SPEAKER_1: Welcome to StarTalk, your place in the universe where science and pop culture collide.
SPEAKER_1: StarTalk begins right now.
SPEAKER_1: This is StarTalk, Neil deGrasse Tyson here, your personal astrophysicist.
SPEAKER_1: I got with me Chuck Nice, Chuck.
SPEAKER_2: What's up, Neil?
SPEAKER_1: All right, this is another installment of Things You Thought You Knew.
SPEAKER_2: Yes.
SPEAKER_1: With each segment goes some place where you thought you knew and maybe you didn't.
SPEAKER_2: And you didn't.
SPEAKER_2: Yeah, no, let's be honest.
SPEAKER_2: You did.
SPEAKER_2: And don't be one of these people that says, I knew that.
SPEAKER_2: I knew that.
SPEAKER_2: I did.
SPEAKER_2: I knew that.
SPEAKER_2: No, no, you didn't.
SPEAKER_2: So just relax.
SPEAKER_2: All right.
SPEAKER_1: We're going to lead off with the first segment on the topic of transparency.
SPEAKER_1: I just want a general discussion about transparency because I think it's fascinating.
SPEAKER_1: Okay?
SPEAKER_1: So if we're in the same room and I see you, you know, there's a day when you say, well, there's nothing there, so that's why I can see you.
SPEAKER_1: Except, of course, there's air there.
SPEAKER_2: Of course.
SPEAKER_2: All right?
SPEAKER_1: So it's not that there's nothing between me and you blocking the view.
SPEAKER_1: Air is blocking the view, except that air happens to be transparent to the light that we are detecting.
SPEAKER_2: Okay.
SPEAKER_1: It is transparent.
SPEAKER_2: Air.
SPEAKER_1: All right.
SPEAKER_1: So now when we build domiciles, homes and whatever, you want to be able to look outside.
SPEAKER_1: You can just cut a hole in the wall and look outside because air is transparent.
SPEAKER_1: But we don't.
SPEAKER_1: We want to protect ourselves from the elements.
SPEAKER_1: So instead of having air in the window, we put something else in the opening on the side of the wall that is itself transparent to visible light.
SPEAKER_2: Mm-hmm.
SPEAKER_1: And that's what we call windows.
SPEAKER_2: Yes.
SPEAKER_1: Which are variations on SiO2, silicon dioxide.
SPEAKER_1: So that's transparent.
SPEAKER_2: Right.
SPEAKER_1: The sun is peaks in the energy that it sends to earth.
SPEAKER_1: It peaks in the red, orange, yellow, green, blue, violet part of the spectrum.
SPEAKER_1: The visible light part of the spectrum.
SPEAKER_2: Mm-hmm.
SPEAKER_1: And within that, it peaks right at the green-yellow boundary.
SPEAKER_1: Okay?
SPEAKER_1: So the sun gives more green-yellow light than any other kind of light that's out there.
SPEAKER_1: That's part of why we say the sun is yellow.
SPEAKER_1: Except it's also giving just as much green and no one says the sun is green.
SPEAKER_2: The sun is green.
SPEAKER_1: So, you're right.
SPEAKER_1: So, but it's the mixture of all of those gives us the color of the sun, which is basically white.
SPEAKER_1: My point is, how does sunlight reach us here on Earth?
SPEAKER_1: Because the atmosphere is transparent.
SPEAKER_1: Mm-hmm.
SPEAKER_1: But occasionally a cloud moves in.
SPEAKER_1: Clouds are not transparent to visible light.
SPEAKER_1: They're happy.
SPEAKER_1: So, they block the sun.
SPEAKER_1: Right.
SPEAKER_1: This sounds all very basic and simple.
SPEAKER_1: Agreed?
SPEAKER_2: I'm, right now, I'm with you on every step.
SPEAKER_1: So, now, what else is transparent?
SPEAKER_1: All right.
SPEAKER_1: You are in your home.
SPEAKER_1: You have glass in the windows.
SPEAKER_1: You have walls.
SPEAKER_2: I do.
SPEAKER_1: You have a roof and a floor.
SPEAKER_2: Okay.
SPEAKER_2: That's true.
SPEAKER_1: And then your cell phone rings.
SPEAKER_1: Well, is your cell phone using visible light?
SPEAKER_2: No.
SPEAKER_2: No, it isn't.
SPEAKER_1: No.
SPEAKER_1: It's using microwaves.
SPEAKER_2: By the way, I have a really crappy carrier, so my cell phone doesn't ring.
SPEAKER_1: It's not working.
SPEAKER_1: So, the microwaves have no hesitation penetrating your walls, with or without the window.
SPEAKER_1: You could use your cell phone in a windowless bathroom.
SPEAKER_1: So, two microwaves, which are part of the electromagnetic spectrum, your home is transparent.
SPEAKER_1: So, if you had microwave vision, your home basically disappears.
SPEAKER_1: You might see the door frames, depending on how it's framed out.
SPEAKER_1: You might see some metal wiring and things, but overall, the house disappears.
SPEAKER_1: In the same way, when you look out a window, you're not looking at glass.
SPEAKER_1: The glass disappears to you.
SPEAKER_1: And you know it does when people walk into that stuff in stores.
SPEAKER_2: Actually, I'm looking out my window right now, and I'm like, maybe I need to clean these because this glass is not disappearing.
SPEAKER_2: This is straight up safety glass that I'm looking at right now.
SPEAKER_2: No one is walking through this glass.
SPEAKER_1: Yeah, so you know what safety glass is?
SPEAKER_1: It's glass that breaks into a zillion tiny pieces.
SPEAKER_2: I didn't know that.
SPEAKER_1: You thought it was what?
