okay now now so those outer four planets Jupiter Saturn Uranus Neptune those four planets also have a name and that name is Jovian Jovian so the outer four planets are called the jovian planets there we go the jovian planets and just like terrestrial means earth-like Jovian means Jupiter like okay so we basically have two major types of planets earth earth is the model for the terrestrial planets and Jupiter is the model for the jovian planets oh and some of the somebody asked why do we have these pictures from the moon we have other pictures of the planets that are not from the moon like that but I think that they just thought that those particular pictures look pretty cool the reason that the moon is in the picture is that the ones that have the moon close up like that are from satellites we had orbiting around or at least flying by the moon's at that particular time and they just got some cool pictures of the planets while they were taking pictures of the moons so that's where those came from okay so what we're gonna end up doing in a second is we're going to look at we're gonna list differences between these two groups of planets but before we do that I want to talk real quick about what they all have in common okay what do they all have in common can you think of anything just anything that all of the planets have in common just give me anything no matter how basic that all of the planets have in common they all orbit the Sun that's a good one that's a good one they all orbit the Sun in fact to be considered a planet you have to orbit the Sun ah somebody said they're all round that's another good one they're all round there's some times in cartoons they have though you'll have some times like a square planet or a star shaped planet or a triangle planet or something in real life we don't get any of those shapes we only have round planets okay and we'll talk about why that is after a while but for now yes they're all round they all orbit the Sun there's a bunch of other things we could list I do want to say something else about their orbits around the Sun what shape is the orbit of every one of these planets what shape is all of their orbits by the way let me get some pictures go in here what shape is the orbit of every planet kind of going back to test one material here an ellipse right an ellipse every one of these planets has an elliptical orbit okay and here's the thing you probably have seen like models of the solar system before where you got the Sun floating in the middle and you got planets I mean here's here's the Sun you got planets orbiting around it if you if this was earth let's say this was earth orbiting or any of the planets orbiting like this if Earth's orbiting like this or any of the planets orbiting like this yes or no no no so another thing we can say that the planets have in common is that they all orbit the Sun in the same direction right all of the planets orbit the Sun in the same direction so if you laid out all of the orbits of the planets the that part of the solar system is basically flat okay flat solar system you don't have any planets going like this we can say that all of the planets orbit roughly in the same plane okay that means that everybody is in the same place and they all go the same direction around the Sun why good question good question one that I'm not gonna fully answer right now but I will give you a little bit of a hint edit so somebody's asking why do all the planets do this so the reason that the planets all orbit the same direction is the same as the reason that the planets are different specifically it's because of the way our solar system formed okay we're gonna talk about that soon okay not today but we're gonna talk about that later but the reason that the solar system has all of the properties that it does all of the similar is between the planets and all of the differences is because of the way those planets formed while the Sun was forming okay and so basically everything that we talk about today is actually a clue that we used to help us figure out how our solar system formed okay and by looking at other solar systems that are currently in the process of forming we've been able to back that up that our ideas of how the solar system formed are basically correct okay so we'll get our way up to that okay now let's start talking about differences okay so one your in your notes make sure you have enough room for this if you're way down at the bottom of a page you might want to flip to the next page because again what I like I said what we're gonna do is we're gonna get to long lists of differences between these two groups how long I don't even know if we're gonna finish them today okay but we're gonna get as many out the differences as we can get on here before we head out so let me get back here before we go into the kind of the obvious difference between these two groups of planets let me just ask about a very basic difference and that is in the size of the orbit okay the size of the orbit what what's the difference in the size of the orbits of the terrestrial planets and the size of the orbits of the jovian planets don't overthink this what's the size of the orbits of the terrestrial planets like all I'm looking for is like small or large small right all of the terrestrial planets have very small orbits and all of the jovian planets have very big orbits that's why they're the outer planets and these guys are the inner planets it's because of the size of their orbit right so the first thing I want to put on to our list is small orbits