Cosmic Queries – Navigating the Cosmos

Neil deGrasse Tyson and comic co-host Harrison Greenbaum answer fan-submitted Cosmic Queries that explore the techniques, inventions, and ideas for navigating the cosmos including celestial maps, GPS, the North Star, and more. NOTE: StarTalk+ Patrons and All-Access subscribers can watch or listen to this entire episode commercial-free. Thanks to this week’s Patrons for supporting us: Stella Burkey, Derek Pavan, Travis Dunn, Michael Jonsson, Chad Hunt.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

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

• 0:16Neil deGrasse Tyson?

  This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. I got with me Harrison Greenbaum. Hey!

• 0:23Harrison Greenbaum?

  Oh, hey, how you doing?

• 0:24Neil deGrasse Tyson?

  Anybody call you Harry?

• 0:26Harrison Greenbaum?

  My mom got really mad one day when somebody called me Harry, so I put the kibosh on any nicknames. I wanted to be like an encyclopedia-

• 0:31Neil deGrasse Tyson?

  She wants all the syllables, Harrison. She wants the whole thing.

• 0:33Harrison Greenbaum?

  Yeah, I thought, I was big into Encyclopedia Brown as a kid, so I thought I could be Dictionary Greenbaum.

• 0:38Neil deGrasse Tyson?

  Uh huh.

• 0:38Harrison Greenbaum?

  And that never stuck.

• 0:39Neil deGrasse Tyson?

  Harrison is very waspy, though, isn't he?

• 0:41Harrison Greenbaum?

  Yeah, it's great, because they see the first name, and they're like, "Oh, we should let him in the country, bud." And then they hear Greenbaum, and they're like, "Get that Jew out of there."

• 0:48Neil deGrasse Tyson?

  Okay, so you have, so you have personality issues.

• 0:51Harrison Greenbaum?

  Yeah, exactly.

• 0:52Neil deGrasse Tyson?

  So, thanks for joining me for a Cosmic Queries edition.

• 0:54Harrison Greenbaum?

  My pleasure.

• 0:55Neil deGrasse Tyson?

  Very good. And this particular edition, we've called questions from our following on navigation. That's a thing.

• 1:05Harrison Greenbaum?

  Yeah, I can barely navigate through the city, let alone through space, so...

• 1:09Neil deGrasse Tyson?

  Well, we've gotten lazy with GPS, of course.

• 1:12Harrison Greenbaum?

  Yes.

• 1:12Neil deGrasse Tyson?

  So, we let GPS do it, even if we know in our heart it makes no sense what it tells us to do. We just do it. We've stopped thinking about it. But I'm curious, I haven't seen any of these questions, and so, bring it on.

• 1:24Harrison Greenbaum?

  All right, let's start with Rudiam2010 from Instagram.

• 1:29Neil deGrasse Tyson?

  Nice.

• 1:30Harrison Greenbaum?

  "How is the North Star used in navigation? Besides the North Star, are there other elements in the sky that have been used or can be used to navigate?"

• 1:37Neil deGrasse Tyson?

  Yeah, so, the North Star happens to be sort of near the projection of Earth's North Pole on the sky. So imagine we have longitude and latitude, right, on Earth, we all know that, right? So, how might you put a coordinate system on the sky? So, one way is you take the longitude and latitude and just sort of project it out to the sky. And so, the sky has its version of longitude and latitude. Okay, so now, as you walk to the North Pole, we rotate, as Santa knows this, obviously. Earth rotates.

• 2:10Harrison Greenbaum?

  Who's definitely real, children, who's watching?

• 2:14Neil deGrasse Tyson?

  By the way, there's no land on the North Pole. It's all just an ocean.

• 2:17Harrison Greenbaum?

  So where are all the toys?

• 2:18Neil deGrasse Tyson?

  I know, so they're on, they're on ice floes.

• 2:21Harrison Greenbaum?

  There's elves in scuba suits?

• 2:22Neil deGrasse Tyson?

  They're just, they're just floating in the ocean. And most renderings of Santa's workshop, they're like usually trees and mountains and things. No.

• 2:31Harrison Greenbaum?

  Oh, no.

• 2:31Neil deGrasse Tyson?

  No, he's on an ice floe with the polar bears, whatever those are left in the winter. Uh, so if you walk to the north, north, the Earth rotates around that axis. So if you look at the night sky, all the stars would just make circles around you. In fact, on the North Pole, nothing rises or sets at any given, on any given night. It all just turns around you. And what's directly overhead, kind of directly overhead, is a star that we call the North Star. It's not exactly over the pole, it's like a little bit over.

• 3:05Harrison Greenbaum?

  Right.

• 3:05Neil deGrasse Tyson?

  It's, it's like a couple of full moons.

• 3:08Harrison Greenbaum?

  The way I do recipes, it's just like, close enough.

• 3:10Neil deGrasse Tyson?

  A pinch of this, a pinch of that. So, so now here's, here's, here's the rub. Do you know your latitude when you're on the North Pole?

• 3:19Harrison Greenbaum?

  I guess it keeps going up until it...

• 3:21Neil deGrasse Tyson?

  Yeah, yeah, but there's a number, the latitude.

• 3:23Harrison Greenbaum?

  Oh, is it zero?

• 3:24Neil deGrasse Tyson?

  No, that'd be the equator.

• 3:25Harrison Greenbaum?

  Oh, gotcha.

• 3:26Neil deGrasse Tyson?

  So you have one more, one more, one more try.

• 3:28Harrison Greenbaum?

  Oh, God, a million.

• 3:30Neil deGrasse Tyson?

  A million, excellently wrong. So, uh, the equator is zero degrees latitude. Uh, we are, uh, recording this from New York City, which is 41 degrees latitude. And you keep sort of going north, that number increases until you get to the North Pole, and you're 90 degrees latitude.

• 3:47Harrison Greenbaum?

  Gotcha, a right angle.

• 3:48Neil deGrasse Tyson?

  A right angle, very good. You remember that from eighth grade, very nice. Who's your teacher?

• 3:54Harrison Greenbaum?

  And they said I never need to use that again.

• 3:57Neil deGrasse Tyson?

  They'd say, what, are you a comedian? Well, yeah, as a matter of fact. So, uh, so, so notice that your latitude on Earth is 90 degrees. And what is the elevation above the horizon of Polaris? The North Star. How high up it's an angle. What's that angle? Straight up?

• 4:16Harrison Greenbaum?

  A straight up a hundred, hundred and eighty?

• 4:18Neil deGrasse Tyson?

  No, that'd be like the other.

• 4:19Harrison Greenbaum?

  Oh, yeah.

• 4:20Neil deGrasse Tyson?

  That'd be a.

• 4:20Harrison Greenbaum?

  Right, ninety would be.

• 4:21Neil deGrasse Tyson?

  It'd be ninety. It's ninety.

• 4:22Harrison Greenbaum?

  Yeah, ninety, yeah.

• 4:22Neil deGrasse Tyson?

  Okay, so in fact, the elevation of Polaris above the horizon, measured in an angle, is your latitude.

• 4:32Harrison Greenbaum?

  Wow.

• 4:32Neil deGrasse Tyson?

  On Earth. So from New York City, Polaris is forty-one degrees up. You march all the way to the equator, Polaris gets lower and lower in the sky, and on the equator, it's right on the horizon, zero degrees up. So that's, so Polaris can let you know what your latitude is on Earth. But that's still like huge circles around the Earth.

• 4:53Harrison Greenbaum?

  Right. And if you're in the Southern Hemisphere, that's gonna be.

• 4:55Neil deGrasse Tyson?

  Oh, they don't have, oh, thank you. They don't have a star.

• 4:59Harrison Greenbaum?

  Oh, they're just screwed?

• 5:00Neil deGrasse Tyson?

  They're totally screwed.

• 5:01Harrison Greenbaum?

  Oh, no.

• 5:02Neil deGrasse Tyson?

  So, yeah, the, the.

• 5:04Harrison Greenbaum?

  So you're trying to navigate Australia, you're.

• 5:05Neil deGrasse Tyson?

  There is no, there is, there is no star conveniently positioned over the South Pole, uh, above Antarctica. So, no, so there's not some easy star to get your latitude. You have to be a little more clever and use met tools and instruments and tables and charts and this sort of thing. But still, it's nice to know where you are in latitude, but if you wanna conquer the world as early Europeans felt the need to do, uh, they, uh, you need other ways to find longitude, right? It's not good enough just to know what your latitude is. You wanna know where you are in that big circle that is your latitude, and that's way more complicated. If you look, look at early.

• 5:50Harrison Greenbaum?

  Yeah, look at Columbus. He thought he was in India.

• 5:52Neil deGrasse Tyson?

  Right, right, for example, right?

• 5:54Harrison Greenbaum?

  I celebrate Columbus Day, by the way, by just walking into a bar and declaring it mine, and then murdering everybody else.

• 5:58Neil deGrasse Tyson?

  Oh, yeah, so this, yeah, times have changed for Columbus.

