Things You Thought You Knew - The Ancient Planets

Is the sun bigger than we think it is? Neil deGrasse Tyson and comedian Chuck Nice break down things you thought you knew about the diameter of the sun, how we got leap year, and the days of the week.

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

• 0:00Neil deGrasse Tyson?

  This is StarTalk, a things you thought you knew edition. Of course, I got Chuck Nice with me. Chuck? Yeah, that's right. And I don't think I know anything. That's why I'm here. That makes you a perfect co-host. That's it. That's right. For this excursion. I'm happy to be here. Not knowing a thing. All right. Let's get this party started.

• 0:20Neil deGrasse Tyson?

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

• 0:33Neil deGrasse Tyson?

  Chuck, I got another explainer. Awesome. The diameter of the sun. Okay, this sounds boring.

• 0:43Neil deGrasse Tyson?

  The diameter of the Earth is about 8,000 miles. Thank you. And that's it. Did not know that, so I'm already good. It's about 8,000 miles. About 8,000 miles. Okay. And from that, you can know the circumference, if you remembered pi. Okay. Because circumference equals pi times the diameter. Okay. And how much is pi? 3.14 of something, something. Exactly. So a little over 3. Right. So you multiply 8,000 miles times 3 and a little bit, you get at least 24,000 miles around. And some change. It's about 25,000 mile circumference. Right. Okay, fine. And we did, I think we did on a separate explainer that the diameter of Earth pole to pole is less than the diameter of Earth.

• 1:28Neil deGrasse Tyson?

  And the equator. At the equator. I think we talked about that. Um. Earth is slightly flattened. Oblate spheroid, I think. Yeah, yeah. That's what an oblate spheroid is. You're flattened top to bottom. Okay, yeah. The sun is also shorter top to bottom than across its equator. Interesting. Not by much, but it's measurable. Okay. So when someone asks, what's the diameter of the sun, what answer are you gonna give them? Are you gonna give them pole to pole? You gonna give them across the diameter? Mm-hmm. You gonna take the average of those two? I just want you to appreciate that when you look up a numerical answer to a question. Right.

• 2:10Neil deGrasse Tyson?

  Depending on what it's answering, the question might not have an actual answer. We just have to sort of set the rule, the diameters are gonna be across the equator for everybody. What's the diameter? Oh, that's, you need the high frequency. Right, you need. You know, that lets him know that it's not exact. Okay. Yeah. So, so now you say, all right, let's say we do equator. Now you look up at the sun with filters. Then you see this sharp edge. Right? The edge of the sun has an edge. Right. Okay. But wait. Uh oh. The sun is made of what? Plasma. Plasma, just gas, basically, okay? Plasma gas.

• 2:54Neil deGrasse Tyson?

  When's the last time you saw gas have a sharp edge to it? Wow, that'd be my Uncle Daryl.

• 3:04Neil deGrasse Tyson?

  When that smell moved across the room? It had a sharp edge? Sharp edge. You either in it or out of it. Man, you know, it's time to go. Yeah. The spherical ball that is the sun. Right. Oblate spheroid that is the sun. We speak of an edge, but that's an edge made of gas. Right. Okay. How do you even have that? That's my point. It's like Earth's atmosphere. Right. Where's the edge of Earth's atmosphere? No, there is no edge. It's gas that becomes sort of thinner and thinner. You know you reached it when you're like.

• 3:41Neil deGrasse Tyson?

  So when we see the sharp edge of the sun, in practice, we were referring to what's called the photosphere. Oh. The photosphere is a layer of the sun's atmosphere, which is the last point of contact with the photon trying to get out of the sun. Oh, okay. Okay? And now the photon can move at the speed of light in a straight line. Until that point, it was bouncing back and forth among other molecules and other atoms. Right. And other particles. By the way, had that photon been moving in straight lines? You'd be able to see deep inside the sun. Oh. That's what light moving in straight lines means.

• 4:25Neil deGrasse Tyson?

  Right, yes. Why is a window transparent to you? Because the light moved in a straight line through the window. Right. But then I smoked the window. What do you do when you? Frost. Frost the, I frosted the window. Right. And now the light, I can't get through. I gotta jiggle a little bit. I'll still come through, but I'm not in a straight line. Right. You cannot see through the window. Now, yeah, the window's lit up, but you can't see what's on the other side. The light's coming through, but it's not a straight line. Not a straight line. Okay, all right. So, the photon gets to this place, an edge, where it can now escape for free. There's not enough above it to keep bouncing around. Right. That edge is the photosphere, and that is our definition of the edge of the sun. That's only using visible light.

• 5:10Neil deGrasse Tyson?

