StarTalk Podcast: Cosmic Queries – Edge of the Universe with Neil deGrasse Tyson and Janna Levin

hello youtuber verse Startalk coming up next cosmic queries the edge of the known universe this is Startalk I'm your host Neil deGrasse Tyson your personal astrophysicist today we're doing cosmic queries topic the edge of space-time the edge of the universe Chuck hey now you're gonna join me there I am but we can't do it alone that shirt you know you know whether you're watching or listening that I wear cosmically colorful clothes yes but my shirt I'm wearing today is particularly cosmically colorful yes it's in your face its smackdown it's it's well we're gonna have to yeah you're gonna have to go to youtube we'll take a picture of it and you have to see this shirt you have to yeah seriously it's pretty lovely celestial bodies getting on there we have Jan 11 2014 10 so what do you have so we got cosmic queries as well as we glean from all over the Internet and of course we always start with the patreon patron because I'm just a quick check you did so your book black hole blues yeah it says every time you walk past it on the Shelf all you just heard so that was about the discovery of gravitational waves yes moving through the universe yeah exactly so right right before that succeeded in the fifty years it took this well we successfully measured it yeah ray Weiss was mighty original architects just was shaking his head and saying you know we don't detect black holes this thing as a failure so like the whole title was kind of like it's the black hole blue Nobel Prize jig he said all the way to the bank on that one yeah yes thank you for that let's start off our though with a patreon patron uh this is Chris Hampton who supports us on patreon who wants to know this could it be that the universe that we are in is actually finite however the universal structure is infinite via size and relatively meaning the universal structure gets infinitely smaller and vice-versa kind of like infinitely dividing in half I imagine it would look something like a very complex fractal question for Chris first is it sativa ended which is the one that he would have fallen asleep before making it to the end of the tweet [Applause] when I actually use that it was called we didn't put any other name like if you would easy to pronounce and remember that was it right if you went to your dealer and you win some a sativa anyway so you want to take a shot at this okay so my first book is about whether or not the universe is infinite or finite it's a question we don't know the answer yet how the universe got its spots I remember that yeah Hell universe card spots is about could we tell the shape and size of the universe by looking in the hot and cold spots in the Big Bang and then light left over from the Big Bang but but the question let's just take it really theoretically we absolutely do not know that the universe is infinite and it may well be that it's finite the way the earth is finite that you know we leave New York City we travel in a straight line is maybe we'd have to swim a little get on a boat but you traveled a straight line you're gonna come back to New York City again and so it could be that when you can travel forever I was gonna say it's infinite in what you can try and where you can travel infinite in you know you don't get to an edge right never get to an edge which is beautiful so exactly the same thing with the universe you're not gonna sail off the edge of the earth right look you know Spanish explorers waved goodbye and wondered if they'd just go off the side but no we know that's not what happens it's so similarly we could leave the Milky Way galaxy we could watch it recede behind us we could travel in a straight a line as possible and find ourselves coming back to the Milky Way again you know and it's it's so planet of the apes right it's like through my interpretation of that was that they went all the way around and so the interesting thing is that also means that if you look at distant galaxies the light is also traveling all the way around the universe so it could be at some of those distant galaxies are the Milky Way and we're seeing the light from the Milky Way wrap all the way around and come back to us we'd be seeing the Milky Way in the past so we it would be hard to know like maybe we'd see an active black hole quasar with jets flying out in the early phases of the Milky Way and we think oh that's just a different galaxy Wow yeah so we've galaxies the the young galaxies look very different from mature galaxies right and we used to think that there were different kinds of objects in the outer universe like boys ours why they all distant how comes not a quasar right next door with these monstrous nuclear emissions and we had to like figure out that it's it's likely just younger galaxies and maybe we'd used to look like a quasar and we don't anymore right so even a distant galaxy looking back at us is seeing us in the past given the light travel time so we could still look like a quasar to a distant galaxy like we're I have this huge active galactic well and then it gets more because there are reasons that people start to suspect that there are extra spatial dimensions and that they are not only finite but really technically really small like that journey to go all the way around them is something that would would happen incredibly quickly and it's too small for us to like literally stick our hands in that direction in some sense so we're looking everywhere those