This is StarTalk, a Things You Thought You Knew Edition. Of course I got Chuck Nice with me Chuck. Yeah, it's right I don't think I know anything that's why I make you a perfect
Oh, that's it for this for this excursion. I'm happy to be here. All right. No one at thing. Let's get this party started Welcome to StarTalk Your place in the universe where science and pop culture collide StarTalk begins right now Chuck out another explainer awesome the diameter of the Sun. Okay, this sounds boring The diameter of the earth is about 8,000 miles and thank you and that's it
Okay, did not know that so well. I'm already good. It's what 8,000 miles. Okay And from that you can know there's a conference if you remembered pi okay, where circumference equals High times the diameter. Okay, then how much is pi? 3.14 something something exactly so a little over three right so you multiply 8,000 miles times three and a little bit you get at least 24,000 miles away and some change
It's about 25,000 miles circumference. 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 the diameter of earth and the equator at the equator We talked about that. Um earth is slightly flat Spheroly. Yeah, yeah, that's one of the blight's spheroid is your flattened top to bottom. Okay. Yeah, the Sun Mm-hmm is also shorter top to bottom Then 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 going to give them? Are you going to give them pole to pole? You're going to give them across the diameter. Mm-hmm You're going to take the average of those two. I'm just want you to appreciate That when you look up a numerical answer to a question, right? 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 going to be across the equator for everybody. What's the diameter? We need the high frequency, right? You need Oh, you know that lets you 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 the sharp edge Right the edge of the Sun as an edge, okay, but wait Uh-oh the Sun is made of what?
Plasma plasma to gas basically okay plasma gas. What's the last time you saw gas have a sharp edge to it? Well, that would be my uncle Darrell When that smell moved across the room You know sharp edge sharp edge you have the in it or not man. You know It's time to go The spherical ball that is the Sun right oblate sphere Roy 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 Right gas that becomes sort of thinner and thinner and you know you reached it when you're like So when we see the sharp edge of the Sun
In practice, we were referring to what's called the photosphere. Oh 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 great 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 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 you know what he what do you do when you cross the I crossed the window right and I the light I can't get through I got a jiggle a little bit. I'll still come through but I'm not in a straight line
Right, you cannot see through the window. No, yeah, the windows lit up, but you can't see what's on the other side The lights coming through, but it's not a straight line. Okay. All right So the photon gets to this place in edge where it can now escape for free Is 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. Oh God Had to be a twist in this
Ha so we are visible light bias 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 you own damn eyeball can see right We all 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 diameter of the Sun is where the visible light comes from And specifically yellow light Okay, right in the middle of the spectrum red arms 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-hmm 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 Could be really big or really small so that changes on 11-year cycle, but wait the Sun Has a magnetic field that extends beyond the corona Right that's called the magnetosphere Shouldn't that be part of the diameter of the Sun? I
Part of the Sun is part of it. It's not all right. Yeah, all I'm saying is if you seek the truth my Sun Mm-hmm be aware that the truth has many faces Mm-hmm 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 It's truth may seem because others will be speaking their truth Quietly and clearly And you must listen to them as well Do I have to snatch a pebble from your hand now?
