From the Big Bang to Black Holes: Time, the Universe, and Everything

[Music] ladies and gentlemen if you could please take a seat I'd like us to get started as soon as we can good morning everyone I'm Elliot Gerson and I want to tell you that this is actually a historic morning of sorts in that as we thought about the tenth anniversary of the ideas festival and some of the things we might want to do differently for those of you who've been fortunate enough to be here before we thought that we would launch a series of something we would call and brand as Aspen lectures most of you know that the style of what we do at Aspen is typically conversational and usually with a panel of several people but we knew many people were saying that they were thirsty for at least some content that was in more depth and an opportunity to hear from some of the extraordinary people we have here alone and at at some length so you could all take a somewhat deeper dive in a subject than is often possible in a moderated discussion so we decided to launch a series of Aspen lectures and they will be called Aspen lectures they will have a long and we hope distinguished life on the web independently of the ideas festival and one of the first people we thought of to give such a lecture and again to reflect the breadth of what we try to cover here at the ideas festival from the sciences to the humanities and the arts was jan 11 men II of you of course heard Janna yesterday briefly in the opening she is a distinguished as astrophysicist she's at Barnard College she's also a wonderful writer she also in the Aspen spirit of things bridges the Arts and the sciences she even had a position at the Ruskin school of fine art and drawing at Oxford and I think you're all in we're all in for a treat her very modest topic for her lecture today is from the Big Bang to black holes time the universe and everything and so she's also said she would leave some time for questions I don't quite know why there would be questions given the fact that she's going to talk about everything there can't be any questions after that but she but she will so it's my great pleasure to introduce jan 11 thank you so much for having me here actually this talk is really going to be a talk about questions in some sense they want to talk about little questions and how they lead us inadvertently to huge questions and how we sometimes have to come back again I I wanted to tell you one of the first questions I remember asking which is what else is out there I don't know what it was like where you were but I lived in cities most my life and I would look out my childhood window at the little patch of the sky and I couldn't see much I couldn't this certainly wasn't my view at my window this is from the European Southern Observatory and it's from their telescope so it's actually not taken by a telescope it's just taken on the ground but where they have a lot of health scopes in the Atacama Desert in Chile but at my window you know all I could see were some little spots little stars and I just remember wondering what they were and what else was out there and I remember having this feeling almost of restlessness of wanting to be connected with just that big sky you know what almost wanting to be let in but I really never considered being a scientist at that age and I think if somebody had told me I'd be a physicist I would have been offended I thought physicists memorized equations and just had an accumulation of facts and that seemed totally antithetical to being a creative or inspired person I had a very negative opinion of physics in particular which is very funny so it sort of as my punishment you know I became a physicist and I remember it was years before I started to understand that it's really quite the opposite scientists are excellent at asking questions and they love not to know stuff and that's just the best face to not know something to hone in on the question and to try to find an ingenious solution and I and I talked about it as really like creativity crashing into truth you know there's kind of constraint of reality and constraint of truth if physicists or scientists in general will often say is a great compliment that's a great question it's a huge compliment to give to another scientist so so I wanted to give a talk about question and to start with I want to start with a simple one you know simple question any human being on the planet could ask when they look up at the night sky whether or not their view is this great but it's just the simple question what is that does anyone know what that is is that it's our galaxy I didn't give you a chance to answer I'm the one who knows I mean it's our galaxy that's the amazing thing it's not obvious if you were to look up at the sky what that is that is a collection of a hundred billion stars our Sun being one very ordinary Starring sure many of you have heard this story before it turns out we live in a little family of a hundred billion stars if you were able to get some distance from the Milky Way it would look like this that's a very good representation of the Milky Way it's about a hundred thousand light years across 2,000 light-years thick and we're very much inside this galaxy we can't get that bird's-eye view if you look at our earliest probes like the Voyager spacecraft that were launched in the 70s they just barely gotten out of our solar system there are about 16 light hours out I think that's the right number and we're nowhere near sending spacecraft hundreds of thousands of light years out to send a spacecraft traveling at the speed of light to get that view we had a second ago would take you know maybe a million years and so so we're nowhere near being able to have that view but that's not a cartoon either that's really constructed from astronomical maps and cleverly reconstructed to give us a three-dimensional image so it's not a cartoon but there we are with that big beautiful scar above us and we're forever really locked beneath it and we live inside the galaxy and that's why it looks like that ridge because we're looking at it edge on so once you ask this very simple question what is that you discover it's got a hundred billion stars the next natural question is well are there other galaxies out there this was not a question Einstein knew the answer to people talked about it you know sin can't people were saying there are these little smudges they look like they're not stars are they other Island universes and what are they it wasn't really until Edwin Hubble working in the Mount Wilson Observatory in California in the 1920s began to make these extraordinary plates where I don't know if you can make out the image that well but that is indeed a whole other galaxy and he started to answer this question 1923 this plate is marked and Einsteins huge burst of creativity was in 1905 when he started thinking about space and time and his real crowning achievement when who