  Oh, God. Okay. I knew there had to be a twist to this. So, we are visible light biased. Right. I don't mind that, but don't declare that this be the diameter of the sun if the diameter of the sun is simply what your own damn eyeball can see. Right. Okay. Oh, my. Right, so if you look at the sun in X-rays. Okay. It has a different diameter. Really? X-ray photons are coming from a different place. Okay. A different surface. So, we are biased, and I think we need the occasional reminder that we are eyeball biased.

• 5:52Neil deGrasse Tyson?

  Diameter of the sun is where the visible light comes from, and specifically, yellow light. Right in the middle of the spectrum. Red, orange, yellow, green, blue, violet, right in the middle. Let me keep going. Go ahead. There's a layer of sun's atmosphere on top of that. On top of this photosphere? Yes. You know what that's called? Mm-mm. The corona. Oh, yeah, okay. That's part of the sun. That's part of the sun. Why is your diameter not including that? Right. That's part of the sun. The corona, depending on where the sun is in its cycle.

• 6:24Neil deGrasse Tyson?

  Can be really big or really small. So that changes on an 11 year cycle. But wait. The sun has a magnetic field. That extends beyond the corona.

• 6:37Chuck Nice?

  Right.

• 6:38Neil deGrasse Tyson?

  That's called the magnetosphere. Shouldn't that be part of the diameter of the sun?

• 6:42Chuck Nice?

  Yeah, it's part of it.

• 6:44Neil deGrasse Tyson?

  Like part of the sun?

• 6:45Chuck Nice?

  It's part of it.

• 6:46Neil deGrasse Tyson?

  The sun, alright.

• 6:47Chuck Nice?

  Yeah.

• 6:47Neil deGrasse Tyson?

  All I'm saying is, if you seek the truth, my son.

• 6:52Chuck Nice?

  Mm-hmm.

• 6:52Neil deGrasse Tyson?

  Be aware that the truth has many faces.

• 6:56Chuck Nice?

  Mm.

• 6:57Neil deGrasse Tyson?

  One face may deceive you into thinking that it is the face of the answer to that question. Let you not be blinded by how authentic its truth may seem. Because others will be speaking their truth quietly and clearly. And you must listen to them as well.

• 7:18Chuck Nice?

  Do I have to snatch a pebble from your hand now?

• 7:26Neil deGrasse Tyson?

  Go ahead. Snatch the pebble from my hand.

• 7:31Chuck Nice?

  Wow, you got some quick reflexes, man. Alright.

• 7:38Chuck Nice?

  Oh, snap! You have some really, like, uncannily fast reflexes. Like, this shouldn't be. Whoa!

• 7:53Neil deGrasse Tyson?

  You are not ready, my son. Come back another time. Okay, one last fun fact about the sun.

• 7:59Chuck Nice?

  Okay.

• 8:00Neil deGrasse Tyson?

  Alright, if we're about 8,000 miles across.

• 8:02Chuck Nice?

  Right.

• 8:03Neil deGrasse Tyson?

  If you look up the diameter of the sun, it'll give you something like 864,000 miles, something like that.

• 8:10Chuck Nice?

  Jesus.

• 8:11Neil deGrasse Tyson?

  Okay, alright, so now, let's round that down, just so the numbers come out fun.

• 8:16Chuck Nice?

  So that...

• 8:16Neil deGrasse Tyson?

  Call it 800,000 miles across.

• 8:18Chuck Nice?

  It's 100 times bigger.

• 8:19Neil deGrasse Tyson?

  It's 100 times...

• 8:19Chuck Nice?

  100 times.

• 8:20Neil deGrasse Tyson?

  100 times across.

• 8:21Chuck Nice?

  Across.

• 8:21Neil deGrasse Tyson?

  So you can take Earth...

• 8:22Chuck Nice?

  100.

• 8:23Neil deGrasse Tyson?

  And position it 100 times, back to back, belly to belly, and you'll span the width of the sun.

• 8:30Chuck Nice?

  Wow.

• 8:30Neil deGrasse Tyson?

  Okay, 100 times now. By the way, that's about the size of sunspots. So the sun has blemishes larger than the Earth. Just so you know.

• 8:40Chuck Nice?

  Gee.

• 8:41Neil deGrasse Tyson?

  Alright, so now, if it's 100 times across, that means it's also 100 times deep.

• 8:49Chuck Nice?

  Deep, yeah.

• 8:50Neil deGrasse Tyson?

  It would be 100 times top to bottom.

• 8:54Neil deGrasse Tyson?

  So how many Earths could fit into a hollow sun? Pour into the sun. Pour into the sun. That's 100 times 100 times 100. Give me what that number is. 100 cubed?

• 9:09Neil deGrasse Tyson?