Go ahead Snatch the pebble for my Wow you got some quick reflexes man All right You have some really like uncannily fast reflexes like there shouldn't be You are not ready my son come back another time. Okay one last fun fact about the Sun. Okay. All right Uh if we're about 8,000 miles across right if you look up the diameter of the Sun It'll give you something like 860 4,000 miles something like that. Jesus. Okay. All right. So now let's round that down
Just so the numbers come out fun. So that's a hundred thousand miles across a hundred times bigger It's a hundred times hundred times a hundred times across. So you can take Earth 100 and Position it 100 times back-to-back belly to belly and you'll span the width of the Sun Wow, okay a hundred times now By the way, that's about the size of Sun spots So the Sun has blemishes larger than early or just so you know see all right So now if it's a hundred times across
That means it's also a hundred times deep. Yeah, it would be a hundred times top to bottom So how many Earths Could fit into a hollow Sun into the Sun into the Sun That's a hundred times a hundred times a hundred. Give me what that number is 100 cubed Thank you The precise response hundred times a hundred is 10,000 right and a hundred 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 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 It was like no, we're not making Earth first and then assembling something a million times larger and having orbit the Earth Right, anyhow the universe works doesn't doesn't yeah, they had I guess that's my song I'm Olican hemorrhage and I support star talk on patreon This is star talk with Neil deGrasse Tyson
So Chuck yeah, did we ever have a conversation about leap days? I have a vague memory
But maybe just slipped into other explainers. I was gonna say we've discussed it but not specifically on its own turn It's not like Sun. I'd like to talk to you about leap days The time has come You're old enough now to know about leap days I people seem to be mystified by it right the day just shows up in the calendar Yeah, what does yeah and it seems very arbitrary it seems that's feel arbitrary like some high council Yes, 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? I'm well, it should be should why not? I mean why not like okay? Yeah, that's a day. Okay So now Earth also goes around the Sun Right how long do we does that take that's about a year about it? 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 or it goes around the Sun. That's true. Okay, but they're totally unrelated phenomena Right, okay exactly. So we count days by a rotation of the Earth, right? We count years by revolution around the Sun And it turns out a year last 365 of these things
Plus one fourth of a turn. Okay, a quarter turn. It's 365 days and six hours six as a fourth of 24 hours. Okay. Yeah That's how long it takes Earth to go around the Sun What are you gonna have? That's too much So what are you gonna do with the six hours? Right. It's too much right by the way It's six hours this year and then the next year it's six hours added to the previous six hours. I got 12 hours Now you gotta know what to do with right so to half a day. Are you gonna celebrate the new year?
On a moving six hour platform. I'm thinking about no, it's interesting. I'm kind of thinking about that right? I'm not you so be right six and one right. Oh no, forget it then again, that depends. That's a hell of a party That's a hell of a party man So so the first of those years you celebrate at six a.m. Right next year 12 a.m This is on the 366th day, right? And the next year would be like six p.m. Right all right And then next year back at midnight. Yeah, okay
I'm just saying that be kind of a that be kind of cool. Just be kind of dope. Yeah Let me kind of dope. Let's just like yeah What time is new year this year? Right in order to not have to do that right let's go back to ancient Rome in the Julian calendar. Okay. They figure this out I wrote of course and they said let's pocket those six hours. Right don't tell anybody right okay And we just celebrate the new year six hours early, but nobody knows. Nobody knows
It's just a complete day you're doing it midnight. We're good to go. Right okay. You pocket that there you go next year go by Sounds so much like the Roman Senate So you've got the the first year goes by you pocket the six hours right second year goes by pocket another six third pocket the six
We're up to six 12 18 hours a pocket is getting full the fourth year comes around You don't pocket that right because now you got a full 24 hours you put the day back in the calendar boom There you go there it is look at that the leap day empty your pockets on that day every four years You're throwing a leap day and you give it to the neediest month right okay exactly. I mean, why not right
Which of course is black history that's the neediest I think an ancient Roman wasn't black history month yet. Oh, yeah I'm sure It was slave history month right right is that Oh everybody because don't care who you were in Rome you was a slave You know, I mean like wait a minute man is is that a white slave over there? Hey brother. This is Rome So there you have that that is the fundamental origin of a leap day right, but here's what happened okay It turns out it takes a little less
Then 365 days and six hours to go around the Sun. Oh god. It's not an exact six hours of course It will it couldn't be right because that would be make too much sense. It's a right that would make that would be too easy That even that would be technically evenly divisible right like a whole number of hours exactly a little bit less
Romans didn't know this right of course they didn't know this well Can you blame us we're using sundial so 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 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 and a shifting right so the first day of spring the Vernal Equinox March 21st right Over the centuries became March 20th and then March 19th right then March 18th March 17th March 16th March 15th Oh, and they would just live in with it. Yeah, not figure what what what has happened in the spring guys It's spring of us spring is this springing all over the place. We can't have spring sprung in the trap
Where it was marching its way early in the calendar century by century, right? Okay. This was a concern Why right cause 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 hope Gregory We're now in like the late 16th century so 1580s all right hope 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 Hmm 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 So ruin Easter right. Yeah, 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 has scientists yes get out. Yes 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 Pope's and who are they they are the Jesuits the Jesuits are the academic order among the orders of Christian and
Catholic Catholicism okay, so that's what 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, okay. That's too many and and that was not reckoned and that that shifts the Vernal Equinox backwards in the calendar Okay, all right in order to fix this they said all right
Let's jump started put put the Equinox back on March 21st got to put it back there. Okay. That's where belongs And what you do without them days Okay, by then it was on March 10th well, okay, so in October of 1582 October now October okay They're saying time to jumpstart the system all right, so they took ten days out of October Let do it you to Pope you have the power to do this. I'm gonna say that's too much power one man to hand He's just like guess what October You just got cut
I'm sure the Pope sounded exactly like that. I'm just like angry black man. Yeah, or guess what October Dominus is bitter to Half the month's gone right ten a third of the month is gone and you know why because that's when we oh rent So they took ten days out of October. So October like 15 followed October 4th Okay, did I get my numbers right there?
