: Oh, I just never thought about obviously the fact that there would also be Southern lights. Is it just cause there's not as many people that tend to witness that? Why, why did the Northern lights get all the credit in

0:04:54 Bryan: Yeah, it's just because there are so many more people in the Northern Hemisphere.

0:04:58 Thomas: The range of that? Uh, okay. But

0:04:59 Bryan: That either already live close to them or can travel there quickly. The the Northern Lights are called the Aurora Borealis and the Southern Lights are call Aurora Australis. They're called the aurora in general. But the Southern Lights is visible from just Australia and New Zealand. Then, not too commonly, They're most often seen by people who are, you think they were first observed by Westerners on ships that were exploring the Southern Hemisphere. Now that there are more residents of Australia and New Zealand, they get seen more commonly. But yeah, they just don't get talked about as much. The down the Southern hemisphere just get forgotten about.

0:05:39 Thomas: They've got got lights lights too.

0:05:41 Bryan: Definitely.

0:05:41 Thomas: I, you know, I also saw the Northern Light's just on a flight, cause the, across the country usually does that like upward word geodesic or whatever the heck it's called and you're usually like

0:05:48 Bryan: Yeah. Yeah. Yeah. Can see a lot farther north when you're up higher.

0:05:53 Thomas: And took me a second to realize what it was. I was like, what in the hell is that? And then I thought of it. It's like, maybe that's the Northern Lights. I never thought of like the angle, you know, being able to see kind of further than you than you might think, but it is a really cool looking thing or

0:06:00 Bryan: Yeah, yeah, definitely. So a bit about them in general. Already covered the where for the northern lights, but if you want to get a bit more technical, the form in a ring around the poles. They aren't actually at the poles, but in a wing around them. And then you can see them from much farther outside of that ring. Then if you get too far away, the curvature of the earth gets in the way, typically, unless, of course, you're in a plane, in which case you can see much farther.

0:06:36 Thomas: If you're a flat earther, then exactly because it it, it, it respects your religion, and they're just visible all the time.

0:06:38 Bryan: Then can always see them. Yeah, yeah. The next is probably what. What do they look like? A of people have probably seen the Northern Lights without without realizing it, as one of the forms they take is just a glow in the north. And I've actually seen that rather commonly living in Scotland as well, within the zone where you can see the Aurora under normal conditions. And I an app on my phone which gives me alerts for that. If you also live in the UK, it's called Aurora Watch UK, for Android. I think they also have an iPhone version. Actually gave me an alert tonight. So after we're done recording this, I might have to go and check and see if we can see them again.

But most often when I get an alert, it's just, oh, there's a bit of a glow to the north. Which, yeah, that is them. But it's not the fantastical displays you see people posting pictures of. And what it actually turns out is going on with a lot of those pictures is what people are posting online, line mostly are long exposure photographs, which can pick up much more subtle contrast in the sky than you can see by eye.

So the photos actually look a lot better than the Aurora look in reality, unless you're lucky enough to live in a place that's far away from any light pollution, which almost definitionally most people don't. Most people live in cities where there are lights even at night. But those who can get from it, can have the Northern Lights being the only significant source of light aside from the stars in the sky, and get some fantastic shows that can just be seen by eye.

0:06:59 Thomas: That would be cool. Know, I would say it was one of the most disappointing things the day I learned that those, a lot of the coolest photos just of anything are the long exposure stuff, like the night sky. I'd be like, boy, you sure can see a whole lot of that Milky Way when you're, I guess, I don't know, somewhere other than here, and it's like, well, no, a camera just was left on for a month, and then that's what it looks like.

0:08:25 Bryan: Yeah.

0:08:44 Bryan: And a lot of that we could have seen if it weren't for all of the light. And of the frustrating things is light pollution is one of those things that isn't really good for anyone. Wasteful of energy if you have light that's going off into the sky. And there are, you very often some simple modifications that can be made to street lights. Like, need the light to go down. So if you just put a reflective surface above it, you'll only need half the intensity to get the same light going down.

0:09:12 Thomas: No kidding.

0:09:12 Bryan: And a lot of of places people are doing that, but then you also get things like office buildings which their leave lights on, or they just have to have their logo displayed at full brightness overnight, and all of this stuff adds up. And the faint light that we get from the Aurora is usually drowned out, and so a lot if these displays are going on, we just can't see them. And it's a shame, really. Yeah.

0:09:37 Thomas: Yeah. What's happening? Is the planet burning or something? Is it climate change? Why we got... I mean, it's pretty crazy. Is it for once going to not be something horrible that's responsible for this crazy phenomenon going on?

0:09:40 Bryan: Um.