SPEAKER_2: I thought it was glass that didn't break.
SPEAKER_2: No, no, no, no.
SPEAKER_1: That could be a variant on safety glass, but in cars where they say safety glass, when the car windshield breaks, it completely shatters into tiny little bits of glass.
SPEAKER_2: That doesn't make me feel safe.
SPEAKER_1: No, no, no.
SPEAKER_1: But you ask how deep into you can a tiny piece of glass go?
SPEAKER_1: Like the depth of the tiny piece of glass.
SPEAKER_1: Whereas if the windshield broke in these huge shards, it could penetrate you and get into your heart, break your jugular or whatever.
SPEAKER_1: The worst you need is a bag of Band-Aids at the end of the broken glass of safety glass.
SPEAKER_1: That's all.
SPEAKER_1: It's designed to be completely shattered.
SPEAKER_1: That version of that variety of safety glass is designed for that.
SPEAKER_2: I got you.
SPEAKER_1: But that's not what we're talking about.
SPEAKER_1: We're talking about the fact that to microwaves, your home is transparent.
SPEAKER_1: Your home is also transparent largely to radio waves.
SPEAKER_1: Now if you're old school, some of our listeners are old school.
SPEAKER_2: And know what radio is?
SPEAKER_1: Radio is you'd go into a tunnel.
SPEAKER_1: If you were listening to FM, the FM signal would drop out.
SPEAKER_1: If you're listening to AM, it would stay.
SPEAKER_1: AM has greater penetration through the surroundings of tunnels than FM does.
SPEAKER_1: So it's all a matter of who is transparent to whom.
SPEAKER_1: Now let's tune our eyes so you have those red, orange, yellow, green, blue, violet.
SPEAKER_1: Below red, we have infrared.
SPEAKER_1: And below infrared, we have microwaves.
SPEAKER_1: So microwaves get through stuff.
SPEAKER_1: But microwaves have a hard time getting through metal.
SPEAKER_1: The metal interacts with them.
SPEAKER_1: It prevents that.
SPEAKER_2: I learned that's a hard way in my oven, but go ahead.
SPEAKER_2: That's a whole other story.
SPEAKER_1: In your microwave oven, you have a metal...
SPEAKER_1: So the door is made of glass.
SPEAKER_2: Right.
SPEAKER_1: Microwave goes right through glass.
SPEAKER_1: No problem.
SPEAKER_1: But it's not only glass.
SPEAKER_1: Your door has this mesh on the inside.
SPEAKER_2: Right.
SPEAKER_1: And the wavelength of microwaves is like a few millimeters up to maybe a couple of centimeters in that zone.
SPEAKER_2: Wow.
SPEAKER_1: So that mesh has holes that are smaller than the size of the microwave so they can't come through.
SPEAKER_2: So I can see in, but the waves bounce back.
SPEAKER_1: You can see in because you're not using microwaves to see.
SPEAKER_2: I'm using visible light, which goes through the holes.
SPEAKER_2: Right.
SPEAKER_1: Visible light is way smaller than those holes.
SPEAKER_2: So I'm not getting irradiated because the waves can't get through the holes so they bounce back into the microwave.
SPEAKER_1: Back into the microwave.
SPEAKER_1: Correct.
SPEAKER_1: So now let's look at infrared.
SPEAKER_1: That's brilliant.
SPEAKER_2: What a simple thing.
SPEAKER_2: That's freaking brilliant.
SPEAKER_1: This is why science and engineering, these are the foundations of civilization.
SPEAKER_2: I can't believe I got a science oven.
SPEAKER_2: Oh, that's so cool.
SPEAKER_1: So now let's go to infrared.
SPEAKER_1: So now let's look around us in infrared.
SPEAKER_1: You'll see things that are...
SPEAKER_1: Infrared is a good measure of temperature.
SPEAKER_1: Because things will glow if they're glow...
SPEAKER_1: We know this from...
SPEAKER_1: From Predator.
SPEAKER_2: We know it from Predator.
SPEAKER_2: Let's be honest.
SPEAKER_2: That's how we know about infrared.
SPEAKER_2: Okay.
SPEAKER_2: We didn't pay attention in school, but then we saw the alien monster up in the tree and it was making that gurgling sound like...
SPEAKER_2: And it was looking at Arnold Schwarzenegger like...
SPEAKER_2: You know, and we saw him, you know...
SPEAKER_1: Damn, you remember the sound effects too.
SPEAKER_1: If it bleeds, we can kill it.
SPEAKER_1: Which is brilliant.
SPEAKER_2: Yeah, but that's it.
SPEAKER_1: That's true.
SPEAKER_1: That's the most brilliant line in the movie.
SPEAKER_2: He was wrong, by the way.
SPEAKER_1: If it bleeds, we can nuke it.
SPEAKER_2: Exactly.
SPEAKER_2: Because that's how it died.
SPEAKER_2: It nuked itself.
SPEAKER_2: So he was wrong.
SPEAKER_1: It didn't bleed to death.
SPEAKER_2: It did not bleed to death.
SPEAKER_2: He blew up half the deck on jungle, okay, because he lost first.
SPEAKER_2: And the Predator is a bad loser.
SPEAKER_2: Let me just tell you that right now.
SPEAKER_2: I ain't never lost no game and been like, that's it, I'm nuking this whole place.
SPEAKER_2: This whole place is going up mushroom cloud and all.
SPEAKER_2: Screw you humans.
SPEAKER_2: That has nothing to do with what I'm trying to say.
SPEAKER_1: You're going off on a Predator tangent.
SPEAKER_1: All right, so, but you are correct.
SPEAKER_1: Predator has vision, has infrared vision.
SPEAKER_1: By the way, SOTU did Terminator, interestingly, also played by...