  Thank you, Chuck, for that precise response. 100 times 100 is 10,000. Right. 100 times 10,000, million. And then? If, that's it. I did it three times already. Okay, right. So, so the sun were hollow, you could pour a million Earths into it. Wow. And still have room left over. Damn. Yep. Yet, for millennia, people were walking around saying, "The sun and the moon were like the same thing on the sky, and we're the center of the universe." If you read Genesis literally, the earth was created before the sun and the moon. And when we came to these realizations over the millennia, over the centuries,

• 9:52Neil deGrasse Tyson?

  it was like, no, we're not making earth first, and then assembling something a million times larger and have it orbit the earth. Right. That ain't how the universe works. Doesn't, doesn't, yeah. Ain't how that goes. We're not that special.

• 10:16Speaker 02

  I'm Ali Khan Hemraj, and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 10:34Neil deGrasse Tyson?

  So Chuck? Yeah. Did we ever have a conversation about leap days? I have a vague memory, but maybe it just slipped into other explainers. I was gonna say, we've discussed it, but not specifically. Not on its own terms. It's not like, "Son, I'd like to talk to you about leap days."

• 10:50Neil deGrasse Tyson?

  Oh no, come on. The time has come. You're old enough. You're old enough now to know about leap days. People seem to be mystified by it. Right. The day just shows up in the calendar. Yeah, well, cause yeah. And. It seems very arbitrary. It seems, does feel arbitrary, like some high council. Yeah. Decided. Right. That the February needed a day. Exactly. So it's very simple. So here's Earth tipped on its axis, spinning. So the time it takes Earth to spin once on its axis, what do we call that? A day. A day. Are you sure? Um, well, it should be. Should be. Why not? I mean, why not? Okay, that's a day. That's a day. So now, Earth also goes around the sun. Right.

• 11:35Neil deGrasse Tyson?

  How long do we, does that take? That's about a year. It takes exactly a year. Okay. Exactly a year. All right. That's the definition of a year. Of a year. Okay. We made a trip around the sun. There's no law in the heavens that requires the rotation of the Earth. Okay. To divide evenly into the time it takes Earth goes around the sun. That's true. Okay. They're totally unrelated phenomena. Right, right. Exactly. So we count days by rotation of the Earth. Right. We count years by revolution around the sun. And it turns out, a year lasts 365 of these things, plus one-fourth of a turn. Okay, a quarter turn.

• 12:16Neil deGrasse Tyson?

  It's 365 days and six hours. Six is a fourth of 24 hours. Right. Okay. That's how long it takes Earth to go around the sun. What are you gonna? That's too much. That's too much. So what are you gonna do with the six hours? Right, it's too much. By the way, it's six hours this year, and then the next year, it's six hours added to the previous six hours. Now you got 12 hours. Now you got 12. To do with. Right. So it's a half a day. Are you gonna celebrate the new year on a moving six-hour platform? I'm thinking about that. No, no, it's interesting, right? Thinking about that right now. Celebrate at midnight, you celebrate at six in the morning. Right, oh no, forget it. Then again, that depends. That's a hell of a party. That's a hell of a party, man. You know what I mean?

• 13:00Neil deGrasse Tyson?

  So, so the first of those years, you celebrate at 6:00 AM. Right. Next year, 12:00 AM. This is on the 366th day, right? And the next year would be like 6:00 PM. Right. All right, and the next year, back at midnight. Yeah. Okay. I I'm just saying.

• 13:16Chuck Nice?

  That'd be kind of a uh that'd be kind of cool.

• 13:19Neil deGrasse Tyson?

  It could be kind of dope.

• 13:20Chuck Nice?

  Yeah, it'd be kind of dope. Let's just like, yeah. What what time is New Year this year?

• 13:26Neil deGrasse Tyson?

  Right. In order to not have to do that.

• 13:29Chuck Nice?

  Right.

• 13:29Neil deGrasse Tyson?

  Let's go back to ancient Rome in the Julian calendar.

• 13:32Chuck Nice?

  Okay.

• 13:32Neil deGrasse Tyson?

  They figured this out.

• 13:33Chuck Nice?

  Of course.

• 13:34Neil deGrasse Tyson?

  And they said, let's pocket those six hours.

• 13:37Chuck Nice?

  Right.

• 13:37Neil deGrasse Tyson?

  Don't tell anybody.

• 13:38Chuck Nice?

  Right.

• 13:39Neil deGrasse Tyson?

  Okay. And we just celebrate the new year six hours early, but nobody knows.

• 13:43Chuck Nice?

  Nobody knows.

• 13:43Neil deGrasse Tyson?

  It's just a complete day. You do it at midnight. We're we're good to go.

• 13:46Chuck Nice?

  Right.

• 13:46Neil deGrasse Tyson?

