"Lawrence Krauss - Life, the Universe, and Nothing: A Cosmic Mystery Story "

[Applause] [Music] [Applause] [Music] thank you all thank you very much for coming and um oh it's a little loud I wonder if I could turn that down it's okay I'm going to stand up here and I don't want feedback so we'll see okay we're not getting feedback yet you want to make a bet okay good anyway thanks for coming yes I heard the University Bookstore wouldn't bring books so you should buy books on amazon.com not at the University Bookstore in any case it's a pleasure as I say and I'm sorry that some people over there in the rover flow room but as pointed out I will be answering your questions first I put these quotes up here so you'd have something to read when I was being introduced and and but this is actually probably pretty appropriate it's one of my favorite quotes from Lees bogan but it really epitomizes what I want to talk about which is and one of the reasons I run a an institute called the origins project is that really the interesting question is how did yet to the starting point and that's pretty well true for all of science the most interesting Zoar origins questions and I will talk a lot about origins today in terms of the universe now in fact the question well by the way this these this is a globular cluster it's the beautiful night sky the stars are beautiful what I used to live in Cleveland and I used to have to tell people that these were stars but but I and I've been in in Vancouver for a little over a week and and I guess I would have thought I would have to tell you the same thing but I was gone one day with sunny in any case as beautiful as that is as was pointed out the night sky is indeed beautiful but the really important stuff it turns out as the stuff between the stars the stuff you can't see as I'll talk about and it's changed everything about the way we think about the universe from its origin to its future and the present as well now the question that I do want to deal with because it does relate to the new book is it is a key question that's been around for as long as people have asked questions why is there something rather than nothing it's often been taking to be a religious question or a philosophical question but it is neither it is a scientific question because something and nothing our physical quantities and therefore the domain of science and science has completely changed the way we think about this question and and as I'll talk about the philosophers and theologians have very little to add well they had didn't add anything in the first place but anyway now there's a number of different ways to answer this question and this is the first way but that doesn't tell you anything it doesn't explain anything it's just intellectually lazy it just relies in a story made up by people written down before anyone even knew the earth orbited this Sun but it certainly doesn't explain anything it's a nice story but it doesn't predict anything it doesn't tell you how the universe evolved so so as I say I want to go back the story I want to tell you is based on actually looking at the real universe the universe we live in and trying to force our beliefs to conform to the evidence of reality rather than the other way around so I want to begin this mystery story a little bit differently so let's begin it was a dark and stormy night I'm not referring to the origin of the University I'm talking about the the the night that Albert Einstein dotted the last period on his greatest Theory the theory of general relativity it was a theory of gravity but more importantly it was the first theory that was not just a theory of how things move through space but in fact a theory of space itself in fact it he showed that space was dynamical it could respond to the presence of matter and energy and and because it was a theory of space it was the first theory that could really be a theory of the universe and he knew that and but he was very disappointed by a simple fact it turned out not to describe the universe in which we lived nowadays that doesn't bother physicists so much but it used to and Einstein worked very hard to try and change the theory to to be in accord with the universe in which we lived you see because the problem is in 1916 when Einstein developed general Tiffiny the universe was static and eternal as far as science was concerned the conventional wisdom was that the stars and galaxies twelth stars in fact had been around forever if you look at the night sky it's more or less the same day after day and it would always be that way now there is a problem and there's a problem with not just general relativity but Newtonian gravity and any of you who've taken physics which is all of you I've to know that gravity sucks it always it always pulls it never pushes and you can't have a static universe if gravity sucks because you put stars out there and they'll eventually always collapse together and so Einstein realized that and he and he revised his equations a little bit and I've written them down here and we're locking the doors in both this and the overflow room now that's it and I've written them down here so but I first put them in user-friendly fashion this is for the the biologists there we go it's not it's not completely facetious but but we're all ok with this the left-hand side equals the right-hand side people are comfortable ok in in general relativity it really means something because the left-hand side of the equation relates to the geometry of space because matter can curve space and therefore produce interesting geometry so the curvature all the geometric terms are related to on the left-hand side and the stuff that produces the curvature the energy and momentum of the universe is on the right-hand side so energy and mentum produce curvature which affects the evolution of energy and momentum and that's fine science equations and now I'm a theoretical physicist as was pointed out so I have to write down the Greek letters and there that's much more illuminating to many of you I'm sure but this is the problem this is the theory in which gravity sucks and this was the theory that didn't describe the universe so Einstein realized that consistent with the mathematics that had led him to develop general relativity with the symmetries he could in fact add an extra term a new term on the left-hand side of his equations which he called the cosmological term and this term would produce a small repulsive force throughout all of empty space so small that you wouldn't notice it here on earth and you wouldn't affect any of the wonderful calculations that led Newton to understand the orbits of the planets around the Sun it wouldn't affect any of that but it could build up so that on the scale of our galaxy that small force could finally hold apart distant stars and he thought that could produce a static universe now the problem was there was a problem and in fact very shortly after he wrote down the equations it began to be realized that the universe wasn't static and in fact when I was on leave a few years ago in Switzerland I got a postcard from Einstein to Hermann vile it was very famous mathematical physicist and some of your German is better than mine but this was if you get rid of a quasi static universe then out with the cosmological term because he realized that if the universe wasn't static you didn't need this repulsive force anymore because if the universe was expanding gravity could be purely attractive and slow the expansion and the big question of 20 century physics the holy grail of 20th century physics became is there enough gravity to stop that expansion and cause the universe to collapse inverse of the Big Bang a Big Crunch and the big question became as the universe gonna end with a bang or a whimper and so he realized it was no need for that term and he said it was his biggest blunder and he'd wished she'd never he'd never introduced it now even though this was from 1923 already but the person that convinced the world that the universe is expanding came later and he is one of my he he's one of my heroes because he gives me great faith in humanity this is Edwin Hubble he began life as a lawyer and then became an astronomer and so there's hope for everyone and Hubble was what did several amazing things the first amazing thing he did which is somewhat peripheral to what I want to talk about but nevertheless it sets the framework up till 1925 when he worked with the Mount Wilson telescope if you look through telescopes in our galaxy you saw these little fuzzy things and up to that point our galaxy was it the universe was our Milky Way galaxy and you looked at our galaxy saw these fuzzy things they were called nebulae which is Greek for fuzzy thing and and when you saw them they didn't know what it was a big debate about what they were but in 1925 with the Mount Wilson telescope he was actually able to not only to distinguish individual stars in these objects but to show that there were other Island universes other galaxies and we now know that they're over 400 billion galaxies in the observable universe 400 billion and a single human lifetime ago 87 years ago we knew of one so it's not too surprising that we're surprised we're like the early map makers just beginning to understand the universe on the larger scales and it's remarkable and I want to celebrate those revolutions in our understanding today so Hubble was the one who convinced the world that the universe was expanding and how did he do that well he looked out with his telescope and these are not sperm these are galaxies by the way and this is us and what he did was he looked out of galaxies as he saw that the the on average all the galaxies were moving away from us and in fact those that were farther away were moving faster those