• 6:01Harrison Greenbaum?

  Yeah.

• 6:01Neil deGrasse Tyson?

  Yeah, it was, it was good probably up until nineteen ninety-two, right? Cause that would have been the, the five-hundredth anniversary.

• 6:10Harrison Greenbaum?

  Right.

• 6:10Neil deGrasse Tyson?

  Right. Then after that, people re-thought that.

• 6:13Harrison Greenbaum?

  Yeah. Like he kept calling it America, like what's going on?

• 6:16Neil deGrasse Tyson?

  Yeah, what?

• 6:17Harrison Greenbaum?

  They're Indians?

• 6:17Neil deGrasse Tyson?

  What? Who? What? And what happened after he came? And what happened to us? And what happened to them? So, yeah, yeah. So his stock value is dropping rapidly. But if you look at early maps of the world, they're highly distorted images of coastlines. They're, they're actually, you wouldn't necessarily know this by looking at them. They're actually accurate north, south. But they're really bad east, west. Look at any early map of the United States. It's like, what were they thinking?

• 6:47Harrison Greenbaum?

  Right.

• 6:48Neil deGrasse Tyson?

  They did not know their longitude. And that was not really perfected until...

• 6:52Harrison Greenbaum?

  It's like my mental map of the United States.

• 6:53Neil deGrasse Tyson?

  Oh, really?

• 6:54Harrison Greenbaum?

  They have a very good picture of the coast. And then the middle is sort of a blur.

• 6:57Neil deGrasse Tyson?

  It looks like how a third grader would draw it from memory. So, um, so if you know what other stars are in the sky at what time of night, um, and you have charts and tables and you have an accurate clock, you can basically infer what your longitude is with ever greater accuracy, depending on how good your tables are and how good your clocks are. And you didn't have world conquering, um, uh, cultures until you had navigation. This is, navigation enabled this. And I feel bad because the navigation involves stars and that's my thing.

• 7:36Harrison Greenbaum?

  Right.

• 7:36Neil deGrasse Tyson?

  So, so the early astronomers, my sort of historical brethren, were handmaidens to hegemony.

• 7:46Harrison Greenbaum?

  I love the alliteration at least.

• 7:48Neil deGrasse Tyson?

  That's a good word? That's a good word. All right, so next one.

• 7:50Harrison Greenbaum?

  All right, next one. Um, what's up, Neil? I don't know if that counts as a question for a query.

• 7:56Neil deGrasse Tyson?

  Uh, uh, the universe is up.

• 7:58Harrison Greenbaum?

  There you go, Science Bob on Instagram.

• 8:00Neil deGrasse Tyson?

  In fact, it's, you know, I said, I see, I put, keep looking up in my Twitter handle, which I've never done before, but of course I say it on every one of these shows. But that tells me that none of my Twitter followers listen to StarTalk for some reason. They say, keep looking up. Where'd you get that? Was that right? By the way, just a quick thing on that. Uh, that's a common phrase between astro folk, keep looking up. And it, but it was made popular by a guy from the Miami Planetarium named Jack Horkheimer. And he had this PBS spot lasted...

• 8:34Harrison Greenbaum?

  Is it weird that I'm picturing him in a speedo with a telescope?

• 8:38Neil deGrasse Tyson?

  He wore a silver shiny leisure jacket.

• 8:43Harrison Greenbaum?

  Oh.

• 8:44Neil deGrasse Tyson?

  Kind of thing. Yeah, you're, you're, you're close.

• 8:45Harrison Greenbaum?

  Okay.

• 8:46Neil deGrasse Tyson?

  And it's okay. And the name of the show was The Star Hustler. And he come walking down off of the ring of Saturn and then he had a kind of squeaky voice, like a car salesman squeaky.

• 8:58Harrison Greenbaum?

  Oh, I got a star for you.

• 9:00Neil deGrasse Tyson?

  Exactly.

• 9:01Harrison Greenbaum?

  Are you interested in the Antromeda Galaxy?

• 9:02Neil deGrasse Tyson?

  He'd give you like that week's night sky. So it was great. And he'd always end by saying, keep looking up. So, so many people associate that with him. He died a little earlier than he should have. And so.

• 9:12Harrison Greenbaum?

  Ironically buried him down.

• 9:14Neil deGrasse Tyson?

  Yeah.

• 9:16Neil deGrasse Tyson?

  You could bury up if you'd launched it into space.

• 9:18Harrison Greenbaum?

  Yeah, there you go.

• 9:18Neil deGrasse Tyson?

  No, no, he didn't have the budget for that. So he, uh, so I figured somebody's got to keep that going. So we always say it among ourselves, but in the popular spheres, I figured, let me just keep. So it's a shout out to Jack Horkeimer, the Star Hustler. So, so keep looking up. So up is any direction opposite the way gravity wants to pull you.

• 9:39Harrison Greenbaum?

  So it might be down depending where you are related to that other person.

• 9:43Neil deGrasse Tyson?

  Uh, if you're upside down, then it's down for you relative to your body.

• 9:48Harrison Greenbaum?

  Right.

• 9:48Neil deGrasse Tyson?

  But, um, the center of the earth is down for everybody on earth.

• 9:52Harrison Greenbaum?

  Right.

• 9:52Neil deGrasse Tyson?

  So people were thinking that up is some uniform thing that is the same direction for everyone. It is not.

• 9:58Harrison Greenbaum?

  Right. Unless you're a flat earther and then somehow there is a way for everything to be up.

• 10:02Neil deGrasse Tyson?

  Everything be up. Now, so down is down. Let me tell you how down works. You ready to get schooled on down?

• 10:08Harrison Greenbaum?

  Oh, absolutely.

• 10:09Neil deGrasse Tyson?

  Okay. New York City.

• 10:11Harrison Greenbaum?

  Like I said, absolutely. I should have said, I'm down.

• 10:13Neil deGrasse Tyson?

  Okay. There is no, up, up until the 1970s, late 60s, I forgot the exact year, but there was no connection between Brooklyn and Staten Island. You had to take a ferry. Okay. So Staten Island was kind of isolated there. There were bridges getting you into New Jersey, but if you want to get into the rest of your own city.

• 10:33Harrison Greenbaum?

  Right.

• 10:34Neil deGrasse Tyson?

  You had to take a ferry.

• 10:35Harrison Greenbaum?

  Then it quarantine the way it should be.

• 10:37Neil deGrasse Tyson?

  For Staten Island. So that's one of the five counties that comprise New York City. Okay. And we look, we call counties boroughs here. All right. It's, it's one of the few cities that's bigger than its counties. Isn't that interesting?

• 10:49Harrison Greenbaum?

  Yeah.

• 10:50Neil deGrasse Tyson?

  Yeah. Yeah. So it might be the only one, actually. So the Veron, so they went to the narrowest point between Brooklyn and Staten Island. It's called the Veronzano Narrows. And they said, let's put a bridge here. Generally, bridges are always at like the narrowest point, just to save money.

• 11:07Harrison Greenbaum?

  Right.

• 11:07Neil deGrasse Tyson?

  Right, okay. But that was still really far. All right. It was farther than anyone had ever put up a suspension bridge.

• 11:17Neil deGrasse Tyson?

  So they built the Verranzano Narrows Really Long Bridge. As the longest bridge in the world. And my, when I read the records on this, I learned that it's the first bridge where they had to put the uprights, the uprights are what's holding up the middle of the bridge.

• 11:36Harrison Greenbaum?

  Right.

• 11:36Neil deGrasse Tyson?

  Right, okay. The two uprights are not parallel to each other.

• 11:40Harrison Greenbaum?

  Oh, wow.

• 11:41Neil deGrasse Tyson?

  They're actually at an angle to each other because they're each pointing straight to the center of the earth.

• 11:49Harrison Greenbaum?

  Whoa.

• 11:49Neil deGrasse Tyson?

  And the curvature of the earth between one upright and the other forces them to not be parallel.

• 11:55Harrison Greenbaum?

  Whoa.

• 11:56Neil deGrasse Tyson?

  Whoa. That's some badass engineering there.

• 12:00Harrison Greenbaum?

  Or that's their excuse for they went, they tried to get them straight up and they leaned back a little bit and like, no, no, no, you don't understand.

• 12:05Neil deGrasse Tyson?

  That's on purpose.

• 12:06Harrison Greenbaum?

  Oh, yeah. It's the curve of the earth.

• 12:08Neil deGrasse Tyson?

  We meant that.

• 12:09Harrison Greenbaum?

  Yeah, wink, sure.

• 12:11Neil deGrasse Tyson?

  So those are two different downs, even on the same bridge.

• 12:14Harrison Greenbaum?

  Amazing. And it's still up.

• 12:17Neil deGrasse Tyson?

  Yeah, that's because we have engineers in the world.

• 12:20Harrison Greenbaum?

  Right.

• 12:22Harrison Greenbaum?

  All right, so he-

• 12:23Neil deGrasse Tyson?

  We love our comedians, but at some point, you gotta turn to an engineer.