SPEAKER_2: That same guy.
SPEAKER_1: So, all right, so infrared, I look around and I see things glowing.
SPEAKER_1: Then I try to look out the window and I can't.
SPEAKER_1: It's opaque.
SPEAKER_1: It is opaque.
SPEAKER_1: And you can test this yourself.
SPEAKER_1: You ready?
SPEAKER_1: So, put someone on one side of the window and have them turn on a flashlight.
SPEAKER_1: The other side, they can see the flashlight.
SPEAKER_1: Now have someone turn on something that turns red hot.
SPEAKER_2: Like an iron.
SPEAKER_1: Like an iron, you know, a red hot iron.
SPEAKER_1: And have them go on the other side of the window and ask if you feel the heat of the iron.
SPEAKER_1: You do not feel it at all.
SPEAKER_2: That's so cool, because glass is like an insulator.
SPEAKER_1: Glass prevents the transmission of heat.
SPEAKER_1: So, glass, transparent glass, is opaque to infrared light.
SPEAKER_2: To infrared light.
SPEAKER_1: Yes.
SPEAKER_1: Nice.
SPEAKER_1: Well, let's keep going.
SPEAKER_1: How about radio waves?
SPEAKER_1: Well, like radio waves are what you get when you go beyond microwaves.
SPEAKER_1: They have excellent penetration depth through everything basically.
SPEAKER_1: That's why it works as communication.
SPEAKER_1: Otherwise, you say, I'll call you at 310, but get out in the street and face the radio tower when we're talking.
SPEAKER_1: That's not what it is.
SPEAKER_1: Wherever you are, we can find you and we can communicate with you.
SPEAKER_1: Right.
SPEAKER_1: So I'm just trying to have people broadly think about the fact that when you say something is transparent, technically you should be specifying transparent for what wavelength of light.
SPEAKER_2: Right.
SPEAKER_1: For what wavelength, correct.
SPEAKER_1: By the way, you know what else is opaque to what glass blocks?
SPEAKER_1: UV.
SPEAKER_1: Glass blocks UV.
SPEAKER_1: Glass out of the box will absorb 97% of UV that hits it.
SPEAKER_1: And I've done this experiment using in a laboratory.
SPEAKER_1: Out of the box, it's a UV filter.
SPEAKER_1: When you buy special sunglasses that say UV blockers, UV protections, right, they're getting you from the 90s.
SPEAKER_1: If they're made of glass, they're getting you from the 97% it gets for free up to like 99%.
SPEAKER_1: Okay.
SPEAKER_1: Now, there are physicists when they were testing atomic bombs and they had high energy radiation there, what they would do is they would dip behind the windshield of the Jeep that drove them out there.
SPEAKER_1: It would still be bright, visually bright, but the high energy radiation would be blocked by the transparent glass.
SPEAKER_1: So glass blocks infrared on one side of the visible spectrum and ultraviolet on the other side of the spectrum, which is beyond violet, and it transmits by definition what we call visible light.
SPEAKER_1: And that's what makes glass quite a fascinating thing in our culture and in our civilization.
SPEAKER_2: So that's why Wonder Woman never gets a tan, because she's riding around in her invisible glass ship, or, you know, plane.
SPEAKER_1: I forgot about that.
SPEAKER_2: It's a flying thing.
SPEAKER_2: It's a flying thing, but we don't know.
SPEAKER_1: It's a transparent flying thing.
SPEAKER_2: Yeah, because we call it a plane, but the truth is we can't see it, so we don't know what it is, to be honest, because it's invisible.
SPEAKER_2: And by the way, she only flew it once, and that was, you know.
SPEAKER_1: Okay, all right, all right.
SPEAKER_2: Yeah, she got out of it, and then she couldn't find it.
SPEAKER_1: So, in Harry Potter, they had the invisibility cloak.
SPEAKER_2: Oh, that thing is cool.
SPEAKER_1: Okay, so here's what you do is, since you are in the way between me and what's behind you, okay, I can't all of a sudden make you transparent, but we have research such as what they had in Harry Potter, whereas you put on this invisibility cloak, and what happens is the light from behind you hits the back of your cloak and is channeled around the front and then comes straight back out from the front of you.
SPEAKER_1: This is very complicated optical pathways that the light has to take.
SPEAKER_1: If it does that, then my pathway goes to your chest, around you and to the wall behind you, and I don't even know you're standing there because I don't know the light took that securitas root because it comes straight to my eye.
SPEAKER_1: So I can make you transparent if the light behind you is brought around to the front of you.
SPEAKER_1: This was also shown in a James Bond film.
SPEAKER_1: I forgot which.
SPEAKER_1: He can make his Aston Martin disappear.
SPEAKER_2: But really you're just diverting, bending the light to the front.
SPEAKER_1: You're bending the light around it.
SPEAKER_1: Correct, correct.
SPEAKER_1: And it means you should still be able to shoot it.
SPEAKER_1: The bullet's not going to say, hey, where'd the car go?
SPEAKER_1: I don't know what to do.
SPEAKER_2: That's funny.
SPEAKER_1: The bullet still has its trajectory, and it's going to be right to the target.
SPEAKER_1: So that was just a little, I thought I'd spend a couple of minutes talking about transparency.
SPEAKER_2: I liked it.
SPEAKER_1: Chuck, we've got to take a quick break.
SPEAKER_1: But when we come back more, Things You Thought You Knew on StarTalk.
SPEAKER_2: I'm Joel Cherico, and I make pottery.
SPEAKER_2: You can see my pottery on my website, cosmicmugs.com.
SPEAKER_1: Cosmic Mugs, art that lets you taste the universe every day.