0:09:49 Bryan: Far as humanity knows, um, are not to blame for the Northern Lights. They've been going on since humanity was around, and they look, this must have been like one of the things that convinced people of the the supernatural. If you see these weird light displays in the sky and have no understanding whatsoever of what science could possibly cause it. One of the things that, yeah, I get why people would believe in like fairies or something causing it because, well, these even days we don't fully understand the science behind it. We've got a lot of pieces of the puzzle put together. There are just a few steps in the middle where we aren't sure what's happening.

0:10:09 Thomas: Yeah. Hmm.

0:10:29 Bryan: So, so I'll give you what steps we do know. So step one, we've already covered where, and the where is a pretty big clue as to what's happening, and that they occur in rings around the poles. And this is a strong indication that one of the factors influencing them is Earth's magnetic field, that we can get into magnets in a bit, but let's save the technical stuff for a bit later on and just wait on that.

The other clue is that they are very strongly correlated to activity in the sun. Now that we're able to monitor the sun with telescopes, we can check for solar storms, what call coronal mass ejections, which is when there's like a big bubble in the sun that bursts and spits a bunch of particles at us. Whenever something like that happens, we get typically a much stronger auroral display. And that type of thing is why we're going into a period of seeing a bunch more auroral displays.

Like, the sun has, you know, long-term weather changes. Like you know know how on Earth every few years we get El Nino and La Nina, the long-term weather changes. The sun has things like that, too. There's an 11-ish year cycle, and we're hitting the peak of it. Well, just starting to hit the peak. And we should be expecting to see a and more common Aurora coming up over the next few years or so.

0:11:59 Thomas: The heck makes up the sun's weather, though? Like, I just assume the sun is just all hot. It's just hot a lot. Just lots of hotness. What different things are happening?

0:12:10 Bryan: Hot, but remember a few episodes back, we talked about turbulence and it's the kind of chaotic thing like, oh, just on your recent episode with Dr. Sutter, you talked about the turbulence of the three -body problem. And I just have to get this off my chest. The show is called Three -Body Problem, But it features a four body problem. The planet is a body too. Okay.

0:12:26 Thomas: Hmm. Yeah.

0:12:35 Thomas: So It's tiny, though, that they don't count it, I think. I think that's what it is.

0:12:40 Bryan: No, you do have to count it. If you just have a planet and two stars, you still do have two account for the planet, particularly because the planet is where all the people are, its path gets a very important. Okay,

0:12:51 Thomas: Don't know. How far away do you have to be to be a habitable planet from system like that? Because I'm trying to defend the good name of three -body Problem, because one thing that Paul said was that the we don't sweat this in our solar, is like it's just a series of two -body problems and the other planets are so tiny it doesn't really matter, you know?

0:12:58 Bryan: Yeah, yeah, yeah Yeah. A factor. Like, the other planets aren't going to send the sun careening off or the Earth. The issue with, like, you can have chaos with just two stars and one planet, even if the planet is infinitesimally small. If you trace the path of that planet, that planet's path will still be chaotic, even if the paths of the two stars aren't. So if you care about what happens to the people, it is the how many stars plus one planet problem.

0:13:31 Thomas: Oh, okay. Interesting. Gotcha.

0:13:41 Bryan: Anyways, yeah, point is chaos affects the weather, and chaos, basically boiling it down, particularly particularly for those who didn't listen to that episode, is a physical system that is not random. Intuitively thinking chaos is randomness. When we speak in physics jargon, it isn't. Chaos means something that's perfectly deterministic. It follows the laws of physics. If you rewind everything and run it again, it will happen the exact same way.

But the difference with chaos is that while the present perfectly predicts the future, the approximate present doesn't predict the approximate future. So if things at the beginning were slightly different, the future will be vastly different, pretty much unpredictable. And weather is one of the quintessential chaotic systems. And so the sun effectively, it has its own weather.

It's a lot lot of particles in a hot plasma throughout it, and a lot of it being a nuclear fission engine, and the specific distribution of particles is very complicated near in a sense, and what this means is that over time, small changes in positions of the sun will build up into bigger effects, and these lead to large weather effects. And some of these will have predictable patterns, and some won't. It'll just be chaotic.

And these coronal mass ejections, you can predict the overall frequency and how that will change over time, but you can't predict exactly when one will occur until it's basically already started. So that's how we get weather in the sun, and that's why the auroras are sometimes stronger than others. The two pieces we have so far to the aurora is you get activity from the sun, spews out particles. These particles hit the Earth, do something with the magnetic field. We'll get back to that something.