really understood gravity and space-time was in 1915 1916 so this is 1923 is the first time that they had completely definitive conclusive evidence that there were other galaxies out there this is andromeda it's pretty nearby it's a few million light years away and it's much bigger than we are okay so we're we're kind of puny compared to Andromeda now the Hubble Space Telescope after named after this astronomer Edwin Hubble sees extraordinary images of galaxies just all the time and I'm sure you've seen many of these this is andromeda through the satellite through the hubble space telescope and we see galaxies all the time they're extraordinary we see them if you hunt a few hundred million light-years away we see them a billion light-years away it's called the Whirlpool Galaxy it's got a little companion in its arm they we see galaxies colliding they're extraordinary and then we see this this is a stunning image this is called the Hubble Ultra Deep Field if you were to look at the moon and you were to take a tiny patch about a tenth of the moon this square fits inside that tiny patch and in this square the Hubble Space Telescope found its deepest images of the furthest galaxies there are about 10,000 galaxies in this little tiny patch of sky so if you were to reconstruct the whole sky by extrapolation there are hundreds of billions of galaxies in our observable universe that we can see from Earth and that means there are as many galaxies that we can see as there are stars in our own no I mean this is very bedazzling right this is an extraordinary universe to be in you know yesterday I said we need a little perspective on our insignificance like this sort of helps hundreds of billions of galaxies that means an untold number of stars and around them many many planets we know there are many planets now even in our own galaxy right around us we know that there are other solar systems so so this creates this whole field the simple question what is that it's a galaxy are there others yes there are others and they're vast and they they surround us but so this leads to a whole area of cosmology but Hubble did something very extraordinary in addition to this which answering these simple questions which is that he made this discovery when he was looking at these galaxies he realized that yes not only are the other galaxies but they're moving away from us oddly and the picture he reconstructed was that on average when you look at all of these galaxies they're all moving away from each other he said it's not like an explosion happening in space it's more like the space is stretching between the galaxies okay so at any point in the universe if you were to look out it would look like the galaxies were expanding away from you this was actually suggested before Hubble made this observation it's the observation definitive observation that the universe is expanding okay nobody asked that question nobody said hey is the universe expanding no it was not on people's radar but right after Einstein was working on his great theory of space-time and the universe some other scientists came along and they asked this simple question what would gravity what would space-time look like if it was full of stuff it was just full of stuff everywhere like we see in this picture and what they concluded mathematically to their surprise was that Einstein's theory predicted that the universe was expanding they predicted this many years before Hubble and Einstein thought this is absurd he rejects this idea totally he doesn't want to believe it and this story is told over and over again because people so excited that Einstein was wrong you know I mean Einstein said about himself you know when I was a student I was no Einstein so you know he didn't mind being wrong he was the stream he was a very confident person I mean we should ask Walter Isaacson probably knows more than I do about Einstein but but he really didn't he wasn't ashamed to be risky and to make mistakes and to be wrong but he really did not believe that the universe was expanding and the reason why or one of the reasons why is because if you just logically run that movie backwards the universe is expanding today it means in the past everything must have been closer together and these everyone knew this from extrapolation that if it was all closer together there must have been a time when galaxies were too close to be galaxies they were too close to be stars they were so close together smashed in so extremely that they would just be like a hot primordial soup of the highest energy stuff and this is what earned the name big bang okay it was coined the term Big Bang was coined as in in derision what a stupid idea what do they think there was a big bang so the name stuck and that's what they said they said you know if we extrapolate backwards there must have been a moment when the universe began when there weren't galaxies and there weren't stars there certainly weren't people right to ask these questions and I think that was the hitch the idea that the universe wasn't permanent the idea that the universe had a beginning now we see tremendous evidence that this is indeed the case the universe is about 14 billion years old and we see the light left over from the Big Bang in this extraordinary picture where the Big Bang happened everywhere every point of the universe was once at the center of the Big Bang every point of the universe is in during the expansion still from that Big Bang in 1920s after Hubble did his work Einstein capitulates he realizes it was this tremendous blunder he could have predicted the expansion of the universe and he didn't but he had he comes to accept it as a scientific fact so these simple questions what happens if the universe is full of stuff leads to this absolutely extraordinary discovery which now leads to kind of frightening questions like what happened before the Big Bang you have to ask this question don't you I mean if you really think the universe had a beginning you have to start to wonder things like what happened before I'm often asked how long was it before the Big Bang I have this nice clock from an artist friend you know there's really we often dismiss that question and say look that's meaningless before the Big Bang there wasn't time because what is time time is the passage of change if I'm floating in empty space how do I know that the time is passing I accumulate thoughts I have memories maybe I age I mark change in the absence that the universe is crushed down to the point where actually it ceases in some sense to exist we can't even talk about clocks to measure change to measure the passage of time but what it does is it emphasizes that we actually don't really even understand what time is we start to think well I don't really know what is time time is the measure of change but does that mean time itself began with the Big Bang clock started ticking if we start to think about time is being created