  Okay. You pocket that.

• 13:48Chuck Nice?

  There you go.

• 13:48Neil deGrasse Tyson?

  Next year goes by.

• 13:50Chuck Nice?

  Sounds so much like the Roman Senate.

• 13:52Neil deGrasse Tyson?

  So you've got the the the first year goes by, you pocket the six hours.

• 13:56Chuck Nice?

  Right.

• 13:57Neil deGrasse Tyson?

  Second year goes by, pocket the six.

• 13:58Chuck Nice?

  Another six.

• 13:59Neil deGrasse Tyson?

  Third, pocket the six. We're up to six, twelve, eighteen hours.

• 14:01Chuck Nice?

  Our pockets are getting full.

• 14:02Neil deGrasse Tyson?

  The fourth year comes around, you don't pocket that.

• 14:06Chuck Nice?

  Right.

• 14:07Neil deGrasse Tyson?

  Because now you got a full twenty-four hours.

• 14:08Chuck Nice?

  Twenty-four.

• 14:09Neil deGrasse Tyson?

  You put the day back in the calendar.

• 14:10Chuck Nice?

  Boom, there you go.

• 14:11Neil deGrasse Tyson?

  There it is.

• 14:11Chuck Nice?

  Look at that.

• 14:12Neil deGrasse Tyson?

  The leap day.

• 14:13Chuck Nice?

  Empty your pockets on that day.

• 14:15Neil deGrasse Tyson?

  Every four years, you throw in a leap day, and you give it to the neediest month.

• 14:19Chuck Nice?

  Right.

• 14:19Neil deGrasse Tyson?

  Okay.

• 14:20Chuck Nice?

  Exactly.

• 14:20Neil deGrasse Tyson?

  I mean, why not?

• 14:21Chuck Nice?

  Right. Which, of course, is Black History Month. That's the neediest.

• 14:24Neil deGrasse Tyson?

  I think in ancient Rome, it wasn't Black History Month yet.

• 14:26Chuck Nice?

  Oh, yeah. I'm sure it was.

• 14:32Neil deGrasse Tyson?

  It was Slave History Month, right?

• 14:33Chuck Nice?

  Right, exactly. For all, everybody, because I don't care who you were in Rome, you was a slave. You know what I mean? Like, wait a minute, man. Is is that a white slave over there? Hey, brother, this is Rome.

• 14:45Neil deGrasse Tyson?

  So there you have that. That is the fundamental origin of a leap day.

• 14:48Chuck Nice?

  Right.

• 14:49Neil deGrasse Tyson?

  But here's what happened.

• 14:50Chuck Nice?

  Okay.

• 14:51Neil deGrasse Tyson?

  It turns out, it takes a little less than three hundred sixty-five days and six hours to go around the sun.

• 14:59Chuck Nice?

  Oh, God.

• 15:00Neil deGrasse Tyson?

  It's not an exact six hours.

• 15:02Chuck Nice?

  Of cour- well, it couldn't be, right? Because that would be make too much sense.

• 15:05Neil deGrasse Tyson?

  It's a right, that would make.

• 15:07Chuck Nice?

  That would make too easy.

• 15:08Neil deGrasse Tyson?

  That even that would be technically evenly divisible, right? Like a whole number of hours.

• 15:13Chuck Nice?

  Exactly.

• 15:13Neil deGrasse Tyson?

  It's a little bit less.

• 15:14Chuck Nice?

  A little.

• 15:15Neil deGrasse Tyson?

  Romans didn't know this.

• 15:16Chuck Nice?

  Right.

• 15:16Neil deGrasse Tyson?

  They they didn't know this.

• 15:17Chuck Nice?

  Well, can you blame us? We're using sundials, sir.

• 15:23Neil deGrasse Tyson?

  Oh, you and your fancy astrophysical atomic clocks. What happened then, over the centuries, there were days accumulating that were not accounted for. Oh, they lost days. No, no, no, they would, yeah, yeah, the days that should have been reckoned and were not. And they were not. Okay, so, all right. So, the consequence of this is that key moments in the calendar related to like the universe end up shifting. Right. So, the first day of spring, the vernal equinox, March 21st. Right. Over the centuries became March 20th, and then March 19th, and then March 18th, March 17th, March 16th, March 15th. Oh.

• 16:07Neil deGrasse Tyson?

  And they were just living with it, not figuring what. What is happening in the spring, guys? Spring is just sprunging all over the place. We can't have spring sprung in February. Right, it was marching its way early in the calendar, century by century. Right. Okay, this was a concern. Why? Right. Because the Julian calendar, with its rules for Easter, Easter because Christianity was now in charge, okay? So, Easter, the definition was, Easter is the first Sunday. Right. After the vernal equinox. Right. Pope Gregory, we're now in like the late 16th century, so 1580s. All right.