• 12:25Harrison Greenbaum?

  No, absolutely.

• 12:26Neil deGrasse Tyson?

  All right.

• 12:26Harrison Greenbaum?

  I'm a punchline engineer. I construct ha-has. So Science Bob said, what's up, Neil? We answered that. And then it seems-

• 12:33Neil deGrasse Tyson?

  We haven't got to his question yet.

• 12:34Harrison Greenbaum?

  Oh, yeah. No, he had two questions. That was the first one. And then he said, it seems that geomagnetic reversal is imminent. Will all compasses in the world need to be recalibrated when the magnetic poles reverse?

• 12:44Neil deGrasse Tyson?

  Did he say eminent or imminent?

• 12:46Harrison Greenbaum?

  Imminent.

• 12:47Neil deGrasse Tyson?

  Imminent, good. I think you read eminent.

• 12:49Harrison Greenbaum?

  Oh, I'm so sorry.

• 12:49Neil deGrasse Tyson?

  Yeah.

• 12:50Harrison Greenbaum?

  Science Bob.

• 12:51Neil deGrasse Tyson?

  Yeah, because, you know, geomagnetic north would be an eminent thing.

• 12:57Neil deGrasse Tyson?

  You're eminent, so we're, that's where, so, uh, many people, I don't know if you know or don't know, but certainly boy scouts and girl scouts knew this, a compass points north.

• 13:08Harrison Greenbaum?

  Right.

• 13:08Neil deGrasse Tyson?

  Okay? But it doesn't really.

• 13:12Neil deGrasse Tyson?

  It points to Earth's north magnetic pole, which is not in the same place as Earth's north pole where Santa lives. They're not in the same place.

• 13:24Harrison Greenbaum?

  There's some child who set out on a journey like a children's movie.

• 13:27Neil deGrasse Tyson?

  With a compass.

• 13:28Harrison Greenbaum?

  With a compass and he ends up in the wrong place.

• 13:30Neil deGrasse Tyson?

  And he gets to the point where the compass is spinning and said, I know I'm on the north pole. And Santa ain't nowhere to be found. So.

• 13:37Harrison Greenbaum?

  Coming soon to Disney Plus.

• 13:39Neil deGrasse Tyson?

  If your precision of navigation is not all that important, the compass will generally tell you which way north sort of is. But the closer you get to where that north magnetic pole is, which is somewhere lost in the northern islands of Canada. Like in Canada, if you are north of the north pole, magnetic pole, it'll point south.

• 14:02Harrison Greenbaum?

  Right.

• 14:02Neil deGrasse Tyson?

  Okay, so.

• 14:04Harrison Greenbaum?

  But that's where the white walkers are. So I think.

• 14:05Neil deGrasse Tyson?

  Oh, is that right? Okay. I didn't know that. Very, very Game of Thrones of you.

• 14:10Harrison Greenbaum?

  Yeah. Is that still current?

• 14:12Neil deGrasse Tyson?

  A very old stale Game of Thrones of you. This is 2020, dude. So, so a compass, if you really needed accuracy, you had to have a table of correction angles depending on where you were on Earth. And it would say, okay, we know as you walk north and you're sort of to the right of the north magnetic pole, the compass is going to start pointing west when you think it's pointing north. All right. So we have to, we want to correct for that. And so you look up at a table and you put in the correction. All right. This is, this is like so ancient now, given that we have GPS.

• 14:50Harrison Greenbaum?

  Right.

• 14:51Neil deGrasse Tyson?

  So compasses are like curiosities now. They're not really, you know, nobody's using.

• 14:56Harrison Greenbaum?

  Although my phone has one, which seems crazy that I would pull that app up instead of my GPS app.

• 15:01Neil deGrasse Tyson?

  Okay, that is not a magnetic compass. Your phone compass is, you might have a mode where it can look to the geomagnetic north, but probably not. I think it's going to Santa.

• 15:10Harrison Greenbaum?

  Gotcha.

• 15:11Neil deGrasse Tyson?

  Right.

• 15:11Harrison Greenbaum?

  And they're using the table essentially to adjust to make sure I'm always going north.

• 15:14Neil deGrasse Tyson?

  No, it knows where north is.

• 15:15Harrison Greenbaum?

  Oh, okay.

• 15:16Neil deGrasse Tyson?

  It's connected to the frigging satellite.

• 15:17Harrison Greenbaum?

  Fair enough.

• 15:18Neil deGrasse Tyson?

  Yeah.

• 15:18Harrison Greenbaum?

  I like to picture-

• 15:19Neil deGrasse Tyson?

  That would be so unnecessary.

• 15:20Harrison Greenbaum?

  It would be so cool though.

• 15:21Neil deGrasse Tyson?

  You have the power of an iPhone.

• 15:23Harrison Greenbaum?

  And there's a little tiny compass inside.

• 15:25Neil deGrasse Tyson?

  A little tiny actual compass correcting for north. It knows where north is. Just ask the GPS chip that's in the satellite.

• 15:33Harrison Greenbaum?

  I like to go backwards. I like to break the screen and put a little thing up and use as a sundial.

• 15:38Neil deGrasse Tyson?

  That was so- let me get obscure on you. In the novel, Jonathan Swift's novel, Gulliver's Travels, we all know the one where he visits the little people.

• 15:46Harrison Greenbaum?

  Right.

• 15:47Neil deGrasse Tyson?

  Lily Poitier. There are other stories in there. One where he visits the big people, all right? And there's another one where he visits this floating island of basically crazy scientists.

• 15:59Harrison Greenbaum?

  Ah.

• 16:00Neil deGrasse Tyson?

  And I think it's a parody on what people think scientists do, right? So there are these scientists with like, with, with, you know, they're like lab coats on and they're like really intense and they, they can't even have a conversation with you. And one of them is working on crushing freshly mined marble into material that they can make pillows out of.

• 16:26Harrison Greenbaum?

  Interesting.

• 16:27Neil deGrasse Tyson?

  Right, right, right. So all their experiments are like the complete opposite stupid thing you would never do.

• 16:33Harrison Greenbaum?

  Right.

• 16:33Neil deGrasse Tyson?

  Right? There's another one where there's a weather vane, which tells you the direction of the wind. You know, it's usually like a rooster or something on the top. Uh, you're, you're from New York, so I have to tell you what a weather vane is, right?

• 16:45Harrison Greenbaum?

  Exactly.

• 16:46Neil deGrasse Tyson?

  So a weather vane, it points the direction of the wind with an arrow.

• 16:48Harrison Greenbaum?

  I've seen Wizard of Oz.

• 16:49Neil deGrasse Tyson?

  Okay, good. Very good. So, so in another experiment, they would rotate the house in such a way so that they would, it would help them interpret which way the weather vane was pointing.

• 17:05Harrison Greenbaum?

  Gotcha.

• 17:06Neil deGrasse Tyson?

  So, so I'm just saying-

• 17:06Harrison Greenbaum?

  The exact opposite.

• 17:07Neil deGrasse Tyson?

  It's just crazy opposite things. So if your iPhone actually read the geomagnetic north and then put a correction on it to get the true north, that would be a very Jonathan Swift move from Gulliver's Travels. That's all.

• 17:21Harrison Greenbaum?

  I take that as a compliment.

• 17:23Neil deGrasse Tyson?

  So, um, so you, he's talking about the, the reversal.

• 17:27Harrison Greenbaum?

  The reversal, yeah.

• 17:27Neil deGrasse Tyson?

  Yes. And in fact, we're running out of time in this segment, but I will tell you when we come back, what happens when the magnetic poles of Earth flip?

• 17:38Neil deGrasse Tyson?

  Sounds spooky. Only on StarTalk when we return.

• 17:57Neil deGrasse Tyson?

  We're back on StarTalk, Cosmic Queries, Harrison Greenbaum.

• 18:02Harrison Greenbaum?

  Oh yeah, we were about to reverse the poles here.

• 18:04Neil deGrasse Tyson?

  In the house.

• 18:05Harrison Greenbaum?

  It sounds terrifying.

• 18:06Neil deGrasse Tyson?

  Sounds really scary. Go back to that question that we left off on.

• 18:09Harrison Greenbaum?

  It seems that, he said, "What's up Neil?" We answered that. This is Science Bob on Instagram. And it seems that geomagnetic reversal is imminent. Very casual about that. Will all the compasses in the world need to be recalibrated when the magnetic poles reverse?

• 18:24Neil deGrasse Tyson?

  Okay, so a couple of things. Nobody gives a shit about compasses anymore. Let's just, let's just not worry about the compass, alright?

• 18:32Harrison Greenbaum?

  There's a couple of Boy Scouts listening who just very sadly put theirs in the drawer. Okay.

• 18:38Neil deGrasse Tyson?

  So, so A. B, the magnetic field is getting weaker, measurably weaker, and when that has happened in the past, it's, it's been the beginning of a magnetic field flip, okay? Where the south pole goes to the north and the north pole goes to the south. The big worry, realizing this, is, wait a minute, our magnetic field shields us from harmful charged particles from the sun. These are bad particles. And they, and what happens is it deflects them towards the poles and they collide with the-

• 19:18Harrison Greenbaum?