extra dimensions are everywhere but we can't actually notice them and so a dimension to be smaller than another dimension but yeah I mean so think of like a straw is a good example where it's a two-dimensional surface drawers were made of I'm gonna go with flax it's cuz flaxen hair oh yeah that's connection between flex and strata there there so so a straw is small in one direction on the surface right if you you think there's a direction in which it's totally wrapped up and small and then there's a long direction so straws are mostly long they're mostly long and you could glue the top and at the bottom of a straw to make that long direction also finite so then you travel around the one it could be really big you know mile around but still be connected but it's only a few millimeters around in this direction in this other dimension so literally the length of traveling before you come back to where you started it's small so most of how you use a straw does not access that other dimension usually the length you're trying to get the liquid from here to here yeah of yours you using the long dimension yeah we done the question we start to ask is what if the universe is a kind of space-time origami when it's created in the Big Bang that all the dimensions are wrapped up and maybe in very complicated ways like the dimension of the straw being wrapped up but one dimension just gets very very big or in our case three can be very very big we have three big dimensions we have time which is a fourth so we you know there's up-down north-south-east-west that's it you specify those things and you definitely know where you are in space you specify time and we can actually meet right here we are but those extra directions just maybe didn't ever expand and so one of the things even then I'll work on and string theorists will work on people is why would only three dimensions get large if those other dimensions exist interesting mm-hmm so it could be that will understand the large connectedness finite nature space by looking in like really high energy accelerator experiments because people have asked at the Large Hadron Collider could you perceive these extra dimensions if they exist okay weeks worth of that is a big step as a fascinating stuff just fascinating an extra okay so let's let's move on to Paul love who says given that because you can pronounce his name let me tell you something as a matter of fact I think I'm just gonna call everybody Paul love Paul says this given that our universe expanded from a single point and is expanding in all directions how does that not define the shape of the universe as spherical how could something flat or saddle shape come out of that well it is true if there is an explosion in space it tends to have a kind of spherical cloud leftover is debris so when a star explodes we will see alpha nebula and they they're like sphere often spherical fish a beautiful very beautiful and you know sometimes they plow into stuff and it changes shape but basically yeah then you can point inside this debris point to where the center of the explosion was so that's not how it works for the big thing so for the Big Bang you cannot imagine that the space exists first and that you're exploding into the space right actually a creation of the space itself right so everywhere right in the universe was once at the center of the explosion exactly there is no plowing out it's as though and you can think of it any shape you want make some crazy you know people like the balloon analogy so now make some crazy balloon twist it up crazy thing and poodle a poodle and the whole thing stretches and the whole thing was once a point so every single point on that surface that fabric if you want to call yeah we are as is every other point in space can I say that different will you allow me to save different can I say there is a center the only way you can access it is to go back in time to the beginning of time well you could say okay the center of all of this only at one coordinate systems at T equals zero I would say that's their if time line is just always there there's the center yeah if we're gonna be really you know split space up in very fine-grain terms this point was at the center back at T equals zero and this point was at the center back at T equals zero they just rolled right so the whole it's just the collapse of those points at TI zero yeah gotcha yeah but I like what you said though which i think is what people have to really think yes the space itself was created the second not second look the millisecond microsecond whatever nano seconds afterwards that's that space was created then along with everything else I think that's like 10 to the minus 43 seconds you know right then so that I mean that if you think of it that way because what what you're thinking about is these distances between these stuff that we see yeah and we think they're empty but they came from actual steam effects Wow go ahead here's where people get tripped up with the balloon analogy because it's flawed as are all analogies is that a lot of people immediately want to point to the center of the balloon the empty space inside but you got to give up on that all that exists is the skin of the balloon all that exists okay with the center of the balloon because that's where the balloon was at T equals zero right so you could think of it good I can only consider the center of the balloon as snapshots like movie frames so it once was there and then it was a movie frame over here that same balloon is