were two times as far away or moving two times as fast were three times as far away we're moving three times as fast and so on so what does this tell you well it's obvious tells you where the center of the universe obvious just look at it well as some of my friends remind me on a daily basis however that's not the case in fact it tells us that the universe is expanding uniformly now why is why well why is that and why it's so hard to tell what the thing is we're stuck in our universe well most of us are the Republican candidates aren't but the rest of the world is but then yeah you can that's an easy laughs this is Canada so it's easy but anyway but if we want to see what this really implies we got to get outside of our universe which we can do not easily in our own universe but I can make a universe where you can look outside the box and here's the universe that I can create it's two-dimensional we can stand outside of it and here are a bunch of galaxies a part of the universe and I put them at regular intervals and at some time t1 here they are and you can see at time t2 the whole bit of the gap of the universe is bigger the galaxies have moved apart so if you were standing outside that universe it would be obvious that the universe was expanding but what would it look like if you lived in that universe well pick a galaxy any galaxy say that galaxy and to see what it would look like I just have to superimpose this image on top of itself placing that galaxy on top of itself right there what do you see you see exactly what Hubble saw everything is moving away from you and those that are twice as far away have moved twice the distance at the same time those are three times as far away and move three times the distance and so on and it doesn't matter what galaxy you picked any galaxy you see exactly the same thing so depending upon your mood either every place is the center of the universe or no place as a senator universe it doesn't matter what really matters it the universe is expanding and that changed everything because event the universe had a beginning and that had profound implications for science as well as theology the universe had a beginning which we now know is 13 while we except in Arkansas and Ohio and a few other places we now know is 13.7 billion years ago and it's amazing to me that we know that number to that accuracy as I'll talk about now this is so important for what I want to talk about that I want to tell you how we know this because Hubble this is physics so you measure things and Hubble saw that the velocity of distant galaxies was proportional to their distance so that means you have to measure velocity and distance so how do we do that well velocity turns out to the easy part these two Cowboys on the plane know how to in the prairies they know how to do that they're looking at strain and one says to the other I love hearing that lonesome wail of the train whistle as the magnitude of the frequency the wave changes due to the Doppler effect and what they're talking about is the well-known fact that that as a train is coming towards you the whistle sounds higher and as it's going away from you it sounds lower that's because the sound waves get scrunched up in front of the train and stretched out behind the train now it turns out for very different reasons the same thing is true for light so we look at distant galaxies if the light is stretched they're moving away from us and by the amount by which the light is stretched you can tell how fast now the long wavelength end of the visible spectrum is the red end of the spectrum so we say those things are red shifted and the greater the redshift the greater the velocity so what Hubble discovered is that objects that are progressively further away from us are moving away from us faster with a bigger redshift but that's the redshift how does he know the distance how do you know that they're progressively further away from us that's the hard part that's always been the hard part in cosmology because we don't have tape measures of that long we can't measure distance directly so we have to figure out a way to indirectly measure distance and that's the problem how do we do it well of course we use the laws of physics I could measure the distance to the back of the room by turning out all the lights here except for one of the lights in the back that might be a hundred watts and then if you're as old as I am you remember cameras when they had light meters and and if I had a light meter here and I knew that was a hundred Watts and I received one watt of light into my camera then I know how fast light spreads out or what how it spreads out over over space I could work backwards from one watt if I knew was 100 watts I could work backwards and find the distance to the back of the room so if the universe were populated by hundred watt light bulbs we'd all be fine but it's not so we have to find the equivalent we have to find something we call a standard candle something whose intrinsic brightness we understand and then we look at it through a telescope we see how bright it looks and we know how far away it is and that's the hard part and in fact they're so hard that this is Hubble's original data from 1929 and this is velocity versus distance so we saw that it was increasing this is one of the reasons he was such a great scientist too he knew to draw a straight line through that data set not at all obvious he also did something very important for the rest of us he got the answer wrong by a factor of 10 and astrophysicists have been trying to emulate that ever since in fact but but it's actually was profoundly significant because if he were found that the universe was expanding 10 times faster than it actually is and if you work that through if you know how fast the universe is expanding you can figure out how old it is because you can figure out how long it took objects to get out to where they are and if the universe were really expanding at this rate the universe would be one and a half billion years old which was a problem even in 1929 when this data was published because again except for Arkansas no high at a few other places we knew the earth was older than one and a half billion years old so it was really embarrassing that the earth was older than the universe for most cosmologists and and of course it's part and what's interesting about science is that if that had worked out that would have been a real problem for the Big Bang and we would have had to rethink things but of course he got the answer wrong we now know it's about almost 10 times smaller and the universe is 13.7 two billion years old now we can do better now because we have a new type of standard candle and here it is this is one of my favorite Hubble Space Telescope pictures well they're all my favorite actually but this is a galaxy long long ago and far far away it's not that far away actually it's only about 50 million light years away so it takes 50 million years for the light from that galaxy to get to us and it's a spiral galaxy like our own once you've seen one you've seen them all more or less and you know and this galaxy contains about a hundred billion stars as our galaxy does and you notice something strange here the center of the galaxy here contains about 10 billion stars and this star here is as bright as the whole center of that galaxy now how can that be well the first assumption would be that it's just a star in our galaxy that got in the way the picture which would be a good assumption but it's wrong in this case it actually is a star at the edge of that galaxy and it is burning with a brightness of 10 billion stars how can that be it's a star that's just exploded the greatest cosmic fireworks around a supernova and when stars explode they briefly shine with the brightness of about 10 billion stars for a period of about a month now these turn out to be wonderful standard candles now the problem is that stars don't explode very often well it's actually good news for us for the most part but it's actually important for us that they explode because you wouldn't be here if they didn't because it turns out every atom in your body essentially every atom in your body was once inside a star that exploded maybe more than one star because you see in the Big Bang the only elements that were created in the Big Bang were hydrogen helium and a little bit of lithium but the importance of Ulithi is important but for the rest of you carbon nitrogen oxygen iron all the stuff that makes your life livable those elements were created in the Big Bang the only place that were created is in the fiery core nuclear furnaces and the cores of stars and the only way they could get into your body is if the stars were kind enough to explode and in fact over the history of our galaxy about 200 million stars have exploded and so it is true that every atom in your body was it lean in at least one of them and the atoms in your left hand may have been in a different star than your right hand you're literally star children you're star dust it is without a doubt in my opinion the most poetic thing I know about the universe you are star children and well that's all peripheral but it's so nice I couldn't resist but these supernovae occur once every hundred years per galaxy so how can we study them that's the problem well simple we saw in a graduate student each galaxy 100 years about the right time for PhD [Music] graduate students are cheap if they die you just get a new one it's really easy but we don't have to do that actually we rely on another fact which most people don't realize and it's important is the universe is big and old and that means rare events happen all the time and if you took your went went out on a rare clear night here and held your hand up to the sky and and and held a dime-sized