for the terrestrial planets small orbits and we'll put large or big orbits OB here small orbits large orbits and that seems like a very very basic difference between the planets but it turns out that almost every other difference between these two groups of planets comes from the fact that these guys have small orbits and these guys have large orbits pretty much every distance comes from the fact that the terrestrial planets are close to the Sun and the jovian planets are far away from the Sun now somebody does have a question about the picture I showed you guys so if you look on that picture way down here on the bottom says somewhat aw do you see Pluto down there yes you do see Pluto down here I suspect that this is an old image from the book where before Pluto was declared not a planet so they put it on this oh yeah normally in class I go up here and I make a big old joke about Pluto being trash and I cross it out just make a big old deal about crossing it out but you just have to use your imagination let's just imagine we grab that we just and then we we just threw it away just there we go get rid of that trash right there okay now again we're getting close we're getting close now that we're talking about planets we're getting close to where are we gonna talk about why that I keep saying that Pluto is trash and why it's not a planet so we're getting there we're getting there but not today that's probably tomorrow okay so here we go let's talk about more differences between these two groups of plants okay what's the most obvious difference between this group of planets and this group of planets what's the most obvious difference here that even like a little kid could point out Oh most immediately yeah the size is clearly different I'm not gonna bother wasting time asking you which ones small and which ones big I think you can all tell that the terrestrials have a small size and the Jovians have a large size so let's uh let's add that to our list here okay let's add that to our list small size were small boys and large size there we go small size large size oh and by the way I forgot to mention in this image all of the sizes are roughly correct compared to each other but these are not the proper distances away from the Sun okay this image is to scale in terms of size but not in terms of distances away from the Sun if the earth was this close to the Sun we would all be dead okay we don't want to be this close to the Sun okay now okay okay jovian planets are much bigger than the the terrestrial planets which planet is the biggest you can actually probably tell if you look closely on this image right here which planet is the absolute biggest out of all the jovian planets and when we're talking about the size of planet we don't include its rings when we're talking about its size so which one of these is the biggest Jupiter yes Jupiter is the absolute biggest planet out of all of them on the other hand mercury up here mercury is the absolute smallest planet okay mercury is less than half the width of the earth okay mercury is very very very very small in fact there are some moons that are actually bigger than the plan mercury okay there are moons that are bigger than the planet Mercury in fact Jupiter I think has a few of them okay if those moons are bigger than the planet Mercury why is it that mercury gets to be a planet and those moons aren't planets if mercury is smaller than some moons why do why does mercury get to be a planet when those moons don't get to be planets yeah we're getting some more differences between the planets down there that's good we'll talk about those but what is mercury do that moons don't do I'll go ahead and tell you I'll go ahead and tell you mercury mercury orbits to the Sun right mercury orbits the Sun and the moons of a planet don't orbit the Sun okay and actually somebody got it before I mentioned it so that's good so yeah you have to orbit the Sun in order to be considered a planet okay now now okay all right now somebody asked about rings actually let's go ahead and add that on to our list we said that saturn has rings is Saturn the only planet that has rings Saturn the only one that has rings yes or no No right like if you looked closely in these pictures you probably saw rings around Uranus so Uranus has a ring right here right if we look right here check out Neptune Neptune Neptune's got a ring Jupiter have any rings Jupiter have rings let's take a look at that picture does Jupiter have rings if you look real close and depending on what you're viewing this what quality you're viewing this streaming you might not be able to see this but if you look real close right here this is a ring right here this is a ring and it cuts across you can barely see it sticking out the other side right there so what can we sell here's another question does uh does Earth have a ring does Earth have a ring no we don't get a ring Oh same with Mars no ring Venus no ring mercury no ring so what could we say what could we say is a difference between the planets what can we add to our list based on that information what kind of planets have rings let's put it that way yeah terrestrial planets have no rings jovian planets do have rings okay so let's just add rings to this list there we go and over here on terrestrials we could put no rings now what are those rings and why don't we get to have them we'll talk about that well specifically we'll talk about that when we talk about Saturn probably so we'll get to that but for now we'll just know that Jovians got them terrestrials don't