Your questions, unexplained

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It's Unexplainable.

I'm Noam Hassenfeld here with Neil Denesha.

Hello.

And Bird Pinkerton.

That's me.

And Bird, you don't just produce and report for the show, you've also kind of become our communications director, in a sense.

You are basically the one that is responding to tons and tons of emails all time.

the Just wildly overenthusiastic responses.

But you had this idea for a show based entirely around listener emails.

Yeah.

So we have this email.

We also have a form where listeners can kind of submit their questions.

And some of those questions do turn into episodes, right?

Like

yawns, I think.

Yes.

Yawns.

There was hiccups.

Whale beaching.

Whale beaching.

Whale beaching.

Yes.

Exactly.

But like, sometimes I'm just like, there's so many good ideas here that are just sort of sitting.

Right.

And I wish we had time to, if not pursue all of them, at least pursue more of them.

Yeah.

So you challenged us, I guess, to pick some of those questions and see if we can do an entire episode of mini unexplainables.

Exactly.

I wanted us to sort of take three listener questions, unexplain them.

And then at the end, I thought we could sort of bring those unexplanations to the listeners and see if they satisfied their curiosity.

Unexplanations.

I like that.

So, okay.

Bird, you want to start with the first unexplanation since this was your idea?

Boy, do I.

Okay.

So my listener question came from a bunch of listeners.

Shout out to Ben and Kendra and Lisa, but also a guy named Jonathan.

Hi, I'm Jonathan.

I'm from Malaysia originally.

I'm both an experimental experimental psychologist and a parish priest.

And my question is about the reversal of the North and South poles.

So Jonathan and other listeners were asking more specifically, like,

what would it mean for life on Earth if the magnetic poles flipped?

So what does that mean?

So basically, Earth has this like giant magnetic field, North Pole, South Pole.

And according to one estimate, about four to five times every million years or or so on average, those poles flip, like north becomes south, south becomes north.

Okay.

And there's been a lot of coverage of this in the last couple years, like these pieces with titles like, When our magnetic field flips, say goodbye to modern life,

which is scary.

And people in these articles are sort of like, look, in the process of flipping, like all our satellites would stop working, like everything would be bad.

So I called up this kind of like friendly geophysics professor at the University of Alberta named Mathieu Dumberry to basically see like if we should be concerned.

Yeah,

I'm concerned.

It's like a Y2K, but for compasses.

So I'll start with just the basics here, right?

So at the center of the Earth, scientists think there's lots and lots of molten metal, mostly iron, moving in big loops.

And they think that that flowing iron generates this giant magnetic field that surrounds the Earth.

And that field helps shield us from a whole mix of cosmic radiation.

And it does that along with the atmosphere, but it's also helping maintain the atmosphere.

It's helping keep particles in.

So it really is this kind of invisible skin, essentially.

Like it's protecting us, it's keeping things together.

It is very nice to have around.

Yeah.

And then

generally, I enjoy having skin in all circumstances.

Good thing to have.

But this is where kind of the flipping comes in.

So like I said before, the rock record shows that four to five times every million years or so, the magnetic field around the Earth flips.

Right.

And when it flips, there's a period when the whole field gets much weaker and then sometimes it collapses and then it has to rebuild.

So that means we're like really kind of exposed and vulnerable.

Business skin.

Yeah.

It's like a super thin thin skin moment.

And like life has obviously survived in those periods, but

there are patches right now where the magnetic field is weaker.

And that's where this like satellite stuff is coming in because in those patches, like our satellites stop working.

So it could potentially be bad for like our modern life that's built on satellites.

And so I was like, oh, when, like, when was the last time that this happened?

Like, how soon might this happen again?

And Mucho was was telling me that like the last time that it happened was around 780,000 years ago.

So that is close to a million years ago.

Yeah.

And if you're doing the math in your head, right, like four to five times every million years, something's not.

Yeah.

Yeah.

Like we're due for some magnetic field problems.

Right.

So Macho was like, we're not due.

Like it doesn't work that way, right?

So this is actually an average that was taken over the last like 20 million years.

There's also a stretch before that where it seems like no flips happened for tens of millions of years.

So you can have like multiple happening really close together and then a stretch where nothing happens for a really long time.

That makes sense.

But part of the reason that people are sort of talking about this or concerned is that before

a flip happens, there tends to be like a weakening period.

Okay.

And we are seeing that.

Like we're seeing the magnetic field weaken.

Not great.

So again,

I I kept on in this interview, I kept on being like, I'm less concerned.

I'm more concerned.

I'm less concerned.

But this where we get concerned?

Matthio said, these weakening periods don't always lead to a flip.

So that's sort of like thing number one.

And two, and I think this is the most important thing.

Like

the flip is happening really fast in geologic time, but fast in geologic time is like still a time scale of thousands of years.