hole in there and held it up to a dark spot of the sky where there are no galaxies no stars no nothing with one of the largest telescopes we have on earth today if you looked in that region you could see a hundred thousand galaxies and if you think about it once 400 years per galaxy 100,000 galaxies on a given night you'll expect to see a few stars explode and astronomers do that they apply for telescope time and on a given night they'll see some stars explode and that means we can study them and here we can take movies of them before they explode and afterwards and either sort of peat so this is a star that's going to explode in this galaxy we can measure its brightness over the course of time most importantly we can measure its colors because those colors tell us it's a particular type of exploding star called the type 1a supernova and it turns out for reasons I don't have time to explain here the type 1a supernovae are great standard candles there's such good standard candles in fact that we can use them to study the expansion of the universe and in fact there's such good standard candles of the people who use them won the Nobel Prize in Physics this year just for doing that as I'll talk about okay in fact we can use them to make a much better Hubble plot than mr. Hubble could this is after the profound realization that on a log-log plot everything looks like a straight line but but even without that guide to the eye we can now measure the Hubble constant the expansion rate of the universe not to a factor of 10 uncertainty but to ten percent or five to ten percent accuracy so we know how fast the universe is expanding we've got that down finally and then the next question is is what will happen to that expansion and in fact actually that's the reason I got into cosmology my backgrounds in elementary particle physics but I realized as I'll talk about that that I could use those ideas to maybe to be the first person to know how the universe would end which which seemed like a good idea at the time so I got into the field and the reason that is the case that that if we're gonna determine the future of the universe based on how its expanding now we need to know about the gravitational pull that's slowing down the expansion and it turns out as I told you general relativity tells us that space is curved in the presence of matter now I can't draw a curved 3-dimensional spaces because we're three dimensional beings so but I can draw curved two dimensional spaces so you can see these but these are just guides to the eye our universe is three dimensional but it turns out that our universe can exist in one of three geometries so-called open closed or flat and I can picture them if they're two dimensional they're hard-hearted a picture if they're three dimensional but I can tell you what they'd be like for example in a cult in a closed universe if you look far enough in that direction you see the back of your head light would go around the University come back okay and all that sounds nice but what's really important is in a closed universe dominated by matter the universe will expand slow down and stop and rikka lapse an open universe dominated by matter the universe will keep on expanding forever and the flat universe it's just the boundary between the two of the universal expand and slow down and slow down and never quite stop and therefore if we're gonna know the future the universe we just have to know what universe we lived in I thought and therefore if I could determine the geometry of the universe by how much matter there was I would be the first person to know how the universe could end how can we determine how much matter there is very simple you weigh the universe it's easy how can you do that well I wrote a whole book about it once but it turns out that I can show you a simple way because now we've done it and I want to I want to give you a little history lesson here because I want to take some of you back to a kind leur gentler time this was 1936 and this is the journal science of prestigious scientific journal and this is there's an article that was written in 1936 called lens like action of a star by the deviation of light and gravitational fields okay but this is how the article began some time ago our W Mandal paid me a visit and asked me to publish the results of a little calculation which I had made at his request this note complies with his wish trying to try and publish that nowadays in science magazine you wouldn't get in now it turns out the author had some credentials his name was Albert Einstein so they maybe gave him a little leeway but he what here he published here was a calculation that he thought was incredibly irrelevant and unimportant he really had already shown that light could bend in the presence of matter and then he realized that if if you have a big enough mass and you have a light source behind the mass the light can go around it been to come back and be magnified as my glasses magnify things so space can act like a lens or if you had like a cutback glass goblet and I looked in this room now I see lots of different images of all of you and he realized that space could do that but he said it would never be observable he just thought the effect was so small be never observable he thought it was an irrelevant calculation this is the calculation from his notebook in 1936 and it was so actually he thought it was so unimportant that he actually forgot that he did exactly the same calculation in 1912 if you look at his notebook there you see exactly the same calculation but he did ignored it because it was so irrelevance and I really like the way he wrote to the editor after was published and he said let me thank you for your cooperation with the little publication which mr. Mandal squeezed out of me it is of little value but it makes the poor guy happy that's how science is done now it turns out it is more than of a little value because we use it to weigh the universe and here's a picture of the thing that Einstein said we'd never see this is another Hubble Space Telescope picture it's a cluster of galaxies clusters of galaxies the biggest bound objects in the universe they're about ten million light years across and almost all galaxies live in clusters and because are the biggest objects anything that could follow to anything will fall into a cluster and therefore if you can weigh the cluster you can weigh the universe now by the way I mean in this picture I should point out that every dot is a galaxy not a star and every one of these galaxies contain about 100 billion stars and this cluster is five billion light-years away from us that means the light from these galaxies left the galaxies five billion years ago before the earth and Sun even formed and many of the stars in this picture no longer exist and the civilizations that may have existed around the there's no longer exist so every time I look at a picture like this I I'm inspired it's kind of amazing to think of how as I'll talk about if I went significant we are but you don't have to be a rocket scientist however to realize there's something strange in this picture and that's these weird blue things these objects are in fact our multiple images of a single galaxy located five billion light-years behind that cluster and space has produced a lens it's magnified the galaxy it's distorted and it's produced multiple images they're all images of precisely the same object so this is proof that space is curved if you want and it's wonderful but now we can turn it around we know general relativity works so we can work backwards and say how much mass is in this system and where is it distributed so you can produce that image it's a complicated mathematical thing called an inversion but we can do it and we do what we get the following image so this is a picture of where the where the mass is in that system and the spikes are where the galaxies are but what you notice is most of the mass in the system is where the galaxies aren't there's 40 times as much mass in this system as meets the eye most of the mass is where the galaxies aren't and physicists because we're so creative call that dark matter because it doesn't shine and what we've discovered is not just in this cluster but in all clusters and in fact in galaxies themselves ninety percent of the mass of stuff in the universe is dark it doesn't shine and what makes that interesting is it turns out there's so much of it we're reasonably certain that it's not made of the same stuff as you and me because we can we know how many protons and neutrons are in the universe it turns out for reasons again I won't explain and there's about ten times more stuff here that can be accounted for by all the protons and neutrons in the universe and stuff that makes you out so we think that dark matter is some new type of elementary particle which makes it interesting because it's not just up there it's in this room it's going right through your bodies as you're not off during this lecture okay and that means we can do experiments here on earth to look for not on the surface of the earth but we go deep underground places the sub berry neutrino Observatory say why because the earth is bombarded by cosmic rays and they get stopped but we think these dark matter particles interact so weakly they go right through the earth on average without knowing it was there and if you build a detector deep underground you might have a chance of of interacting with one of those objects and their detectors like that being built all around the world in fact I'm pleased to say about 25 years ago I'd proposed the detectors that are now being used to do that and one of them any day might discover the dark matter particles and discover what is the identity of this stuff that makes up most of the universe but