


Main content
Current time:0:00Total duration:12:55

Video transcript

in the last video I hinted that things were about to get wacky and they are so if we start where we left off in the last video we started right over here looking at the distance tool to the nearest star and just as a reminder in this drawing right here this depiction right here this circle right here this solar system circle it's not the size of the Sun it's not the size of the orbits of the earth or Pluto or the creeper belt this is close to the size of the Oort cloud and the actual orbit of Earth is about one well the diameter of the orbit of Earth is about 150 thousandth of this so you wouldn't even see it on this it would not even make up a pixel on this screen right here much less much less the actual size of the Sun or something much smaller and that and just to remember that orbit of the earth that was at that huge distance it takes 8 minutes to get from for light to get from the Sun to there this super long distance if you shot a bullet at the Sun from Earth it would take you that 17 years to actually get to the Sun so once again this huge distance wouldn't even show up on this picture now what we saw in the last video is if you travel it unimaginably fast speeds if you travel at 60,000 60,000 kilometers per hour and I picked that speed because that's how fast Voyager 1 actually is traveling that's one of the I think the fastest object we have out there in space right here and it's actually kind of leaving the solar system as we speak but even if you were able to get that fast it would still take it would still take eighty thousand years 75 or 80 thousand years to travel the 4.2 light years to the Alpha Centauri cluster of stars to the nearest star it would take 80 thousand years 80 thousand years and that scale of time is already amount of time that I have trouble comprehending you can imagine all of modern civilization has occurred in well definitely in the last 10,000 years but most of recorded history is in the last four or five thousand years so this is 80,000 years to travel to the nearest star so it's a huge distance another way to think about it is if if the Sun if the Sun were the size of a basketball and you put that basketball in London if you wanted to do it in scale the next closest star which is actually a smaller basketball right over here Proxima Centauri that's smaller basketball you would have to put in Kiev Ukraine Kiev Ukraine in order to have a similar scale so these are basketballs sitting in these cities and you would have to travel about 1,200 miles to place the next basketball and these basketballs are representing these super huge things that we saw in the first video the Sun if you actually made the earth relative to these basketballs these would be little grains of sand so if there are any little small planets near over here you they would have to be grains of sand in Kiev Ukraine versus the grain of sand in London so this is a massive massive distance already at least in my mind unimaginable and when it gets really Rocky is when you start realizing that this even this is a super super small distance relative to the Galactic scale so this whole depiction of kind of our neighborhood of stars this thing over here and this thing over here is about this thing over here is about give or take and we're doing rough estimates right here so it's about 30 light years 30 30 light years I'll just do ly for short so that's about 30 light years now and once again you cannot actually you can you can take pictures of our galaxy from our point of view but you actually can't take a picture of the whole galaxy from above it so these are going to be artist depictions but if this is 30 light years this drawing right here of kind of our local neighborhood of the galaxy this right here is roughly these are all approximate approximations this is about let me do this in a darker color this is about 1000 1000 light years and this is the thousand light years of our Suns neighborhood if you can even call it a neighborhood anymore even this isn't really a neighborhood if it takes you eighty thousand years to get to your nearest neighbor but this whole drawing over here it would take forever to get anywhere over here it would be one thirtieth of this so it would be about about that big this whole drawing and what's really going to blow your mind is this would be roughly a little bit more than a pixel on this drawing right here that spans a thousand light years but then when you start to really put into perspective so now let's zoom out a little bit so this drawing right here this thousand light years is now this thousand light years over here so this is our the local vicinity of the Sun and I you know once again the word local is used in very in a very liberal way at this point so this right here is a thousand light years a thousand light years if you're sitting here if you're sitting here and you're looking at an object that's sitting let me do this in a darker color if we're sitting here on earth and we're looking at an object out here that's five hundred light years away we're looking at it as it was five hundred years ago because the light that is reaching our eyeballs right now or our or our telescopes right now left this guy over here five hundred years ago I'm sorry right five hundred years ago in fact he's not going to even be there anymore he was probably has moved around a little bit so just even on this scale we're already talked about these unimaginably huge distances and then when we zoom out this is kind of our local part of the galaxy right over here this piece right here this is called or the Orion spur and people are still trying to work out exactly what the actual the details of the actual shape of the Milky Way galaxy the galaxy that we're in but but we're pretty sure you know we actually we're very sure we have these spiral arms and we have these Spurs off of them but it's actually very hard to come up with the actual shape especially because you can't see a lot of the galaxy because it's kind of on the other side on the other side of the center but really just to get a sense of something that at least I mean it blows my mind if you really think about what it's saying this these unbelievable distances show up as a little dot here this whole drawing shows up as a dot here now when we zoom out over here that dot would no longer