still now at the outer reaches at that balloon because it came from the center of the balloon Oh imagine you painted dots all over the little infinitesimally small balloon but if they were glued to do no there's stains on the skin the balloon there dots themselves don't move and then you push all that down so all the dots are together and then you pull them apart in some sense those are the galaxies that came later the galaxies aren't moving right just stayed on the balloon doesn't move it's the the skin the stretching between those spots so in fact nothing piles up the way it does when a supernova explodes everything actually just gets more and more diffuse as a universe expands wildman all right that was that was great thanks Paul all right here we go let's go - Brendan Rico suave you just girl with me Brendan okay Brendan wants to know this I've recently heard of a new study that states the universe is thought to be in the shape of a loop whereas previously it was thought to be flat but in the explanation given the nature of the loop shade states that it travels far enough in one direction that you'll end up back where you started which is what we talked about earlier my question is wouldn't this happen regardless of actual shapes of the universe so this point is like no matter what shape and if would that happen yeah and I think that you can say I think that we have to take a break when we come back Janna Levin is gonna tell us do we live in a loop universe or not on Startalk we're back cosmic queries start off Chuck nice mykos thank you all right Jenna left friend colleague up it Barnard in Columbia doing that physics thing it's got to do it blow people's cosmological mind so so tell us as the question had asked do would the universe loop back on itself no matter its shape so not necessarily you know what shape the universe is in the first place yeah it's really we don't ultimately know the shape we know that we can see the distance light has been able to travel since the Big Bang because we can't see anything faster than the limit of this beautiful light travel time and and we know that the universe is expanding so that's actually 92 billion light years across about that week and that's what we call the observable universe now it's possible that it's not 92 billion light-years across that even within that range that the universe has folded back onto itself in some way and we're actually seeing repeats of things we're starting to see it's kind of like a Hall of Mirrors thing we're starting to see the light multiple times how would you know yeah I was is very very hard to figure out so there have been extremely clever ideas and most of them would look out and I see Chuck waving at me it's true we're looking at ourselves in the past which is very hard to distinguish if for instance if we're looking at galaxies that's very hard to do but there are patterns and the hot and cold spots left over from the Big Bang if it fits into a specific shape so imagine something just totally platonically beautiful and crazy that the universe is like a dodecahedron all of whose faces are glued together so it's a crazy origami that thing is I mean there has so many loops and yeah that is triangles right and that is conceivable kind of what we call topology or connectedness of the space there it would actually start to imprint that the the patterns of the dodecahedron in the light left over from the Big Bang so if you imagine there's tiny little hot and cold spots that you would start to see in the distribution of the hot and cold spots that she's that shape would be reflected in a very subtle way really yes the reason the udemy reflected literally you mean manifest manifested so so how the leopard got its spots is actually a very similar mathematical problem because you're asking about enzymes being higher low in the developing embryo and it turns out that the shape and the size of the animal and like whether it's tubular or when no spots or hitting it that it will determine what kind of spots the animal gets its actual leopard in an actual effort zebra stripes like these things are things you can predict by solving for the mathematics of of things that are above a certain threshold or below a certain threshold that that pattern of stripes or spots will reflect the geometry and black panther's of leopard you knew that yes I did know that black heather has spots now that is this game it's has spots when it's kids you look very carefully you can see the spots right Wow amazing well so so how the universe got it spots as a similar mathematical problem we're solving for hot and cold spots in a particular geometry when the universe was like a developing embryo basically and this goes back to Alan Turing who solved some of these problems for the animal but like a black panther does the universe care about injustice [Laughter] or does the universe have vibranium you know we can hope that we're the bad example and then elsewhere in the universe there are better examples nice well well said well said i Chuck what else yeah all right here we go this is Tim braid who wants to know this a very recent study in the Astrophysical Journal found that galaxies may be rotating in sync with other galaxies millions of light years away galaxies separated by six mega parsecs were found directly interacting with each other what is your opinion on this first of all is that empirical the the fact that these galaxies were actually interacting with one another I think that that study is probably still