  But some of them are fine particles.

• 19:20Neil deGrasse Tyson?

  None of them. I don't want to get hit by any of them. And so, they get deflected towards the poles, because that's what the magnetic field, you ever see on a bar magnet, you know, the magnetic field lines?

• 19:32Harrison Greenbaum?

  Yes.

• 19:32Neil deGrasse Tyson?

  They go from pole to pole. But we have those in space. And so, the particles come from the sun, they get deflected towards the poles, and as they descend through the atmosphere, they collide with the atmospheric molecules, pump them and give them energy, and then they re-release that energy as, as beautiful light.

• 19:49Harrison Greenbaum?

  The northern lights.

• 19:49Neil deGrasse Tyson?

  A dancing curtain of lights. And your bias there, it's, there's also the southern lights.

• 19:54Harrison Greenbaum?

  Ah.

• 19:55Neil deGrasse Tyson?

  There's another half of the earth, you know.

• 19:56Harrison Greenbaum?

  That's true.

• 19:57Neil deGrasse Tyson?

  Okay.

• 19:58Harrison Greenbaum?

  But my parents keep trying to go to Iceland in order to see.

• 20:00Neil deGrasse Tyson?

  So there's the aurora borealis in the north and the aurora australis in the south. Usually they have equal intensity because it happens symmetrically. So if the pole reverses with the magnetic field going through zero,

• 20:16Neil deGrasse Tyson?

  then we'll lose the aurora borealis, we'll lose the aurora, okay? And, well, we may still have it, but it just won't be concentrated in those places. You can still get hit by these particles and it'll still excite the atmosphere, but it won't be all concentrated in the northern and southern caps. So the aurora will dim significantly and probably disappear altogether. The.

• 20:38Harrison Greenbaum?

  That's the sound of a million people cancelling their travel plans.

• 20:41Neil deGrasse Tyson?

  And there was worry that some birds might be migrating north-south.

• 20:50Harrison Greenbaum?

  Right.

• 20:50Neil deGrasse Tyson?

  By some measurement of the magnetic field. And if they don't, then it would kill all birds because they wouldn't know to fly south and they'd freeze to death.

• 20:58Harrison Greenbaum?

  Oh, that's not good.

• 20:59Neil deGrasse Tyson?

  Okay.

• 21:00Harrison Greenbaum?

  That sounds.

• 21:01Neil deGrasse Tyson?

  There's some worry about that, but I don't think we understand this mechanism.

• 21:05Harrison Greenbaum?

  If all the birds dropped out of the sky dead, would New Yorkers be scared or celebrate?

• 21:09Neil deGrasse Tyson?

  Celebrate because it would be the pigeons.

• 21:11Harrison Greenbaum?

  Right, exactly.

• 21:11Neil deGrasse Tyson?

  There's only one species of bird in the universe to a New Yorker, it's the pigeon.

• 21:16Harrison Greenbaum?

  I think we would be okay in Manhattan. We'd be like, this is great.

• 21:18Neil deGrasse Tyson?

  This is totally cool.

• 21:20Harrison Greenbaum?

  Is there a way to kill the rats?

• 21:22Neil deGrasse Tyson?

  So, so you, so there was some, there was a genuine concern until we dug up, the geologists dug up the history of the magnetic field on earth, which you can do.

• 21:36Harrison Greenbaum?

  Ooh.

• 21:36Neil deGrasse Tyson?

  You know how you do that? You look at volcanic deposits. There's iron particles that can be launched out of volcanoes. And, and before it solidifies, it'll align to the, to the magnetic field of the day. And as you look at the history of volcanoes, you can see that there are times when it didn't align at all, and times it aligned south, and times it aligned north. So we have a full record of this, of the changing magnetic field of the earth. And it happened on relatively short timescales compared to evolution, and we still have birds.

• 22:06Harrison Greenbaum?

  Right.

• 22:07Neil deGrasse Tyson?

  So birds are fine.

• 22:08Harrison Greenbaum?

  Yeah.

• 22:08Neil deGrasse Tyson?

  Birds are, you know.

• 22:10Harrison Greenbaum?

  There's no layer filled with just bird bones, and then magnet, magnet, bird bones, like a KFC dumpster.

• 22:18Neil deGrasse Tyson?

  That's exactly the evidence we would be looking for, and we don't find that.

• 22:22Harrison Greenbaum?

  Gotcha.

• 22:22Neil deGrasse Tyson?

  Okay, so, and by the way, the magnetic field flip is not an unusual thing, it happens in the sun. The sun has a very strong magnetic field, and it flips every 11 years. And a sunspots always come in pairs, and there's one, there's a positive spot and a negative spot. And when the magnetic field flips, the spots flip in their orientation. It's very cute to watch this.

• 22:48Harrison Greenbaum?

  And for the, for the earth, when it does reverse, it's a gradual thing, or?

• 22:51Neil deGrasse Tyson?

  It's gradual.

• 22:52Harrison Greenbaum?

  Gradual.

• 22:52Neil deGrasse Tyson?

  It's gradual, right. And so, well, not in your life, it takes a long time, thousands of years, but it is gradual. Yeah, so just don't worry about it, really. And, and, and we're done with the compass, give it up.

• 23:04Harrison Greenbaum?

  Yeah, so stop recalibrating a thing that doesn't matter anyway.

• 23:07Neil deGrasse Tyson?

  Now, let me tell you something, I don't want to, you know, blow your mind, okay?

• 23:11Harrison Greenbaum?

  No, go for it.

• 23:12Neil deGrasse Tyson?

  Are you okay with that?

• 23:12Harrison Greenbaum?

  Absolutely.

• 23:13Neil deGrasse Tyson?

  Permission to blow your mind?

• 23:14Harrison Greenbaum?

  Hundred percent.

• 23:15Neil deGrasse Tyson?

  Okay. You know, in magnetic fields, opposites attract.

• 23:19Harrison Greenbaum?

  Right.

• 23:19Neil deGrasse Tyson?

  Right, so if you have a magnet, the south pole attracts the north pole, and vice versa, okay? On your compass, the side that points north is the north part of the north-south needle.

• 23:36Neil deGrasse Tyson?

  Okay?

• 23:37Harrison Greenbaum?

  Okay.

• 23:38Neil deGrasse Tyson?

  So the north on your compass is pointing north on earth.

• 23:44Neil deGrasse Tyson?

  Which means it's pointing south.

• 23:48Harrison Greenbaum?

  Right.

• 23:49Neil deGrasse Tyson?

  Okay, so Earth's magnetic north pole is our southern, is the south part of the Earth magnet.

• 23:59Harrison Greenbaum?

  Gotcha.

• 24:00Neil deGrasse Tyson?

  We just all agree to call it north.

• 24:01Harrison Greenbaum?

  Right, it was like when The Secret came out, do you remember that book?

• 24:03Neil deGrasse Tyson?

  No.

• 24:04Harrison Greenbaum?

  There was a book called The Secret, and they were like, well, like attracts like, and that if you believe something will happen, then it will happen. And they're like, that's how magnets work, is like attracts like.

• 24:14Neil deGrasse Tyson?

  No.

• 24:14Harrison Greenbaum?

  And that's when I was like, this book is BS.

• 24:18Neil deGrasse Tyson?

  Yeah, mag, it's the opposites attract.

• 24:20Harrison Greenbaum?

  Yeah, exactly.

• 24:20Neil deGrasse Tyson?

  Right, right, right. So, so it's just weird that, I mean, they never tell you this when you learn about compasses, that all compasses point to Earth's south magnetic pole, which we just agree to call north.

• 24:32Harrison Greenbaum?

  Right, exactly. That's incredible.

• 24:35Neil deGrasse Tyson?

  All right.

• 24:36Harrison Greenbaum?

  So, that question, uh, let's do, ooh, this one is a long one, but interesting. Alex Land Photos at Instagram says, hello, Dr. Tyson, Alexander M. here, a Russian in Norway.

• 24:48Neil deGrasse Tyson?

  Ooh, okay. That's the beginning of a novel.

• 24:50Harrison Greenbaum?

  Yes.

• 24:51Neil deGrasse Tyson?

  The Russian was in Norway.

• 24:52Harrison Greenbaum?

  The whitest person. Uh, given how everything in the universe rotates around something else, say planets around stars, stars around galaxy center, et cetera, is there truly a good coordinate system possible at all? It, it is, is, it is, if, I think he means if it is, is there something already invented to find stars, not on the sky in two dimensions, but in space?

• 25:14Neil deGrasse Tyson?

  Ooh, there's a lot going on there.

• 25:16Harrison Greenbaum?

  Yes.

• 25:17Neil deGrasse Tyson?

  So let me unpack it.

• 25:18Harrison Greenbaum?

  Why is he in Norway?

• 25:21Neil deGrasse Tyson?