in the Big Bang we have to ask questions like why does it always move forward is it a dimension the way honest I talked about if I can go from the east coast to the west coast in space why can't I go forwards and backwards in time you know why can't I turn around and go back to the Big Bang it's time something that always exists like is the big banks still there in our past and we just can't access it we're marching ever forward and we don't know why so these questions sound like we were a bit adrift but these are fundamental questions now in physics what is the nature of time why does time always move forward what is the arrow of time it's is time something that exists only momentarily or is it there behind us and in our future like space I can't answer those questions I have a feeling some of you're gonna tell me your theories over cocktails do but they're where okay so let's let's take a step back let's say okay we're we're adrift we're lost we're asking questions are too hard to answer let's go back into the universe there was a big bang there was a moment when the universe was created this much we know we have scientific evidence for it so now we ask all was it the only time it ever and as a BIGBANG ever happened before will it happen again is there a Big Bang in our future have there been some in our past have other parts of the universe in some sense had their own Big Bang's are there other Big Bang's out there this idea of a multiverse is something that's taken seriously I don't know if it's right or wrong I don't think people know if it's right or wrong but there's seriously on the table an attempt to ask the question are there other universes out there some which are slightly different from ours maybe each time a Big Bang happens the laws of physics are slightly different maybe in some of those universes galaxies form maybe in some they don't maybe in some of those universes life emerges on planets maybe in others they don't the laws of physics aren't tuned right maybe there's an infinite number of these possibilities and I don't I'm not going to say more about that except to say that it is natural to start to ask these questions and they may be questions that actually have scientific answers now they may not but they may be okay they may not but they may be there's another really interesting question that we can ask when we start to look at the Big Bang and that is is it infinite there's our universe infinite if something that is created at a specific moment in time 14 billion years ago comes into existence space itself explodes out of the Big Bang is it infinite are those galaxies that we see in the sky do they go on forever if we could look for long enough would it never end Einstein also said only two things are infinite the universe and human stupidity and then he said and I'm not so sure about the universe once you start to talk about space and time in this way you you have to start to wonder if maybe the universe isn't infinite if it is infinite it means or it might mean that somewhere else in the universe there's a galaxy so similar to ours because every infinite possibility is realized and in that galaxy there's probably a planet that looks very much like ours and so somewhere else in the universe there's an aspen ideas festival you know going on in there talking about us on the edge of the horizon wondering if we exist right and that possibility could be realized an infinite number of times so maybe slightly different every time okay so it starts to get a little seeming like maybe that's not the most natural solution so what's the alternative if the universe might be infinite seriously I don't know but here's the alternative the alternative is that it's not infinite it's finite so imagine another finite world the earth so before explorers had mapped out the earth everybody knew sort of their local region but not the globe people didn't know the earth was a sphere right you would have thought remember this I don't know if it's an apocryphal story but explorers sailing off the European coast and people fearing they were going to fall off the edge right and we know that there's no edge what happens if you leave the European coast and you travel in a straight line as you possibly can if you come back to where you started eventually can you leave Spain behind you and you travel in a straight line and you go around the globe and you find yourself coming right back where you started that's the image we have for the possibility of a finite universe this is a computer code a game written by a great mathematician Jeff weeks a good friend where he constructs what the world would look like if you did that journey in a finite universe you left your galaxies your beautiful spiral galaxies behind you and you began to travel out into the universe and you travel in a straight line and you go for billions of light-years and you never turn left and you never turn right just like those explorers you're travelling in a straight line as you possibly can in a finite and universe the entire universe is finite you would be surprised when you saw a distant galaxy approaching you to realize that in fact that was the same galaxy left behind just like if you came back to the shore of Spain you would have to realize that was the the same continent he left behind so in this image of a finite universe in this particular universe that Jeff weeks created there's only one galaxy in the entire universe all those other galaxies you see are really just copies they're just they're just images of the single universe the single galaxies in the entire universe now we know our universe isn't that small we know our universe is big enough to accommodate lots of other galaxies but it's still a realistic question how big is the universe and what is the shape of space let's see there's another very intriguing question that we get to at this stage which is if the universe can have a shape if it could be finite if it can have three dimensions are there is there a possibility for extra dimensions when we think about the shape of space we think that there's an up-and-down one dimension a front and back a second dimension a left and right a third dimension and with that information you can totally locate somebody in space but there is the possibility that it's taken seriously more and more that there are extra spatial directions I can't point to it very easily but mathematically we can think about it in this idea of there being extra spatial dimensions let's imagine we just look at a slice of our universe just a two-dimensional slice of our universe that extra dimension would be orthogonal to that slice and it would be everywhere you guys are going what is she talking about so if you were wondering what is she talking about I have done my job there used to be a saying at MIT and I'm sorry I can't remember the attribution but it said every talk about physics should have something for everyone