• 16:46Neil deGrasse Tyson?

  Pope Gregory notices that Easter is moving with the equinox, because it was defined by the equinox. Right. And there was a risk that Easter would land on Passover. Oh, we can't have that. Can't have that. Oh, you know you can't have that. It was hard enough to get people, might have otherwise been Jewish, to be Christian. Exactly. Okay. Okay, yes, exactly. Your Eminence, I believe the Jews have a plot. Ruin Easter. Right, so you can't have that. Plus, think of what effort it took. Right. To call Sunday the Sabbath. He's noticing this and said, we've got to fix this. So he gets his smartest folks in his contingent. Wait, the Pope had scientists? Yes. Get out. Yes.

• 17:31Neil deGrasse Tyson?

  Serious. Serious, highly educated scientists. Okay, to this day, there's a Vatican Observatory. Did you know that? I did not know that. Yes. The Popes, and who are they? They are the Jesuits. The Jesuits are the academic order among the orders of Christianity, of Catholicism. Catholicism. Okay, so. As with priests. Yes, and so they founded many of the Catholic universities that persist to this day. Right. Okay, for example, okay. He tasks them to say, fix this. They study the movement of the sun, moon, and stars in the sky. And they say, we have not been properly reckoning leap days. And they conclude, extra leap day had accumulated every hundred years. Okay.

• 18:12Neil deGrasse Tyson?

  Okay, that's too many, and that was not reckoned, and that shifts the vernal equinox backwards in the calendar. Okay. All right, in order to fix this, they said, all right, let's jumpstart it. Put, put the equinox back on March 21st. Got to put it back there. That's where it belongs. And what you do with autumn days? I don't know. Okay, by then, it was on March 10th. Wow. Okay, so in October 1582. October now. October, okay. They're saying, time to jumpstart the system. All right. So they took 10 days out of October. Look dude, you're the Pope. You have the power to do this. I'm gonna say, that's too much power for one man to have. Just like, guess what, October.

• 18:56Neil deGrasse Tyson?

  You just got cut. I'm sure the Pope sounded exactly like that, like angry black man. Guess what, October, Dominus' spitter to half the month is gone. Ten, a third of the month is gone. And you know why? Because that's when we owe rent. So they took 10 days out of October. Damn. So October, like 15th followed October 4th. Okay, did I get my numbers right there or something like that? Yeah, yeah, yeah. And you have to like, I don't know if that was the invention of amortization, but how do you decide what rent to pay? Right. You have to sort of get the fraction of the month. Yeah, yeah, yeah. Multiply, divide. Exactly. Multiply by your rent, but a fraction, and that's what you pay. Okay. We still stay with the four year rule, except every 100 years, which is still divisible by four. Right.

• 19:41Neil deGrasse Tyson?

  100 is divisible by four. Every 100 years, we take out the leap day that would otherwise be there. There you go. And now we're, now, now we're balancing out. We're balancing out. Nice. Okay. Nice. However. Okay. The Jesuits were badass. All right. They said, that under corrects it. That under corrects it by a little bit. Okay? I gotta tell you, this, this moving New Year's Eve thing is looking real good right now.

• 20:07Neil deGrasse Tyson?

  So, if you look at the under correction, now it's gonna happen on a even longer timescale. So what you find out is, at what rate have you under corrected it? Every 400 years. You gotta put a leap day back in. Back in. Uh huh. Cause of 400 years is still on 100 year cycle. Right. But every 40, you gotta put it back in. Now, who is alive to remember to do this? That's what I'm saying. So, this was the amazing fact about the year 2000. Okay. If you didn't know what I just told you, you say, well, of course, it's a leap day. It's divisible by four. Right. No. You know how rare that leap day is? It's a century year divisible by 400. Right. That gets a leap day. 1900 didn't have a leap day. 1800 didn't have a leap day.

• 20:52Neil deGrasse Tyson?

  1700 didn't have a leap day. So no day put in. Okay, 1600 did, because that was right after. That just happened. Cause 1582 is when it happened. Exactly. So 1600 still got the leap day put in. Behold, the Gregorian calendar. Look at that. What a mess. No. Wait, wait. The Jesuit priests figured that out without a telescope. Oh, that's amazing. Telescope was not yet invented. So they just looked up at the night sky to do that? Yes, and made measurements. And made measurements. Yes. Wow. Now, that's impressive. There you go. Yeah. So, uh, so the leap day simply makes up for the fact that we don't count years by whole numbers of days. And we gotta throw in a day.

• 21:36Neil deGrasse Tyson?

  Every four years and not every hundred years, but then back again every 400 years. Now, if you're born on a leap day.