Right.

So like we're not probably going to like wake up tomorrow and have no magnetic field around us.

So if somebody loses sleep on the fact that, oh my God, the magnetic field is decreasing and may reverse what's going to happen to me.

That's not really a concern, right?

And again, like life has persisted on the planet in the past when the field has flipped.

So like this is not,

I would say that there are other things to probably be more concerned about than the magnetic field flipping.

But

he does think that, like, this

question of when will the field flip, or like, what does it mean?

It's an opportunity to explore a much more basic, really interesting unknown here, which is like, we have a lot to learn about this amazing magnet-generating core that's deep under our feet.

More about why it flips to begin with.

There's lots of like fluid dynamic stuff that researchers would like to know to figure that part out.

And my favorite part of all this was that Mathieu told me that since this sort of magnetic field skin helps create an atmosphere on a planet potentially, it could play a role in making the conditions for life possible.

So, you know, we just did this whole series on life and where it came from.

And I love the idea of instead of sort of focusing on like the apocalypse on Earth, looking at the magnetic field instead as like potentially helping to generate life, which is, I don't know, it's just like more hopeful and less grim.

Yeah, it's like, don't look at the magnetic field half empty, look at the magnetic field half full.

Okay, so Bird, I've got a mini unexplainable that's a lot less sort of existentially, cosmologically huge.

And it comes from a listener named Rebecca.

My name is Rebecca Nagel.

I'm from San Antonio, Texas.

I'm a grad school student and I'm a staff accountant.

And what I wanted to know was why we sleepwalk and

how did our theories about sleepwalking evolve?

So I went out and I called up another nice Canadian researcher.

It's this guy Antonio Zadra, who's a sleep and dream researcher in Montreal.

Here's what he said.

He said, sleep and wakefulness isn't black or white.

There's a lot of gray.

Your brain doesn't just all fall asleep at once.

There's also phenomena known as local sleep that we know you can have little islands of your brain, which are asleep, surrounded by other areas that remain fully awake.

Huh.

And then in the transition from sleep to wakefulness, the brain can get stuck.

And again, some parts can come online and some parts can stay asleep.

Wow.

That is fascinating.

So he just like blew my mind right off the bat, right?

I was like, that is not what I thought about sleep.

But when you think about it, it makes a lot of sense.

Like you sleep in a new place or you go camping, maybe there's bears around or something, you know, you're not going to get the most restful sleep.

Parts of your brain are going to be a little bit more vigilant, like a little more attuned to the outside world.

Oh.

And you see this in animals.

So if you think of a flock of ducks, here's like an interesting duck fact I'm going to give you.

Duck fact.

But

when ducks sleep, they sleep in kind of like a circle and the ducks on the outside have the half of their brain asleep that's on the inside of the circle.

And then the half of their brain that's on the outside is awake.

So it's attuned to like stimuli from the external world.

And then they move into the

good duck fact.

That's the A plus duck fact.

And then they move into the middle of the circle and they get their kind of full sleep.

Like their whole brain shuts down.

Yeah, their whole brain goes to sleep.

And you'll see this kind of parts of the brain sleeping and parts of the brain being awake with birds that are flying a long way, dolphins that have to sleep.

And

yeah, exactly.

Dolphins can't go to sleep fully because they have to, you know, come up for air once in a while.

So it makes sense to begin with.

And Rebecca, a specific thing that she was asking was, like, how have theories of sleepwalking changed over time?

And the main thing that Antonio told me was that people used to assume that sleepwalking was acting out your dreams.

I mean, that's what I assumed it was.

It seems kind of intuitive.

But it turns out that vivid dreams mostly happen in REM sleep.

So that's rapid eye movement sleep when your eyes kind of moving all over the place.

And sleepwalking mainly happens in slow wave sleep.

And that's a part of sleep that is the deepest kind of sleep and you don't really dream as much.

So sleepwalking isn't necessarily acting out your dreams.

So then what

is it?

Yeah.

So you could think of it as something like.

augmented reality.

So if you imagine wearing those goggles or, you know, using a phone and you can kind of like see the real world, but have this digital overlay yeah so in sleepwalking you are attuned to the outside world your brain can actually see stuff around you but you have sort of a weird unconscious overlay so he gave me a couple stories where like

this guy threw a tv at imaginary intruders because he thought the red light on the tv was the scope of a sniper rifle or something oh what or what this other guy he picked up his dog and ran the dog into the shower and turned the water on.

And it turns out he basically saw the dog, but he thought the dog had these flames coming out.

So he had to, you know, throw it in the shower.

So it's not dreaming.

It's like you're seeing things and then adding,

I guess, dream is not the right word, but like another layer to them.

I'm struggling with that too, a little bit.

Dream is not the right word, but we'll just call it like sleepy layer or something.