can understand out of respect for the audience something only a few people can understand out of respect for the experts and something nobody can understand out of respect for physics so so this is that part so there this idea that the universe had extra spatial dimensions was brought up again very soon after Einstein started to think about his ideas people started to realize the universe was expanding they started to talk about all of these things and then it kind of stalled and they said no that's crazy we don't talk about it now in modern theories of physics there are definitely a place for considering contemplating the possibility that there are extra spatial dimensions and it's it's something that we we may or may not be able to get closer to one of those scary questions where you wonder if you've gone too far too far adrift somebody asked me the other day well what does it really look like when you're when you're working on these things I just want to tell you that we don't just throw around these crazy words and and these ideas and and and have these sort of stories we sit down we really try to do the math this is from a blackboard talking to Brian Greene who I know has spoken at the Aspen ideas festival before and he and I asked the question well are there extra spatial dimensions as many other people have and and what would the implications be for the universe so so what we really do is really math at the end of the day and we can disprove a lot of our ideas on the blackboard or on pen and paper without even having to look at the universe we can kill it by inconsistency we can kill it by mathematics but if it starts to survive then we try to think of ways to look out into space to see confirmation and and we're not close to doing that yet but I'll tell you why we think it's still interesting to contemplate okay so maybe we've just gotten lost let's bring ourselves back we asked these questions what is that it's a galaxy are there others yes the sky is full of them and then we were driven to these very surprising discoveries the universe is expanding it had a big bang and that led us to question the nature of time whether the Big Bang had happened before if there is a multiverse if the universe is finite if there are extra dimensions okay we can't answer all those questions but we can come back into the universe that we do live in that we do understand and and I want to show you this map of the universe this is again not a cartoon this is from the Sloan Digital Sky Survey it's a construction of what we actually see out there all of those are galaxies that we see and the galaxies are plentiful and they pile up on these structures and and so we look at this and we can wonder is that universe infinite would it go on forever or maybe some of those distant galaxies copies like if we traveled in this space to one of those distant galaxies would we realize we've come back to the Milky Way we've traveled around space and come back to where we started okay probably not probably not but there is something very extraordinary that we do know about this universe that we see in data that we know to be true and that is that's not everything we're certain of that that is not everything when we look at galaxies we have the surprising result that they're much heavier than they appear to be we see the light coming from them but we can tell by the effect that they have on things around them that they're actually much much heavier than they look it would be like if you were looking at me up here and it turned out you know that I crushed the stage and I weighed four tons you know you would suspect there's other matter there right there's other mass and that's what we call it we call it dark matter dark matter is this proxy that just means there's matter out there and we don't know what it is but we know it's unlike anything we've ever seen before it is not the matter that is in our bodies that is in the chairs that's in the stars that we see it's a different kind of matter so that is a very dramatic discovery that the universe is full of dark matter then there was another very dramatic discovery which is that not only is the universe expanding today but the expansion is getting faster and faster and we have no idea what's doing that it's a significant amount of energy driving the universe to expand faster and faster and we've given that a proxy name which is dark energy we don't know what it is we don't know where it comes from we've never seen anything like it in our laboratories so what we do know is that dark matter and dark energy which are the most significant components making up the energy density of the universe we're less than 5% or a little bit of ash everything we see all that stuff I showed you not just us all that stuff I showed you it's less than 5% of the energy density of the universe it's like this little residue and the rest of it is stuff we don't know what it is it's very likely that the answer to the question what is that right what is the dark energy in the dark matter lies in the very early universe very probably the dark matter is created probably earlier than the first trillionth of a second after the Big Bang and we we can't make it in our laboratories yet we're trying and the dark energy very well may have been formed again in that very early moment after the Big Bang and understanding it understanding something that's right there that's affecting the universe that we actually live in might require that we ask and answer questions like what is time are there other universes has the Big Bang happened before is the universe finite are there extra dimensions that blackboard I showed you Bryan and I were asking the simple question if there are extra spatial dimensions why can't I see them no and and the idea would be that those dimensions are also finite that they're so small that we come back to where we started immediately if I make any motion in that extra direction I'm right back to where I started I can't even in some sense I have no thickness in that direction and we asked could little dimensions like that trap energy could little dimensions like that be trapping the dark energy could the dark energy be our first evidence of the existence of extra finite dimensions we did pretty well we did pretty well we got pretty far but there are things that aren't quite right we don't understand the math is hard you're Brian's a brilliant mathematician and a great physicist and we get stuck we get stuck so but these are real questions that might actually be connected with our universe so just to come back to where we started you know here we are under the Milky Way and we've discovered all of that really more or less from our backyard all of that we've discovered from our backyard and that's that's pretty amazing scientists most scientists do not work on these really crazy questions and a lot of times I also don't work on these crazy questions sometimes