• 21:42Chuck Nice?

  Oh, too bad.

• 21:47Chuck Nice?

  You got screwed.

• 21:48Neil deGrasse Tyson?

  Okay, so the real way to do birthdays is to know exactly where Earth is in its orbit.

• 21:53Chuck Nice?

  Right.

• 21:54Neil deGrasse Tyson?

  And celebrate that moment every year.

• 21:56Chuck Nice?

  Oh, there you go.

• 21:57Neil deGrasse Tyson?

  And then you don't have to worry about what they call the day, what day of the week, what day of the month. It's the orbital time, how do you count in time around the sun?

• 22:04Chuck Nice?

  And that's how, that's your birthday.

• 22:05Neil deGrasse Tyson?

  That's your birthday. And what also weird is how precise we count the new year.

• 22:11Chuck Nice?

  Right.

• 22:11Neil deGrasse Tyson?

  Let's go into Times Square or wherever.

• 22:13Chuck Nice?

  Right.

• 22:13Neil deGrasse Tyson?

  And you see the countdown clock.

• 22:15Chuck Nice?

  Right.

• 22:16Neil deGrasse Tyson?

  Okay, and then it hits midnight, but excuse me, it hits midnight for your time zone. There's 24 time zones.

• 22:23Chuck Nice?

  Exactly.

• 22:23Neil deGrasse Tyson?

  All right, the 24 slices of the earth.

• 22:25Chuck Nice?

  Yeah.

• 22:25Neil deGrasse Tyson?

  All right, so, and then they celebrate it, and they celebrate it. There's nothing magical about the moment.

• 22:30Chuck Nice?

  We're not all celebrating the new year.

• 22:32Neil deGrasse Tyson?

  Correct.

• 22:33Chuck Nice?

  Right, you're celebrating the new year where you are.

• 22:36Neil deGrasse Tyson?

  Where you are.

• 22:37Chuck Nice?

  And that's it.

• 22:38Neil deGrasse Tyson?

  Right, by an agreed upon calendric system. The timeframe.

• 22:43Chuck Nice?

  And if you're in Times Square, you probably missed it because you were peeing in a bottle.

• 23:10Neil deGrasse Tyson?

  So, Jack.

• 23:11Chuck Nice?

  Yes?

• 23:12Neil deGrasse Tyson?

  We haven't talked about planets in a long time.

• 23:14Chuck Nice?

  This is true.

• 23:14Neil deGrasse Tyson?

  Right, we're overdue, throw in a little extra planet pop culture. Can you recite the planets in order?

• 23:20Chuck Nice?

  In order? You're like coming from Mercury.

• 23:24Neil deGrasse Tyson?

  Okay.

• 23:24Chuck Nice?

  Right, and then Venus, Earth, right, and then Mars going out after that. That's a big one. There's Jupiter. And then you got Neptune behind Jupiter.

• 23:36Neil deGrasse Tyson?

  No, you got Saturn.

• 23:37Chuck Nice?

  Oh, I'm sorry.

• 23:37Neil deGrasse Tyson?

  How you gonna leave out Saturn?

• 23:39Chuck Nice?

  God. Venus, Saturn, Neptune, and then, you know.

• 23:43Neil deGrasse Tyson?

  Uranus.

• 23:45Chuck Nice?

  Right, Uranus, Neptune, sorry, and then.

• 23:48Neil deGrasse Tyson?

  No.

• 23:49Chuck Nice?

  No, and, yeah.

• 23:50Neil deGrasse Tyson?

  We're done.

• 23:50Chuck Nice?

  Uranus, Neptune, and then.

• 23:52Neil deGrasse Tyson?

  We're done. The planet count over the years has fluctuated.

• 23:57Chuck Nice?

  Yes.

• 23:57Neil deGrasse Tyson?

  To the ancients, there were seven planets. I will recite them for you.

• 24:01Chuck Nice?

  Okay.

• 24:02Neil deGrasse Tyson?

  Mercury.

• 24:03Chuck Nice?

  Okay.

• 24:03Neil deGrasse Tyson?

  Venus.

• 24:03Chuck Nice?

  Yes.

• 24:04Neil deGrasse Tyson?

  Mars, Jupiter.

• 24:06Chuck Nice?

  Jupiter.

• 24:06Neil deGrasse Tyson?

  Saturn.

• 24:07Chuck Nice?

  Saturn.

• 24:07Neil deGrasse Tyson?

  The sun.

• 24:08Chuck Nice?

  The what?

• 24:08Neil deGrasse Tyson?

  And the moon.

• 24:09Chuck Nice?

  All right. Now, I could see the moon being considered a planet because, you know, it's like coming and going.

• 24:16Neil deGrasse Tyson?