SPEAKER_2: And I support StarTalk on Patreon.
SPEAKER_1: This is Star Talk with Neil deGrasse Tyson.
SPEAKER_1: Welcome back to StarTalk's Things You Thought You Knew.
SPEAKER_1: Chuck, you know what we're going to talk about now?
SPEAKER_2: That's the thing I thought I knew, but clearly I don't.
SPEAKER_1: Things You Thought You Knew, we're going to talk about the International Date Line.
SPEAKER_2: Oh, okay.
SPEAKER_1: There might be some stuff in there you didn't know about.
SPEAKER_2: Oh, believe me.
SPEAKER_2: I'm letting you know right now, I don't care what you say about the International Date Line, I did not know it.
SPEAKER_1: It's kind of a weird place, you know?
SPEAKER_1: Just one spot on Earth's surface, and then it's yesterday or tomorrow, right?
SPEAKER_1: And it's the same time, but a different day.
SPEAKER_2: Yeah, that's true.
SPEAKER_1: That's a little creepy, right?
SPEAKER_1: It's a little weird.
SPEAKER_2: It is.
SPEAKER_1: I just thought you never thought about that.
SPEAKER_2: You know, because to me, I get it that we're in motion, and so that's why there's got to be different times.
SPEAKER_2: But I'm going to be honest, it's one of those things that I never get right.
SPEAKER_2: And I'm talking about here on this continent, North America, I'm not even talking about leaving our shores.
SPEAKER_1: Okay, you're talking about, you don't get time zones right.
SPEAKER_2: I screw every single time zone up, no matter what email, even when they explain it to me, and then I still screw it up.
SPEAKER_1: For what it's worth, what prevents me from screwing it up is, I re-derive time zones from first principles almost every time I think of them.
SPEAKER_1: So I say, okay, Earth is rotating west to east, the sun therefore rises first for everyone east of us.
SPEAKER_1: So everyone east of us has to be, has to be later than us than the ones west of us.
SPEAKER_1: So I reconstruct that in my head so that I get it right every time.
SPEAKER_2: See, I am too busy for that.
SPEAKER_1: Time is valuable to me.
SPEAKER_2: That was valuable, man.
SPEAKER_2: That is too much time thinking about time.
SPEAKER_2: However, that's a very good, that's a good way to do it, you know what I mean?
SPEAKER_2: If you're in that discipline to do it that quickly.
SPEAKER_1: Yeah, okay, so here's the thing.
SPEAKER_1: So you say, well, how do we even know you need one?
SPEAKER_1: Yeah.
SPEAKER_1: Okay, so watch this, so watch.
SPEAKER_1: Do you remember who was the first to circumnavigate the globe?
SPEAKER_2: That was the man who went around the world in 80 days in that balloon.
SPEAKER_1: That's the, it's exactly not the person I'm talking about.
SPEAKER_1: So, Ferdinand Magellan, okay?
SPEAKER_1: This is after Columbus and after a bunch of other voyages to the New World from Europe.
SPEAKER_1: He goes around the world and returns to the port that they sailed from.
SPEAKER_1: And I think it was actually in Portugal.
SPEAKER_1: But it doesn't matter for what I'm about to describe.
SPEAKER_1: So anyway, so they leave Europe and they head west.
SPEAKER_1: There's a scribe on board named Antonio Pegafetta.
SPEAKER_1: I think it was a wealthy nobleman who was not part of the crew.
SPEAKER_1: He just went along joyriding basically.
SPEAKER_1: But he kept very good records of what was going on.
SPEAKER_2: It's easy to do when you don't have any work to do on the ship.
SPEAKER_2: Exactly.
SPEAKER_2: Everybody else is lowering the boom and hoisting the missing mast.
SPEAKER_2: You over there writing it down.
SPEAKER_2: Isn't that lovely the way you did that?
SPEAKER_2: Oh, that was wonderful.
SPEAKER_2: Oh, the men.
SPEAKER_1: Can you show me that again?
SPEAKER_2: What a knot, what a great knot.
SPEAKER_2: What do you call that knot?
SPEAKER_2: I'd like very much to make a notation of that particular knot.
SPEAKER_1: That was basically what this guy did.
SPEAKER_1: And he kept track of who died on board because disease would go through the crew.
SPEAKER_1: And at some point, Magellan was killed by natives on an island that they arrived at.
SPEAKER_1: And so, Magellan did not complete the voyage because he died on route.
SPEAKER_1: But the ship made it, as so did Antonio Pigafetta.
SPEAKER_2: Of course.
SPEAKER_2: You know Antonio will make it.
SPEAKER_1: All right, so here's what happened.
SPEAKER_1: So he goes west.
SPEAKER_1: And you keep track of what's called local noon.
SPEAKER_1: All right, so when is noon?
SPEAKER_1: It's when the sun is at its highest point in the sky.
SPEAKER_1: Okay.
SPEAKER_1: And that's the middle of your day.
SPEAKER_1: And whatever day that is.
SPEAKER_1: And he's marking these days on his calendar.
SPEAKER_1: Okay.
SPEAKER_1: And as they keep traveling, we have another day upon us.
SPEAKER_1: And there's the sunrise and sunset.
SPEAKER_1: There's quote, local noon.
SPEAKER_1: All right.
SPEAKER_1: And he does this.
SPEAKER_1: And he keeps track.
SPEAKER_1: And he's good at this.
SPEAKER_1: Okay.
SPEAKER_1: He's a wealthy, educated Italian nobleman.
SPEAKER_1: And he's good at it.
SPEAKER_1: Okay.
SPEAKER_1: They come around the world and come back.
SPEAKER_1: And he thinks it's Wednesday.
SPEAKER_1: And everyone there thinks it's Tuesday.