controversial and probably still requires these things can happen but it just sounds not that likely so there will be a lot of people doing observations from different wave bands with different perspectives to try to break any possibility that it's a quirk of this particular yeah observation but six megaparsecs you know that's pretty far away yes and and so you would think that you would be dominated there by the expansion of the universe and not interactions we definitely interact with other galaxies that's not a big surprise yeah Andromeda Sanjana that's a happy future like imagine when a German it gets much closer how cool the night sky is gonna be it won't be as cool as you say at the end of your answer is it coming in edge-on no it's a disturbing reason why it's not gonna be cool well now you just I'm sorry because I'm yeah but all over the place but I gotta get this in before we move on yeah so speaking of edge-on so if you're looking at something agile and how do we flip it to get the imagery to know that we were looking at the disc from the edge so we do that with our own Milky Way we're in the Milky Way so we're seeing the rest of the galaxy edge on right we've never seen the Milky Way as human beings from above but we have these beautiful constructions because we just map things as accurately as we understand where they are also in space okay so we just we build an atlas of it basically you killed them you build a numerical model based on all of your observations of the Milky Way the gas the dust the stars everything where the spirals are where the gaps are and then you just allow yourself to move in that digital world and look down from above but it's an experiment of making once you have a map you go anywhere you want three-dimensional map you go anywhere yeah plus we see all the gas and we're quite a flattened in the sky and there are other galaxies out there that are flattened and we can see them at all not one galaxy of different angles but a million galaxies all scattered in random angles so it's pretty easy to figure out what we look like we look like until we collide with Andromeda but one of the things I took solace in but I feel like Neil's about sorry but the whole solar system supposed to stay together right and get knocked around we should stay together so we might end up in Andromeda before we fully acquired like they could pass each other they could collide move through each other and we could end up in Andromeda looking at the Milky Way we're gonna leave a forwarding address so what will happen is there'll be a lot of sort of dissipated energy and the system will of course pass through each other and back and forth we've done this on a computer and it's like a rubber band kind of thing and it kind of dies down and it settles into one double large massive system okay so what's a bad news okay so that sounds like good news yeah so if Andromeda were a hundred times closer it wouldn't be any brighter on the sky hmm interesting yeah okay I'm Lively okay yeah tell me what it's not obvious okay okay okay all right so Andromeda has a certain size on the sky correct okay it has a certain extent mm-hmm and on a very dark night mm-hmm not in the city but where this moon is not out you can see this fuzzy thing in the sky so that's in the Andromeda galaxy it's two million light years away all right there's a certain amount of light coming from Andromeda in that patch on the sky right so we we reference it's something called a surface brightness it is how bright is Andromeda over that patch of sky over that surface patch on the sky surface brightness okay if we bring it half as far away okay they make it only half as far it is how many times brighter it's got like the square square but then the enemies four times brighter by a factor of four yeah so so so the whole system is getting brighter but the surface area is remaining the same so it is not going to be more apparent to you in the night sky that our own Milky Way is on our own night sky I'm very sad to report that no it'll just still be fuzzy can I see it gotta get out of the city moon now I see the colliding galaxies no sorry I'm very sorry about this that's right I'm you know it'll just look like our own Milky Way galaxy drummer right here next to it just look like our Milky Way yeah it's guy I cannot see from you but you can see with one of those apps like you can just and it could be like down there and it'll show you like a Andromeda on its way and you pump up the count the day the intensity needs eyes we're practically blind this is the moon bottom for astronomy yeah she is so right on this Chuck yeah Chuck we call glasses as the as the centuries went on we discovered how blind we actually were yeah that's amazing yeah all right there we go okay let's move on to David oh by the way those Hubble photos yes if you go to those objects you don't see what the Hubble saw because the Hubble sees better than you do a lot I mean if your eyeballs were like like god Dan target you would then it'll look like what the Hubble seen right all right cool all right this is David Eduardo Morales Martinez who wants good there yeah well not bad you know my wife is Puerto Rican here again Joe David or what would be David Eduardo Perales Martinez Martinez yes who says this why is it so hard to prove the existence of other dimensions thank you David from Mexico oh yeah Mexico asked that a slightly different way yeah if there was another dimension as big as the three that were in would completely manifest to us