This leads to something happening around the poles. And the final piece we know for sure is what causes the colors to be emitted from the auroras. Part comes from just what's in the air. So in the high upper atmosphere where the aurora's come from, the most common elements are oxygen and and nitrogen. And particularly in the highest regions where we see the auroras, oxygen is more common in its atomic form. If you remember back to high school chemistry, you probably remember that oxygen, as we most often experience it when it's on its own, is in O2 or

0:16:33 Thomas: Right, yeah.

0:16:34 Bryan: A of two 2 -oxygen, yeah, and nitrogen is most commonly N2. In the high upper atmosphere, due of factors going into it, oxygen is most commonly in atomic form. Nitrogen is still in molecular form. It bonds to itself so strongly that it's so hard to get apart.

0:16:35 Thomas: Maybe 03. Three. Why?

0:16:53 Bryan: But oxygen, yeah.

0:16:53 Thomas: Don't You just Marry yourself, nitrogen, am I right? So,

0:16:57 Bryan: It would if it could, trust me.

0:17:00 Thomas: Poles this are where the single oxygens go to you, the field, Kind of thing. Okay, most oxygen, monogamous, pair bonding forever, yeah.

0:17:03 Bryan: Yeah. Yeah. Yeah. So, what's going on in the northern lights is basically a rave. So, think of it this way, that energy gets injected them from the particles coming in from the sun, and then the energy, you know, they get knocked around a bit by these particles, and then they let out a yell of, of excitement. And this yell of excitement is the light we see.

0:17:15 Thomas: There, you go, it's Like a mosh pit, like,

0:17:33 Bryan: Got a lot of atoms in a mosh pit, and they let out yells of excitement, and because of quantum mechanics, the yells they let out can only be of very specific wavelengths. And each, you can think of it like a miniature solar system with a nucleus with electrons orbiting it. Quantum mechanically, it's more complicated, but the electrons can only orbit, in quotes, at certain levels. Again, due to quantum mechanical weirdness in the way wave functions work, they can only be at certain levels.

If one of those electrons gets injected with energy, it goes from an inner level up to an outer level. And then, after a while, it lets out a yell of excitement and falls back down to a lower level. Distance in energy between these levels is always a fixed value. So the photon that it spits out is always going to have exactly the same amount of energy.

Result The of this is that we get what we call emission lines coming out of the particles, and for the aurora, we primarily see two lines from oxygen, one red line and one green line, coming out, and a bunch from nitrogen.

Nitrogen, as it's a molecule, has much more complicated behavior in what light we can see, so there are a lot more potential emission lines, but the oxygen ones dominate, and so this is why the aurora looks like it does, and this also explains why we see different colors at different altitudes. If you look at most pictures of aurora, you'll most commonly see green, which matches one of the two lines from oxygen. This line is stronger, and the human eye is also more sensitive to green. So most of the time, auroras are going to look green. But sometimes you'll see the red line as well, particularly at higher altitudes.

0:19:34 Thomas: During Christmas and stuff when

0:19:36 Bryan: Yeah, yeah, when it wants to be all Christmassy. Line is always shows up, but sometimes it gets suppressed. Electrons, it doesn't have a chance to let out a yell. Basically, a nitrogen comes by, bumps into it, and steals some of the energy. Green one is more able to let it out, and all of that combined gives an interesting mix of red and green, and then all of the other colors that come in from nitrogen, only when you can really see them well. This part, we've got a good handle on, and um,

0:20:08 Thomas: So northern lights, they're pretty much always somewhat going, is that true, or I guess on both poles there, it's always Some amount of the sun's energy is doing whatever it does, you know, in the privacy of the bedroom of these molecules, it, it makes something let out some energy, something, something light. I sort of understand at least what's going on there, but it's just a question of it being stronger and going further down the planet or whatever. Why, why does that, I guess I'm having a hard time understanding, like, the difference in how it comes up or down, I

0:20:15 Bryan: Yeah. Yeah. Yeah. Yeah. So, The strength of it usually depends on how much is coming in from the sun. So, going back to our mosh pit example, you know, it's always like, you've got people in a mosh pit, and there'll be a bit of noise coming out, they just kind of shuffle around, occasionally bump each other, let out an, sorry, but then when the band gets on stage and starts to play and injects a lot of energy into them, the mosh pit gets loud. So these, solar activity, when it starts, um, and spraying us with many more charged particles, inject a lot more energy into the system, so more atoms, atoms get excited, and more excited atoms give off more light, and it gets brighter.