SPEAKER_1: He can't believe it.
SPEAKER_1: And he's writing.
SPEAKER_1: I think they're pulling a trick on me.
SPEAKER_1: They want to fool me.
SPEAKER_1: Then he went to check other people.
SPEAKER_1: And everyone says it's Tuesday, whatever day of the month it was.
SPEAKER_1: And he's still thinking it's Wednesday.
SPEAKER_1: And again, whichever days it is.
SPEAKER_1: But he has a different day.
SPEAKER_2: He's off.
SPEAKER_1: He's got a different day.
SPEAKER_2: He's off by 24 hours.
SPEAKER_2: He's off by day.
SPEAKER_1: He's off by day and he can't figure it out.
SPEAKER_1: And he said, I kept very good notes.
SPEAKER_1: I don't know what happened here.
SPEAKER_1: And it's just sitting there in his notebook.
SPEAKER_1: The confusion of a nobleman scribe.
SPEAKER_1: And it is laid bare the discovery of the need for an international date line.
SPEAKER_1: That was the discovery.
SPEAKER_2: Fascinating.
SPEAKER_1: Yes.
SPEAKER_2: That's fascinating.
SPEAKER_2: Because there's no need for it unless you're actually going to make the trip.
SPEAKER_1: Yes.
SPEAKER_1: Do you and I give a rat's ass what's in the center of the Pacific Ocean?
SPEAKER_1: It doesn't matter.
SPEAKER_1: But if you're going to make the next trip, you're going to make that trip, you need to know it.
SPEAKER_1: And he discovered it by accident, which I thought was just so...
SPEAKER_1: It's the kind of things you discover when you're very good at...
SPEAKER_1: When you're very careful in your observations and in your data recording.
SPEAKER_2: Yeah.
SPEAKER_1: He was being a scientist without even knowing.
SPEAKER_2: Without even knowing it.
SPEAKER_2: And of course, for weeks, he still walked around like, come on, man, seriously, what the hell?
SPEAKER_2: Come on.
SPEAKER_1: Stop messing with me.
SPEAKER_2: You can tell me now.
SPEAKER_2: It's just us here.
SPEAKER_2: Come on, seriously.
SPEAKER_2: It's Wednesday, right?
SPEAKER_2: It's Wednesday.
SPEAKER_2: Come on.
SPEAKER_2: How'd y'all all get in on this?
SPEAKER_2: Come on.
SPEAKER_2: Who was it?
SPEAKER_2: Was it the king?
SPEAKER_2: Because he said, he said we'll not get back, right?
SPEAKER_2: Come on.
SPEAKER_2: He told it to everybody.
SPEAKER_1: He pinned up a broadsheet in the center of town and said, don't tell anybody.
SPEAKER_2: That's funny.
SPEAKER_1: So anyway, and of course, if you go the other way around the earth, you would be a day behind.
SPEAKER_1: So the point is, if you go west, you're chasing the sun because the sun sets in the west.
SPEAKER_1: Right.
SPEAKER_1: So if you're going in the direction the sun is, and so you are adding a whole day to your life as you go around that other people are not enjoying.
SPEAKER_1: And so I put it out there.
SPEAKER_1: I don't know how many people know that story.
SPEAKER_1: But it's in the notes of Magellan's Voyage kept by Anton Pigafetta.
SPEAKER_1: Yeah.
SPEAKER_2: Pigafetta.
SPEAKER_2: That's what it was.
SPEAKER_1: Pigafetta.
SPEAKER_2: Pigafetta.
SPEAKER_2: What a great name.
SPEAKER_1: Oh, by the way, clearly there's no reason for there to be bias in those observations that he made.
SPEAKER_1: He's just checking local noon, sunrise, sunset.
SPEAKER_1: He's counting days.
SPEAKER_1: But in other places in his writings, he talks about there was a disease that afflicted the crew and many of them died and they had some natives from the island that they befriended and came on board.
SPEAKER_1: And if you die on a ship, you know what do you do with the body?
SPEAKER_2: I would say bury it at sea because dead bodies are not...
SPEAKER_2: Yeah, they're not very pleasant to be around, dead bodies.
SPEAKER_1: Yeah, not on your ship.
SPEAKER_2: Not on the ship as they're rotting next to your food supply.
SPEAKER_1: Right, exactly.
SPEAKER_1: So you toss it overboard.
SPEAKER_1: And there he writes carefully and he says, oh, and natives and other non-Christians floated face down and all the Christians floated face up towards heaven.
SPEAKER_2: This is in his account.
SPEAKER_2: First of all, how do you know what's in their heart?
SPEAKER_2: Haha, you don't know this, but guess what?
SPEAKER_2: I was actually a Jewish person.
SPEAKER_2: There you go.
SPEAKER_2: Mr.
SPEAKER_2: Pig Feta, I converted.
SPEAKER_2: Yeah, now why am I floating face up?
SPEAKER_1: So, you know, statistically, I guess that could have happened that way or would the clothing do that?
SPEAKER_1: But he was deeply religious as were so many European explorers back then, wanting to convert the world to not simply Christianity, but Catholicism specifically.
SPEAKER_1: And so this was a...
SPEAKER_1: This is also in his writings.
SPEAKER_1: So basically, if you're going to evaluate the work of someone who's an acute observer, you want to ask, could they have a bias of any kind before you go into what it is they write?
SPEAKER_2: Right.
SPEAKER_1: And if he's deeply religious, there could be a religious bias.
SPEAKER_1: You have to watch for that.
SPEAKER_1: But he's not going to have a Tuesday, Wednesday bias.
SPEAKER_1: You don't expect that.