I just work on really concrete practical in-your-face things like black holes and at least we know black holes exist so that's me being concrete they have there they're a billion years ago they collided that's you know recent history for me and and so most of the time we do work on things that are more connected with the world we see but we can't help but drift into these other questions and this is the greatest time to be alive I think you're here scientists say that stuff all the time it's the greatest time to be alive because there are these great mysteries the dark energy in the dark matter that are foisted on us we know we don't know everything we have really good questions to ask and to solve and and so you know it's as though we're rewarded with answering some simple questions like what is that and what else is out there with even greater and more challenging puzzles thank you I I want to sleep Lenny time for questions so I think there are mics and people are welcome to try to find the mics I think there's some some questions up here you spoke about the visible stuff and the tangible stuff means 4% is that growing or do you expect to see that like dark energy and dark matter to sort of sublimate into stuff yeah it's a good question can they change you know energy we talk about conservation of energy one kind of energy converting it to another can dark matter and energy turn in sometimes okay but the dark matter can't turn into the regular matter that we see it has different properties it doesn't interact with light first of all that's why it's dark it does not interact with light and and it has very specific properties that make it so that it doesn't okay and and that's why it's dark out there and that's not easy to convert but but but having said that when we go to our accelerator experiments like you go to the Large Hadron Collider in CERN where we found the Higgs particle where they're smashing together ordinary matter they do think they can create the dark matter from that interaction so you create dark matter and a bunch of other stuff so in that sense yes we can smashed together regular particles and if we smash them together hard enough we might be able to create dark matter in the laboratory so the big thing that people are hoping for now that the Higgs was discovered and people might want to ask what what that is is will we see dark matter next that would be very exciting so the conditions that they're reproducing in terms of the energy scale at the Large Hadron Collider are very very high energy conditions that are the kinds of conditions we expected in the very very early universe and also for the dark energy it could decay one day it could decay into something else we just don't know what happened to the string theory that we heard about for so many years yeah so string theory is the idea that when I look at the smallest level of matter I'll find out that it's not little point particles little billiard balls but it's actually little loops of string and that all of us are made up these little loops of string playing different harmonics and so we're all kind of made up of one thing there's one unifying idea that was my string theory was so amazing and exciting was this it was this attempt to say there's one law of physics only one and it was all down to string theory and we're all strings and so it's a very exciting idea and string theory requires extra spatial dimensions for its own mathematical consistency and so that's why extra dimensions who started to become very popular again in terms of people asking about cosmology because if string theory requires it to make sense where are they where are those extra dimensions so we started to imagine these small finite dimensions so string theory is still out there it's still it's still in progress it's a very difficult theory and it's not completely understood yet and the architects of the theory don't completely understand it and this is one of these things some some scientists say well then string theory is wrong and it should just go away and we should start over and try something else and other people say there's no guarantee that we solve problems in a human lifetime it was 300 years between Newton and Einstein yeah maybe it'll be 300 years before you figure out string theory so it's an active field as all I can tell you and it's an important and active field and it's a really interesting and active field but it's not solved and those questions are not simple I can tell you and the way the the the level of the questions have become very very hard and I think that bothers people there's lots of questions here I think we just need to wait for mics if their mics could be passed around right here in the front I'm sure they're questions in the back and I'm just not seeing you yeah okay well well are there more mics so we can get them started over in the back too okay please if the big thing brought on the inception of the universe or universes which is all in everything what went bang yeah again that's a really I gave this sort of wanted to correct myself a little bit I gave this very naive notion that when the universe contracted back to the origin you know back to the moment of creation that before that there was nothing that's kind of an old-fashioned story I don't think people really talk like that anymore they sort of imagined there was space and time and a little bubble of it broke off and exploded in some sense it began expanding extremely rapidly so it was like a plume that came off of a larger landscape and and why did it do that okay so that is more consistent with a multiverse there's this landscape and little patches bubble off okay and they bubble off and they create their own universes with their own big bangs and their own histories why do they bubble off so you might have heard of this theory of inflation which was also in the press a lot because there's some excitement that it might have had a really strong confirmation of this theory it says that a little patch of the universe gets trapped in a in a high energy state and it's a lot like the dark energy something drives it to expand incredibly rapidly it's a lot like dark energy and we think we understand how that might happen in terms when we look at fundamental things and fundamental theories so it inflates out because some high energy state gets trapped it blows out and then that dark energy that part of our past decays and our universe sort of bursts out of it this idea of inflation has been around since the 80s and it is very interesting because it predicts certain marks in the light left over from the Big Bang certain little archaeological features and that is what people in the past couple months announced that they believe that they have discovered it's just very strong evidence for inflation so we look at the light left over from the Big Bang I just want to say that that's really an amazing thing I I think there's a