Yeah, okay, 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? Multiplied divide Multiply by your rent but a fraction and that's what you pay okay We still stay with the four-year rule except every hundred years which is still divisible by four right the hundred is the Vosiby for every hundred years we Take out the leap day that would otherwise be there. There you go
Okay, 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 undercorrected that
Undercorrected by a little bit. Okay. I got to tell you this this moving new year's eve thing is looking real good right now 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 four hundred years you got to put a leap day back in back in uh because of four hundred years
It's still on a hundred-year cycle right but every four you got to put it back in now. Who is alive to remember to do this? That's what I'm saying okay 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 now Rare that leap day is it's a century year divisible by four hundred Right that gets a leap day
1900 didn't have a leap day 1800 didn't have a leap day 1700 didn't have a leap day. So no day put in okay 1600 did because that was right after Yeah, it happened. It just happened 182 is when it happened exactly 1600 still got the leap day put it in hold 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 and made measurement. Yes. Wow. Yeah, 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 got to throw in a day
Every four years and not every hundred years but then back again every four hundred years now if you're born on a leap day. Oh too bad What you got to you got screwed okay, so the real way to do birthdays is to know exactly where earth is in its orbit Right and celebrate that moment every year Oh, yeah, you know, and then you don't have to worry about what they call the day what day the week right what day the month It's it's the orbital time
How do you count time around the sun and that's how that's your birthday? That's your birthday And what also is weird is how precise we count the new year right let's go into time square or wherever right and you see the countdown Right, okay, and then it hits midnight, but excuse me hit smidnight for your time There's 24 times zone exactly all right, but 24 slices of the earth. Yeah, right? So in the nay celebrated and they celebrate it
There's nothing magical about them. We're not all celebrating the new year correct If we're right, you're celebrating the new year where you are where you are and that's it Right by an agreed upon count calendars systems the time time frame and if you're in time Square You probably missed it because you were peeing in a bottle So Chuck yes, we haven't talked about planets in a long time This is true right at the we're overdue. They're a little extra planet pop culture
Can you recite the planets in order in order? Yes, like coming from Mercury, okay, right and then Venus Earth right and then Mars going out after that. That's a big one Jupiter and then you got Neptune behind Jupiter. No, yeah, I'm sorry. I wouldn't leave out Saturn God Viva Saturn Neptune and then you know Uranus Right Uranus Neptune. Sorry. And then no No, and yeah, we're done it Uranus Neptune and then we're done
The planet count over the years has fluctuated yes to the ancients. There were seven planets. I will recite them for you Okay, Mercury okay Venus Mars Jupiter Saturn the Sun What and the moon all right now? I could see the moon being considered a planet because you know It's like the definition of planet has changed. I can know what they're the day Yeah planet was anything that moved against the background sky Okay, so all the other stars are staying kind of where they are correct
And then you have these little stars fixed star. I think you got these little bodies that just kind of Size didn't matter. Wander alone size didn't matter. Okay. It's didn't matter. Did you move? Did you move against the background stars? So any satellite the Greek word for Wanderer because these are things that wander among the background stars right is planitas Let me test. Yes. That's very romantic. Yes. That's where we get the word planet from and the fact that they use the word wander
