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it was our original question our original question was what is the universe expanding into so what does expanding mean to you let's walk um here we are in our universe we look out we see everything moving away from us that could either mean that things are actually moving away from us or it could mean that the universe is expanding does the difference make sense oh not officially so you look up into the sky and you see galaxies moving away from us in every single direction and you could either think like things are just moving away from us but then you notice something a little bit weird which is that so have you ever heard of the description of like a loaf of raisin bread in the oven yes did i tell you about that or did you usually read about
that damn it i've told you too much you've got a loaf of bread in the oven as it's baking it expands it rises and so if you've got raisins in the bread then they move apart because they're moving with the expanding dough but if they were moving through the dough like if the dough stayed the same size and they were moving through the dough it would be weird but you would imagine like here's us in the center and raisins are just moving away from us in your bread that sounds ridiculous for bread but with the universe it sounds more reasonable for things to move away from us than it does for the entire universe to be expanding and space to be stretching that sounds crazy
but when you look at the evidence and you see all the objects that are a billion light years away they are all moving away from us at the same speed and then you look at the objects that are two billion light years away and they're all moving away from us at the same speed but faster than all the ones at one billion light years and then three billion milliliters all the same speed but faster than the inner layers and that pattern is exactly what you would see if the universe would were expanding because if you stretch that loaf of bread then the raisin right next to you is just going to move a little bit away from you but a raisin across the loaf is going to expand really far away from where you are so
the further away you are from something the faster it moves away from you and once you discover the expansion of space you discover a whole well it brings up so many more questions and you discover a whole lot more things what is it expanding into this is the whole question of the video what would you guess yeah what would you guys how would you answer that question i don't think i have an answer it's expanding into the concept of nothing and making it something i actually really like that answer so there are a couple ways of thinking about it if the universe is infinite if there's just endless universe out into the vastness of the forever then it always was infinite and it always will be infinite which is why this idea of like things expanding from
a single point is wrong so let's rewind back and let's talk about yeah let's talk about the history i think it's actually really interesting how the expansion of the universe was first discovered in 19 do you have any ideas actually i would just guess that we saw in telescopes like the further away something was the faster it was moving that's totally it along the way there were all of these mind-blowing discoveries so the first thing that happened was that in 1912 there was an astronomer named vesto slifer probably butchered it but anyway vesta's life looked out into the sky and he saw what he called a spiral nebula moving away from us interestingly he saw this on something he called a spiral nebula
nebulous are these clouds of dust and gas from an exploding star and as far as i know there are no spiral shaped nebulas at this time in 1912 they didn't even know that there were other galaxies yet all we knew was the milky way and then some of these random nebulas outside of it we had no idea we didn't even know there was a universe yet at this point because we didn't know that there were other galaxies outside of our galaxy it's a decade between that and the next step so then there was an astronomer named alexander friedman who looked at einstein's equations of general relativity which are basically these equations that describe space and time and how space works and so he looked at those
and he thought the universe should be gravitational and stable if it's static because up until that point we just thought like okay here's the universe there it is he looked at that and he was like everything would maybe collapse back together and then he looked at einstein's equations and he figured out that you could have a universe where space itself is not the static thing it can stretch and warp and curve and then you could have a universe which started much closer together and over time expand but we didn't have any evidence for it yet so then 1927 another astronomer named george lamata lamotra fancy name he's a carrot in one of the letters he came up with a relationship for what the speed of a galaxy moving
away should be related to the distance away velocity equals some constant times the distance that indicates the further away you are the higher the velocity should be so he imagined a beginning of the universe that started a lot more dense densely packed and then blew outwards and expanded and that was kind of the origin of the big bang but it was also the origin of the idea of the big bang singularity that's why people are always asking where did the big bang happen have you ever wondered that yeah really yeah before we get into where the big bang happened i want to share a fun activity from the sponsor of this video varsity tutors if you're looking for more interactive experiences in the world of
stem for you if you are a kid or for your kids if you have kids then check out the curious world stem club if you join this after school club then you get access to special bonus learning content from me and other stem experts for you and a group of six to nine fellow explorers the club meets weekly for a range of topics that change every single month and the link is in the description to this video to sign up to my club page and if you do become a member of the curious world stem club then you get your first month 50 off thank you to varsity tutors for making after school clubs for kids and for sponsoring and supporting this video and now back to the idea that the universe started in one tiny dense point the initial
singularity i think they call it which is when everything in the early universe would have been just like all compacted into a singular point where the laws of physics break down infinite mass into this single point are you aware that's an outdated idea um the initial singularity not until recently when you told me but i thought that's just what the big bang was i thought the whole universe started at a single point yeah a lot of people do i it's actually crazy that's one of the misconceptions about the universe that really sticks because what we understand now is more of this concept of a rapid expansion of space that the universe all started very small but not in a single point what really happened yeah is that the
big bang happened everywhere and it wasn't a bang it was really much more of a an expansion the big expansion everything was closer together but it was like an infinitely closer together and it just expanded everywhere so hard to conceive of so back into history so um with this idea of like the big bang happening or the expanding universe happening and then two years later 1929 hubble observed that evidence he found galaxies well he thought at this at the time that they were nebula extra galactic nebula um but they were other galaxies so he saw those moving away and the further away they were the faster they were moving away so he saw the evidence but in this case it was kind of a theory
that seemed far-fetched at the time in fact the matchup had a paper he put out with some paragraphs that would probably have given him more credit for the discovery of the expansion of the universe eventually hubble was credited for that it was recently discovered that some paragraphs were taken out of his paper and that led to him getting less credit for this discovery and so there's like a recent investigation into who took out the paragraphs and some people thought oh maybe it was hubble or hubble's people because they wanted him to have credit but it turns out it was la mata himself that took the paragraphs out who knows why like we'll never know but probably because the ideas were so far-fetched at that time
that he didn't want he was like oh this seems crazy like he didn't want to leave it in but it turns out he was right yeah so hubble came along 1919-29 we got evidence for the expanding universe it's pretty amazing so space-time is not stagnant it's this ever-changing dynamic fabric and it stretches and expands and because that can happen new space is being created between galaxies all the time so the 100 billion galaxies or more in our universe galaxies are moving away from each other and galaxies are moving outside of our observable universe and galaxies are moving away from us faster than the speed of light it's incredible it was our original question our original question was what is the universe expanding into
so if the universe is infinite it's basically just expanding into itself you'd expand infinity and it's still infinity and it came from infinity and it always was and always will be infinity that's it conceptually impossible to wrap your head around and if it's not infinite then we have no idea what it's expanding into yeah maybe expanding into nothing if it's the universe expanding into nothing then there's nothing outside of it because the universe is defined as everything that we know so yeah that was a pretty good answer maybe there's another universe is expanding into maybe it's like actually a bubble in a finite universe and our bubbles expanding and the rest of the universe is not expanding maybe a bigger universe is
contracting while our bubble is expanding into maybe there are higher dimensions that the our universe with its dimensions are expanding into maybe there are multiple universes but all of these ideas are things that we'll never know and we'll ever be able to observe because there are things just outside of our universe even dimensions outside of our universe we'll never be able to observe them it like makes us wonder what's beyond our observable universe are there any questions that you have you're just blown like my mind's just so blown right now more questions than before diana excellent
you
