there's one last part of the Sun though that I want to talk about in more detail and that's the photosphere I purposely left this till the end so let's finish this all up by taking a close up look at the at the photosphere okay everybody good all right now if let let me show you guys a close-up photograph sorry I lost my train of thought there for a second let's get back on this train here we go here is a close-up photograph of the photosphere we typically think of the photosphere is just being a perfect yellow circle but it's not all one color we get yellows oranges and reds okay and if we if we buh-buh-buh-buh-buh sorry I'm just trying to report this over here okay there we go all right sorry about that now let's do this let's talk about the photosphere finish this up okay so sorry about that the photosphere what's it like it's got yellows oranges and reds what's probably different about the these different regions what's probably different about the different colors of the gas here what's different about the yellow parts the orange parts and the red parts temperature that is correct it's the temperature that is different right and if if we if we think of in that terms essentially what's happening is that the yellow parts are our hotter areas and the redder parts are colder areas and those hotter yellow regions are called granules granules that spelled g ra in UL e granule so why are there hot patches and dark patches well if you remember the photosphere is just the top of the convective zone and if we view that kind of from the side essentially what's happening is wherever the hot stuff is rising in the convective zone you're gonna get a granule you're gonna get one of those hot or yellow regions and then that material will cool down turn more orange and red and start sinking back down so these granules are not permanent they're just the top of the convection okay but the final thing that you're going to see on the on the photosphere is a particular feature that we need to talk about and that can be seen in this picture right here okay if we look in this picture right here we see a bunch of spots on the Sun here's a couple of close-ups of those spots on the Sun does anybody know what we call these spots on the Sun what are these spots in the Sun called good job they're called sunspots the spots on the Sun are called the sunspots but in particular their spots on the photosphere now let's see if we can figure them out they're a lot darker than the rest of the Sun so what does that tell us what is what can what is probably true about these sunspots if they're a lot darker than the rest of the photosphere they are colder okay yeah they're colder so a sunspot is a particularly it's a colder part of the photosphere now it's not actually cold okay it's not actually cold it's just colder ER than the rest of the photosphere so it's not producing as much light as the rest of the photosphere so when you look at the Sun your eyes adjust to make this look dark if we could block out the rest of this picture this would actually be bright enough to blind you it just looks black in this picture because these other parts of the Sun are so incredibly bright that you can't see the Sun spot next to them it's kind of like the same problem with not being able to see the corona okay now here we go how do they form it turns out that the clue as to how they formed is that they are also magnetized they are all associated with north and south type magnetic poles okay some of them have a north type magnetic part of a field and some are more south and that tells us that it's the sun's magnetic field that's doing this so essentially what happens is that the rotation of the Sun messes with the the the magnetic field of the Sun okay and I'm gonna try to do this kind of quick so we can get out of here normally the magnetic field of the Sun is shaped just like the planets magnetic fields so it pinches in at the two poles shaped roughly like a pumpkin right but here's something we haven't talked about every part of the earth has to rotate at one speed because our planet is mostly solid does every part of the Sun have to rotate at the same speed no Wai Wai can different parts of the Sun rotate at different speeds why is that what makes it so that that could happen yeah because it's made of gas because it's made of gas and that gas the particles of the gas are not attached to each other different parts of the Sun can rotate at different speeds all of the earth is mostly solid so those atoms are attached those molecules are attached so they all have to spend together but because this is gas different parts rotate at different speeds and it turns out that the equator of the Sun so around here rotates a lot faster than the poles do the poles rotate slowly and the equator rotates quickly and the reason that's important is that the magnetic field rotates with the surface underneath it okay so in other words if I were to uh let me draw one more picture here there we go let's do this okay so here we go if we were to imagine the sun's magnetic field let's say that this is the Sun sorry I'm losing my steam a little bit here we're almost done we can imagine part of the magnetic field looking like that normally because it's shaped like a pumpkin around the Sun but if the equator rotates faster than the poles then that means that this part of the magnetic field will rotate faster than the stuff at the poles so if part of the magnetic field rotates faster than the than the other parts will it be able to maintain this shape over time if part of this pumpkin rotates faster than the other parts will it be able to maintain the pumpkin shape no no it won't so what happens is that the part of the magnetic field over the equator rotates faster than everything else and that essentially causes this to happen let me show you a picture from the book there we go so here's a piece of the magnetic field under normal times and here is the equator rotating faster than the poles and that causes the magnetic field to spiral around the Sun okay and what eventually starts to happen is that when the when this magnetic field spirals it starts to get a little bit tangled so if you look right here they're showing little tiny tangles showing up on the magnetic field okay so as the magnetic field spirals because of this of the rotation of the Sun it causes it to eventually start to tangle a little bit and those tangles will touch the surface of the Sun okay they will touch the surface of the Sun and when they do charge particles in the Sun like magnetic fields so what that means is wherever those tangles like this little guy right here wherever that tangle touches the Sun the gas near it is going to congregate right there and it causes it to jiggle less and if it jiggles less what does that mean happens to the temperature in that spot where the