probably there's a hitch so you would think yes as long as that dimension was very large then we would be talking about a world in which this did not confine us right so let's say I have skin which seems to separate my inside of my outside but right inside you if right if there was another dimension you could do like one of those Spooky's surgeries without your puncturing any skin you could just like go in there and touch people's organs like this would not be a separation of inside and outside analogy to that is if you're only live in two dimensions then you only have sort of heightened with heightened you have height and width but not depth so if you don't have depth when I if I look at you in two dimensions I can see all your organs for you whatever you can't see because you're in the end all you see is the outer skin which is it's a line which is just a line yeah and now our outer skin is a surface right right so which is why you know you can't actually probably have a very effective organism in just two dimensions because let's say they had a mouth and a tube going all the way through them it would actually cut the two sides in half yeah so you can't have what we consider be normal metabolic functions of okay anything else you don't have you don't have porosity in two dimensions yeah they tell me yes oh so if you drop water on soil and then it just soaks in right or you drop it on a sponge and it soaks in okay in two dimensions there's no such thing as there's no silky there's no snow soaking in right so you just have a bulb of water elbow of water correcting on top of porosity enables you have to let's say two rocks or touching here mm-hmm but then the water can just go around another side of the rock right but in two dimensions where they touch there is no way past it right just stay above it is that where you're able to smell what The Rock is cooking okay some people argue that the reason why the universe is three-dimensional is because the universe tries to be many different ways there may have been an infinite number of big bangs in the past in the future can really talk about it in temporal relative nough stood amenity large universe with all the rest rolled up and small you couldn't have organisms in that universe to ask the questions Wow you'd need at least three and then let's say you had four spatial dimensions then you have the problem of things drift away from each other in such a way that it's hard to have organized systems so just like Neil is describing a two-dimensional creature isn't aware of the third dimension but if they became aware they could just kind of float away from their city right it becomes you have more volume of space to fill mm-hmm the cross-section for interaction goes down so now if you add another dimension the cross-section for interaction goes down again no but we successfully exists in three dimensions in spite of the challenges the two-dimensional creature would face upon accessing a third dimension right so why maybe three optimal why don't four dimensional creatures pity us Yeah right well that's that I mean that is a good question could the complexity like I'm just I'm not saying they're true arguments but some people argue that you couldn't in the four dimensions get the successful complexity and some of those arguments are they get you know complicated based on string theory cross sections and annihilations into photons and what's left over after all of these things in the Big Bang it turns out that Tony only a tiny tiny bit of stable matter is left over already in three dimensions what could be wait a minute let me kind of agree with what you just said even though I just agreed yeah what you're saying is in three dimensions it could be optimal for particles to get together and make molecules and molecules to make macroscopic objects if you add a fourth dimension you're adding a degree of freedom of where things can hang out and possibly never then find each other yeah wait if you think about the volume of the universe is going up radically with the volume of dimensions yes then you're diluting everything and the inspiration of what could be so the fact that you're even asking that question means you are a being in an optimized universe to even pose the question in the first place so the two-dimensional people couldn't ask this question right because they couldn't be 2-dimensional people because the structures are too simple to allow and four dimensional people there's too much play space so let's take it let's take you your first question was would we know it if the other dimensions were large here's the hitch you would think we would but here's a hitch even if all of those problems were solvable there is an argument that we could be glued to a kind of a membrane which is a three dimensional surface floating in this higher dimensional space it's the way the fundamental forces work between the keepers they keep us on the membrane and the only thing that happily goes off the membrane is is gravity itself so that all other forces are glued to this membrane that's where they live so that you would think like a particle to you interacting with that membrane could be a string in the higher dimensional space passing through your space as a particle manifesting as a particle so I can Majan cutting a string you would it would look to you like a dot right an infinitely thin string so I'll think about in two dimensions I think of passing a a hollow sphere through two dimensions what would that look like to the two-dimensional