SPEAKER_2: And by the way, I'm just saying, it's really not very much of an accomplishment for your particular deity to allow your dead corpse, there's no other kind of corpse, to float one way.
SPEAKER_2: See, the real deal would be like, we threw the Christians overboard and they started to swim.
SPEAKER_2: What?
SPEAKER_2: Well, they popped back up and landed on the deck.
SPEAKER_2: Praise Jesus.
SPEAKER_1: Wait, or they never got sick in the first place.
SPEAKER_2: There you go.
SPEAKER_2: That's even better.
SPEAKER_1: You got to be kidding me.
SPEAKER_2: Yeah, anyway.
SPEAKER_1: I'm pretty sure they would have thrown you overboard, whether or not you were dead.
SPEAKER_2: Let me tell you something.
SPEAKER_2: Before we left port, my ass would have been thrown.
SPEAKER_1: The kind of humor not accepted at the court gesture level.
SPEAKER_2: Off with his head.
SPEAKER_1: We're going to take a break.
SPEAKER_1: That is so cool.
SPEAKER_1: And we just said, well, let's put it there, but it has to line up with the Prime Meridian.
SPEAKER_1: So that, because it's the opposite of the Prime Meridian.
SPEAKER_1: And that all worked out, because Greenwich, England, all right, if you extend the line around the other side of the earth, it goes right down the middle of the Pacific Ocean.
SPEAKER_1: And you got to avoid some islands that are, you don't want part of your country to be on a different day.
SPEAKER_1: So if you watch, if you look at it, I think it has to accommodate Hawaii.
SPEAKER_2: It bends a little to the side and it comes back.
SPEAKER_1: It's got a little, okay.
SPEAKER_1: It's got a little, you know, some movement, because it's, at the end of the day, do you really care what, you know, the precise location on earth?
SPEAKER_1: The 24 time zones are highly fungible, right?
SPEAKER_1: I mean, the Eastern time zone is not exactly where the line would be.
SPEAKER_1: You'd include the states that want to be part of that club.
SPEAKER_2: That want to be part of that, yeah.
SPEAKER_1: Right, right.
SPEAKER_1: And hardly anybody lives in the mountain time zone.
SPEAKER_2: And why do we have it?
SPEAKER_2: Why do we have mountain time?
SPEAKER_2: You just...
SPEAKER_1: Okay, so what I'm saying is that has the lowest population, right?
SPEAKER_1: And so it's also very narrow.
SPEAKER_1: So I don't know if it's TV, schedulers, whatever.
SPEAKER_1: They give the time, and then the slash central time, right?
SPEAKER_1: So that main time is East Coast, West Coast, and then central time, nobody reports mountain time.
SPEAKER_2: Nobody reports mountain time.
SPEAKER_2: That's why I don't know why we have it.
SPEAKER_2: Did you notice that?
SPEAKER_2: No, because there's no...
SPEAKER_1: Did you notice they don't report mountain time?
SPEAKER_1: They have to adjust on their own.
SPEAKER_1: Who's there?
SPEAKER_1: No one's there.
SPEAKER_2: That's why.
SPEAKER_1: Yes, a few people live in mountain time.
SPEAKER_1: There are a few people, I know.
SPEAKER_1: The same as like the 20 mile radius of Manhattan, right?
SPEAKER_1: But still, people live in mountain time.
SPEAKER_2: The same.
SPEAKER_1: Montana, Utah, Colorado, Arizona, New Mexico.
SPEAKER_2: Whatever.
SPEAKER_2: There it is.
SPEAKER_1: Mountain time people, send all your hate mail to Chuck.
SPEAKER_2: How about this, mountain time people?
SPEAKER_2: Get a new time zone.
SPEAKER_2: There you go.
SPEAKER_2: And then we won't have to have this conversation.
SPEAKER_2: You won't be mad at me.
SPEAKER_2: I'm doing you a favor.
SPEAKER_1: All right.
SPEAKER_1: We're done here with the international dateline.
SPEAKER_1: Oh, by the way, a quick one.
SPEAKER_1: There was a TV show, I forgot what network it was on, Zack and Cody.
SPEAKER_1: Okay, it was like a show for Disney or something.
SPEAKER_1: Disney or Nickelodeon, they had an episode where they were on an ocean liner that crossed the international dateline.
SPEAKER_1: And they turned it into like a Groundhog Day reliving the incident.
SPEAKER_1: So every time it went across, it like, the ship flipped back and forth.
SPEAKER_1: It reset and then all the events are happening again and they got to replay it.
SPEAKER_1: So people think magical things happening there, but it's a completely arbitrary place where we put it.
SPEAKER_2: Nice.
SPEAKER_1: We could have put it right down the middle of Manhattan if we wanted, but that would have just been weird.
SPEAKER_1: I'll see you next Tuesday.
SPEAKER_2: That's a whole nother dateline.
SPEAKER_2: Very good, Chuck.
SPEAKER_2: All right.
SPEAKER_1: We got to take a quick break, but when we come back, the third and final installment of this episode of StarTalk, Things You Thought You Knew.
SPEAKER_1: We're back for the third and final segment of Things You Thought You Knew.
SPEAKER_1: So Chuck, I'm an acute observer, airplanes, air traffic, airports, all of it.
SPEAKER_1: I just think it's one of the great, beautiful things of civilization that we can fly.
SPEAKER_1: And I bet if you ever seen a 747 take off, you're thinking to yourself, oh my gosh, this thing flies.
SPEAKER_1: Right, the 300 ton aluminum or whatever much it weighs, the thing flies and it looks like it's in slow motion when it's flying.
SPEAKER_1: That's even more stunning, right?
SPEAKER_2: Amazing.
SPEAKER_1: Amazing, okay.
