- The video begins with assembly instructions for a day trip at IKEA, including taking meatballs, a bed that doubles as a bouncy castle, and room planning sessions.
- The hosts then discuss a segment called "Things You Thought You Knew" (TYTTYK) and how it has been popular.
- They talk about compasses and how Einstein was fascinated by them as a child.
- They explain that the Earth has a magnetic field and how compasses work.
- They discuss how the South Magnetic Pole is actually in the north and does not align with Earth's Geographic Pole.
- The hosts joke about Santa Claus and Canadian stereotypes.
- They explain that the North Magnetic Pole is moving towards Siberia at a rate of almost a mile per week.
- This movement is due to the Earth's core, which has molten iron that conducts electricity and creates a magnetic field.

- The video discusses the concept of torque and how it applies to magnetic fields.
- The magnetic field is not required to align exactly with the geography of a planet.
- Planets with solid cores do not have magnetic fields, while Earth does due to its active core.
- Pulsars are magnetic neutron stars that emit radio waves as they rotate and swing past the field of view.
- The sun's magnetic field weakens and flips every 11 years, causing sunspots to disappear.
- The video also mentions the flipping of Earth's magnetic field and the presence of a compass rose in Grand Central Terminal.

- The sun rises due east and sets due west on the equator every day of the year.
- As you move north, the sun's arc in the sky goes farther south.
- In the Northern Hemisphere, if you face the sun, you will never be facing north.
- Sundials were one of the first timekeeping devices used, and they track time in the same direction as the sun's movement.
- Clocks and digital timekeeping have caused people to lose the ability to think of time geometrically.
- The precision of digital time can be unnecessary in many situations.
- The use of synchronized watches in heist movies is now outdated due to smartphones having accurate time.
- Wristwatches used to lose or gain a minute a day, making it difficult to match the time with others.

- The video discusses the concept of time and how people perceive it differently
- It mentions a friend who kept her clock 20 minutes early to avoid being late
- The video also touches on the history of chronometers and how they were used for navigation
- The speaker wonders how future generations will view our current technological advancements
- The video briefly mentions the development of area codes in phone numbers and their significance
- It concludes with a discussion on the shortest dialing area code in New York City.

- The video discusses the history and significance of area codes in major cities such as Los Angeles, Chicago, and New York.
- The purpose of area codes was to minimize the time spent dialing long distance calls in heavily populated cities.
- With the introduction of push buttons, the need for area codes became less important.
- As the population and number of phone numbers increased, municipalities needed multiple area codes.
- The video also mentions the social significance of area codes, such as the prestige associated with having a 212 area code in New York City.
- The video concludes by acknowledging the efforts of those who worked to improve communication technology.

- The video discusses assembly instructions for a day trip at IKEA and a segment called "Things You Thought You Knew" (TYTTYK).
- It explains how compasses work and the movement of the North Magnetic Pole towards Siberia.
- The video explores magnetic fields, torque, and the presence of magnetic neutron stars.
- It discusses the flipping of the sun's and Earth's magnetic fields and the use of sundials for timekeeping.
- The video touches on the perception of time, the history of chronometers, and the development of area codes in phone numbers.
- It concludes by acknowledging the importance of communication technology.

Is your compass actually wrong? Neil deGrasse Tyson and comedian Chuck Nice explore magnetic fields, why clocks go clockwise, and how phone numbers got their area codes.

The following are assembly instructions for a day trip at IKEA.

Take 8 plump meatballs at least, and 1 bed that doubles as a bouncy castle.

Add 3 45-minute room planning sessions, as many activities for kids as possible, and add 1 extra slice of dime cake.

Combine all together and you have the perfect day out at IKEA.

For the rest of this day, I'm just going to be playing out the gang rats of New York.

Every rap mafia movie, you know, rap Corleone.

Welcome to StarTalk, your place in the universe where science and pop culture collide.

This is StarTalk, a Things You Thought You Knew edition, which abbreviated is T-Y-T-T-Y-K.

There's just stuff you might've known about,

but maybe didn't know everything you could've known.

And it's something that I know something that maybe you didn't know, and I'm just putting it out there, that's all.

And it's some of our most popular segments have come from things you thought you knew.

No, the thing is, you don't know what you don't know.

I was thinking the other day about compasses.

Oh, it came with its own little like, you know, little sharp stabby thing on the end of it.

So you were carrying instruments of math destruction.

No, no, that's not that compass I'm talking about.

All right, that's all I'm talking about, I'm sorry.

That's why I did not become an astronaut.

Yes, he is a hazard to the math department.

So, you may know that Einstein, as a child, was fascinated that this compass and this little needle would always find its way north.

There was some magic force with no strings attached that moved the compass, Okay, the compass needle.

Yes, was that during his time at Hogwarts?

So we've known for a while that Earth has a magnetic field, Okay?

And there was lodestone, which is a naturally occurring variant of iron that is basically a magnet.

And the people just experimenting with it, playing with it, would notice that it aligns without anybody touching it.

We would ultimately perfect this into a compass and the compass points north so there's a little needle with an N on it and that little needle points north every time So a couple of facts just to consider Okay in magnetism opposites attract and in love Okay, well opposites attract and the North Pole of the needle of my compass points North, that means Earth's South Magnetic Pole is North.

Because that 1 might've hurt a little bit.