people they'd see a dot they say well that's cool right oh then it becomes like a circle and it gets bigger and bigger and bigger then it maximizes out at the diameter but they don't know this and then it gets smaller then it gives a point and disappears and they have no idea no in spherical mystical manacles hypotheses come out yes and the scientists to analyze it would you say stuff pops in and out of existence we don't know so what one of the yeah absolutely so one of the things that we've worked on with extra dimensions that make them not just an oddity but maybe something we've already observed one of the things we've worked on on our extra dimension superhero nemesis character in the making my superhero character name is Jan 11 isn't it good and it's a prime number Jan I mean I've got a work that you don't want to be the Nemesis so the interesting thing there that where people have thought about is that maybe something like dark energy is actually a quantum phenomenon trapped in the extra dimensions that we can't perceive the extra dimensions directly but we're indirectly perceiving them through the dark or dark matter is regular matter in the higher dimensions leaking over and - right and which is this membrane we just turn this and it's just mysteriously there yeah we people have definitely one that is the medium is that the gravity is space-time so gravity can't be confined got to otherwise that would be no meaning to the extra dimension stupid [Laughter] take a quick break okay when we come back more with Jan 11 on the edge of the universe and beyond in star talk returns we're back start off cosmic queries the edge of the universe there's only one person in arms reach out there that who could do this generally Janet these are go to the person yes totally do I have actually written papers on extra dimensions it is a genuine direction in my mind in them in my research is to think so what she disappears just be so just like caught up and then like went into the fourth dimension this is yeah Monsters Inc yeah the doors yeah that came out of the factory right this was an uncelebrated fact of that movie these are four dimensional portals that basically wormholes h door this is the door to the kids room and the monster takes it home at the end of the day and they open the door and the other side of the door is the kid's closet right okay okay and then they come out the closet scare the kid go back through the door and they're back at home it is a great movie let's let's go to well you know what let's go back to a patreon patron this is uh solar Cyril dare I okay who says what do y'all think what do y'all think about the idea that matter consumed by black holes has been recycled and manifested back into the universe as dark energy so matter coming out the other side maybe right okay is there any correlation between the matter consumed by black holes and dark energy black holes and dark energy dark matter be different sides of the same coin I mean where to begin with this saying there's an urge to take everything you don't know and assume it's related right so I've got people talking about dark matter consciousness God yeah and dark energy or as one thing right quantum quantum spookiness yes someone asked me when they take ayahuasca is it possible that they have gone to a higher okay okay my answer to in an attempt to not be totally dismissive was to say well if it's a platonic form that we can learn about by exploring the mind then in that sense maybe right right like a perfect circle doesn't exist in reality nor will a perfect circle ever exist anywhere in the universe but you can touch it in your mind right and it's an experiment we can all perform so that in that sense we go places unlocking secrets in the minds the physical universe itself yes yes about dark matter dark energy so let's just with the falling and coming out and so there there were very early on people who thought a black hole could be bigger on the inside than the outside it could be as big as an entire universe on the inside it could actually lead to a white hole which is basically a Big Bang so so you fall into the black hole and you know that is completely confined by the event horizon nothing ever comes out but inside it is like something as big as an entire universe right another universe right exactly it's just like doctor who's TARDIS and and so we would never know about that universe it would not connect us check-check street-cred TARDIS is an acronym for what oh no relative dimension in space relative dimension in space it doesn't make it into the acronym I'm just gonna say you know okay so so so that was an interesting idea and a lot of people object to it because it in some subtle way suggests an unstable 'no stew BIGBANG's that might make it so that this world couldn't be stable if that with you but honestly it's not completely off the table there's a lot you could talk to some very important early relativists able still say that's what happens relativist an expert on relativity and relativity so then there's a separate totally separate question about dark there is a suggestion that the black hole's themselves could be dark matter meaning that they are invisible like dark matter is technically and and they could populate the universe almost arguably large enough to explain this missing mass this missing matter it's on the edge it's definitely under pressure right but there's a problem with like Big Bang nucleosynthesis if it's ordinary matter mm-hmm the black hole's don't