okay so there we go we know that the Sun is doing this because of the neutrinos coming out okay now we're finally done with that super technical thing now what we're going to talk about is we're going to talk about the layers of the Sun okay so what I'm gonna do is I'm gonna go back to my document cam alright here we go and I'm gonna hope that it's still working looks like it is what we're going to do and I recommend that you do this with me is or at least go back and do it if you view the video later is we're going to draw a little diagram of the layers of the Sun you're gonna need to know the order of the layers of the Sun for the test so what I'm gonna do is I'm going to draw a big rectangle there we go here's a big rectangle alright and this rectangle is gonna represent the layers of the Sun the very center of the Sun is the bottom of the rectangle and up here is the top of the Sun does that make sense so we're kind of like a slice of the Sun and we just talked about the middle layer which was the core so I'm gonna label that as the core okay and we're gonna work our way up now couple of questions as you go away from the core as you go towards the surface of the Sun what do we expect to happen to both the temperature and the density what should happen to the temperature and density as you go away from the core that's correct they should go down they should decrease right they should decrease as you go away from the core and so that means the next region of the Sun above the core is going to be not as hot as the core and not as dense as the core but still very hot and very dense okay this particular region is the radiative zone radiative zone okay there we go and be very very very careful it's not the radioactive zone be very careful with that it's the radiative zone that means something totally different I'll explain the name in a second but think of it is it's like the core but it's not quite hot enough and dense enough for fusion to be happening fusion only happens down here not here okay now that said it's still extremely hot and extremely dense so all of the atoms here are ions okay they're missing which part which part of the atom is missing here in these ions in the radiative zone which parts missing yes yes the electrons it's missing the electrons now let me bring back something from a long time ago when we were talking about how atoms absorb light when we were talking about the fingerprints the part of the atom remember when I when I got up on the tables and I fell off of all the tables over and over again in class I was trying to explain like atom levels when we were talking about that we learned that the electron is the part of the atom that absorbs light okay so we just made a whole ton of gamma rays down here in the core and they're gonna try to work their way up but because this layer has no electrons attached to the atoms that means the atoms in this area are not going to be able to absorb the light so that means the light is free to make its way up through this region without getting absorbed okay but it's still extremely crowded in the radiative zone okay let me give you guys a metaphor okay let's say that you went to a party okay you went to a party and it was not a lame party let's say that it was extremely lit okay it was just an amazing party okay like it was packed way beyond the fire code for whatever building you were in okay and everybody's dancing and it's just amazing party everybody's dancing really energetically because the temperatures really high ha ha ha this party is the radiative zone by the way that's the metaphor and I was trying to get a public domain picture of a party to bring up to help illustrate this and I thought it was funny the very first couple of pictures that came up when I searched for a party where's this so here you go here's our here's our amazing bumpin party it's uh there it's amazing so here you go yeah you're at this party right here and okay just imagine this was was more amazing than you thought okay so these people they're all listening to you know dubstep or something I don't know and you know they've got they've got their live their goofs up here there's passing their deuce around and let's say bit like this that's you okay that's you and you're just oh you're just yeah yeah okay you're over here yeah and then you notice uh-oh I've got to go to the bathroom okay and the problem is the bathrooms way over here all right the bathroom is way over off this side are you gonna be able to just rush in a perfect straight line just Beauty dudududududududududu just zoom through this party are you gonna be able to travel in a straight line through that party when you're trying to get out let's assume that you're not a jerk okay let's assume you're not a jerk so instead when you get up to people what's gonna happen is as soon as you get up to a person you might accidentally bump them but you're gonna kind of go out of the way and then you're gonna turn and you're like excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me excuse me and then you finally get off to the bathroom okay so like over here you're stuck in the back corner you want to get to the bathroom you got before you get out right lots of bobbing and weaving exactly so what that means is you can think of the picture we were just drawing right here this radiative zone is the party zone right this is the party zone and the the light is stuck down here at the bottom of the party zone and the bathrooms up here it wants to go through the party is the light going to be able to go in a straight line through this party no it's not it's going to have the same exact problem that you had going to the bathroom right so what its gonna do is on the way out of the core it's gonna bump off of tons of atoms on the way out and it ends up going in a random path on its way up to the top of the party so the light slowly works its way up through this zone it's not able to go in a straight line and check this out every time it bumps into something when it's going through the party zone what happens to its energy what would you expect to happen to its energy every time it bumped into something on the way out exactly it loses energy remember the type of light that's being made in the core is gamma rays but we know that it's visible and UV that comes out of the Sun and that's because mainly because of the radiative zone the party zone it bumps so many things on the way out that it loses a ton of that energy so that by the time those photons come out of the Sun at the edge of the party they are now in the form of UV and visible light which are much lower energy okay so that's why we're not getting blasted with gamma rays all the time it's a good thing that this