SPEAKER_2: And the fact that it's like three, it looks like it's three stories tall.
SPEAKER_1: Right, right, with it inside.
SPEAKER_1: Yeah, yeah.
SPEAKER_2: Inside, yeah, it's crazy.
SPEAKER_2: I mean, it's just crazy.
SPEAKER_1: Right, so I just wanted to update you on some things that have happened slowly that you might not have noticed.
SPEAKER_1: All right, so airplanes today, when they leave the runway, typically take off at a steeper angle into the air than they once did many decades ago.
SPEAKER_2: Well, I didn't know that.
SPEAKER_1: So the engines have enough power, so they can accelerate at a steep angle without getting more horizontal velocity to try to get the lift, okay?
SPEAKER_1: If you take off at a steep angle, the air can hit the wing and push it up with your engine.
SPEAKER_1: So you get a lift that is, if the fuselage and the engines are done correctly for this, it can take off at a steep angle.
SPEAKER_1: What that does is reduce the acoustic footprint of the airport.
SPEAKER_2: That makes sense because you're not spreading it out over a larger distance.
SPEAKER_1: Correct, correct.
SPEAKER_1: So it gets higher faster so that the sound is not disrupting whatever is going on on the ground.
SPEAKER_1: So you can sell real estate closer to the airport without the airport badly influencing those real estate values.
SPEAKER_1: So that's one little thing that has changed over the years.
SPEAKER_1: The engines are more powerful to enable that.
SPEAKER_1: Not only that, the engines are quieter than they ever were.
SPEAKER_1: When I grew up, and I'm not that much older than you, Chuck, this would have overlapped some of your day.
SPEAKER_1: If a plane flew overhead, you had to stop your conversation, let the plane continue flying and then you continued your conversation.
SPEAKER_1: You could not speak over the sound of the engines if a plane was flying overhead.
SPEAKER_2: Now, are you sure you didn't grow up next door to an airport, because that could have been the problem?
SPEAKER_1: I distinctly remember this, okay?
SPEAKER_1: I can't impress upon you how much quieter jet engines are relative to even just a few decades ago.
SPEAKER_1: So you combine how much quieter...
SPEAKER_2: I'm trying to figure out how that happens though.
SPEAKER_2: It's still a jet engine, you're still sucking in a bunch of air.
SPEAKER_1: Yes, yes, yes, yes, yes.
SPEAKER_1: No, no, you design the cab, the engineers do this, okay?
SPEAKER_1: This is like, it's reducing noise pollution, all right?
SPEAKER_1: As we slowly reduced air pollution and water pollution and all these things that were big buzz terms in the 1960s and 70s, we made great progress across the board in all of these categories, okay?
SPEAKER_1: Did you know that in 1969, when the Mets were in the World Series, Mayor Lindsay redirected traffic from LaGuardia to not fly over the stadium because when planes flew over the stadium, everything stopped.
SPEAKER_1: The announcers couldn't speak.
SPEAKER_1: I remember this.
SPEAKER_1: That's how old I am, okay?
SPEAKER_1: I'm just saying.
SPEAKER_2: That's pretty damn loud.
SPEAKER_2: Now that, anytime a stadium full of roaring people can be drowned out by a plane, and LaGuardia is very, very close to the, that's insane.
SPEAKER_1: So, other little things you might not have noticed.
SPEAKER_1: When was the last time you saw someone throw up on an airplane?
SPEAKER_2: Well, you know, every time I fly.
SPEAKER_2: Oh, you're the one.
SPEAKER_1: Okay, except for you.
SPEAKER_1: No, here's the point.
SPEAKER_1: Here's the point.
SPEAKER_1: There was a day when it was the duty of the pilot to sort of do what they can as they fly it to maintain the stability.
SPEAKER_1: And you'd have turbulence and things like that.
SPEAKER_1: There are control surfaces on the airplane controlled by computers that make micro adjustments in the flaps that maintain a level of stability, the likes of which planes have never seen before.
SPEAKER_2: Yeah.
SPEAKER_2: It's funny you say that, because the last time I flew, which was a very short time ago, I was sitting in the chair thinking, God, it is almost peaceful up here.
SPEAKER_2: This is my point.
SPEAKER_1: But that's not my favorite part of the airplanes.
SPEAKER_1: My favorite part is...
SPEAKER_2: Okay.
SPEAKER_1: I might have said this in another...
SPEAKER_1: This all just jumbles in my head.
SPEAKER_1: Here it is.
SPEAKER_1: Ready?
SPEAKER_2: Go ahead.
SPEAKER_1: Okay.
SPEAKER_1: Have you ridden modern roller coasters lately?
SPEAKER_2: Oh, yeah.
SPEAKER_1: So, modern roller coaster is not...
SPEAKER_1: You're not in a cart with a thing.
SPEAKER_2: You're actually in an open air-type cockpit with just a harness over top of you, and that's it.
SPEAKER_1: You're basically dangling there, okay?
SPEAKER_1: And when the thing makes the turn, your gondola swings out.
SPEAKER_2: Swings out.
SPEAKER_1: To bank that turn.
SPEAKER_1: Do you ever notice that?
SPEAKER_1: Oh, yeah.
SPEAKER_1: Well, what's going on there?
SPEAKER_1: Oh, well, at the speed you're going and the radius of curvature of that turn, the free-floating gondola, whatever you want to call this thing you're in, will swing out to the precise angle where your effective gravity is still into your pants, into your seat.
SPEAKER_2: All right.
SPEAKER_2: Oh, oh, oh, oh.
SPEAKER_1: This is important.
SPEAKER_1: Okay.
SPEAKER_1: So you're tipped at an angle, but you don't feel the angle because the combination of gravity and centrifugal force is such that your up or down is still straight into your seat and up above your head.