But

and it makes sense sense because I was saying that different parts of your brain are awake and asleep.

And so Antonio said that things like movement or perception might come back online, but things like judgment or planning or pain perception might still be asleep.

So he told me about a story where someone had fallen down the stairs and his wife was like, Are you okay?

And he's like, Yeah, I'm totally fine.

And he went back to bed.

He didn't remember this at all.

And then he woke up in the morning and he was in excruciating pain because he'd broken something in the middle of the night, but his pain perception was kind of asleep, even though his communication areas were awake.

Yeah, because he was like, he was able to communicate with his partner that he was okay.

Exactly.

But he didn't.

He wasn't fine on the surface.

He was still able to communicate, but he couldn't feel the pain.

And Antonio says that 80% of sleepwalkers who have injuries and have consulted clinics over them say that they've had these injuries where they couldn't feel the pain, where they didn't realize they had this injury.

So it really emphasizes the idea of like, part of your brain is asleep and part of your brain is awake.

Like, we are all the ducks.

We are all ducks for sure.

Just reminds me of so many

things I feel like in our

episodes about the brain.

Like, every time that we try and do an episode about the brain, what we're confronted with is like, ha ha, like, forget the molten core at like the middle of the planet.

We don't know anything that's happening

in our own heads.

Yeah.

And when it comes to sleepwalking, I mean, like we know

a little, we know genetics plays a role.

We know stress and anxiety plays a role.

We know if you're sleeping in a place that makes you uncomfortable, that plays a role.

But this is like surface level stuff.

There's still obviously so much we don't understand here.

Yeah.

So that's sleepwalking.

What about your question, Neil?

I'm getting a little bit of deja vu because Noam's question kind of reminds me of my own, which is also about the brain.

What's your question?

I'll tell you after the break.

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You are about to witness Unexplainable in the making.

I'm actually getting a little bit of deja vu because Noam's question kind of reminds me of my own.

It's also about the brain, but it's a little bit different.

I feel like we've done this before.

What's your question?

Well, it's about deja vu.

I feel like we've done this before.

Oh, no.

Oh, yes.

My question came in from a bunch of people, including one listener named Rachel.

Hi, I'm Rachel.

I'm from Baltimore, Maryland.

And I wanted to know what is really happening when somebody experiences deja vu.

So to find out, I also called a researcher outside of the United States.

This time, he was not in Canada.

He was in Scotland.

His name is Akira O'Connor, and he's a lecturer at the University of St.

Andrews, where he studies what he calls subjective sensations of memory that are hard to put your finger on.

AKA deja vu.

Aka deja vu and the other little times when our memory seems to not quite be working the way we think it would.

Right.

Okay.

So according to Akira, there's a lot of theories about how deja vu works.

He said that theories of deja vu formation are a bit like toothbrushes.

Everybody who researches deja vu has one, but no one wants to use anyone else's.

Oh.

Which incredible.

It's so gross.

So good.

So good.

But the theory that he's working with is that deja vu is essentially a form of error correction or fact-checking.

It's our brain fact-checking itself.

Akira's theory works on the idea that different parts of our brain are responsible for different things.

And so in the middle of our brain is where feelings of familiarity come from.

It's sort of like what...

our recognition center is.

And the front of your brain is the thought-making center.

It's where all of these other signals come to, and those kind of end up your thoughts.

And that part of your brain is also the fact-checking region.

So it sort of tells you whether or not something is true.

Okay.

And so his theory is that in the middle of your brain, every now and then, there are these misfires, essentially these little twitches that kind of happen at random, which make you think that you recognize a situation.

And that signal travels to the front of your brain where this fact-checking center realizes, oh, wait, that's not actually true.

But it can't stop that first signal of recognition.

And so what it does instead is it sends out a fact-checking signal, essentially.

And so you get these two conflicting signals coming really quickly, one after the other, which is sort of like, I recognize this.

And then, then, no, wait, that's not actually true.

And that creates a sort of like uncanny feeling of deja vu where you think you recognize something, but you also know that something's off.

Sounds very plausible to me.

Yeah, I think so too.

So this

theory is saying that like

the feeling of deja vu is really based on a false signal.

Exactly.

Interesting.

I mean, like, honestly, and like Akira said, this is just like one theory of deja vu, right?

And so one toothbrush of deja vu.

Yeah.

And, and the really interesting thing about this is that it can sort of tell you a lot about how our brains develop and deteriorate over the course of our lives.

Because young people, like teenagers and people in their 20s, are more likely to experience deja vu because their brains are especially active and they're developing and they're especially good at catching these these misfires.

Are they

firing more signals that are incorrect?

Like are their brains more active and they're therefore like fact checking more because they're firing more incorrect recognition signals?

Or are they

just better at fact-checking the misrecognition signals?

It's a combination of both.