have to be made by collapsing stars out of ordinary matter but you're absolutely right we don't know how to make enough narrations right so they're not made from stars so it can potentially my black hole let's do it I want to know what's inside the lunch box okay and inside of it is a black hole thermos but of course it is confusing if you fall into a black hole like this I guess you can't see your hands oh yeah yeah you'll disappear in front of yourself okay so you have a black hole thermos and it is filled with okay so liquor this is an inversion of the known universe because in this particular case inside your black hole I have the Milky Way outside the black hole because the black hole is always inside the Milky Way I am just gonna say that that was the most committed joke I have ever seen in my life those of you who don't have a camera I'm just telling you Neil had an actual Milky Way candy bar inside of a black hole thermos okay that's black hole lunch box okay so the last question which is pretty hard is could they all be connected the stuff that falls in and comes out and classically would say no way that horizon separates everything with me inside the outside but then there's quantum entanglement visor maybe some particles on the inside are also the same thing as the particles on the outside they're the same particles because of entanglement and wormholes and some crazy stuff at nobody really it's all just very conjectural now but maybe we'll come back in 20 years we'll be open for it yeah as a follow-up to this cosmic queries 20 years from now yes people roll us in wheelchairs so we got a round here Chuck yeah we so Jan you're gonna answer these sound bites okay amped this is bunters 85 on instagram and wants to know this I know it's off topic but one of your last shows you were talking about the information on the surface of a black hole what do you mean by information D mean temperature or speed or what is information ultimately we are completely definable in terms of our quantum numbers just list of facts about us information about us and relative locations and organisms in my body take let's take a single fundamental particle in your body it has mass charge spin and it's identical to every let's call it an electron in this case every other electron identical one's not a little bit heavier one's a little bit lighter and we're completely definable in terms of that information and you cannot destroy that information interesting and so so in quantum mechanics you start to stop thinking and if I melt Chuck yeah technically all of that information is still in the universe right just arrange two strands oh my god that's sensible there's a puddle on the ground yeah that's a different Chuck from the chuck I'm talking to right now how's that information still there yes it will never change having information preserved doesn't mean there can't be local change right so I can definitely change things locally but I still have to have the same information trying to total system the total system so I have to be able to reconstruct something it doesn't mean that there's a change in the system with what's in the system have to necessarily be able to reconstruct the exact same thing information right in principle I should be able to if I took a page of the encyclopedia and burnt it I should be able to reconstruct it in principle of course nobody can ever really do that it would take longer than the age of the universe and we don't have that kind of computing power so there's physical impossibilities but ignoring those complications black hole the argument is that what actually might be happening is that the information as it's falling in which is basically all you know everything everything right never actually makes it inside the black hole it becomes encoded on the boundary which is you meant horizon so it's actually a hologram elías 82 from Instagram says NASA reported that Voyager 2 discovered two new details about interstellar space how does that change our understanding of dark energy beyond our solar system or does it it probably doesn't because it isn't a detector of dark energy or dark matter we have no detectors of dark energy or dark matter yet none successful and so what but it is amazing that is the first human-made object that's gone interstellar and that really is quite spectacular it's just broken out of basically the sun's magnetic influence so it's able to get cosmic rays and things that that are protected in the solar system by the sun's may need to think the solar system was how far out of the planets and then you have like the Kuiper belt comets then you have the more cloud then you say well really at what distance does an object no longer know that the Sun is in this direction right because the Sun has magnetic influences that go very far and you reach the point where all the field measurements are sort of in this soup that permeates the entire galaxy and so it's a transition from the Sun is this way - I got stars in every direction right and so still moving so slowly that it will take what ten thousand years to reach another no 70,000 70,000 yes Robert who says thanks so much for educating and inspiring us what news in science do you find most interesting and important right now with respect to your field wow that's a great question well we do live the soundbite yeah we are in a very lucky time because we have discovered bear black holes in this miraculous way so I do think that the most exciting is yeah is eating meals Milky Way so I do