microphone back here and then we can keep passing the one out front was there one is there what what is the smallest element that's actually part of this expansion after all we're here and we don't expand yeah so what is the smallest element so you're forcing me Woody Allen quotes so you remember this when he he won't do his homework because he realizes the universe is expanding and he has like an Annie Hall and his mom says you live in Brooklyn Brooklyn is not expanding it's none of your business yeah it's none of your business we're not expanding it's true and that's because the expansion of the universe is not strong enough to rip apart the the matter - matter attractions in our body it's also not strong enough to rip apart the earth because of that gravitational attraction is pretty strong between the earth and its matter and the solar system stays together and the galaxy stays together the Milky Way is not expanding and in fact we're not even moving away from Andromeda we're falling into Andromeda okay so we will collide with Andromeda in a few billion years so all of that gravitational stuff is actually stronger than the general expansion and it's only when you get to the sort of diffused spaces between very distant galaxies that you see that that's stretching now that might change in the future the universe expansion might get faster and faster and stronger and stronger and we might have galaxies ripped apart and things like that might happen Brooklyn might expand okay but that's very very far in our future like I wouldn't worry about it cuz the sun's gonna blow up long before that happens so whoever has a mic can ask a question basically and then we're gonna try to pass the mic around yes how do you think our understanding will change when the James Webb telescope goes in 2018 how our understanding of the universe will change it so the James Webb telescope is a very ambitious project that's sort of the next generation like Hubble I think that one of the things I mean there's obviously many many things in astronomy in physics that I have gotten nowhere near all the details about colliding black holes and how black holes are these massive engines that that have these very energetic outbursts all this there's tons of things in the universe that can be seen by other telescopes but also in terms of the topics that we've touched on it could have it could have important implications for understanding exactly what's going on with this with this expansion that is the universe really getting faster and faster in such a way that we can extract more information more details about how that's happening can we understand how it's accelerating and there's things that we could we for sure could understand and in terms of even this conversation and you know I'm very theoretical my work is totally mathematical all the time we've really I we really need those observers and people who who build things and look at stuff so that we don't get lost in these other questions but that we're constantly being anchored in some kind of reality right because that is the real criticism is that look these aren't scientific questions anymore you're getting lost and so we have to keep stepping back and and do what we can to actually look and see what's out there dude this might be passed around yes I'm a question okay due to the nature of the Big Bang coming from one one point does that mean that matter at the edge of the universe if there's an edge is accelerating faster away from the center and if so does that does that have anything to do with the theory of like the cosmic fabric ripping and coming back together so I would say I'm really glad you asked that question because we have to think of the Big Bang is very different from that so we look at a star exploding and the star explodes at a point in space we know where it happened it happened over there you know and we see all the matter expand out and it all kind of accumulates out here on the edge our image of the Big Bang is radically different from that it says every part of space-time was once at the center of the explosion the explosion did not happen at one point in space the explosion was space bursting out and expanding there was no single location to the Big Bang I can't look out into space and point to where it is the Big Bang happened here it also happened 15 billion light-years away because that point and this point where once together so the Big Bang happened everywhere and the whole space is expanding and there is no edge and it's a really challenging picture ok you guys got it there I can tell so one one one analogy that people use which I'm not crazy about but I'll say it here people say imagine the universe is the skin of a balloon and you've drawn little dots on the skin of the balloon and those represent atoms or galaxies or something and the balloon is stretching the dots the ink stains the skin of the balloon and doesn't move but the skin between the space between the dots stretches and that's really what we're thinking of with the universe the reason I don't like that analogy is because we all know it's expanding into something and the universe isn't the universe isn't expanding into something the universe is everything so who's got the mic or the other questions on it this goes to what Walter Isaacson talks about is that genius is the intersection between art and science and what I'm trying to follow in your conversation is you have a theory and you have the math or you have the discovery through the telescopes or through the Hubble or what have you it's not a chicken or egg which comes first the math or the discovery but could you kind of take us through one or two examples in the last few years I would say most many people there's a sort of story that's told to young physicists growing up that all of the discoveries are really driven by observations first and the theory comes later general relativity might be the idea of a curved space-time that Einstein came up with might be one of those examples there what's not the case he was thinking purely theoretically and and his ideas were about imagination crashing into truth that's what Einstein did really beautifully there'd be some simple fact that was discovered like the constancy of the speed of light and there's some argument about how how much Einstein cared about the experiments that were done but he did accept that there was this fundamental limit to nature the constancy of the speed of light and nobody else wanted to believe this limit right so he accepted this hideous constraint strange and surprising whose constraint and in it he just dreamt and imagined and had these thought experiments and thought through what the implications were and it forced him to give up space and time as we knew it and to understand relativity a relativism of space and time so that's an example where where the ideas are coming out of almost you know consisted philosophical consistency