there's another way we may find out about it because well these dark matter particles were created around the beginning of time and we could detect them but there's another way you could actually try and produce them if you had a machine that recreated the conditions at the beginning of time and we have such a machine it's called the Large Hadron Collider in Geneva it turned on it didn't make a black hole that destroyed the world but it it it reproduces over a very small region conditions is appropriate to the very early universe so we may actually create those particles in the lab so it's a race between the dark matter detectors underground and the Large Hadron Collider to see who might discover the nature of dark matter but it turns out for our purposes it doesn't matter what it's made of how much of it is there because when we know how much of it there is when since it dominates the mass in the universe we can weigh the universe and we have now done that after 80 years of trying we know the answer and here it is I heard a gasp well actually when physicists find something important they always give it a Greek letter because we want to sound scholarly and this is Omega and Omega is the ratio of the total amount of mass and the actual universe divided by the amount you'd need to make a flat universe if Omega is less than one there's not enough matter to make a flat universe so it's an open universe if Omega is greater than one it's a closed universe if Omega is equal to one exactly it's a flat universe and therefore we have discovered with no and with no ambiguity that we definitively according to this don't have by a factor of three there's three times too little matter to make up a flat universe we live in an open universe case closed story over great well not great because it turns out we theorists knew the answer we always know the answer we're rarely right but we always know the answer and we knew that the universe was flat we knew was flat because it's the only mathematically beautiful universe and these damn observers were coming up with the wrong answer as they usually do and we were and it was really good discouraging for us but of course this is a very indirect way to measure the geometry of the universe you measure the expansion rate and you find out the total amount of matter and you put it all in an Einstein's equations and you see what what the what the universe is gonna do but wouldn't it be better to measure the geometry of the universe directly and we can now do that in the last decade or so and I would have never thought it was possible actually did well actually turns out I actually wrote a paper on it 20 years ago but I forgot I wrote it but but how can you measure the geometry the universe directly well let me ask you a simpler question how could you measure the curvature of the earth if you couldn't go into a satellite around the earth and you couldn't go around it it's very simple you draw a triangle and then you ask a European high school student what's the sum of the angles in a triangle and or maybe a Canadian High School's - you don't ask an American one I know that and they'll tell you it's 180 degrees and then you say that's fine but you learned your geometry from Euclid on a sphere I can do something a little bit different I can draw a triangle this way go along the equator I can make a 90 go up to the North Pole and make another nine degree angle come back down to the equator and I have a triangle with three 90 degree angles three times 90 is 270 that tells me I'm not on a flat surface so if you could draw a big enough triangle on the surface of the earth you'd know it wasn't flat well it turns out this mathematics works out not just for curved two-dimensional services but for curved 3-dimensional surfaces and if we could draw a big enough triangle in a curved 3-dimensional space and measure the angles we would measure the geometry the universe directly and we have been able to find such a triangle but again just in a little over the last decade by using the most important observable in cosmology the cosmic microwave background radiation the afterglow of the Big Bang it was discovered by accident in New Jersey of all places by two people they didn't know what the hell they were doing but they won the Nobel Prize anyway because you you don't have to know what you're doing to win the Nobel Prize you just you just have to be lucky and sometimes you just have to make an important discovery and they did they discovered the afterglow of the Big Bang so how do we what's this stuff well if we if we're the earth year and we look out at galaxies that are a billion light years away we're looking back a billion years in time as I've told you so we're really doing cosmic archaeology when we look out at the universe now if the universe is 13.7 billion years old you'd think if you look out far enough you'd see the Big Bang and a principle that would be true but we can't see all the way to the Big Bang for the same reason I can't see outside this room these walls are opaque and if I look out at the universe as I get I looked early in earlier times it was hotter and hotter and hotter and when it was only about a hundred thousand years old the temperature of the universe was about three thousand degrees and at that temperature the dominant stuff in the universe hydrogen gets broken apart by radiation into protons and electrons and every time it tries to combine it gets broken apart again so matter is low longer neutral before this time it's what we call a plasma of charged particles and plasmas are opaque to radiation you can't see through them so the universe is opaque back at these early times so if I could run the film forward it's opaque opaque opaque and then boom it cools down to three thousand protons capture electrons matter becomes neutral and then it's transparent so just like I can see that wall my laser on that wall there it's because the light gets absorbed and re-emitted by atoms on the surface of the wall but the air between me and the wall is transparent so I can see all the way back to it so one of the predictions of a Big Bang is is that there should be radiation coming at me from all directions from this what so called last scattering surface and the radiation will have cooled from 3,000 degrees now to three degrees and that's the radiation that these observers discovered by accident in New Jersey actually many of you are old enough to have seen it yourself I should point that out because you're at least as old as me in the days before cable TV do you remember those some of you do TV stations used to end and then maybe a test pattern and then they'd be static one percent of the static on your television screen is radiation left over from the Big Bang so disconnect the cable tonight free yourselves and then and then look at the radiation from the Big Bang it's kind of amazing now on this surface one important distance scale occurs this distance here it's band by one degree this distance corresponds to a hundred thousand light years now if the universe is a hundred thousand years old and this is a hundred thousand light years Einstein tells us no information can propagate faster than light and that means that nothing that happened over here at that time could affect anything over there because light can only travel that far but it also means if I have a lump of matter say that's this big it starts to collapse due to gravity and heat up and all sorts of things happen but if I have a lump that's this big across it doesn't even know it's a lump because gravity can't travel across it and the age of the universe so it's like wily coyote if you remember the cartoons he goes off the cliff and he sort of stands there for a while before he realized he's supposed to fall that's the case with these big lumps they won't start to collapse so the biggest lumps that we'll have started to collapse significantly are this big across and that gives us a triangle it's a triangle unknown distance away from us we're one length of it is a hundred thousand light-years across and in a flat universe what really defines a flat universe is light rays travel in straight lines so if you asked what angle that will September I a hundred thousand light year across ruler it will September one degree but in an open universe where light rays diverge as you go back in time the ruler will look smaller it will September that angle it looked like half a degree so the ruler will actually look smaller in a closed universe where light rays curved inward is to go back in time the angle spanned by that ruler will be bigger it looked like maybe two degrees so all we have to do is take a picture of those lumps in the cosmic microwave background radiation and ask are they half a degree one degree or two degrees and we can directly measure the geometry the universe and that's what we've been able to do this was the first experiment that was able to do it significantly it's um it's called the boomerang experiment and Antarctica and it was a balloon and a microwave radiometer sent way above the Earth's atmosphere and it and it went around the world which is easy to do in Antarctica is it the South Pole you do this just right but they weren't quite there they were its McMurdo and it took about two weeks for this balloon to go around came back to where it started which is why it's called the boomerang experiment and it looked at a small region of the sky and measured very accurately the microwave radiation coming from the Big Bang and this is a image of the data it returned a false color image but nevertheless an image these are the lumps the hot spots and the cold spots in the microwave background radiation that lay by the way this is a baby picture of the universe this is how it looked when it was a hundred thousand