think it is where the small meets the large and it will be that way for a long time meaning what the big bang tells us about dark matter and dark energy and the universe on the larger scale and why those things are folded together thinking about the the universe on the biggest scale and on the small scale so where quantum physics meets general relativity fresh air is an unresolved territory that's right and so that's why we use all these real settings right if you want to if you want to understand what quantum mechanics meets gravity you got to do it in the Big Bang around black holes all right this is Pablo Grist insko I don't know Pablo I'm sorry can you please help me put inside my head one more dimension three is fine but how can I grasp more that's a what do you do with what do you do with people to let them understand I think it is absolutely imperative that everyone understands that nobody can just blanketly visualize higher dimensions we're accustomed to looking at dimensions from the outside looking down we can't do that so what we can do with the kinds of things that Neil is describing earlier which is imagine three dimensional cross-sections of things so visualizing a hyper sphere which is a higher dimensional sphere as an intersection of it with our three dimensions and it would be a series of console it would be a series of spheres right that would max out and then spheres would go back but the one last thing is to do the to do the difficult example of being a flatlander and you will actually just by going down and dimension to get it yeah and I can add that if I've said this in a couple of our talks before there's another moment to do so if a line is bounded by points mm-hmm and a square is bounded by lines and a cube is bounded by squares then a hypercube is bounded by three-dimensional cubes the sides of a hypercube are three-dimensional cubes right mathematically just work your way up just keep going on we'll take you there there that's their math set you free think you know this is a real example where the math makes it a lot easier okay they just said no one ever math to make it easier geometry okay this is uh Eric Spence and Mark Eric Benson he says this Neil you have said before the Dark Matter should really be called dark gravity and it really stuck with me and helped me understand it better do you have a similar and alternate name for dark energy that better summarizes the phenomenon I'll give it a shot but I want to hear it let's see what Janus Edison's yeah I would say I would just call it dark expansion stuff but definitely dark gravity is what dark matter is it is literally dark gravity and I'm totally cool with that are you totally cool with that totally cool is a neutrino dark gravity oh that's a form of dark matter like we have examples of forms of dark matter that we have detected they're just not plentiful enough to explain so much of it yeah but there are things called neutrinos which we do detect and they are dark meaning they don't interact with light that was rough man with the dark energy that what if we thought of it it's like an invisible ocean because that's sort of what the dark energies around us all the time and it's it's as though we're in a storm of dark particles and it's just it's really that it's invisible is the thing you can see right through it it's not that if you had it in your hands it would look dark it's Jim visible right right so yeah so both dark and energy really don't apply we need yeah okay you know so it's really in the vacuum vacuum bad okay okay okay half a sound bite this is Hector Salazar who says this can other universes influence our overlap with our own and is there any evidence that this might be happened this would be the parallel universe yeah very speculative but if you consider a universe let's say we're floating on a three-dimensional membrane and a higher dimensional space and there's another one of those floating also in the higher dimensional space parallel or in some sense anyway they both share this membrane you're talking about that sense would call them universes and yes it is possible that they have interacted in the past and that there would be some archaeological record of that or in the future if they intersect is there an intersection line the three-dimensional line in which you live in both universes so technically if you mean by universe the galaxies and everything you see and not the whole space-time then technically yes two universes two membranes can can interact and can can coexist yeah I like the idea of living on the boundary between two universes people many other universes aren't a-holes as long as the laws of physics there are the same name as ours because you don't want to decompose into a pile of goo yeah that would be bad that would be bad the charge of electron is different we gotta call it quits they're always good to have you on so much fun Jan 11 / physics up at Columbia and Barnard College I'm Neil deGrasse Tyson your personal astrophysicist signing off first our talk bidding you as always 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Channel: StarTalk

Views: 824,051

Rating: 4.8950925 out of 5

Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, Chuck Nice, Janna Levin, edge of the universe, cosmology, dimensionality, 4th dimension, Monsters Inc, Big Bang, birth of the universe, dark matter, dark energy, invisible ocean, Voyager 2, interstellar space, Earth, Episode

Id: Ek3VqAED2wo

Length: 53min 25sec (3205 seconds)

Published: Thu Apr 09 2020