even show up it wouldn't even register a pixel on this drawing right over here and then this whole drawing this whole thing right over here this whole picture is is this grid is this grid right over here it is this right over here so hopefully that gives you a sense of how small how small even our local neighborhood is relative to the galaxy as a whole and the galaxy as a whole just to give you a sense has 200 200 to 400 billion billion stars billion stars or maybe I should say solar systems just to give you a sense that you know we saw the social it's not just the Sun there's all this neat dynamic stuff and their planets and asteroids and-and-and solar winds and so there's there's 200 to 400 billion stars and for the most part 200 and 400 billion solar systems so it's an unimaginably uh I guess a complex or or huge place and just to you know make it clear you know even when we zoom in to this picture right here and I think it was obvious based on telling you about this that these little you know white pockets right here these aren't this isn't one star this isn't two sorry these are thousands of stars here so when you go over here each little blotch of white that you see that's not a star that's not a thousand stars we're trying to talk in the millions of stars when you look at certain blotches here and there I mean maybe it might be one star that's closer to you or it might be a million stars that are far apart and that are just relatively close together and everything has to be used in kind of loose terms here and we'll talk more about other galaxies but even this isn't the upper bound of galaxies people believe the andromeda galaxy has a trillion stars and it truly in solar systems we're talking about this huge huge immense distances and so just to give you a sense of where we fit in the picture this is the rough location of our Sun and remember that little dot I drew just now is including millions of stars millions of solar system's already unimaginable distances but if you really want to get the sense relative to the whole the whole galaxy this will this is an artist's depiction once again we could never obviously get this perspective on the galaxy would take us forever to travel this far so that you could see the galaxies from above but this is our best guess looking at things from our vantage point we actually could never even see we actually can't even see this whole area over here because it's on the other side of the center of the galaxy which is super super dense and super bright and so it's very hard to see things on the other side we think actually we there's a supermassive black hole at the center of the galaxy and we think that they're at the center of all or most galaxies but you know the whole point of this video actually this whole series of videos this is just kind of I don't know but MIT put you in all a little bit of just how huge this is cuz when you really think about the scales it's it's I don't know I know no words can really describe it but just to give you a sense we're about twenty five thousand we're about twenty five thousand light-years let me twenty five thousand light-years from the center of the galaxy so whenever even when we look at things in the center of the galaxy that's as they were twenty-five thousand years ago it took twenty five thousand years for that light to get to us I mean you know when that light left the center of the galaxy I don't even I won't even guess to think what what what what what what humanity was like at that point in time so it's it's these huge distances and the whole galaxy over here and once again like solar systems it's hard to it's hard to say the edge of the galaxy because there's always going to be a few more stars and other things orbiting around the galaxy as you go further and further out but it gets less dense with stars but the main density the main disk is about a hundred thousand light years 100,000 light years is the diameter roughly of the of the main part of the galaxy and it's about a thousand light years thick so you kind of imagine it as this disk this thing that's fairly flat but it's a thousand light years thick it's a thousand light years thick you would have to do you would have to do you would have to do this distance you would have to do this distance 250 times just to go from the the top part of the galaxy to the bottom part much less going across the galaxy so it's it's it might seem relatively flat so but it still immensely immensely thick and this is another way to visualize it if this thing right over here that includes the Oort cloud roughly roughly a Lightyear in diameter roughly a Lightyear in diameter is a grain of sand a millimeter millimeter in diameter grain of sand then the universe as a whole is going to be the diameter of a football field and if that you know that might say okay those are two tractable things I can imagine a grain of sand a millimeter a wide grain of sand in a football field but remember remember that grain of sand that grain of sand is still is still 50 or 60 thousand times the diameter of Earth's orbit and Earth's orbit it would still take a bullet or something traveling as fast as a jet plane 15 hours to just go half of that or a second acted 15 years or 17 years I forgot the exact number but you know 15 16 17 years to even cover half of that distance 30 years to cover an entire diameter of or so 30 years just to cover the diameter of Earth's orbit that's 160 thousand of our little grain of sand in the football field and just to kind of really I don't know I have an appreciation for for how how am i a mind blowing this really is this is actually a picture of the Milky Way galaxy our galaxy from our vantage point as you can see we're in the galaxy so we're seeing and this is looking towards the center and even this picture you start to appreciate the complexity of what a hundred billion stars are but but what I really want to point out is even in this picture when you're looking at these things some of these things that look like stars those aren't stars those are thousands of stars or millions of stars maybe it could be one star closer up but when we're starting to approach the center of the galaxy these are thousands and thousands and millions of stars or solar systems that we're actually looking at so it's really it starts to boggle the mind to imagine what might actually be going on over there