0:21:03 Thomas: Don't Know why I'm having a little bit of a mental block on, like, so why is it, it's around the poles because the magnetic field of Earth is like, like, more around there, or, and so how does that relate to these oxygen, like, the mosh pity thing, why What, yeah, how What's the relation of that, oh

0:21:30 Bryan: Yeah, yeah, yeah. Okay. Yeah, that's the tricky part. Okay, so let's just put a in that for one second, because there was one other part that's relatively easy to address, is what happened A week ago, as we talk about this, if anybody's looking at this far in the future, that would be around 10th of May 2024, it wasn't just that they got brighter than usual. They also got significantly further south than usual, and I think the trick here is that where they occur are also subject to weather patterns on Earth. That the upper atmosphere is affected by weather as well, and this shifted the zone where all these charged particles were hanging out further south so that they could be more visible. That part relatively straightforward, at least as straightforward as weather can be, but we still have to get into the question of why they're hanging out up north in the first place. And And to do that, we're probably going to have to get into trying to explain magnetism as best I can over an audio medium.

0:21:46 Thomas: Okay, sure. Yeah. Yeah. Hmm.

0:22:18 Thomas: When A mommy magnet and a daddy magnet love each other very much, literal

0:22:53 Bryan: Yeah, so let's start. Thomas, what do you know about magnetism? How would you describe it?

0:23:01 Thomas: Magic that wizards invented to

0:23:03 Bryan: Basically that Insane Clown Posse song, Miracles, fucking magnets, how do they work? Where you're at.

0:23:08 Thomas: Heard of it, but fully agree with that message. Fully agree with, endorse. I could have written that apparently.

0:23:11 Bryan: OK, yeah. Okay. Everyday experience of magnets is they're chunks of metal, which do things, all of which seem to be related. They have two ends, which behave differently. We call them poles. Like, a magnet will have a north pole and a south pole. And if the magnet is able to move on its own, it will typically rotate to align with Earth's magnetic field so that the north pole of the magnet points south and the south pole of the magnet point north.

And, if you have two magnets, they'll do the same thing, where the north pole will be attracted to the south of the other, and vice versa. So, magnets, opposites attract. Will also tend to stick to a lot of metallic surfaces that aren't themselves magnetic. This is something we call induced magnetism. It basically temporarily turns other metals into a magnet and then sticks to them because of that. So magnets are in attractive or repulsive force depending on how they're aligned. Would exactly. Now one other interesting thing about magnets is if you look at a magnet, let's say you've got a bar magnet, one side is the north pole, one is the south pole, what happens if you cut that magnet down the middle? What do you have then when you split apart?

0:24:21 Thomas: Good Good looking they are. Yeah.

0:24:37 Thomas: Which dog style or hamburgers? Down

0:24:41 Bryan: Hamburger style.

0:24:41 Thomas: The, down the, oh, oh wait, what? Down, like, do you cut it in half long ways or short ways?

0:24:48 Bryan: Ways, between the north and south poles

0:24:49 Thomas: Gotcha. Okay. Yeah, that's a good question. Do you get too, interesting. Do you get two magnets with a north and south pole, or do you get a north magnet and a south magnet? Ah, I don't know, really.

0:24:49 Bryan: Of the magnet do This is something that's, um, yeah, hard to just imagine, but very easily to do experimentally, and this experiment is done, and you always get two magnets, each with the north and south pole, and you can repeat this, cut each of the smaller ones in half, you'll then get, like, four, each with their own north and south. You can keep doing this all all the way to the atomic level, and eventually you'll get a single atom of iron, typically iron. You can make permanent magnets out of other things, but iron is by far the most common, and that atom acts as its own small magnet with a north and south pole, which you can't split apart any further. I mean, if you split iron, you'd get a nuclear explosion. Well, actually, Actually, no. Iron, you can't even split to get a nuclear explosion. It's already an amendment. You have to inject a ton of energy.

0:25:56 Thomas: So You split it, what would happen? That's

0:26:00 Bryan: Have to pour a tonne of energy into it. You'll get a fizzle. Iron is the one element that you can get energy out of by either splitting or fusing to.

0:26:03 Thomas: Yeah. Is that coincidental, or is that, like, the reason why it is the magnet? That's

0:26:14 Bryan: I think this part actually is coincidental. The Why actually comes down to the way the electrons are around iron. So if we go back to what I was talking before, that electrons are like miniature solar systems around nucleus, this is wrong. And it is very importantly wrong, because if electrons were always going in circles around atoms, every atom would be magnetic. But in practice, really only iron and a couple others are. So what's going on quantum mechanically is that each electron is more in a cloud of probability space of where it could be. And most energy levels look something like a cloud or a blob or something like this. They get built up in a very weird way. The thing is that eventually, when you get exactly to iron, the newest energy level you add is the first one that's actually a ring. That's the first time you could say, in some sense, the electron is orbiting, even it's not quite right, but iron puts the electron the state that that energy level of the electron has a constant magnetic moment, we

0:26:15 Thomas: Oh, Okay. Gotcha, hmm.

0:27:37 Thomas: Interesting.