years old and these are the lumps that would later collapse to form all the galaxies and stars and planets and aliens and everything but what we care about here I've superimposed it on this image just to give you a sense of scale is we asked how big are those lumps and to do that well we can draw a universe on a computer and here's the actual image again in different colors and these are universes we create on a computer a closed universe a flat universe in an open universe and you see in a closed universe the average hundred thousand year light year across lump should look that big to us but that's bigger than these lumps and in a open universe the average hundred thousand light year across lump should look about that big but that's smaller than these lumps but just like Goldilocks in a flat universe it's just in fact we now know to an accuracy of 1% that the universe is flat so we pat ourselves on the back but there's a problem if you've been awake some of you have I noticed 10 minutes ago I showed you that there's only a there's only one third as much matter as you need to make the universe flat that's a problem because the universe is flat we're missing 70% of the mass energy of the universe where could it be well if it isn't where galaxies are it must be where galaxies aren't but what is where galaxies aren't nothing ok let's go back to Einstein he said it was his biggest blunder he wanted to throw out the cosmological term but the problem is it's kind of like putting the toothpaste back in the tube after you get it out if Einstein hadn't developed the cosmological term someone else would have because now through the miracle of modern mathematics we have a very different understanding what through the miracle of modern mathematics we can rewrite this equation now that's that's a small step for a mathematician but a giant leap for a physicist okay not not not that it's that hard to take that term and put it over there that we can do but you see in physics equations mean something unlike in mathematics and and and and in this case the stuff in the left hand side corresponds to geometry but on the right hand side to energy so when we put that term over here it corresponds to a new type of energy in the universe and what could produce such a term only one thing nothing and by nothing I mean nothing I mean if you take some space and get rid of all the particles and all the radiation and everything there if that space weighs something it will give such a term okay now that's crazy of course space empty space can't weigh anything it's you know if you ask a four-year-old I was gonna say if you ask two Republican candidates for that would work if you ask a four-year-old what's the end of GMT space you're gonna tell us-- nothing because you know there's nothing there it's a good answer unfortunately the four-year-old hasn't taken quantum mechanics and relativity because you put those two things together and it turns out empty space ain't so empty anymore in fact empty space is a bubbling boiling brew of virtual particles popping in and out of existence at a timescale so short you can't see them now that sounds like philosophy if you can't see them but it's physics because while you can't measure these particles called virtual particles you measure you don't see any of them you can't measure them directly you can measure their effects indirectly and that's what this image shows here this is an actual calculation of what the space inside of a proton looks like it's a calculator short of the Nobel Prize ceremonies about seven years ago by the people who developed the theory that allowed us to calculate what the space inside of a proton looked like these fields here are popping in and out of existence and they are relevant to your life because you may have learned in high school that protons are made of particles called quarks three of them but it turns out if you add the mass up of those quarks they only add up to 10% of the mass of proton 90% of the mass of protons and neutrons comes due to the effect of the energy of these virtual particles and since they make up your body 90% of your mass is due to these things and you wouldn't be around if it wasn't for them so virtual particles really exist even though we can't see them now if we can do the calculation of how much energy they contribute to a proton one of the most exciting calculations and physics we've been able to do we can then apply the same reasoning and try and calculate how much energy these virtual particles should give to empty space and we do that we go from one of the greatest calculations in physics to one of the worst you can't see the one there but we calculate that in fact the energy of empty space should be roughly a gazillion times the energy of everything we can see and that's just impossible if it was that big then the universe would be a bit expanding so fast nothing we would never reform this is indeed the worst prediction in all of physics we come up with a number which is a hundred and twenty orders of magnitude too large okay and it's okay it's been around since I was a graduate student and it was so bad we never talked about it but we knew the answer because we're theorists we know what the answer was the answer was zero it had to be zero because zero is a pretty number but more importantly we you couldn't imagine calculating a number that are cancelling a number that's this big with another number leaving saying something leftover in one hundred and twenty first decimal place that's crazy but you can make zero really easily in in physics because you're gonna have new mathematical symmetries that make exactly equal in opposite things like the total charge of the universe cancels out is exactly zero so we knew that there was some new symmetry of nature that we hadn't discovered that would explain this and we could go to bed at night but the important thing is the universe is the way it is whether we like it or not something I have to keep you're minding people it's vitally important to recognize that and therefore we may not you know we may think the only sensible universe is one that has the number zero here but physics is an empirical science and just hoping Eric arguing it's logical or sensible is irrelevant what's logical and sensible is completely irrelevant it's up to the universe book to tell us what's logical and sensible not to us as well as I'll get back to when I talk about theology a little bit later so we actually have to measure the energy of empty space how can we do that quite simple because it turns out that remember the energy of empty space if it has energy it will produce a gravitational repulsion that's what the cosmological term did and therefore instead of slowing down like any sensible universe should do it was dominated by the energy of empty space it should be speeding up and in 1998 two other groups of astronomers who didn't really know what they were doing well they knew what they were doing they didn't know why they were trying to measure the rate at which the universe was slowing down because they wanted to determine exactly how much mass there was and this is was the cover of science magazine actually in 1998 it may not look like much but it changed the world because this is the Hubble plot that I showed you earlier that rate of it and we're looking to see if it's curving and to see about that I could just draw a straight line through that data set bring the whole thing down horizontally and if the universe were decelerating as any sensible universe should do all these distant supernovae should be found lying along this curve but they're not they're not even below the straight line they're above the straight line what does that mean well one of two things the date is wrong which usually is or the universe is accelerating the expansion the universe is speeding up and if just for fun you want it to fit and say how much energy would we have to add to empty space to fit that data you get exactly what we're missing if you put 70% of the energy of a flat universe into empty space everything works so that is the cockamamie universe in which we live completely different than we imagined a for 70% of the energy of the universe resides in nothing 30% in some form of dark matter that's made of self different than URI and a little bit a bit of cosmic pollution that's left over to create everything we can see so the first important lesson of this talk is you are far more insignificant than you thought you get rid of awesome the galaxies and everything we see and the universe would be essentially the same so so much for a universe that was created for us we're relevant okay now this is so important it's changed everything and it's the reason I wrote this last book and and it's it's it's given us clues that are amazing about a universe that could be come from nothing the dominant energy in universe resides an empty space we have no idea why it's there and if anyone comes here at one of these lectures and tells you they know why it's there they're lying especially if they're a string theorist okay its existence is probably tried to the very beginning of time and it will determine our future as I'll talk about now talking about our future remember I want got into this business because I wanted to know how the universe would end and and and there's a simple way to determine it using high school physics or kindergarten physics probably nowadays I don't have a coin here but if I had a coin you know we can determine what's gonna happen the coin I throw it up comes back down I throw it up faster coming back down longer I throw up really fast if there's no ceiling and it doesn't come down at all how can you determine when something's going to escape the earth well it turns out we can do that and then and and all of you