party is so lit right okay so here we go here we go now what's happening next all right the next zone is even less dense and less hot in this zone a lot of the atoms have some of their electrons attached to them you start getting some regular atoms mixed in with your ions and if some of these atoms have electrons what can those atoms do when this light gets to them what can the atoms in this zone this next zone do if they do have electrons what can they do when the light hits them that's right they can absorb the light so as soon as the light enters this next zone it gets absorbed so it gets absorbed at the bottom of this zone so every time one of them comes up they get absorbed now that's gonna make the gas that absorbed the light hotter than everything around it and what's gonna happen to that hot gas if that gas is hotter than all the gas around it what does it want to do the gas that just absorbed that light got hot what will it want to do what happens when you have a hot gas or liquid it's actually taking us back to something we talked about about the planets yes yes it rises it rises that's exactly correct so what's gonna happen is in the party zone the gas just jiggled around randomly but in this region because the gas is now picking up that light and getting hot it's going to want to rise so hot gas will rise there we go and as it gets to the top of this zone the gas gets thinner and thinner and thinner that it loses its light at the top of this zone which makes that gas cool back down and then the cold gas will sink again so in this region we have hot gas rising taking light up to the top losing its light getting cold and sinking right back down to pick up another shipment of light ok what do we call that what do we call hot gas rising and cold gas sinking what's that process called hot gas rising and cold gas sinking what is it called yes yes yes it's called convection and so this part of the Sun is called the convective zone so this zone is not a party okay this zone is not a party the core is where the light gets made the radiative zone is the party zone that all of the gap the light has to bump its way through on the way to try to get to the bathroom right and then the convective zone is like somebody kidnapped it and threw them in its trunk and drove it to the edge of the zone and then just toss them out on the side of the road so the convective zone is where the light gets a ride whether it wants it or not okay all right now yes sorry things got a little dark in the convective zone figuratively okay now um here we go here we go at this point remember you guys said that the density keeps decreasing as we go up so when we get to the top of the convective zone the Sun is so thin that the gas can no longer block the light so as soon as the light gets here the light just leaves and goes to space okay the light of the Sun leaves the Sun at the top of the convective zone and so that means when you look at the Sun what you're actually looking at you can't see the core you can't see the radiative zone you can't see most of the convective zone but because the light is leaving at the top of the convective zone you can see the upper edge of the convective zone so that big yellow circle that you normally think of the Sun being that's the very top of the convective zone that you're seeing and because that's the part we see we give that part a different name it's technically the top of the convective zone but we give a very very thin layer of gas right there at the top of the convective zone the name the photosphere photosphere okay so it's called the photosphere because that's where the light leaves the Sun and remember light is thought of as a bunch of particles called photons so you can think of the photosphere is where the photons leave and so again the photosphere is the part you see when you look at the Sun also don't look at the Sun looking at the photosphere can permanently damage your eyes and seconds okay you could go permanently blind looking at the photosphere in seconds please don't look at the Sun okay one quick thing if the light right here is this if this is where the light leaves the Sun does anybody remember how long it takes that light to get from here to the earth how long does it take the light to get from the Sun to us how long yeah just a few minutes about eight minutes okay and so this the light goes a crazy insane distance in eight minutes this distance between the core and the photosphere is not even a billionth of the it's billions of times smaller than the distance from the surface of the Sun to us so I might be exaggerating that a little bit it's a lot a lot a lot smaller okay so what of time would we expect it to take the light to go from the core to the photosphere how long does it take the light to go from the core to the photosphere would you expect seems like it would be like that like seconds at the most right but it turns out that it takes light about a hundred and fifty and fifty thousand years to go from the core to the photosphere a hundred and fifty thousand years to get from the core to this to the photosphere to leave of the Sun so that's a big difference so can anybody figure out why why does it take a ridiculous amount of time for the light to get out of the Sun yeah yeah mm-hmm it's the party zone the party zone is so packed it's so it's so bumping that it takes it the light hits so many things on the way out that the that it's it's so crowded that it takes a hundred and fifty thousand years or so for that light to get out of the Sun okay so it's ridiculous is what I'm getting at does that make sense and then as soon as it's free it can take just eight minutes to go to the to the earth all right now okay now just so you know we sometimes called the photosphere the surface of the Sun and all of this stuff underneath it is the interior or the inside of the Sun but can you walk on the photosphere even like assuming you could survive the temperatures or whatever could you walk on the photosphere could you walk on it no you can't why not why can't you walk on the photosphere even if you could survive the temperatures yeah it's made out of gas every single part of the Sun is made out of gas technically again a lot of its plasma but it's gas right so all of this down here is gas and the photosphere is gas and everything up above it is gas so us calling that the surface is kind of just a convenience for us to make it seem like something we we're familiar with but all up even though this stuff is considered the interior of the Sun and the rest of it photosphere on up is considered the atmosphere of the Sun there's not really a physical difference in the type of material we're talking about that much okay it's all gas