and then the math came came later he was not a great mathematician in a sense you know he struggled with the math so I can't say there's one way it's done okay there's we have what's beautiful about scientific collaboration is that it is a collaboration and that there are many different minds and many different ways of thinking and many different approaches and so I don't make a very good experimentalist but I'm I like to do theory and and and and so we collaborate and we work together people build stuff and I admire tremendously and that's how it works to say which comes first is sometimes an accident of history I think that was kind of a rambling answer to your question say I I want to thank you for an informative and well-constructed talk they say that Alex de Grassi has nothing on you I think you mean Neil yeah I'm sorry and I want to tell him you said that you could go right ahead he's a big guy yeah I'm interested in reflecting on your big question from yesterday the insignificance that the information you're posing paints us in and that means all of us including you and your social actor and your whole life has not lived in in the theoretical world and what I want to know about is how the information you pursue in this realm informs you about you're insignificant as an actor in that social world where gravity social gravity is a compelling force that in many ways isolates and vulcanize --is us in not very constructively well I would say that because of my perspective on the universe I have exactly no relationship problems whatsoever never have I have no anxiety and I worry about nothing no I think you know unfortunately it's harder to put into practice and I'd like it to be but I do think it I just think it helps in the global perspective to not squander what we have going on here and it won't last forever you know and so so I can't say that as a personal philosophy I am totally trying not the Buddha but but I do think it helps and I think globally much especially we talk about different cultures and we talk about social issues people being confined by by stereotyping or any of these things I think it really helps to step outside into you know to look at us from the outside maybe I'll develop this into an ology and then we'll have a we'll have a little temple of some kind or whoever has to make oh somebody's got a mic and then keep passing those mics around yes so you mentioned the large he thought he'd drawn a Collider you mentioned black holes and back when they lit that thing up for the first time there was a lawsuit about whether it could destroy the earth and everyone say what a bunch of crackpots and yeah I thought maybe some informed commentary on like what is the largest particle accelerator that you would be comfortable to have someone on planet earth before they're actually would be a risk that something highly untoward could happen and say we would become you know as much a different configuration of matter in the universe there are extra spatial dimensions we don't want them to start unraveling or something like that you know we don't want to start floating we don't want to do something catastrophic we know we think becomes big and now we float off into a different direction or something the black hole controversy was interesting because it wasn't that people said look there's no way we'll make black holes that's not they said they said okay yeah we might make little black holes we might it's very unlikely but it's possible they just said they won't destroy the earth and and here's the here's the argument trust me so no the argument is that a black hole this this will be my next talk next time I come back to Aspen I want to do a talk on what black holes really are black holes are kind of like fundamental gravitational particles so if I smash things together hard enough just like I can make Dark Matter I make make little black holes and and that was taken seriously but we think that they evaporate nearly instantaneously because of Hawking radiation Hawking became very famous because he realized that even though black holes emit no light and reflect no light they actually in this very subtle quantum process can evaporate away and and the calculations were very convincing but there's something better than that which is that we know there are particles that hit the Earth's atmosphere that are reaching the energy scales of the Large Hadron Collider and they are not making little black holes that are destroying the earth so it would have happened already without our intervention okay so I would be comfortable making black holes little black holes because they're varied they don't survive okay they don't survive think of they're gone it's the big ones you got to worry about and there is a big one in our galaxy there's a big one 26,000 light-years away there's a black hole let me just say is for fun that's four million times the mass of the Sun and we are in orbit around that black hole and we are in safe distant orbit around that black hole and there's probably millions of black holes in the galaxy hi my name is Layla and I have a question about dark matter and dark energy it was really fascinating I know a lot of physicists they try to find like there's so many particles for different types of phenomena is there a particle for dark matter and if so I know you said it's like undetectable but our physicists working on a way to possibly detect it yeah definitely physicists are working on a way to detect dark matter definitely it's a major campaign to try to build to guess what the dark matter might be to ask the question what is that to guess what it might be in the scheme of things that we do know we if you might have heard of neutrinos you know people wondered if there's a kind of a neutrino which is a particle that does not scatter off of light is there a kind of heavy neutrino that could be responsible for the documentary people think about this very hard they think about how to detect it they build machines we just haven't done it yet it means we've honed in it's not this it's not that it's not this we're chasing it around the space of possibilities it's literally we're literally guessing it what it might be and chasing it I'm very confident we'll discover dark matter I just you know we don't know when exactly obviously but I feel very confident that we'll discover it and I think for sure it's going to tell us something about the early universe that matter comes from the early universe it comes from less than a trillionth of a second after the Big Bang we can't even make it now you know it's so hard to make that's the only time it could have been made yeah hi um I want to know if computer models are helping there's a lot of these things and more generally do you think discoveries are accelerating in this field mm-hmm I think this field had a tremendous burst between 1915 and now a hundred years and unbelievable unbelievable bursts if you look