  So let me unpack it and then repack it. So, first of all, let's fix the vocabulary here. If you turn on an axis, you are rotating. If you move around another object, you are revolving. Okay? So Earth revolves around the sun, and we rotate on our axis. Just to separate the use of those two words. That's all.

• 25:48Harrison Greenbaum?

  Makes sense.

• 25:48Neil deGrasse Tyson?

  Some people say we rotate around the sun. No, we rotate on our own axis. Revolve around the sun. Okay. And the, a revolver handgun, they think the bullets actually revolve around the axis. So that's, otherwise they call it a rotator, but the, the gun manufacturers knew the difference.

• 26:04Harrison Greenbaum?

  Their ability to have the gun revolves around the NRA.

• 26:06Neil deGrasse Tyson?

  Yes.

• 26:09Neil deGrasse Tyson?

  Correct, no, actually revolves around one of the amendments of the constitution.

• 26:12Harrison Greenbaum?

  Right.

• 26:13Neil deGrasse Tyson?

  Right, uh, so, uh, so just to separate that out. Now, uh, what's the person's name again?

• 26:20Harrison Greenbaum?

  This is Alex- Alexander M.

• 26:22Neil deGrasse Tyson?

  So, Alexander is correct.

• 26:24Harrison Greenbaum?

  The N stands for Mmm.

• 26:26Neil deGrasse Tyson?

  Alexander is correct. If everything is moving, how the hell do you have a coordinate system? So here's what we do. Um, we have the night sky and there's a coordinate system on the night sky. Basically a projection of Earth's longitude and latitude, as we said earlier in the show. By the way, Earth, as we rotate, we also wobble, like a top. We rotate once a day and we wobble, we wobble once every 26,000 years. People don't play with tops anymore, but you know what I mean by wobble?

• 26:58Harrison Greenbaum?

  It's spinning, but it's also kinda...

• 26:59Neil deGrasse Tyson?

  It's spinning, it's kinda bobbing, right? Like that. And that means the north pole of the Earth is not always pointing to the same spot on the sky, which means it wasn't always pointing to the north star. In fact, we only call it the north star in modern times. That wasn't always, the other stars that were the north star. Egyptians had a different north star, 5,000 years ago. That's a big number relative to the 26,000 year, uh, period of, the wobble period. So, so not only do you not keep your north star, not only that, you have to tell people

• 27:40Neil deGrasse Tyson?

  what coordinate system you're using when you give them the coordinate of a star. So I say, you say, Neil, what, what star did you look at last night? I said, it's this star right here. I wanna look at it too. What are its coordinates? I give you the coordinates. I have to tell you, this is the coordinate system agreed for the year 2000.

• 27:55Harrison Greenbaum?

  Gotcha.

• 27:57Neil deGrasse Tyson?

  And that's the coordinate it had in 2000. And then you'll put that in your computer, the computer will update it to tonight, when you observe it tonight, and it'll be in the right place. So we have, a little hidden secret in my field. All observing programs are calibrated...

• 28:14Neil deGrasse Tyson?

  And have computing systems in them to make sure we're all looking at the same spot in the same sky, no matter when you reported what it was you saw. So it is a big problem, but it's a solved problem.

• 28:25Harrison Greenbaum?

  It's like distances in New York. Like, they say you're a mile from Brooklyn, but it's an hour. So you need to be, people need to tell you in relative time.

• 28:32Neil deGrasse Tyson?

  Yeah, yeah. Miles are completely useless in New York.

• 28:35Harrison Greenbaum?

  Right.

• 28:35Neil deGrasse Tyson?

  It is the-

• 28:36Harrison Greenbaum?

  How far do you live? An hour.

• 28:39Harrison Greenbaum?

  That could be half a mile, that could be four miles.

• 28:41Neil deGrasse Tyson?

  But as, you know, time and, and, and distance, space and time, we've known they've been inter-inextricably woven together ever since Einstein. Actually, we've known before that, but we didn't realize it.

• 28:54Harrison Greenbaum?

  Yeah, like, time passes slower on Staten Island.

• 28:58Neil deGrasse Tyson?

  But has a higher gravitational field, is that right?

• 29:00Harrison Greenbaum?

  Yeah, exactly.

• 29:02Neil deGrasse Tyson?

  All right.

• 29:02Harrison Greenbaum?

  Alexander M., Russian in Norway. All right, uh, this guy is, uh, oh, this is Mr. Findell on Instagram from Omaha, Nebraska.

• 29:10Neil deGrasse Tyson?

  Very nice.

• 29:11Harrison Greenbaum?

  I'm currently dating a girl from Nebraska, which is a fun sentence to say, because different parts of it are surprising to each of you.

• 29:17Harrison Greenbaum?

  Dating, girl, Nebraska, that's three different plot twists. It's a lot, a lot of M. Night Shyamalan movies. So Mr. Findell-

• 29:25Neil deGrasse Tyson?

  And I have to ask, is she Jewish?

• 29:27Harrison Greenbaum?

  On her way?

• 29:28Neil deGrasse Tyson?

  On her-

• 29:30Harrison Greenbaum?

  Working on it?

• 29:30Neil deGrasse Tyson?

  Right, because I, that might be the only, yeah, I don't know how many Jews are in Nebraska.

• 29:35Harrison Greenbaum?

  I went, we visited her family for the holidays, and I wanted to get her family a menorah, because I'm Jewish and she's Nebraskan. So we, we went to the Target, and I was like, where's the Hanukkah section? And the guy was like, I'll take you, and he let me through. The Christmas section's like half the store. And they went through the toy store, the toy section, and the clothes section, and then he led me out the exit. He was like, you have to go. I was like, from the store? And he's like, from the state.

• 29:57Neil deGrasse Tyson?

  From the state?

• 29:58Harrison Greenbaum?

  Yeah.

• 29:58Neil deGrasse Tyson?

  In fact, that door is the border.

• 30:00Harrison Greenbaum?

  Yeah, exactly. You need to go down. So when I left Omaha, the Jewish population decreased by 100%.

• 30:05Neil deGrasse Tyson?

  There you go. There you go.

• 30:07Harrison Greenbaum?

  So Mr. Findell-

• 30:08Neil deGrasse Tyson?

  Mm-hmm.

• 30:08Harrison Greenbaum?

  Uh, who doesn't have a first name, he's just Mr. Findell, but he wrote, what was the government's role in the creation of GPS? And did they help lead the frontier on that?

• 30:16Neil deGrasse Tyson?

  Oh. You know, should I just pull rank here and say, read my frickin' book?

• 30:22Harrison Greenbaum?

  Ooh.

• 30:23Neil deGrasse Tyson?

  I wrote a whole book, okay? I had a co-author, because it was a huge 600-page book called Accessory to War.

• 30:31Harrison Greenbaum?

  Ooh.

• 30:31Neil deGrasse Tyson?

  The Unspoken Alliance Between Astrophysics and the Military. And you're damn straight. The, the, there is no navigation without an understanding of what's going on in the night sky. There's not, there is no navigation without an understanding of space. There's no, and so there's been an astronomer sitting right next to the generals and the conquerors and the hegemonists and all the rest throughout the history of civilization on this earth. And move that into modern times, throw away the sextant, definitely throw away your damn compass. We will give you coordinate systems delivered to you via satellite. And the military

• 31:13Neil deGrasse Tyson?

  put up a system of global positioning satellites, and there's multiple satellites. They're in middle earth orbit, nothing to do with Lord of the Rings. Okay. And they're MEO, middle earth orbit. So it's LEO, low earth orbit, MEO, middle earth orbit, and GEO, geosynchronous orbit. So they're sort of out there and they're orbiting the earth and your device at any time sees at least three of them. And they will triangulate on you and tell you exactly where you are and where you want to go. The, the software will tell you where you want to go using the information about where you are. That was so that you can guide a missile with very high precision. You can know exactly where your ships are.

• 31:58Neil deGrasse Tyson?

  You can know exactly where coastlines are. You can know exactly where things you have to watch out for that you don't want to crash into are. Okay. It was completely a military project. Not the first Gulf War, but the second Gulf War, the one...

• 32:13Harrison Greenbaum?

  Gulf War II, Revenge of the Gulf.

• 32:14Neil deGrasse Tyson?

  Revenge of the Gulf.

• 32:18Harrison Greenbaum?

  Yeah.

• 32:19Neil deGrasse Tyson?

  Um, that was completely conducted using spaceborne assets.

• 32:25Harrison Greenbaum?

  But wasn't it worth it because now you can track where your pizza is?

• 32:30Neil deGrasse Tyson?

  Or you can swipe left or right and get, you know, there's whole industries that derive their functionality based on exploiting this coordinate system that was invented by the military. And so, yes, it is all military and it's basically now gifted to international commerce. There's no Uber without GPS, for example.

• 32:55Harrison Greenbaum?

  So every time you order an Uber, you're technically responsible for death by missile?

• 32:59Neil deGrasse Tyson?