0:27:38 Bryan: Call it, and causes magnetism.

0:27:41 Thomas: Don't understand it. But I'll take your word for it.

0:27:42 Bryan: Yeah. To get down into to understanding. Let's talk about electricity and electrostatics first, because magnetism is really fascinating. And I have a good story to share about how I uncovered that it's actually two different laws of physics in a trench coat. I was learning about electromagnetism in school, I was surprised to find that they didn't start by teaching us about magnets, which I was like, what, we deal with magnets all the time.

But no, they started teaching us about what they call electrostatics, which is the simpler half of the equation. Electrostatics is kind of like gravity, except the opposite. So gravity is simply mass attracts other mass. And electrostatic just just adds one layer of complication, that okay, charges repel charges that are the same and attract charges that are opposite. So it's a simple opposites attract, like repels. So have things like electrons are negatively charged, protons are positively charged, so they attract each other.

Electrons, both negative, they repel each other, so simple, like that. And then as you go through, they start to introduce how it relates to magnetism, and what happens is that any changing electric field, so this could be caused by an accelerating electric charge, which if you want a stable state, you can have when you have an electric charge orbiting something. It's constantly accelerating towards the center. Any accelerating electric charge causes a magnetic field.

So if you have an electron actually orbiting a central position, you get a static magnetic field, and the way this magnetic field is shaped is is kind of like, imagine a donut that the electron is orbiting around the center of the donut, and the magnetic field lines go around the surface of it, through the hole, down to the bottom, across, up the edge, back over the top, and down. So a field line is just describing where the imaginary magnetic field points at any specific time.

So this would be like your north to south direction. You could trace this out for any region of space, and you'll get a donut shaped with the electron going through the bulk of the donut around the hole, and the magnetic lines going down through the hole, up around the edges. You follow me on

0:30:25 Thomas: I'll Take your word for it, no, I, it's one of those things where it's like fundamental, so I don't, I can't, it's hard to, can't be like, oh, but why, you know, because you've kind of hit either a fundamental why, or just too hard to explain to me why, but well. Okay, so.

0:30:39 Bryan: That? Well, actually, that part I can answer. Can go one layer deeper on that. But before we do, let's zoom back out to the Earth. So the Earth has its own magnetic moment because the Earth has a ton of iron in it. And magnets tend to induce other magnets. So over time, the iron in Earth, a lot of it It aligns their magnetism, and for complicated reasons, it aligns it more or less with the pull of Earth's rotation, which notably isn't always the same direction. There's evidence that historically the Earth's magnetic pull has flipped multiple times over

0:30:40 Thomas: Oh. Yeah. That's.

0:31:26 Bryan: Its history. Um, think the best explanation is that sometimes the Earth gets hit by a comet or asteroid or something, and it knocks everything out of whack, and then it settles back the other way by chance, but um.

0:31:40 Thomas: Crazy.

0:31:41 Bryan: So now it magnetic pull aligns mostly with the axis of rotation. It isn't exactly there. So if you were to follow, like for instance, if you follow a compass, let it point you north, it will point not exactly to the north axial pole, but the north magnetic pole. And right.

0:32:02 Thomas: Which.

0:32:02 Bryan: Now is a over the island of Canada, Ellesmere Island, which

0:32:07 Thomas: It's like the old school equivalent of, like, when Google Maps had the wrong thing at your house or whatever, and, like, drove a bunch of people, ended up at your house, because Google Maps said it was like a you, or something. It's like that, but the old-timey thing, maybe it'd be a bunch of ships, or in that whatever Canadian island, they're like, no, it's not, it's.

0:32:19 Bryan: Yeah.

0:32:27 Thomas: Magnetic north. It's now the real, it's on the North Pole, come on.

0:32:27 Bryan: Well, there actually a bit of an issue with that, but for airplanes, because airport runways are always numbered according to their angle relative to magnetic north, and magnetic north keeps changing. And since Canada is so close to the magnetic pole, they eventually got frustrated with having to keep changing the numbers Of their runways when magnetic north changed. They eventually said, okay, screw it, the rest of the world, you can do magnetic north, we're doing geographical north, so we don't have to keep up with all of this. That leads us to kind of the shape of the magnetic field, and let's go back to our donut example, you draw your lines around the donut, like, start anywhere in the surface of the donut, follow the magnetic field it goes, makes a loop around it. Now, one thing you might notice about these loops, let's say you draw four loops, one pointing out a right and left, one up and and down on your donut. At edge of the donut, these lines, as we call them, are pretty far apart from each other. But in the center, they're close together.

0:32:44 Thomas: Wow. Hmm.

0:33:41 Thomas: Right, right, that makes sense, that's.