will remember this with fondness we it turns out the details are important but in in we determined that there are two terms to the energy when I throw something up there's a positive piece called kinetic energy the energy of motion and a negative piece that comes from the gravitational attraction and we turn physics into bookkeeping if the total sum of these two things is bigger than zero this coin will escape if it's less than zero it'll return so if the positive piece is bigger than the negative piece meaning you make the velocity big enough it'll escape if it's not it'll come back down and and and when it's exactly equal which is the escape velocity from the earth 11 kilometers per second the object will gradually escape but never quite slow down and stop so the interesting thing is that this applies not just to a coin but to the universe because remember here's the picture I showed you from Hubble and if the universe is the same in all directions then what will happen any small region of the universe will happen to every of the universe so all you have to do if you want to calculate whether the universe is gonna expand forever is ask what will happen to any given galaxies in a given region say we're at the center we look out at that galaxy and to determine if it's going to escape we just calculate its total energy well how do we do that well there's a positive piece due to its motion well that comes from the Hubble constant we've measured that we measured the expansion rate we know how fast galaxies are moving there's a negative piece coming from the sum of all the mass in this sphere attracting it well we know that because we've come in the dark matter so we compare the two and if B over a if the negative piece is bigger than the positive piece so B over a is bigger than 1 this will come back down and the universe will collapse if B over a is less than 1 it'll escape the universe will expand forever now the amazing thing truly amazing is that B over a is nothing other than this quantity Omega which I showed you earlier and we've measured Omega and therefore if B over a is equal to 1 if we live in a flat universe that means B is exactly equal day well if B is exactly equal day the positive piece is exactly equal to the negative piece and the total gravitational energy of the universe is 0 and we now have discovered we live in a universe whose total gravitational energy is 0 now if you were going to create a universe from nothing what would you make the total energy be it didn't have to work out this way but we have found in fact that are the energy of our universe is in fact nothing zero zip and this begins the saag I want to talk about in the last few minutes of this talk which will last over the time allotted but anyway nothing number one see there's different kinds of nothing I've discovered because I you know as I've tried to explain how you can get a universe for nothing I get countered by different people as you'll see the universe the first kind of nothing that you'd imagine nothing would be the nothing in the Bible or the or the ancient philosophers were it's an eternal empty dark void that's pretty good example of nothing right but turns out that kind of nothing is always unstable deforming something why well first of all that kind of nothing is fruitful of virtual particles that pop in and out of existence well they're not real particles so that's not something but when we allow them to have gravitational attractions when we add gravity to the mix then you can create virtual particles that pop in and out of existence but if their gravitational attraction is strong enough then the gravitational attraction has a negative energy which counters the positive energy that it took to create them and their total energy can be zero and if that's the case they will be produced and continue to be produced and we are guaranteed in a universe full of empty space if we wait long enough something will arise because nothing is unstable so a first answer to the question why is there something rather nothing is quite simple nothing is unstable now that should be satisfactory but of course it's not because that kind of nothing can produce something and that bothers people so I'm told well that's not really nothing that's not nothing because that nothing has space in it may not have particles but there's space and where did the space come from should I say ok well ok that's what well actually I want to go back because I want to make that that point you can create something from nothing in a universe full of space and it was one of the biggest arguments why we couldn't create something for nothing because something has energy and it's appeared to violate the rules and the point I want to strongly stress is that a universe full of something can have zero energy and therefore there's no laws of physics that forbid creating such a universe but now let's get to a universe without space if you add gravity to quantum mechanics if you take a quantum theory of gravity that instead of having virtual particles flushing in and out of space you'll have virtual universes because gravity is a theory of space and if gravity become if space becomes a quantum mechanical object it will fluctuate and in a theory of quantum gravity you're guaranteed to spontaneously create virtual universes that pop in and out of existence regions of space that literally didn't exist before but that's not something because those universes will collapse just like it will disappear just like virtual particles unless their total energy is zero now the simple thing would be say look we live in a flat universe it's got zero total energy well unfortunately it's not that simple if it was be great but I actually want to tell you the truth we can't calculate the total energy of a flat universe it turns out because it's infinite and there's and there's a lot of ambiguities the only universe whose total energy we know is zero is a closed universe that we can calculate the total energy of and we know it's zero but we live in a flat universe so what gives well a closed universe if you create it of total energy zero a closed universe will in general collapse as I showed you and it turns out if the closed universes you create are microscopic in size in general that collapse at a time of 10 to the minus 43 seconds much shorter than the length of this lecture ok or even how long it seems the only way to make a closed universe to last long enough if after you created you you put some energy in empty space and puff it up well it turns out our fundamental theories of particle physics predicts exactly that phenomenon is called inflation it's been it's a real kind of inflation we predict that the early universe actually increased in size by a volume of 10 to the 90th in a time scale of about 10 to the minus 30 seconds or so and it turns out that that's not just a prediction that's not just a you know it's a random statement that we like to invent it late at night if you have such a phenomenon if the universe that early times is governed by the energy of nothing a huge amount of energy nothing well it turns out they'll be quantum fluctuations that nothing due to particles virtual particles and they'll get frozen in after inflation ends after that energy of empty space goes away and what kind of fluctuations will they produce the proof Salam and the kind of lumps they'll produce are exactly the kind of lumps we see in the cosmic microwave background radiation it agrees exactly with what we predict if that's true that really means we are all here due to quantum mechanics all of the fluctuations a little lumps are later produce galaxies and planets and people started out as little quantum mechanical fluctuations it's remarkable but more importantly when a universe puffs up when a closed universe puffs up just like blowing up a balloon it looks flatter and flatter and flatter and the prediction of inflation is that the universe at the end of this period would look to arbitrary precision flat so the only kind of closed universe that could survive long enough for people to evolve in it and planets deform is a universe that's flat and that's the one in which we live in so if you were going to create a universe from nothing by quantum mechanics the only universe that you could create from nothing that would be live this long must appear to be flat exactly what we see so our universe can come from nothing no particles in space no space you think that'll be good enough but isn't because that kind of universe can come from nothing and some people are bothered by that so they say well look no good you don't have particles you don't spaz but you got the laws the laws who created the laws well let's dispense with that even the laws of physics themselves may be accidental the last result of the last few years of physics and to show you that I have to show you one more figure and then we're done with the figures this is a brief history of time this is this is the density of matter in the universe as the universe expands it goes down and this is the energy density of empty space remains constant because there's nothing to get diluted and this is where we live now we think where the energy of empty space is about three times the energy of matter right there but if you look at this picture you should be disturbed because we live in a very special time it's about the only time in the history of the universe when the empty space is equal to the energy of matter but Copernicus told us that's not supposed to be the case why 13.7 billion years after the Big Bang this random time should we live in the only time in the universe when those two numbers are about the same well physicists have come up with a proposed solution that is the galaxies exist why is that the case well let's say the