  Uh, no, you are, no, because the death by missile happened first. They didn't, they didn't say, one day we'll have Uber with this, so let's invent it and we'll also blow somebody up. No, no. The goal was to target a missile. And by the way, that's why, not to get all, you know, deep into this, but I did write a whole book on this. The, when we think of we're powerful because we have nuclear weapons, it's like, what? You want to like blow up a whole city? Like, and then do what with what remains? Like, what's your point?

• 33:33Harrison Greenbaum?

  It's overkill.

• 33:34Neil deGrasse Tyson?

  Yeah, it's like, it is the greatest act of imprecise war there ever was. Right? So when you have a guided missile, you have a target.

• 33:44Harrison Greenbaum?

  Right.

• 33:44Neil deGrasse Tyson?

  You take out the target. You're done. You got a tank over there, take out the tank. Take out, we know exactly where it is.

• 33:50Harrison Greenbaum?

  Right.

• 33:51Neil deGrasse Tyson?

  Exactly where it is.

• 33:52Harrison Greenbaum?

  Like if I'm dealing with a heckler, I want to shut down that heckler.

• 33:55Neil deGrasse Tyson?

  The heckler.

• 33:55Harrison Greenbaum?

  Nuclear war is pulling the fire alarm and just getting the whole audience out of the place.

• 33:59Neil deGrasse Tyson?

  Just take out the heckler. All right. So, precision warfare has practically rendered nuclear weapons obsolete as tactically obsolete. You might still want them strategically because you want to flex your muscle. Say, we have nuclear weapons, we can completely obliterate you, even though that's not really solving anything. You're killing innocent people. People have just, you know, they're farmers or whatever. They just want to, you know, they just want to live like anybody does. So.

• 34:29Harrison Greenbaum?

  I've been to Nebraska. I've seen those farmers.

• 34:35Neil deGrasse Tyson?

  So, yes, it's all up and in the military, and that's the beginning of a long list of things that we take for granted in our lives that were first used by the military and enabled in part by the intellectual capital of astrophysicists. I'm just saying.

• 34:54Harrison Greenbaum?

  Amazing. All right. Well, that was a great question, Mr. Fendell.

• 34:56Neil deGrasse Tyson?

  Let me just say, I gotta say that we, as a community, are overwhelmingly liberal-leaning, anti-war. So it's an awkward

• 35:06Harrison Greenbaum?

  Right.

• 35:07Neil deGrasse Tyson?

  relationship between being that culturally and politically, knowing that your stuff, knowing that there's a two-way street.

• 35:14Harrison Greenbaum?

  Right.

• 35:14Neil deGrasse Tyson?

  They'll make stuff that we can use, and we think up stuff that they can use. And we, it's a, it's an unspoken alliance. That's the subtitle.

• 35:21Harrison Greenbaum?

  It was like Einstein and the Manhattan Project.

• 35:23Neil deGrasse Tyson?

  For example, but he, once he's

• 35:25Harrison Greenbaum?

  He didn't want to participate in it.

• 35:26Neil deGrasse Tyson?

  Yeah, yeah, yeah. Too late. Cat's out of bed. You can't unsync E equals MC squared.

• 35:32Neil deGrasse Tyson?

  All right, gotta take a break. When we come back, more Cosmic Queries on Navigation on StarTalk.

• 35:43Speaker 02

  It's time to give a Patreon shout out to the following Patreon patrons: Derek Pavan, Travis Dunn, and a special shout out to perhaps our youngest Patreon patron, three-year-old Stella Burkey. Hey, Stella. And thank you to all three of you for being Patreon patrons. If you would like your own special shout out, make sure you go to patreon.com/startalkradio and support us.

• 36:18Neil deGrasse Tyson?

  We're back. StarTalk, Cosmic Queries, Navigation. You all had questions about navigation, and I'm here with Harrison Greenbound to help me answer. You navigated your way to Omaha, Nebraska.

• 36:31Harrison Greenbaum?

  I did. I made it.

• 36:32Neil deGrasse Tyson?

  Using what tools?

• 36:34Harrison Greenbaum?

  Using my Delta app, and I navigated to, I think I was in Missouri, and then Missouri back. It was an indirect flight. It was very weird.

• 36:42Neil deGrasse Tyson?

  Wait, isn't there, isn't there Tinder for Jews?

• 36:46Harrison Greenbaum?

  J-Swipe.

• 36:47Neil deGrasse Tyson?

  J-Swipe, okay.

• 36:48Harrison Greenbaum?

  Yeah, it's like regular Tinder, but if you both swipe right, you get half of our father's business. Yeah, you don't upload photographs. You just kind of list your allergies to see if you're compatible.

• 36:56Neil deGrasse Tyson?

  Okay, so the J finder was warning you that there were no Jews.

• 36:59Harrison Greenbaum?

  I opened J swipe and my phone exploded.

• 37:04Harrison Greenbaum?

  Exactly. Get out while you can.

• 37:06Neil deGrasse Tyson?

  Do not cross border. Nothing here for you.

• 37:08Harrison Greenbaum?

  Exactly.

• 37:10Neil deGrasse Tyson?

  So, all right, so.

• 37:12Harrison Greenbaum?

  All right, the next question is from West Tech City Boy, West Tech City Boy at Instagram. And he asks, I can't even navigate my way to my truck in the grocery store parking lot. That is his entire question. Do you have any response?

• 37:30Neil deGrasse Tyson?

  Okay, uh, next time you buy a truck, um, get one in the color pink. And you just see it from afar.

• 37:39Harrison Greenbaum?

  Is that the easiest color to see from a distance?

• 37:41Neil deGrasse Tyson?

  No, it's that no other car is pink.

• 37:44Harrison Greenbaum?

  I thought there was a scientific explanation.

• 37:45Neil deGrasse Tyson?

  There could be other red trucks. No, I'm just trying to find a colored car I've never seen before.

• 37:50Harrison Greenbaum?

  Yeah.

• 37:50Neil deGrasse Tyson?

  Okay, and but it's if he's from Texas and it's a truck, pink probably is not the color.

• 37:57Harrison Greenbaum?

  Unless he's selling makeup.

• 37:59Neil deGrasse Tyson?

  Out of his truck? Yeah.

• 38:00Harrison Greenbaum?

  Yeah.

• 38:01Neil deGrasse Tyson?

  Yeah.

• 38:01Harrison Greenbaum?

  A lot of makeup.

• 38:02Neil deGrasse Tyson?

  With the gun rack and everything.

• 38:05Neil deGrasse Tyson?

  Yeah, so that's it's an interesting point and but that's been solved. There are apps now that will follow which way you got out of a parking lot that will tell you where it is if you bring up the map. So they're parking apps. He must, I assume he's got a smartphone.

• 38:19Harrison Greenbaum?

  Yeah.

• 38:20Neil deGrasse Tyson?

  I'm assuming that.

• 38:21Harrison Greenbaum?

  Hopefully.

• 38:22Neil deGrasse Tyson?

  He just used a parking.

• 38:22Harrison Greenbaum?

  Yeah, he used his smartphone to type a not question question.

• 38:25Neil deGrasse Tyson?

  Exactly. So, but here's an interesting point. Precision matters. Suppose the GPS was only accurate to 400 yards.

• 38:42Harrison Greenbaum?

  It'll tell you your car is in the parking lot.

• 38:43Neil deGrasse Tyson?

  It will just see, yeah, the car is in this four square blocks.

• 38:46Harrison Greenbaum?

  Here.

• 38:46Neil deGrasse Tyson?

  And it's not useful to you.

• 38:48Harrison Greenbaum?

  Right.

• 38:49Neil deGrasse Tyson?

  But it is useful to know where the mall was.

• 38:52Harrison Greenbaum?

  Yeah.

• 38:53Neil deGrasse Tyson?

  Okay, so as GPS gets more and more precise, you can, it empowers you in more and more precise ways. Right now, it's precise enough to locate your car. It can even locate it on level if there's a multi-level parking lot. Because GPS is not only the two dimensions of Earth's surface. But it's also the third dimension vertically. You can get both. So, uh, yeah, we got apps. There's an app for that.

• 39:21Harrison Greenbaum?

  Amazing.

• 39:21Neil deGrasse Tyson?

  Yeah.

• 39:22Harrison Greenbaum?

  Well, let's get to the Patreon question. Uh, it is Dan Dymick.

• 39:26Neil deGrasse Tyson?

  Patreon, you're supposed to.

• 39:28Harrison Greenbaum?

  Oh, yeah, no.

• 39:28Neil deGrasse Tyson?

  First.

• 39:29Harrison Greenbaum?

  Yes.

• 39:30Neil deGrasse Tyson?

  You saved it for last. No, you saved it for last.

• 39:32Harrison Greenbaum?

  The best for last.

• 39:32Neil deGrasse Tyson?

  Yes, yes, there you go.

• 39:33Harrison Greenbaum?