Which means it's finding the south pole of earth.

If you take it up to any magnet, there's a North and a South Pole, bring the compass near it, that North Pole is gonna point to the, of the needle is gonna point to the South Pole of the magnet.

That's gonna point to the, because that's what attracts it.

therefore, Earth's south magnetic pole is in the north.

The South Magnetic Pole, which is in the North.

Does not align with Earth's Geographic Pole, where Santa Claus is.

When I was growing up, the North Magnetic Pole, which contains the South Pole, right?

So let's just still call it the North because it's easier.

So if you were South of that pole, your compass would basically point North.

But if you were North of that pole, between our magnetic pole and the geographic pole, your compass would point due south, geographically south.

And if you were anywhere to the side, it would bend it inward.

So good Boy Scout books would give the correction for where actual, because you don't at the end give a shit where the magnetic pole is, you care where Santa Claus is.

The geography is what you care about, not the magnetism.

There's nothing for you at the North Magnetic Pole, okay?

So, they would give- Plus, we don't want Santa to be Canadian.

So the only Canadian joke I know is when they're learning how to spell Canada and they said, well, how are you going to spell it?

And well, we just, we think C-N-D, That spells it.

That's how the A's got into the spelling.

All right, so they would give corrections.

So if you knew what latitude you were on Earth, no, what longitude you were, and your latitude, you'd know how to correct the angle for it.

In fact, it moves a little less than a mile per week.

30 to 50 miles per year due north since my childhood, okay?

It started like in middle Canada somewhere and it started going north.

It is passing the North Pole en route to Siberia.

Your compass has never been more accurate before Because it's bite.

It's coming along the left side of the North Pole So it's close to the North Pole North geographic North Pole then it's then it's ever been in like recorded history.

And so it's gonna go on its way over to Siberia.

And this is because Earth's core, which has iron in it, that's molten, that conducts electricity as it convexes, something called a dynamo, where if you have a magnetic material that can move, the movement of that electrically conducting material such as iron will induce a magnetic field that'll take over the whole planet, that'll be manifest across the planet.

So, but that is, if it's the fact that things are moving means it's not perfectly coupled to the rest of the planet.

So the core can rotate at a slightly different rate than the whole planet does.

And it could sort of process back and, it can do things.

And right now what it's doing is it's twerking its North Pole, which is really the South Pole, out of Canada by the North Pole and it's en route to making a beeline for Siberia.

I mean, I don't blame anybody for trying to make a living, even in magnetic fields.

Yeah, It's not, the word should be more familiar than it is, but it's torque.

Yeah, auto mechanics know the word torque, but no 1 else, and physicists, but nobody else does.

Torquing is, you grab onto something and set it to rotate or not.

So, torquing is a force that instead of putting something into straight motion, puts it into rotational motion.

So, this is what's going on with the magnetic field.

that the magnetic field exactly align with the geography.

it wouldn't, because like you said, it's, you know, the core is spinning inside of, you know, this kind of liquid,

So it is some coupling, but it's not tight coupling.

And so, by the way, planets that have solid cores don't have magnetic fields.

So the moon is solid all the way through, no magnetic field.

We think Mars is solid all the way through, it's got hardly any, barely any magnetic field.

So, But Earth we know has an active core.

And by the way, there are stars in the universe, neutron stars, that have magnetic fields that if the magnetic field is steeply angled to the rotation axis, that means when the thing rotates, it swings past your field of view, the North Pole, or whatever its poles, goes like that.

And in so doing, it can accelerate particles and give off radio waves.

But these radio waves will pulse past your field of view.

A pulsar is a magnetic neutron star where the magnetic field axis is tipped so that as it rotates, it swings it past your field of view.

It's just, it's like a lighthouse effect.

Now when I was a kid, a pulsar was a watch.

But they got their word from us, just so you know.

We got it first, we got there first, okay?

So, and we got there first with a whole lot of vocabulary.

You know you guys stole that from Star Trek.

And and half the stuff that that they didn't steal they made up and doesn't exist like dilithium crystals, right?

There's lithium, but there's no dilithium.

There's definitely no dilithium crystals.

There's flux and there's a capacitor, but there's no flux capacitor.

Anyhow, so and this magnetic field, oh by the way, there are times where our magnetic field has flipped, okay?

And the people read about this and they worry that when they say, oh the axis is gonna flip They think it's like our physical axis

they're worried that that'll be the end of the world But no the magnetic axis what will happen is the dynamo slows down dies Dies it fades then the magnetic field disappears and then it reappears but flipped from what it was before.

So in that future, the actual magnetic North Pole will be in the North and compasses will then all point South.

Okay, that's pretty fast for something a million times larger than the earth.

And so it has a magnetic field, that magnetic field slowly dissipates, goes away, comes back and resets itself pointing the other direction.

And the sunspot pair is a positive and negative of a magnetic field.

So magnetism is everywhere It's very cool.

when the Sun's a magnetic field is getting weaker and weaker and before it flips, all the sunspots go away.

So this magnetic thing, it's not just a, I mean, it's an active force operating on this world and others.

to still have 1 of those bar magnets, take a string with a thin thread, tie it exactly in the middle and just dangle it there and it will align it.

You don't have to be inside of a compass vessel.

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Things You Thought You Knew – Magnetic Cores & Flipping Poles