  Definition of planet has changed.

• 24:17Chuck Nice?

  I can.

• 24:18Neil deGrasse Tyson?

  In the day.

• 24:19Chuck Nice?

  Yeah.

• 24:19Neil deGrasse Tyson?

  Planet was anything that moved against the background sky.

• 24:24Chuck Nice?

  Okay, so all the other stars are staying kind of where they are.

• 24:27Neil deGrasse Tyson?

  Correct.

• 24:28Chuck Nice?

  And then you have these little.

• 24:29Neil deGrasse Tyson?

  Stars.

• 24:30Chuck Nice?

  Fixed stars. Then you got these little bodies that just kind of wander.

• 24:33Neil deGrasse Tyson?

  Size didn't matter.

• 24:33Chuck Nice?

  Wander along.

• 24:34Neil deGrasse Tyson?

  Size didn't matter. Brightness didn't matter. Did you move?

• 24:37Chuck Nice?

  Did you move?

• 24:37Neil deGrasse Tyson?

  Against the background stars?

• 24:39Chuck Nice?

  So any satellite?

• 24:40Neil deGrasse Tyson?

  The Greek word for wanderer, because these are things that wandered among the background stars.

• 24:46Chuck Nice?

  All right.

• 24:47Neil deGrasse Tyson?

  Is planetus.

• 24:48Chuck Nice?

  Planetus.

• 24:49Neil deGrasse Tyson?

  Yes.

• 24:49Chuck Nice?

  That's very romantic.

• 24:50Neil deGrasse Tyson?

  Yes, that's where we get the word planet from. And the fact that they use the word wander is evidence they had no clue what was going on.

• 24:58Chuck Nice?

  Right, yeah.

• 24:59Neil deGrasse Tyson?

  Okay, so, seven planets. It is not an accident that there are seven days a week.

• 25:06Chuck Nice?

  Okay.

• 25:06Neil deGrasse Tyson?

  Each day of the week is named for one of those seven planets.

• 25:12Chuck Nice?

  Sunday.

• 25:13Neil deGrasse Tyson?

  That's exactly.

• 25:14Chuck Nice?

  Sunday, Sunday, Sunday.

• 25:17Neil deGrasse Tyson?

  Sunday, Sunday.

• 25:19Chuck Nice?

  Yeah.

• 25:19Neil deGrasse Tyson?

  Is named after.

• 25:21Chuck Nice?

  Sunday.

• 25:22Neil deGrasse Tyson?

  The sun.

• 25:23Chuck Nice?

  The sun.

• 25:23Neil deGrasse Tyson?

  Okay, how about Saturday?

• 25:28Chuck Nice?

  Sabido itante.

• 25:31Neil deGrasse Tyson?

  Sabado is different. You did that, that's Spanish.

• 25:35Chuck Nice?

  Yes.

• 25:35Neil deGrasse Tyson?

  Okay, sabado is Sabbath.

• 25:38Chuck Nice?

  Oh, so it has nothing to do with the planet?

• 25:40Neil deGrasse Tyson?

  No, I'm talking about English, dude.

• 25:42Chuck Nice?

  Yeah, okay, okay, okay, okay. So Saturday.

• 25:45Neil deGrasse Tyson?

  Yeah, Sunday.

• 25:46Chuck Nice?

  It's gotta be Saturn.

• 25:47Neil deGrasse Tyson?

  Saturn.

• 25:47Chuck Nice?

  Saturn.

• 25:48Neil deGrasse Tyson?

  Sunday's the sun. And how about moon day?

• 25:51Neil deGrasse Tyson?

  Well, there you go. Monday. Yeah, guess what? Monday was named after. But now that works in Spanish because it's lunes. Lunes. All right, now what do you do with Tuesday? Now, where are you gonna get a planet? Now, now, okay, now, now you gotta do something impressive because you gotta, you gotta come up with a planet for Tuesday. I will, okay? Planet Mars. Okay. Why are you trolling? Okay, all right, so watch, watch. You're just. Okay, okay, so let's go back to the romance languages. What do they call Tuesday? In the romance language? Yeah, lunes martes. I know it in Spanish, martes. It's Mars. Right. Okay. Okay, all right, there you go, that's cool. So Tuesday, well, Tuesday doesn't sound like Mars, but there is a Norse god called Tuus.

• 26:36Neil deGrasse Tyson?

  Tuus. Yes, and this is a god of war. Okay, it's kind of a wimpy name for the god of war. Stand down or Tuus. Tuus will come kick your ass. Come for you, okay? He'll come kick your ass. So we now have Norse mythology joining in on this naming scheme. Right. Okay, but they have corresponding planets, is all I'm saying. Gotcha. So what's next? That's Tuesday, Wednesday. Wednesday. Okay, so what's Wednesday in Spanish? Mirkoles. Mirkoles, right, which would be Mercury. Right. So Mercury is. Oh, where'd he go, Mercury? Is the god of what? Um. What did he, what's he good at? He was a policeman.