  Absolutely. When we see Mars in the night sky, we're actually seeing the light reflecting off of Mars, where it was about three minutes ago. How does the phenomenon of observed versus actual position come into play for astrophysics like communication with deep space probes or when performing deep space astronomy? Thanks.

• 39:49Neil deGrasse Tyson?

  Happens all the time. Plus Mars is way more than three minutes away.

• 39:52Harrison Greenbaum?

  Yeah.

• 39:52Neil deGrasse Tyson?

  Just FYI, okay? Way far. Well, I mean, it's like on average 20 minutes. But sometimes we're on the same side of the sun as Mars. And then it's quicker. And sometimes we're on the opposite side of the sun as Mars. And it's much longer.

• 40:06Harrison Greenbaum?

  And if we're traveling to it, it's like at least 200 days.

• 40:09Neil deGrasse Tyson?

  I had to calculate that to, to, yeah, yeah. About 200 days, very good.

• 40:13Harrison Greenbaum?

  Right.

• 40:14Neil deGrasse Tyson?

  About nine months. Yeah. Um, nine months, that'd be 1920, about 300 days. Yeah. So, well, actually, you can get there in arbitrarily short amount of time. Just how much fuel you want to burn to do it.

• 40:26Harrison Greenbaum?

  Right.

• 40:26Neil deGrasse Tyson?

  We do it the cheap and easy way. It just takes longer. Where you burn your, all your fuel and then you coast the rest of the way. Okay? And that gives you enough speed to start out. No, excuse. You coast to have just enough speed to cross over from Earth's tug into Mars's tug. Then you fall towards Mars.

• 40:46Harrison Greenbaum?

  Right.

• 40:47Neil deGrasse Tyson?

  So that reduces how much fuel you need to get to your destination. You're exploiting gravity, the competing gravity of the two objects. And why not just fall towards it if it's going to get you there for free?

• 40:57Harrison Greenbaum?

  Right.

• 40:58Neil deGrasse Tyson?

  So what, you want to make sure you had enough fuel to cross that border? Otherwise you'll just fall back to Earth and you don't want that. So, uh, yeah. First of all, when you're controlling rovers on Mars.

• 41:10Neil deGrasse Tyson?

  And you say, "Watch out for the cliff."

• 41:12Harrison Greenbaum?

  It's too late, it's already on the cliff.

• 41:14Neil deGrasse Tyson?

  It's too late. So you had to build rovers on Mars to have some kind of AI. And rovers predate our modern conversations of AI. It had some sense of where it is and what it should not do, based on what it reads in the terrain and the, um... Not just a cliff, but should you go up a hill and accidentally flip over? "There's a rock there, don't go into the rock," this sort of thing. So we've been doing this, yeah. You have to build in the light travel delay, the time travel delay from the speed of light, or speed of any electromagnetic waves, which includes radio waves. Communication. We build that in to the communication. Because we see the universe not as it is, but as it once was.

• 41:54Harrison Greenbaum?

  Ooh, it's also like watching a scary movie. You can yell at it, but it's too late, it's already done. You already made that bad decision.

• 41:59Neil deGrasse Tyson?

  Not only can no one hear you scream, even if they did, it's too late.

• 42:04Neil deGrasse Tyson?

  So, yeah.

• 42:05Harrison Greenbaum?

  That is a very good question. Uh, this one is an interesting one from David Chris. He has a lot of As in his name.

• 42:11Neil deGrasse Tyson?

  Da-a-a-d.

• 42:13Harrison Greenbaum?

  David Chris on Instagram. "If you were a pirate in the 1700s, would you rather have a modern GPS or Jack's magic compass from Pirates of the Caribbean that points to what you desire most? And why?"

• 42:25Neil deGrasse Tyson?

  Magic wins every time.

• 42:27Harrison Greenbaum?

  I think if you showed up with a modern GPS on the pirate's ship, they would murder you for your witchcraft.

• 42:32Neil deGrasse Tyson?

  No, but see, see, no, I'd have a full-up smartphone. And that just would blow them all. I mean, that's just, they could, that, yeah, I would be strung up for sorcery. For sure. So I think magic wins every time, but let me make a philosophical point.

• 42:48Neil deGrasse Tyson?

  I would always prefer magic to reality, but all magic ever declared historically has been revealed to be someone's knowledge of the laws of physics that they exploited over others who knew nothing of it. So in fact, the magic we praise...

• 43:12Neil deGrasse Tyson?

  Is just the deeper understanding of the operations of nature. And that's why I'm a scientist. I want to wield the magic that was only dreamt of in generations before.

• 43:23Harrison Greenbaum?

  And that's why I do card tricks.

• 43:25Neil deGrasse Tyson?

  I think last time we talked about.

• 43:27Harrison Greenbaum?

  Yeah.

• 43:28Neil deGrasse Tyson?

  Yes.

• 43:28Harrison Greenbaum?

  Yeah, I was just in London and I got to see one of the earliest copies of the discovery of witchcraft, which was people were burning people at the stake. And he came out with a book to be like, these are magic tricks. They're based on.

• 43:39Neil deGrasse Tyson?

  Well, actually tricks.

• 43:39Harrison Greenbaum?

  Scientific and technological principles.

• 43:41Neil deGrasse Tyson?

  Right, and either the person performing them didn't know that, or they did know it and were fully exploiting their audience.

• 43:46Harrison Greenbaum?

  Right.

• 43:46Neil deGrasse Tyson?

  So my kids, when they're grown up, they're now like nineteen and twenty-three, but by the time they each turned about thirteen or twelve, because my wife is also a scientist and we, she has a PhD in mathematical science, mathematical physics. So one of the goals we had was to make sure they'd be scientifically literate, no matter what else we achieved, we want scientifically literate kids. And they were that by age thirteen, okay? So if you ask them a question, or you set, no, if you're, if we're at a cocktail party and they're there, and you're, and you're an adult, a full grown adult, and you say something that's not quite fully supported by objective truths, they'll, they'll ask you, they'll say, um, why do you think you're Gemini?

• 44:29Harrison Greenbaum?

  Right.

• 44:30Neil deGrasse Tyson?

  Oh, because I'm this, well, have you considered? And they'll ask you questions politely, but then, then I say, once they achieve that point, I said, I'm done with them. They, they are now inoculated against any future charlatan who might try to exploit the laws of physics to their loss.

• 44:47Harrison Greenbaum?

  I actually figured out why the hot white girls on Instagram love astrology, like figured it out. It's because things go their way so often, that on the rare occasion they don't, they've decided to blame outer space.

• 44:57Neil deGrasse Tyson?

  Oh, interesting.

• 45:00Harrison Greenbaum?

  Yeah, they get to walk into a bar like, oh, I get it. The only thing that can block me right now is the universe.

• 45:04Neil deGrasse Tyson?

  So it is a, it is a, an excuse for failure.

• 45:10Harrison Greenbaum?

  Yeah, I mean.

• 45:11Neil deGrasse Tyson?

  All loading your own accountability to the forces of the universe itself.

• 45:15Harrison Greenbaum?

  If I got rejected by a girl and I was like, I get it, Jupiter.

• 45:18Neil deGrasse Tyson?

  Yeah, or, or retrograde or something, yeah, yeah. And of course Shakespeare had this figured out.

• 45:22Harrison Greenbaum?

  Oh, of astrology?

• 45:25Neil deGrasse Tyson?

  The fault, the root lies not in the stars, but in ourselves.

• 45:30Harrison Greenbaum?

  Here I thought that was just like a movie.

• 45:36Neil deGrasse Tyson?

  A book by, um, what's the guy's name?

• 45:37Harrison Greenbaum?

  By a scientist?

• 45:38Neil deGrasse Tyson?

  No, no. No, it's one of the brothers.

• 45:40Harrison Greenbaum?

  John Green?

• 45:41Neil deGrasse Tyson?

  John Green, yeah, one of the Greens, yeah.

• 45:43Harrison Greenbaum?

  I think, did he have a YouTube channel that was science? Or am I making, am I making that up?

• 45:46Neil deGrasse Tyson?

  They're very sci- that's a scientifically literate pair, pair of brothers right there. Uh, glad they're out there. They're, they're very good for, they're a positive force in civilization, uh, spreading the love of what it is to think rationally about the world.

• 45:59Harrison Greenbaum?

  But there's a son, that means there's an equal negative force of two brothers who are not scientifically literate.

• 46:03Neil deGrasse Tyson?

  Oh, oh, yeah, just make sure they're not in this galaxy and we'll be fine. Did you only have one Patreon question for me?

• 46:11Harrison Greenbaum?

  Actually, we have a, a bonus second one.

• 46:12Neil deGrasse Tyson?

  A bonus second one? All right, give it to me, what do you have?

• 46:14Harrison Greenbaum?

  Absolutely. Uh, Frank Kane, uh, he wrote, "How did early spacecraft like Voyager navigate so precisely over large distances without the benefit of digital computers or high-resolution digital cameras?"

• 46:25Neil deGrasse Tyson?

  Good question, because Voyager was launched, like, back in, like, the seventies, okay?

• 46:31Harrison Greenbaum?