0:33:42 Bryan: Draw a field line diagram, how close the lines are together is proportional to how strong the field is. So the magnetic field is very strong going right through the center of the donut and weak coming up around the sides.

0:33:58 Thomas: Why it's so delicious on that. Part.

0:33:59 Bryan: Yeah. Oh, that's why they sell the whole separate. That's the most delicious part of the magnet.

0:34:03 Thomas: Oh. Yeah. So magnety, oh.

0:34:06 Bryan: So if we take this as Earth, Earth is like the donut hole, or it overlaps a bit with the hole because it has the magnet inside, and so the the field lines are going to be all around it. So you can imagine like the earth embedded in a giant donut. Around the north and south poles of the earth, you're close to the center of the donut hole. So you've got the field line. The field lines close together. And then off to the sides, you're closer to the edges of the doughnut where the field lanes are far apart.

0:34:41 Thomas: Man, but I'm struggling because you're saying the Earth is the donut hole, because if that were true, I would, I would expect everything to be close, those, those field lines, be close together all around the equator, because isn't that where, on The donut, oh.

0:34:52 Bryan: Yeah. Yeah, so the trick is we have multiple donuts, it's, uh, one. Donut inside another, I'm just simplifying.

0:34:56 Thomas: Oh. Yummy.

0:35:00 Bryan: It. Down to one donut, um.

0:35:00 Thomas: Okay. I. Want to. Make sure I. Keep my donut straight because. That was something that, like, when you brought that up, but the field lines, is like, hey, for once I can totally visualize what you're saying, and. Then it didn't work, so I just want to make sure why, oh.

0:35:03 Bryan: But. It's. Yep. Yep. Yep. Yep, exactly, so the thing is we have multiple donuts layered on top of each other, all of.

0:35:19 Thomas: Not just.

0:35:19 Bryan: Which. Which go, it's

0:35:20 Thomas: One. Donut. It's like a three-dimensional donut, like.

0:35:23 Bryan: Well, like you've, you might've heard of a turducken, the, you know, chicken inside a duck inside a turkey. Here we have a do -do -do nut -nut -nut. We have a donut inside a donut inside a doughnut, which is much better and also much less cruel.

0:35:25 Thomas: Sure. Oh. Even. More. Delicious. Okay.

0:35:39 Bryan: Yeah. We have donuts inside donuts and around the poles, the whole parts of these three donuts are are much closer together and they come out of the earth around the poles. So, Closer together, field lines, much stronger field. And then around the equator, the outer edges of the donuts are farther apart. And so, farther apart field lines is weaker field. So overall, the magnetic field is much stronger around the north and south poles than it is at the equator. Okay.

0:35:40 Thomas: Okay. Gotcha. Gotcha.

0:36:13 Thomas: We. Won't get, get into the jelly filling, but that's another episode later on, I.

0:36:14 Bryan: Yeah. So then the other piece of the puzzle is answering, so does the magnetic field cause charged particles to be around there? And this is just another way that electricity and magnetism go together. It's basically that same way that, um, can cause magnetism, magnetism can cause motion in electrically charged particles. And the way it works is if imagine one of these field lines, which is just you draw the line north to south and until it forms a complete loop. If an electrically charged particle gets close to one of those lines, it'll tend to start spiraling around it. So to go with the metaphor, just imagine, imagine somebody who loves trees a lot walking through a forest. Whenever they get close to a tree, they reach out their arm, touch it, and start spinning around it.

0:37:18 Bryan: Up in the North and South Poles, we've got a veritable forest of magnetic tree lines, and all of these charged particles are tree lovers, and they get caught in the forest and start hanging around up up there, and there are many fewer trees out near the equator for the particles to get stuck in. And even when they do, um, know, they might start spinning around the magnetic field line, but they'll also have some velocity either north or south just by chance. And then they'll spin around it while slowly going north until eventually they get to where the field

0:37:16 Thomas: Like that, that's nice, the Big

0:37:54 Bryan: Line starts going down Yeah, no. Yeah, they get to Yggdrasil up at the North Pole. No, no field lines start curving back down into Earth and then other things like atmospheric pressure capture them there, like they'd be fighting against the higher pressure to get down. And so the magnetic field lines basically capture these particles, guide them up to poles where the big mosh party is happening, And they can all celebrate their tree loving together in the big forest.

0:37:55 Thomas: Tree Oh Yeah Right Because it's, it's one of those things where I think I get caught in like magneto mode or not, like I'm like, yeah, it's just the magnetic, whatever, but gotta remember there's also other forces thing like happening all the time as well, so it's like that Interplay of the magnetic force and then also atmospheric stuff going on

0:38:38 Bryan: Yeah. Yeah, The magnets want to guide them one way and then the atmosphere pushes the other and eventually they get balanced out and they just kind of pile up near the poles. And then eventually other things come around, like the solar wind will steadily blow them off. Then when there are, you know, big coronal mass ejections from the sun, they excite all of them. They have a big party, spew out northern and southern lights that we can all see and have a lot of fun. Then a few of them get blown off. Many of them gets blown off in the party. But what we see is just the lights coming from them.