Is evidence then? Oh, what's going on? Right. Yeah, okay. So Seven planets it is not an accident that there are seven days a week Okay, each day of the week is named for one of those seven planets Sunday Sunday Sunday Sunday Sunday Sunday is named after Sunday the Sun the Sun okay about Saturday Saturday Yeah, no sabado is different The you just that's Spanish yes, okay sabado is sabote
Oh, okay, I was not gonna do it the plan. No, I'm talking about English, do you? Okay? Okay? Okay? Okay? Okay? So Saturday Yeah, Sunday. It's gotta be Saturn Saturn. Saturn. Sunday's the Sun and how about Monday Well, there you go the moon day. Guess what moon days now that works in Spanish because this lunas I know what you do with Tuesday Now you're 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 Okay, okay, why didn't roll it? Okay, okay, so let's go back to the romance language. Okay. What do they call Tuesday? In the romance land. Yes, that lunas marked this not I know it in Spanish marked that's Mars right? Okay, okay. All right. Okay. That's cool. So Tuesday Well Tuesday doesn't sound like Mars, but there is a Norse god called twos twos twos. Yes, and this is a god of war Okay, it's kind of a wimpy name for the god of war Stand down to it. Tews
Tews will come kick you. I will come for you. Okay Here come kick you So we now have Norse mythology Joining in on this naming scheme. Right. Okay, but they have corresponding planets is what I'm saying Gotcha. So what's next as Tuesday Wednesday Wednesday. Okay. So what's Wednesday in Spanish?
Merkuley mechorles right which would be mercury right so mercury is oh where did you go mercury is the god of what Um, what did he what's he good at he's a postman with moving fast that's right he's moving fast and Mercury is the closest planet to the Sun
So and when you're that close you move fast so you don't fall in so mercury is the fastest moving planet and the Romans New this the Greeks knew this right so Miracles mercury, but it for us is Wednesday Wednesday so Wednesday right Woden woody woody in days woody 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
uh serving as a as a traveler back and forth to hell whatever they called hell Thursday. We all know that's named after But there's Thor Thor Thor Thor's it's Thor's day Thor's Thor's wheeled what the hammer well the hammer and lightning right okay Who in Greek mythology wheels lightning but Greek and Roman okay Jupiter Jupiter wow so what is what do we have in in the romance languages
What do we call Thursday? Oh wait, I don't know so I don't know who in this Martha's me Oculus weathers. Okay, so it gives a J Jupiter right in French Judea Judea So there you get Jupiter right the corresponding god to Thor okay, that makes sense all right and we're left with Friday Friday and that's the last day this Friday last Saturday Saturn was Saturday. Okay, so Friday What's that in romance languages?
Uh, so it's Spanish. I know it's a beardiness be arenas. Okay, right Uh Venus Venus for Venus the goddess of Love and beauty and all that But we've once again drawn from the Norse traditions there. So that is Friga
Friga Friga is the goddess of a beauty. I didn't know that in the North legend It's a legend sounds like a member of Wu Tang Friga Friga doesn't does this yeah, Friga jigger So I figured at less sort of poetry for that then I think Venus Yes, yes, Venus and beauty go together right yeah, nobody wrote a song about Nobody wrote a song about Friga So we have this amalgam 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 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 1500 and he says you people are dumb ass Because the sun is not a planet We lose the sun and the moon right in the planet count that takes it down to five But we gain what?
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 have five because we lost the sun and the moon okay, right, but we gain one oh Yes exactly Well of course that makes sense we gain but only to find
That we were the wanderer all alone So we went from seven to five back up to six right there 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 And George yeah, we're gonna do it we don't play that Well 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 explain it there you go
All right seven planets. This has been start talk yet another explainer. There's a lot out there for that needs explaining I love everyone. I know all right as always Please keep looking up