at the Hubble Deep Field image and you think of that from from recent times compared to what Hubble saw I mean it accelerated very quickly in some sense we've got cosmology nailed ok it's only because we understand it so well that we were able to admit oh look there's a lot of it that's missing from our picture right so people often say oh you know nothing because you don't know what the dark matter and dark energy is it's really the opposite we honed in so well and these other things so precisely that we could see this this phenomenon so computer models are crucial absolutely we do a lot of stuff numerically because we're on this planet under that galaxy you know there's only so far we can go so computer modeling modeling is like a new kind of experimentation in a way ok think we've only got a couple more questions it's this side of the room been neglected oh that's ok you can ask a question but somebody get a mic over to this side of the room I feel bad for them oh I so obviously when you see the many swirling galaxies it's hard not to feel cosmically insignificant but at the same time so many of the physical laws of our universe are sort of perfectly set in tuned in such a way that life could be possible and then intelligent life what is your theory as to why that is is that just a consequence that the multiverse and we could only exist in the universe that's tuned the way we could exist yeah a lot of people it's kind of an entropic reasoning and a lot of people like that reason a lot of people really dislike it but the reasoning ghosts look if the Big Bang happened many many times in the future in the past if it's you know we live in this ginger root where there are tons of of universe is created and the laws of physics are all slightly different eventually one of them's going to have all the right properties to be tuned for the emergence of life on at least one little planet and that's us and that's an anthropomorphic a lot of people don't like that reasoning at all and that's why people get angry that the multiverse isn't real scientific reasoning it's you know it's hard to say what role that will play I think what people want is they want to say here's something that we see in the universe it's an observation and the multiverse explains that observation and it's the only thing that explained that explains that observation and so people are working to make it more predictive okay and until then I think it's just a very interesting idea on the table that we have to take seriously and and you know I don't know how soon it'll be before we can do better than that I'm sorry question on this side oh sorry I that's okay where are you okay yes so one of my favorite quotes from a physicist is Marie gell-mann's quote imagine how hard physics would be if particles could think so do you ever ask that question could particles think and what would that mean I asked a question are we thinking yeah it sounds cheap and it's actually true you know are we just biological machines and are we just playing out certain code and is there any sense of you know labor with that stuff I think it's pretty they're pretty convincing arguments that yes we are just crunching through that we are just biological machines those are interesting enough particles to worry about thinking I don't really worry about the Sabaton I mean there's complexity argument that are pretty convincing that you need a system complex enough to to even contemplate the emergence of consciousness and and whether or not that consciousness is sort of a figment of our imagination or some real thing is really becomes the realm of neuroscience but computer scientists and therefore physicists and mathematicians do you think about this this dates back to Alan Turing really who discovered just the idea that that you could write a code to think and write a code to do mathematical operations and then he starts going well maybe that's all we're doing you know so he is the inventor of the computer ok I want to take one more question and then we're done whoever has I near an end time can you briefly talk about Kurt qoodles contributions to cosmology specifically his 1949 paper when he was friends with Einstein in his twilight years and talked about the current state of cosmology in the chronology protection conjecture so so lots of interesting stuff there Kurt gödel was the greatest logician maybe of all time he did something very extraordinary which is he realized that there were some mathematical truths that could never be proven to be true this was very shattering for mathematician improved there are facts even among numbers that we could never prove to be true or false totally extraordinary and he was just this incredibly original very odd character he was basically a paranoid schizophrenic but he was good friends with Einstein and he was utterly brilliant he would walk to the Institute in Princeton with Einstein every day where they both worked after they emigrated to the United States and and gödel had this idea you know he realized in Einstein's theory that he could build a space where it was rotating this crazy universe not the one we live in but imagine universe that working mathematically worked out you could go backwards in time you could go in what are called closed timelike curves you could you could travel in one direction and find then you came back into your past okay and and most and then this what you brought up the chronology protection conjecture is the idea that no that will never actually happen in any real universe and will be protected from that but but nobody it's just a conjecture nobody can prove that you couldn't make a universe that does that what you could go on closed timelike curves and go back in time so when I said oh this maybe we've gone adrift to thinking about the nature of time and maybe these aren't questions we should be asking we really do ask those questions about actual universes and space times can we follow a path and go back in time and how would we do it and and there are you know that there are there's lots of progress on that but we've never been able to conceive of a way to do that in our universe with finite amounts of energy and things like that so people think maybe you just won't be able to do it when you actually look at the laws of physics but they can't prove it we decided to add aspen lectures as a feature of the ideas festival and and I and I think we have and I think we have several hundred people here who are going to ask us to have you come back and tell us about black hole [Applause]

Channel: The Aspen Institute

Views: 111,926

Rating: 4.8683729 out of 5

Keywords: Big Bang (Literature Subject), Universe (Quotation Subject), Black Hole (Celestial Object Category), Time (Dimension), Everything (Professional Field), Astrophysics (Field Of Study), Space, Cosmos (Organism Classification)

Id: N-Vbho3331c

Length: 57min 3sec (3423 seconds)

Published: Sat Jun 28 2014