energy of empty space were different 50 times bigger say well these two curves were crossed at a different time what time would that be well when galaxies first formed but if the energy of empty space were bigger than the energy of matter before galaxies formed then galaxies wouldn't form because the repulsive force would beat out the attractive force and no galaxies would form so that people have recognized that maybe this is telling us something and it's led to something I call anthropic mania if there are many different universes and the energy empty space can vary in each one then only those in which it's not much greater than what we measure today will galaxies form and only then will stars and planets form and only then will astronomers form so the universe is the way it is because astronomers are here to measure it then you laugh it sounds ridiculous but it may be true it could be that in fact there are many universes and in fact the reason we're here is because we're here it's like a I mean it sound too many people that sounds religious it sounds like the universe was made for us but that's not the case it's more like a kind of cosmic natural selection it would be very surprising to find ourselves living in a universe in which we couldn't live it would be very sort of what we'd be very surprised in fact and so therefore this tells us that it may be that this fundamental quantity the energy empty space is just an accident it's different in different universes and live with it it's very frustrating except particle physicists have jumped on this because particle physics is way ahead of cosmology because cosmology there's one fundamental number we don't really understand the energy of empty space but in particle physics there's many more numbers we haven't understood for much longer we haven't understood why gravity is the weakest force in nature why the protons 2,000 times have you an electron while there are three generations of elementary particles there's a whole bunch of things we haven't understood and particle physicists have jumped on this is it look maybe we don't have to understand anything maybe it's all an accident maybe all of these fundamental quantities are just accidental and if they were any different than they are then we wouldn't be here and this means you don't need a theory of everything you just need a theory of anything and we have such a theory it's called string theory so I just want to show you one one slide summary in string theory one guy says to another I I just had an awesome idea suppose all matter and energy is made of tiny vibrating strings and the second guy says okay what would that imply first guy says I don't know so that's the story of string theory for the last 40 years okay I'm being a little hard on but still it used to be taught as the theory of everything but the problem with string theory is it predicts a universe that has maybe 10 or 11 dimensions we don't live in such a universe so what how can you how can that be consistent with what we see well a lot of dimensions 6 or 7 would have to curl up well it turns out there are lots of different ways to curl up those extra dimensions 10 to the 500 and each different way you curl them up produces a four-dimensional universe with different laws of physics so in string theory you predict not just one kind of universe but maybe 10 to the 500 and one of them is guaranteed to have the if you think the properties that we measure now that is that science probably not because if you have a theory that can be consistent anything you'd ever measure it's not a theory but whether you we like or not it may be true and if this is the case it addresses that final problem because it means that the laws of physics themselves are completely accidental they come into existence at the same time the universe comes into existence and in that case this this multiverse as we call it many different possible universes is very similar to the prime mover of Aristotle or or the the first cause of the Catholic Church because the big problem the reason people want to have a creator or a mover is because every we're told that every every effect must have every beginning has a cause it's not true but nevertheless if your bothers you you need something that's kind of eternal and outside our universe some people call that God but the multiverse serves exactly the same purpose but there's a big difference it's well motivated we I mean that not facetiously I mean it seriously because when I've debated certain people certain apologists they say well you invented the multiverse because you didn't want God that's not the reason we've been driven to it we've been driven to it because the laws of physics based on observation have driven us there it wasn't a philosophical prejudice that led us there it was nature so the last thing the last thing I want to mention and I will go five minutes overtime is because it's in deference to my late friend Christopher Hitchens who I used to explain try and explain this too and he he would he point out to me that and he was writing the foreword for my new book but when he got too ill and wasn't able to complete it he said nothing is heading towards us as fast as can be because I pointed I said what will the future be like and the future is amazingly interesting and depressing because what will physicists in in the far future see in a planet around a star in a Milky Way galaxy a hundred billion years from now or 200 billion years from now well if the universe is speeding up then all the other galaxies we now see will be moving away from us at faster than the speed of light by that time which is allowed in general relativity but when they are they won't be visible so observers in the far future will discover electromagnetism in quantum mechanics and general relativity they're build telescopes to look out and they'll think they live in the universe we thought we lived in a hundred years ago they'll see one galaxies they're galaxies outside of it they'll see an eternal void a darkness an empty what looks like a static universe all evidence of the Big Bang will have disappeared for such observers and eventually as stars in our galaxy will die out and and the universe will become cold dark and empty nothing so the simple answer in that case to the question why is there something rather nothing is Right simple just wait there won't be for long and again I say had a little fizzy and I don't say it facetiously because it addresses another incredible conceit that humans have in biology we seem to think we're the pinnacle of evolution that it stops here of course it doesn't stop life on Earth continues to evolve where continued to evolve in our own ways similarly people think the universe that we now live in is the pinnacle it was all created for us but the universe the future won't be anything like universe of the president it's not at all the case so in fact that's the second lesson I want to tell you first thing was you are far more insignificant than you thought and the second lesson is the future is miserable I think I'll skip Einstein versus God because he wins I wanna I want I do want to end and well the only well let me just point out you can read this if you want doesn't matter what the story I presented to you today does not say that the universe came from nothing it says that it's plausible that the universe could come from nothing and that I find as remarkable unbelievably interesting and amazing that we've gone to the point where in fact we can imagine a plausible series of steps by which nothing can become something it's kind of and Richard Dawkins was kind enough to write that afterward for this new book and he was he was very kindly compared the new book to the origin of the species which I thought was a little extreme but still in an in spirit there's something there because what Darwin did was say before Darwin life was a miracle the diversity of life on Earth had no explanation and what Darwin show was a plausible mechanism by which the diversity of life on Earth could occur he didn't know about genetics he didn't know about the anybody showed plausibly how it occurs and now we know we are now at the stage in cosmology where we can have a plausible mechanism by which the universe can come from nothing without any divine intervention doesn't require it but it's plausible and as my friend Steve Weinberg's would say science doesn't make it impossible to believe in God it just makes it possible to not believe and and and and that and the multiverse as I point out and you could their argument I give is a lot stronger in the end of the book says to me that God is unnecessary or a best redundant and I find that remarkably satisfying so let me conclude science has demonstrated that a universe from nothing is not only plausible but the other thing is it's likely because if you wanted to describe the characteristics of a universe that would come from nothing it would have precisely the characteristics of the universe we measure but more importantly what we mean by something and nothing as I said has completely changed from the time the classical philosophers and theologians first raised the question so I'm often told you're not addressing the philosophical nothing and my answer is who cares the philosophers nothing is irrelevant it's the physicists nothing that matters the question why is there something rather nothing is not the interesting question the interesting question questions are how did the universe form evolve and how can we find out those are the operational questions those are things that matter not stale old philosophical issues and those are the questions we are trying to answer right now and we have come up with the most amazing discoveries it's worth celebrating and we're sharing so in fact you know