tangle touched it gets colder that's right so what would have formed on the surface of the Sun where that little tangle touches what do we form in that spot yes that's your sunspot okay so check this out here we go normally right here uh that we would expect no sunspots because the there's no tangles touching the surface right but as the magnetic field gets more and more spiraled more and more parts of that magnetic field go into the surface of the Sun and you end up with something like this here's a little piece of the magnetic field and wherever it touches the surface you're gonna get a cold spot that's your sunspots so as the Sun continues to rotate what would we expect to happen to the number of sunspots over time as the tangles built up what will we expect to happen to the number of sunspots we would expect them to happen more and more and more over time but let me show you a quick graph from your book this right here we've been tracking the number of sunspots on the Sun for literally hundreds of years back before the camera was invented we were counting sunspots on the Sun so a lot of scientists went blind for this data right here and this right here is the last hundred years it's the number of sunspots every year and does it just keep increasing over time no what happens over time we increase and then we decrease every 11 years we increase and then we decrease we increase and then we decrease so there's a cycle here called the sunspot cycle that's eleven years long and essentially in the first half of the cycle the sunspots build up like we were talking about before so eventually though the sunspots need to disappear in the second half of the cycle so what happens well it's actually pretty simple here if we go back to this picture imagine like this was a basketball and these were some rubber bands and you spiraled them tighter and tighter and tighter onto your basketball giving you some sunspots what will eventually happen to these rubber bands if you keep wrapping it tighter and tighter and tighter what will eventually happen it'll break that's correct it'll brick so essentially the same thing happens here if the magnetic field rats too tight just like a rubber band it will eventually snap okay it will eventually snap and what happens is that those tangles break - but if the tangles were making the sunspots and we break the magnetic field that was making the sunspots that means the sunspots will start to go away so essentially the reason there's a cycle is that at the beginning of the cycle there's no sunspots then as it wraps tighter it makes tingles that make sunspots but if you wrap it too tight you break your tangles and then the sunspots go away okay and then at the very end of the cycle the broken magnetic field reforms back into a simple pumpkin shape again to just completely restart the cycle over and over and over again okay now somebody's asking a question here I'm gonna answer that question as the last thing that I'm gonna be talking about here and this is important because it turns out that these tangles don't just make sunspots they also make something else okay remember I said that the charged particles of the Sun like the magnetic field and so they kind of congregate right here and that causes them to slow down in this region and so it'll be cold right here relatively but if charged particles like that magnetic field and that magnetic field is starting inside the Sun and goes out of the Sun what is some of the material of the Sun gonna want to do right here what's some of this material of the Sun gonna do in this region yeah it's gonna escape the Sun it wants to follow that magnetic field so while some of the gas congregates right here and cools down some of the other deeper hotter gas of the Sun will actually burst through that region fast enough that it's not gonna heat up the sunspot but you'll get material bursting out of the Sun here and that is called a solar flare let me show you some pictures of some of these in action here's a couple of small solar flares I showed you this picture before but this right here this is a solar flare and you can actually see exactly where the magnetic field of the Sun is as this material is launched above the chrome Koroma sphere and falls back down towards the Sun if it goes out fast enough it can burst straight into space okay and just to give you an idea like here's another solar flare happening these things are amazing if I were to kind of put my finger out here the tip of my finger is about the size of Earth okay the tip of my finger is about the size of Earth in this picture so that's a lot of hot gas bursting through okay here's an even bigger one so here again is hot gas bursting out of the Sun writing that magnetic field okay and that means that there's not always the same amount of solar flares happening and we can look at the Sun and tell if there's gonna be a lot of solar flares happening when are there gonna be a lot of solar flares how can you look at the Sun and know there's a bunch of solar flares gonna be happening what would tell you what would tell you a bunch of solar flares are gonna happen right now yes it's the number of sunspots remember the tangles and the magnetic field are what caused both the solar flares and the sunspots so if you look at the Sun and there's a bunch of sunspots on it that means there's probably going to be a lot of solar flares too and if you look at the Sun at the beginning of the cycle when there's no sunspots there's also going to be very very few solar flares okay right now uh we are closer to a minimum than a maximum I believe so we don't actually have too much of this kind of activity I mean it's happening enough but we're not at a maximum right now so we're not having the whole ton of this happening when this stuff shoots out of the Sun do we need to worry about that is this gonna kill us is this gonna kill us when it come and comes and hits the earth no we're gonna be fine what protects and it's good something protects us if there was no protection from this this would have happened every 11 years so we would have a chance of this coming and hitting the earth every 11 years clearly that's happened in your lifetime and we haven't all died what's protecting us it's the magnetic field it's the magnetic field yes remember the reason this stuff is able to come out of the Sun as it's writing the sun's magnetic field so when it gets to our magnetic field it wants to turn and follow our magnetic field as well it may push in on the magnetic field a little bit enough to interfere with satellites but it's probably not going to get all the way down to the surface of the earth okay it what it would do is it would make the Aurora's look a lot cooler when it was happening because a lot more material would be making it to the poles to light up the poles than usual okay yeah