0:38:43 Thomas: Hmm So Did we complete the loop there, the donut loop, so That's the reason why the particles are hanging out there and then I guess I, so here's what I'm still a little stuck on now, the crazy lights and being, you know, seen by, uh, as far south as, somehow, me, that's not a question of more particles getting getting trapped, right, because that would be all earthy stuff, it's a question of the

0:39:23 Bryan: I the particles do often come from the sun. The oxygen And nitrogen, yeah, those elements come previous stars, but there's also a lot of that that got into the sun at some point and got blown towards us. The whole thing is complicated, but most of that does tend to just come Earth or its atmosphere or the interplanetary medium, that is the gas in the vacuum.

0:39:49 Thomas: So It is that the sun is somehow sending more, I thought the sun was just doing the activating lights part, but

0:40:19 Bryan: It more. These coronal mass suggestions send a lot of particles towards us. It's this big mishmash. You know, most of it by mass is the smaller end of things. But there is a significant amount that are these more massive elements, which the sun doesn't yet produce. It isn't at that stage of its life, but came from previous stars that went through their life cycles and produced them. And then they've just been hanging out throughout the solar system. Some of them ended up falling into the sun and then getting blasted out at us. Others formed into the planets and get into the atmosphere and get knocked up and then slowly come back down. So it's a bunch of things.

0:41:03 Thomas: So when it comes, when, when the lights go further south, it's not because of like a stronger thing is activating stuff further down, it's that there's more of the stuff, the more the trapped particle, like that's, I'm still fuzzy on that, but

0:41:18 Bryan: The same thing. It's a bit of both. The sun Adds more things. This is part of what isn't fully known about it, is how much is it being activated more and how much is more particles being added to the mix, but a lot of it being seen further south is just it gets brighter and the brighter it is the further south you can see it, um, you know, it gets diffused, um, the atmosphere the farther, and and then also just optically the farther something is the fainter it is, um, there are also weather patterns on earth that that affect it, that this was a particular case where The weather was very fortuitous and kind of blew the whole ring much farther south than it normally goes, at the same time that we had a huge storm from the sun activating everything, so basically everything aligned to make them much more visible further south than almost ever happens.

0:41:19 Thomas: Okay Oh Gotcha So lots and lots of variables and they all kind of came up Millhouse for the Uh, the northern lights, well that's cool, so it doesn't mean we're dying or the climate or something, it's none of that stuff

0:42:18 Bryan: Yeah. Yeah, No, no, this is something that happens completely independently from us. Know, if we really wanted to, we could try to pump up extra oxygen and nitrogen into the air. Probably not the best use of our resources.

0:42:35 Thomas: So I just want to get this very straight. Brian Gillis, astrophysicist. We can have a nice thing. You're saying this things.

0:42:45 Bryan: Yeah yeah, this is just a nice thing. You, know, it's like eclipses. It's It's just something nice that happens.

0:42:48 Thomas: Wow. Just happens. Yeah. Global warming didn't cause that eclipse. That's just an eclipse. Wow, all right. Well, that's nice. And you're saying we could expect maybe a bit more of this. Who knows if it'll be all the way in my neck of the woods, but lots crazy raves up there.

0:42:52 Bryan: Yeah. No. Yeah. Yeah. Yeah, not get as lucky again. We might get even luckier. But look around. If

0:43:10 Thomas: Know those particles are getting lucky. Am I right?

0:43:11 Bryan: Enough that they're regular, you can probably get an app for it. The one I use is Aurora Watch UK, and you could probably use that almost anywhere. It's optimized for the UK. It tells you how far into the UK, like if you can see them in Scotland or England, but it'll tell you when the sun is more active at least. So if you're over in, say, Norway, it's probably still useful for you. It'll tell your when it's likely.

If your in one of those regions, get an app. If you're further south, you'll probably get more false alerts than are worthwhile on an app like that. That. Might want to look at news reports. I a lot of people got alerted to it from like NASA's Twitter account or something like that. So yeah, there are other sources. Yeah, it's something to watch out for. Put a pin in, can we go down any further than magnetism? And I Wanted to answer that one for you. I wanted to leave it to the end as it's where things get pretty technical, but it's an interesting story I wanted to share. So let's go back to when I was in high school, learning about electricity and magnetism. They give us all of these equations, like how electric particles cause a magnetic field, and magnetic field will apply a force to moving electric articles other than the ones that cause them.