• 27:21Neil deGrasse Tyson?

  Was moving fast. That's right. He was moving fast, and Mercury is the closest planet to the sun, and when you're that close, you move fast so you don't fall in. So Mercury's the fastest moving planet, and the Romans knew this, the Greeks knew this, so Mirkoles, Mercury, but for us it's Wednesday. So Wednesday. Right. Woden. Woden. Woden's day. Nice. Yeah, yeah, and so he's the closest Norse god as a counterpart to Mercury. Okay. Okay, so Mercury was a messenger god. Woden had some other features about him. Yeah. But it included serving as a, as a traveler back and forth to hell, whatever they called hell.

• 28:06Neil deGrasse Tyson?

  Thursday, we all know who that's named after. Well, Thursday. Thor. Thor. Thor's Day. Thor's Day. Thor. Thor wields what? The hammer. Well, the hammer and? Lightning. Lightning. Right. Okay, who in Greek mythology wields lightning? Well, Greek and Roman, okay? Jupiter. Jupiter. Wow. So what is, what do we have in, in, in the Romance languages? What do we call Thursday? Oh, wait, I don't, I don't know. Lunas, Martes, Myocles, Huaves. Okay, so it gives a J, it's Jupiter. Right. In French? Jude. Oh.

• 28:39Neil deGrasse Tyson?

  Jude. Oh, you put the hand.

• 28:45Neil deGrasse Tyson?

  So there you get Jupiter. Right. The corresponding god to Thor. Okay, that makes sense. All right. And what we're left with, Friday. Friday, and that's the last day. Uh, it's Friday, last day out of the seven. Saturn was Saturday. Okay, so Friday, uh, what's that in Romance languages? Uh, so again. In Spanish, I know it's viernes. Viernes, okay. Right. Uh, at Venus. Venus. Name for Venus, the goddess of? Love. Love and beauty and all that. Hmm. But we've once again drawn from the Norse traditions there. So that is Friga. Friga. Friga is the goddess of, of beauty. I didn't know that. In Norse legend, yeah. Norse legend. Sounds like a member of Wu-Tang.

• 29:27Neil deGrasse Tyson?

  Friga doesn't, doesn't, yeah, Friga, Jiga, and Jizza. The Jizza. So Friga has less sort of poetry for that than I think Venus. Yes, Venus, yes. Venus and beauty go together. Right. Yeah, nobody wrote a song about Friga.

• 29:46Neil deGrasse Tyson?

  Nobody wrote a song about Friga.

• 29:50Neil deGrasse Tyson?

  So we have this amalgam of words that track those seven days of the week. Okay. And we borrowed from Norse, we have Latin, and some of that Latin we would see in the, in the Romance languages. Right. And so. But they all track back to the seven planets. The seven planets, correct. Right. Seven planets. Right. And so here's what goes on. We have the seven planets and Copernicus comes along. Yes. Mid fifteen hundreds. Mid fifteen, and he says, "You people are dumbasses because the sun is not a planet." We lose the sun and the moon. Right. In the planet count, it takes it down to five. But we gained what?

• 30:35Neil deGrasse Tyson?

  Wait, I'm, I'm, I'm, you're losing me. Before Copernicus, we had seven planets. Right. All of them moved against the background stars. After Copernicus. We have five. We, we have five because we lost the sun and the moon. Sun and the moon. Okay. Right. But we gained one. Oh, us! Ah! Yes! Exactly. We, see. Well, of course, that makes sense. We gained one. But only to find that we were the wanderer all along.

• 31:04Neil deGrasse Tyson?

  So we went from seven to five, back up to six. Right. And there it would remain until William Herschel discovers Planet George. Planet George? Yeah. Right. Named it after King George. King George. The George of the American Revolution, George. Oh, okay. That they were contemporaries. Yeah. Right. Yeah, and, and the rest of the world was gonna have none of that. I'm sure. Yeah, Mercury, Venus, Earth, Mars, Jupiter, Saturn, and George. Yeah, we ain't do, we ain't play, we don't play that. Oh, my God, I wish we had kept that.

• 31:36Neil deGrasse Tyson?

  Planet George. George. That's a whole other conversation, other naming schemes, but I just wanted to catch you up on the days of the week. There you go. That was awesome. Days of the week explainer. There you go. All right. Seven planets. This has been StarTalk, yet another explainer. There's a lot out there that needs explaining. That's, I love everyone I know. All right, as always, keep looking up.