  So they had those, like, disposable cameras on board? The ones that you had to, like, wind after each shot?

• 46:34Neil deGrasse Tyson?

  Exactly. Made the little clicks?

• 46:37Harrison Greenbaum?

  Yeah, exactly.

• 46:37Neil deGrasse Tyson?

  The disposable flashbulbs?

• 46:38Harrison Greenbaum?

  I mean, something needed a flash, they had to hold it down for a second.

• 46:41Neil deGrasse Tyson?

  So, so first of all, celestial mechanics, which is the mathematics of getting where you want to go.

• 46:49Harrison Greenbaum?

  And my band name.

• 46:50Neil deGrasse Tyson?

  It, very nice.

• 46:51Harrison Greenbaum?

  Yeah.

• 46:52Neil deGrasse Tyson?

  Is invoking the, the forces of gravity among all the, the players in the, on the terrain over which you're traveling. You're leaving Earth as Earth's gravity, you're, you're going farther out in the solar system. There's Sun's gravity, you gotta go around the Moon, make sure the Moon doesn't perturb you. You might get a gravitational assist from the planet Jupiter to go in another direction. All of this, you can calculate, okay? Now, there could be stuff you don't know could go wrong. So all of our space probes have a little extra fuel.

• 47:24Harrison Greenbaum?

  Hmm.

• 47:24Neil deGrasse Tyson?

  And we say, no, you're off track a little bit, let's do a mid-course correction. And you get a little pulse of a, a jet, uh, a jet pulse in one direction or another. And you have jets' nautilus pointing in all three coordinates so that you can precisely fix what might have been drifting in a direction you didn't want. So it's not like finding your way around a city, which, do I go left here or do I go right? Oh, where, where am I? Oh my gosh, this is a one-way street! Oh, the street's closed! Or is this? That's not what's going on in the solar system. You know, we, we know where stuff is.

• 47:57Harrison Greenbaum?

  Yeah.

• 47:58Neil deGrasse Tyson?

  And by the way, when you are launching a probe to a planet... You don't send it to where it is. You send it to where it will be when it gets there.

• 48:09Harrison Greenbaum?

  With my luck, if I was on a spaceship, I'd be stuck behind a garbage truck, for sure. For sure, there'd be a space garbage truck making it real slow for me to get wherever I need.

• 48:17Neil deGrasse Tyson?

  So that's just part of the bad attitude that goes on in people who calculate these orbits. Just you're going to not where Mars is, but where it will be in nine months. And that's where you're going to intersect it. And we're on a moving platform as well.

• 48:33Harrison Greenbaum?

  That's incredible, yeah.

• 48:34Neil deGrasse Tyson?

  It's all good. It's all good. So thanks for that question, Frank.

• 48:37Harrison Greenbaum?

  Yeah, Frank, nailed it.

• 48:38Neil deGrasse Tyson?

  You're right. I think we have time for like one more question.

• 48:41Harrison Greenbaum?

  Oh, no.

• 48:42Neil deGrasse Tyson?

  You got a good one there?

• 48:42Harrison Greenbaum?

  It's gotta be a good one.

• 48:43Neil deGrasse Tyson?

  Good one, alright.

• 48:43Harrison Greenbaum?

  This one's from Twitter, which is known for its complex thoughts.

• 48:47Neil deGrasse Tyson?

  And its deep reflective commentaries.

• 48:50Harrison Greenbaum?

  You know, when you're looking for smart things, you go right to Twitter.

• 48:52Neil deGrasse Tyson?

  Look, dude, they doubled the character count from 140 to 280, so now...

• 48:57Harrison Greenbaum?

  It's twice as stupid. You can get in twice as much trouble. Fantastic.

• 49:02Neil deGrasse Tyson?

  Alright.

• 49:03Harrison Greenbaum?

  Alright, Adam Labbe, L-A-B-B, accent over the E. He's at Lomest Peculiar. With everything in the universe in constant motion, what landmarks could be used to share our location with extraterrestrials?

• 49:17Neil deGrasse Tyson?

  Brilliant question. I love it. I love it, okay. You ever notice that if you're in an airplane, which I assume most people have been in airplanes by now, but if not, you can picture what I'm saying. When you're on the runway and you're taking off, the airport is like flying past you. Quickly.

• 49:40Harrison Greenbaum?

  Yeah.

• 49:40Neil deGrasse Tyson?

  Okay? You're on a runway and then the runway's not there anymore. Meanwhile, the hill farther away is still there in view. And the city buildings on the horizon, they're just still there. So you're actually passing them just as fast. But if you're far away, it doesn't manifest as noticeably in front of you. Okay? So this is what started the old thing. Mommy, daddy, how come the moon follows me? You're walking down the street, how come the moon, you don't leave the moon behind? The moon is a quarter million miles away and you just walked one block.

• 50:24Harrison Greenbaum?

  Right, yeah. And I tell my kid, it's because you did something bad and it's gonna track you until you do something good. That's why I don't have children.

• 50:32Neil deGrasse Tyson?

  And your kids are in therapy. Your unborn children are in therapy.

• 50:36Harrison Greenbaum?

  Why did the moon follow me? It knows what you did. That's why.

• 50:40Neil deGrasse Tyson?

  So you would indeed leave the moon behind if you walked a quarter million miles in a straight line. Then the moon would be like way behind you. But you only walked a block and the moon is a quarter million miles away.

• 50:52Harrison Greenbaum?

  Right.

• 50:53Neil deGrasse Tyson?

  So.

• 50:54Harrison Greenbaum?

  Although if you do walk a quarter million miles, you get to put on Instagram because people love posting their long distance runs.

• 50:58Neil deGrasse Tyson?

  Then that's like a gazillion calories right there.

• 51:01Harrison Greenbaum?

  Yeah.

• 51:01Neil deGrasse Tyson?

  On the, on the health app. Track, track your walking. So, so here's, here's what's interesting. If you want a coordinate system,

• 51:13Neil deGrasse Tyson?

  you could use stars.

• 51:16Neil deGrasse Tyson?

  They don't, they'll follow you like the moon would, okay? They'll always be there as you walk. But the stars themselves are moving in space.

• 51:27Neil deGrasse Tyson?

  So it would only work for, until they move to a completely, and then the coordinate system. So here's what you do. Use something that's farther away. How about whole galaxies? Okay? If you use whole galaxies, that'll anchor your coordinate system for longer. Except galaxies are big fuzzy things. And how do you get a precise read? And what part of the galaxy are you saying is the spot on the coordinate?

• 51:55Neil deGrasse Tyson?

  We have things in the universe called quasars. Really bright, very tiny sources of electromagnetic energy. And they're the farthest things in the universe. If you set up a coordinate system with quasars, you are good to go because you will never walk past them.

• 52:15Harrison Greenbaum?

  Right.

• 52:16Neil deGrasse Tyson?

  Because they're at the edge of the fricking universe. If you walk past them, you don't need the quasars. You have the power, power beyond local navigation. So yes, you'd want a coordinate system that, that is so far away. Your movement and their movements are irrelevant to each other. And they will preserve themselves as something you can reference now and evermore. Quasar.

• 52:40Harrison Greenbaum?

  That's amazing.

• 52:41Neil deGrasse Tyson?

  Harrison, I forget how fun it is to do shows with you.

• 52:43Harrison Greenbaum?

  Oh, no, this is amazing.

• 52:44Neil deGrasse Tyson?

  We gotta do this some more.

• 52:45Harrison Greenbaum?

  Absolutely.

• 52:46Neil deGrasse Tyson?

  And for those not watching, he's wearing an Apollo 11 patch t-shirt.

• 52:50Harrison Greenbaum?

  Absolutely.

• 52:50Neil deGrasse Tyson?

  It's his one cosmic accoutrement.

• 52:53Harrison Greenbaum?

  Oh, no, I've been gathering all this space stuff.

• 52:54Neil deGrasse Tyson?

  Excellent. So now you gotta come back and wear something different next time.

• 52:56Harrison Greenbaum?

  I have 17 pairs of NASA socks.

• 52:59Neil deGrasse Tyson?

  Really?

• 52:59Harrison Greenbaum?

  I acquired them for Christmas.

• 53:01Neil deGrasse Tyson?

  Okay. That's because during Hanukkah, you only get socks for gifts, right?

• 53:05Harrison Greenbaum?

  Exactly.

• 53:06Neil deGrasse Tyson?

  You don't get the big flat panel TVs or anything.

• 53:08Harrison Greenbaum?

  No, you get a great gift day one, and then you get all the accessories over time until you end up like the batteries for the Game Boy. And the keys for the Game Boy, the game to play it.

• 53:16Neil deGrasse Tyson?

  Okay, so you can't do anything with it until the last day. We get the plug for the wall. All right, we gotta call it quits. So Harrison, good to have you. Thanks for joining us on this episode of StarTalks Cosmic Queries Navigation. I'm Neil deGrasse Tyson, your personal astrophysicist, as always, bidding you to keep looking up.