And one of the things they highlighted was that if you have two wires with electricity flowing through them and they're parallel to each other, the magnetic fields caused by these two wires will cause them to attract each other. That's just the way the math works out. So then I started imagining, okay, so these wires, they have electrons moving through them, and then enough protons there to balance out the charges so that each of them is overall neutrally charged.

We don't have any electrostatic force to worry about. But what if we did? I was thinking, okay, so if we had just two streams of electrons, they would still attract each other through magnetism, but also repel each other from the electrostmatic force. Force. Strength of the magnetism is proportional to how fast the electrons are traveling. So, could they travel fast enough that it exactly balances out? And then I started thinking, okay, what about from a relativity perspective?

So, let's say you have them fast enough that it balances out. And then let's say you go and take a ride on one of those electrons. Electrons, now, as we discussed way back in one of the first episodes I did with you on special relativity, you can basically shift the frame of reference in the universe to any other constant velocity and all the laws of physics are exactly the same.

So if you shift to ride one of those electrons, the electrons in the other stream will all be stationary. For your perspective, you just have two lines of electrons standing there. So there wouldn't be any magnetism in this perspective, but there would be the electrostatic force. So from that perspective, the electrons should be repelling each other. But from the first perspective, forces cancel out and the lines don't move. So what's going on here? Why do we seem to get this contradiction in the laws of physics?

So what I did was I went and calculated, okay, well, what velocity do you need for these two to cancel out? I plugged into the equations and the value I got out was exactly the speed

0:44:07 Thomas: Yeah. Speed.

0:46:53 Bryan: Of light.

0:46:53 Thomas: Of. Light. Yeah.

0:46:54 Bryan: Yeah. Yeah, you predicted it. Yeah and is the trick to all of this, is that I realized that you have to account for both magnetism and relativity. And the thing is that you could actually look, either perspective, just say, okay, from the perspective of somebody riding the electrons, they have to be repelling each other at this rate. And then they're at some velocity, relativity causes time dilation. If we account for time dilation and then go back to our perspective, we see them repelling each other a bit less. And now one other way to characterize they repel each other, a bit of a difference, is saying, okay, there's the normal electrostatic force and there's also this other force pulling them together. And when you do the calculations, that time dilation effect slowing the repulsion is always exactly equal to what the magnetic force does. So what it turns out is that

0:46:55 Thomas: But.

0:48:02 Bryan: Electrostatic magnetism and special relativity are intertwined, that in a way it isn't three three separate laws of physics, but two laws of physics. If you have just electrostatics and special relativity, magnetism just appears there if you want everything to be consistent.

0:48:21 Thomas: Uh, you've, you've, uh, it's a grand unified theory, you solved. Not quite

0:48:24 Bryan: Yeah, Well, that's just one step, but it's one of the themes I've brought up a couple of times is that a lot of these theories you can dig down deeper and show, like talked, I think it was the portal episode that some of the the greatest physicists are those that discover negative one laws of physics. And this is a case where you've unified a few and said that, no, these three things are actually just two things. Although I did happen onto this on my own, of course, I was far from the first to realize This has been long known. And I think actually this was known in a sense of known even before Einstein's theory of special relativity. If you go back to Lorentz calculating it out, he stumbled upon that you need this time dilation to have the constant speed of light. He just didn't put it into a full unified theory.

0:48:35 Thomas: Well.

0:49:15 Thomas: That's crazy. Do

0:49:16 Bryan: The whole thing is crazy. And I just find it all fascinating how this all fits together and you get these phenomenally complicated interplay of different laws of physics. Yeah.

0:49:28 Thomas: You see how much work poor physicists like Brian do, so That you can enjoy, enjoy your northern lights, everyone.

0:49:32 Bryan: Yeah. If we didn't understand it, you wouldn't be able to see it. Yeah.

0:49:37 Thomas: What it wouldn't be there. Yeah, I agree with that, actually. So no, that's super cool. I can't pretend I followed all that. But I think the important stuff, the related analogies will stick. And once again, thanks, Brian. Is there anything you want to plug? Shout out.

0:49:39 Bryan: Yeah. Oh, You're welcome. Oh, Don't have much going on my, my own, so I'm just gonna plug my campaign to update the Opening Arguments icon to use the Garamond font. Yeah.

0:50:04 Thomas: OK. There's a change.org petition going. Yeah, we'll see. I but I can't make any promises, you know. But go to change.org slash Garamond thanks so much astrophysicist Dr. Brian Gillis for the cool explanation and let's all go enjoy some guilt free northern lights near you

0:50:09 Bryan: Oh, Right, okay. Well, Thank You. Thomas All Right, thank you.