SPEAKER_1: Even if that's at an angle.
SPEAKER_1: Okay.
SPEAKER_2: That's true.
SPEAKER_1: So whereas in the old roller coasters, they would occasionally bank the turn, but usually when you're making a turn, you end up leaning into the person next to you like this.
SPEAKER_2: Yeah.
SPEAKER_1: Okay.
SPEAKER_2: Which is why often you needed a neck brace when you got off of the roller coaster.
SPEAKER_2: Yeah.
SPEAKER_1: Okay.
SPEAKER_1: Because it would totally disrupt your musculoskeletal structure because you're getting knocked around like this.
SPEAKER_1: If you ever notice even in the people who film themselves on these high-speed roller coasters, everyone is always in a straight line.
SPEAKER_1: There's none of this going on there.
SPEAKER_1: So now that's because the speed of the roller coaster and the bank of the roller coaster and the radius of curvature conspire so that you always have your net gravity vector straight into the chair.
SPEAKER_1: What I'm telling you is, on an airplane, they solve that equation.
SPEAKER_1: They solve that equation on an airplane.
SPEAKER_1: So when the airplane banks a turn, it does it at the speed and the bank angle such that you don't even know you're turning.
SPEAKER_1: Because everything is just vertical to you.
SPEAKER_1: You can have a glass of wine sitting there and the level of the liquid is perfectly horizontal to you and to the sides of the glass.
SPEAKER_1: Yet you open the window to the left and right and the ground is down here and the clouds are up there and then it does this and the ground is down there and the clouds are up there and your liquid in your glass of water, wine or vodka is completely level.
SPEAKER_1: That is, the computer does that.
SPEAKER_1: Computers know how to combine that so you don't even know you're turning.
SPEAKER_1: And so no longer do you lean into one way or another when the plane is banking.
SPEAKER_1: So this adds to the stability of your entire plane flying experience.
SPEAKER_2: This is very cool.
SPEAKER_2: What I am gaining from this discussion is a brand new appreciation for computers.
SPEAKER_1: Planes aren't really that cool.
SPEAKER_2: It's the computers that are cool, man.
SPEAKER_1: The computers are figuring all this out.
SPEAKER_1: To give you a smooth ride.
SPEAKER_2: A smooth ride, quieter ride, you know.
SPEAKER_1: So the way to do this is try to get the people to your left and to your right.
SPEAKER_1: When you're nearing the airport, because when you're more likely to turn to line up for the runway, have both sides lift up their windows and put a glass of water right in front of you.
SPEAKER_1: Okay.
SPEAKER_1: If you can still have it at that.
SPEAKER_1: Yeah, they're not going to let you do that.
SPEAKER_1: But get it right in front of you.
SPEAKER_2: Then again, wait a minute.
SPEAKER_2: I forgot you fly first class.
SPEAKER_2: You still might be able to get a glass of water.
SPEAKER_1: So it's there.
SPEAKER_1: And it's just watch the level around the rim and then look to the left and right.
SPEAKER_1: And as the plane turns, nothing happens to that water level.
SPEAKER_1: Even though the plane is tilting to bank the turn that it needs to come in for a landing.
SPEAKER_1: This is a...
SPEAKER_1: By the way, you do this in a physics class.
SPEAKER_1: You can ask, what is the speed?
SPEAKER_1: This is how you determine what the bank of a track is.
SPEAKER_1: If you're going to bank a track for something you know is going 150 miles an hour, then you can know what bank and what radius of curvature.
SPEAKER_1: And all those numbers come together so that if you're in the car, you don't feel yourself being pushed to the left or right.
SPEAKER_1: So this is all in airplanes.
SPEAKER_1: I mean, I love airplanes.
SPEAKER_1: They're brilliant and beautiful things.
SPEAKER_2: Listen, I don't disagree.
SPEAKER_2: I just love computers more now.
SPEAKER_2: That's all I think.
SPEAKER_1: I'll tell you something else.
SPEAKER_1: One last thing here before we land this plane.
SPEAKER_1: See what I did there.
SPEAKER_1: So there was a day when computers were still new.
SPEAKER_1: You know, there was an old saying.
SPEAKER_1: They say, to err is human.
SPEAKER_1: To really foul things up requires a computer.
SPEAKER_2: Well, that makes sense.
SPEAKER_1: So in the day, yeah, you'd make a mistake, but a computer will make the mistake a thousand times before you caught it.
SPEAKER_1: So it would really foul things up.
SPEAKER_1: In that mindset, they asked people, do you want a computer flying your airplane?
SPEAKER_1: Suppose something happens to the airplane and something bad happens and you have to land the airplane.
SPEAKER_1: What do you want to land the airplane?
SPEAKER_1: A computer or a trained Navy pilot?
SPEAKER_1: And almost everybody said a trained Navy pilot.
SPEAKER_1: Of course.
SPEAKER_1: But I was really out of the box and I said, the computer, but back then that might have been a controversial answer.
SPEAKER_1: Today, the computer is already doing it.
SPEAKER_1: All right?
SPEAKER_2: Yeah, that's for sure.
SPEAKER_2: Some airline is going to try to tap you to be a spokesperson, bro.
SPEAKER_2: I'm letting you know that right now.
SPEAKER_2: United, American, somebody's coming after you, Jeff Blue, you know, it won't be Spirit because everything you just said, none of that happens on Spirit.
SPEAKER_2: None of what you just said happens.
SPEAKER_1: All right, this has been StarTalk, Things You Thought You Knew edition.
SPEAKER_1: Chuck, always good to have you.
SPEAKER_2: Always a pleasure.
SPEAKER_1: Neil deGrasse Tyson.