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Current time:0:00Total duration:10:50

Video transcript

where we left off in the last video we were just kind of staring amazed at this Earth's view of the Milky Way galaxy just making sure we understood how enormous and how many stars we were looking at and even this even if each of these dots were a star this is a huge amount of stars but a lot of these dots are thousands of stars our thousand stars so this you know our mind was already blown but what we're going to see in this video is that in some ways this is kind of just the beginning and and to something we I'm going to stop doing these these particles of sand and the football field analogy because it's at some point the particles of sand becomes so vast that our our minds can't even grasp it to begin with but let's just start with our Milky Way and we saw in the last video the Milky Way right here we're sitting here about 25,000 light-years from the center it's roughly a hundred thousand light-years in diameter and then let's put it in perspective of its local neighborhood so let's look at the local group and when we talk about local group we're talking about the Local Group of galaxies of galaxies so this right here is the Milky Way's local group that's us right there sitting right over here about 25,000 light-years from the center of the Milky Way you have some of these small and I use the word I use small and quotation marks because these are all so vast entities also unimaginable entities but we have these satellite galaxies around under the gravitational influence some of them of the Milky Way but the nearest large galaxy to us is in dromeda right over here and this distance right over here and now we're going to start talking them in the millions of light-years so this distance right here is 2.5 million 2.5 million light-years it just as a bit of a reference if that's any reference at all 1 light year is roughly is roughly the radius of the Oort cloud and the Oort cloud was or another way to think about it the Oort cloud or one radius of the Oort cloud is about 50 or 60,000 atomic and not atomic astronomical units and that's the distance from the Sun to the earth so you could view this as 2.5 million times 60,000 or so times the distance from the Sun to the earth so this is an unbelievably large distance we're talking about here and that's to get to the next big galaxy over here but even these things are huge things with many I mean just unfathomably many stars but Andromeda in particular you know we said that the Milky Way has 200 to 400 billion stars and dromeda people believe has on the order of 1 trillion 1 trillion stars so even even even I have you know these just start to become numbers it's hard to grasp but we're not going to stop here so in this over here this this whole diagram right here it's about 4 light years across if you go from point to point if you go from one side to the other side this is about not not for light you're sorry this is 4 million light years 4 million 4 million light years 4 light years is just the distance from from us to alpha to the Alpha Centauri so that you know that was nothing that would only take a that would only take a voyage or 180 thousand years to get this is 4 million light years so 4 million times the distance to the nearest star but let's do but even this even this is I mean I'm starting to stumble on my words because there's really no words describe it even this is small on a on an intergalactic scale because when you zoom out more you can see our local group our local group is right over here is right over here and this right over here is the Virgo supercluster and each dot here is at least one galaxy but it might be more than one galaxy and this and more than one galaxies and the diameter here the diameter here is 150 million 150 million 150 million light years light-years so what we saw in the local group in the last diagram the the distance from the Milky Way to n dromeda which was two and a half million light-years which would be just a little dot just like that that would be the distance between the Milky Way and Andromeda and we're looking at the Virgo supercluster that that is 150 million light years but we're not done yet we can zoom out even more we can zoom out even more and over here so you had your Virgo supercluster 150 million light years was that last diagram this diagram right over here I want to keep both of them on the screen if I can this diagram right here 150 million light years across that would fit right about right about here on this diagram so this is all of the super clusters that are near us and once again near has to be used very very very loosely here this distance is about 150 this is about 150 million light years a billion light years a billion light years is two three four five a billion light years is about from here to there so we're starting to talk on fairly massive I guess we've always been talking on a massive scale but now it's you need even more massive scale but we're still not done because this whole diagram now these are you know these dots that you're seeing now I want to make it very clear these aren't stars these aren't even clusters of stars deceive you aren't even clusters of millions or even billions of stars each of these dots are clusters of galaxies each of those galaxies having hundreds of billions to trillions of stars so that we're just on an unbelievably massive scale at this point but we're still not done we're still not done this is roughly about a billion light-years across but right here is actually the best estimate of the visible universe and in future videos we're going to talk a lot more about what the visible universe means so if you were to zoom out enough this entire diagram right here about a billion light years would fit right over would fit right would fit just like that so we're talking about a super a super small a super small amount of of this part right here and this is just the visible universe I want to make it clear this is not the entire universe and we say it's the visible universe because think about what's happening when we think about a point out here and we're observing it and that's let's say 13 billion light years away let's say that point 13 billion we're going to talk more about in future videos 13 billion 13 billion light-years light-years and I feel almost it's almost a sacrilege to be riding on this because this complexity that we're seeing here is just mind-boggling but this 13 billion light year away object what we're observing where the light is just getting to us this light left some point 13 billion light years ago so we're actually doing is observing that object close to the beginning of the actual universe and the reason why it's the visible universe is there might have been something a little bit further out maybe it's light hasn't reached us yet or maybe the universe itself will talk more about this it's expanding so fast that the light will never ever reach us so there's it's actually a huge question mark it's actually a huge question mark on how big the actual universe is and then some people might say well does it even matter because this by itself is a huge is a huge distance and I want to make it clear you might say okay if this if this light over here this is coming from thirteen billion light-years away or if this is thirteen billion light-years away then you could say hey so everything that we can observe or that we can even observe the past of it the radius is about 26 billion light years but even there we have to be careful because remember the universe is expanding when this light was emitted and I'll do a whole video on this because the geometry of it is kind of hard to visualize when this light was emitted where we are in the Virgo supercluster inside of the Milky Way galaxy where we are was much closer to that point it was on the order of it was on the order of and I want to make sure I get this right 36 million light years so we were we were super close by you know I guess astronomical scales we were super close only 36 million light years to this object when that light was released but that light was coming towards and the whole time the universe expanding so we were also moving away from it if you just think about the all of the spaces everything is expanding away from each other and only 13 billion years later did it finally catch up with us but the whole time that that was happening this object has also been moving this object has also been moving away from us and so our best estimate of where this object is now base on how space is expanding is on the order of 40 or 45 billion light-years away we're just observing where that light was emitted 13 billion years ago and I want to be very clear what we are observing this light is coming from something very very very primitive that object that object that or that that area of space that were that light was emitted from has now condensed and into into way more I guess mature astronomical structures if you take it from the other point of view people sitting we're in this point of space now and they've now moved 46 billion light years out when they observe our region of space they're not going to see us they're not going to see earth as it is now they're going to see the the region of space where earth is in a super primitive stage shortly after the Big Bang when I use words like shortly I use that also loosely we're still talking about hundreds of thousands or even millions of years so we'll talk more about that in a future video but but the whole point of this video is you know I almost it's beyond my numbing you know I would say the last video about the Milky Way that alone was mind-numbing but now we're in a reality where just the Milky Way becomes something that almost unbelievably insignificant when you think about this picture right here and the really mind-numbing thing is if someone told me that this is the entire universe this this by itself would would would certainly put things in perspective but it's unknown what's beyond it there are some estimates that this might be only be 1 times 10 to the 23rd of the entire universe and we could even we'll talk there it might even be reality that the entire universe is smaller than this and that's an interesting thing to think about but I'll leave you there because I think no matter how you think about it's just it's just uh I don't know actually before doing this video I stared at some of these photos for like half an hour this is my least productive day just because it's just so inspiring to think about what these dots and dots of the dots really are