And that this is sort of where the age thing comes into play because these misfires happen kind of throughout our lives.

And later in life, what can happen is that these misfires don't get caught by the frontal lobes, which might not be as good at their jobs anymore.

And that leads to, you know, false memories.

And so.

the teenagers and the young people are both experiencing these misfires a lot and are very good at catching the misfires.

So the older you get, the less likely you can fact check yourself.

Yeah.

Akira told me that as you get older, your experiences of deja vu diminish.

And that's definitely happened with me.

You know, as I've gotten older, I felt I haven't experienced deja vu as often as I used to.

It's so interesting because when you mentioned deja vu, I was like, wow, it's been a while since I felt deja vu.

And now I feel

sad about that.

Yeah, that's what Akira said too.

And it was really interesting to talk to him about this because he said to me, like, it's important to remember that, like, you know, because this is one theory and because the brain is so hard to study, like, he doesn't want to

disprove or like immediately discount like all the important ideas that people attach to deja vu.

Like some, sometimes people think, like, you know, it's like a religious or spiritual experience, or like they are suddenly getting a little sign from a loved one.

You know, he said, like, you know, I don't want to take all of that away because honestly, like, this is still such a fuzzy space of study, and that's something worth savoring, according to him.

Wait, I really love that idea, though, that like

this is still unexplainable, right?

But in some ways, like

experiencing deja vu, that it's like watching a good horror movie.

There's that like sort of shiver that runs down your spine, or you do have this like deeply weird feeling, and there's something

kind of

fitting about the fact that we can't explain that fully, or that we haven't been able to figure out why that happens in our brains.

Because it is like,

I don't know, it's a little magic.

Yeah.

And I definitely know that the next time I experience it, which I hope I do,

I'm going to be appreciated a lot more.

Maybe I am right now.

Too old for magic.

Too old for deja vu.

I hope not.

I feel like we've done this before.

All right.

Should we toss this to the listeners and see what they make of our answers?

Yeah, so we got Jonathan on magnetic poles.

We got Rachel on deja vu.

We got Rebecca on sleepwalking.

And we got all three of you together on the call here to talk about your reactions.

So

Jonathan, why don't we start with you?

What did you make of our unexplanations?

So

my reaction reaction to the question I asked about magnetic pole reversal was: I did Bert's thing of switching back and forth between being terrified and reassured.

I felt the same thing.

I wasn't sure

how I was supposed to respond.

And then I had all these other thoughts about, wait a second, like, what is a magnetic field?

What is the magnetic field?

What is truth?

Do I know anything?

Yeah, I feel like every episode, I always just realize how much basic stuff I still don't know.

Yeah.

Rachel, did you have any thoughts on your question?

I was really fascinated by other people's questions almost even more than my own.

But

I don't think that's true.

But

they're still super interesting.

Yeah.

So like, where did your question come from?

Like, why, why did you ask it?

For me, I get...

intense deja vu all the time, probably a couple times a month.

And so it was interesting because I'm in my late 20s.

And so I was like, I thought this frontal lobe has, you know, clocked in.

I thought it was ready to go.

And, you know, apparently it's not yet.

What about you, Rebecca?

I had actually thought that we knew why people sleepwalked.

And I was surprised to learn that researchers didn't really know.

But I really love the idea of us continuing to research and develop theories.

And as we research, develop better theories of the things that we don't know for sure of the things that aren't explainable yet.

Yeah, I think one of life's greatest, like, magical or mysterious things is like unraveling the secrets of the mind.

It's so complex, and there's so much to discover that each of us could spend our entire lifetimes devoted to researching it, and we would still have only a fraction of

the answers that we were looking for.

I think that, you know, so on one hand, you have

scientists

trying to answer questions, and this engenders even more questions, and none of the answers are particularly satisfying.

And like that, that's I like, I think that's kind of a wonderful thing

that questions engender more questions, even through their answers.

And that says to me something about what the world is really like.

That's it for our first ever mailbag episode.

If you have questions that you want unexplained, email us.

We're at unexplainable at vox.com.

We love hearing from all of you and we'd really love to have you on the show someday.

Until then, this episode was produced by Bird Pinkerton and reported by Bird, Neil Denesha, and me, Noam Hasenfeld.

Neil has moved on to other projects, but we miss him a lot.

Neil, can't thank you enough for your work on this show.

We had editing this episode from Brian Resnick and Catherine Wells.

Meredith Hodenaut worked really closely with Bird to help get this new format off the ground.

We had sound design and mixing and scoring from Christian Ayala with help from me.

Zoe Mullick checked the facts.

And Mandingwin is trying to talk to trees.

Again, email us thoughts at unexplainable at vox.com.

And if you feel like leaving us a review or even just, you know, giving us five stars, we'd really appreciate it.

Unexplainable is part of the Vox Media Podcast Network, and we'll be back next week.