I told you that you're insignificant and the future is miserable but you shouldn't be depressed you should be excited because we're here at this random time in the middle of nowhere and we've evolved the consciousness that allows us to appreciate these amazing facets of the universe and instead of being depressed we should make the most of our brief moment in the Sun but if you if you want to think in the future here's something that may make you a little happier the future will be such in the future we'll be lonely and ignorant but dominant and those of us who live in the United States are quite used to that thank you very much [Music] we're still here Wow I didn't expect that thank you for staying most of you so I have some questions yes okay okay we'll start here how did you I mean you mentioned that maybe in the other universe could take other values but how do you prove well okay the question I repeat the question right the question was in particle physics we've argued that there could be many universes in the fundamental constants take different values and in the multiverse I've argued that that happens how can we prove that well the first case in in in there a number of different possibilities of proofs a multiverse the one I showed was from string theory but it turns out inflation also produces a different kind of multiverse but let me just take the string theory example as one example there you can actually in certain cases mathematically calculate what what the forces which forces will exist and what the spectrum of particles would be mathematically if you come to so-called compactify these extra dimensions and so you can look for 11 dimensional universes that compactify to four dimensional universes that have four forces leftover which is like the ones we see you can look for ones that may have three generations of elementary particles but you'll see that each different way you do it you'll end up with different spectra of particles and different forces which is how we know that the laws are different so we can show mathematically that in those universes each compactification will produce a different set of laws of physics the nice thing would be to do which way they haven't been able to do and it would make it exciting if we could is if we somehow found that probabilistically you know you could show that every universe that had four forces in this case also had a spectrum that was like ours and also an energy density was like ours and that would be give you great confidence that maybe this picture worked but that but no one's been able to do that mathematically yet so it's just it's just a speculation but at least we know that if string theory describes reality and there's no evidence that it does I want to emphasize that there's no evidence that they're extra dimensions there's no empirical evidence that string theory is anything but a mathematical idea but it's a well-founded one if it was true then we have good evidence that that the laws of physics are accidental and I won't go in it turns out inflation gives another argument for why that would happen and it very well to find an even more calculable way but since the picture I show them some string theory that's the one I'll give you take a few more questions we take one from the back way in the back over that yeah you yeah you you you you light what's the most important property that makes the universe observable seriously for us it is that we can detect photons for the most part but what's really neat is that we don't need to detect photons to detect the universe we certainly don't need to detect visible photons what is one of the reasons all the reason all of this is possible is because every time we open a new window on the universe were surprised that's why it's worth building new windows like the James Webb Space Telescope or or gravitational wave detectors because what we find is visible light is just a tip of the iceberg we build x-ray telescopes and infrared telescopes and we use all of them to expand what we can detect and then we build detectors that might eventually detect gravitational waves which will be the future because then we'll be able to take waves that came not from when the universe was a hundred thousand years old but we'll be able to detect signals of when the universe was a millionth of a millionth of a millionth of a millionth of a millionth of a second old so we just expand our eyes by finding new ways to detect things which are previously invisible before and I think that that's why we asked why should we build these things or the Large Hadron Collider which allows us to observe the universe on scales so small we never could have seen that way before and the answer is if we stop doing that we'll stop asking questions and and you know people often say but why should we spend money on this I mean I am the first to say that every bit of my research has absolutely no prac to go value whatsoever except for understanding where we came from and to me if you stop asking those kind of questions what's the point to being around I mean it always amazes me when people say ask me well what's the purpose of what you do will make a better toaster will Evan be you know I have a faster car and the but they never asked that a mozart or or or of picasso you know why make a painting why make of a roomful symphony the answer is it's what makes being human worth being human okay i should end there but i'll have to think of something else profound I think I'll take two or three more questions okay you're there in the center yeah I haven't mentioned the Higgs boson which of course is a great interest to people because we're that's one of the things the Large Hadron Collider is being built to detect they expose on it relates to another kind of remarkable cosmic accident it really is I told you quarks have mass but but they don't account for the mass of the proton but where do they get their mass from well it turns out our ideas based on experiment are really remarkable they say that all elementary particles actually have no mass whatsoever but what happens is there's this background invisible field permeating all space and it's kind of like trying to swim through molasses elementary particles are moving through that some of them interact more strongly with that field and have a greater resistance to their motion and act heavier and other ones interact with it more weakly and act lighter so all mass which is responsible for our existence is just an accident of the fact that this field formed what sounds nice but how can you know that well if you if you smash empty space with enough energy you excite this field and you pop out real particles that are associated with this field called Higgs particles and we think that in fact we can smash empty space if you wish hard enough with the energies we've got at the Large Hadron Collider to produce these real particles and if we do and in fact as you probably know there's tentative evidence announced a few months ago at CERN that we've discovered the Higgs bosons if that's the case to me it has apps amazing because it's this theoretical edifice we built up over 50 years without any direct evidence for this idea and it will be true and it and it is it is if you're a theoretical physicist and you're sitting you know in a room at night and it you to think that something you develop might actually relate to the real universe and is actually there it's terrifying and and it will really be amazing if it's true it I will be surprised because again if you're a theoretical physicist the most important to States to be in as off and say are either wrong or confused because it means there's more work left to do and and most of our ideas are wrong which is why you know it takes time and effort and this would be amazing as if this idea we've developed is actually true but it seems to be true and we'll know within a year at CERN they'll be able to redo the experiments and with enact better accuracy and know if the particle they discovered is a Higgs particle and it really will mean that we've answered this profound question about the universe such as why elementary particles have mass and it would be amazing truly ok I got to pick two more I'll take one in the back way over there and then one in the front yes you over there yep yep okay well the good okay the question is as the theoretical physicists how can I explain consciousness the answer is I don't have to that's why I'm a theoretical physicist I'm not a biologist or a neurologist or out for a psychologist or a philosopher consciousness is really hard and I mean one of the Institute that I run one of the things we're worrying about is conscious development of consciousness but it's a really hard question it's much harder than understanding the universe and that's why I do the easy stuff okay yes last question okay the universe is expanding and there's more nothing space why isn't there more stuff being created well the answer is that well the answer is that these that that creating stuff takes a long time first of all the fluctuation or whatever it is that proves to our universe produced a whole space okay with with that was incredibly dense and incredibly hot that kind of thing should happen very rarely okay but the other thing is it could be happening right now all around us because you get you see it's hard to think of space where there was no space before it's a hard concept but if we are creating new universes if not we but if nature is creating new universes it's creating space where there was no space before so it's not space in our universe it's a whole new universe a universe that becomes in fact it from the outside it would look like a black hole microscopic black hole it would shrink down and heat from the inside it would get bigger but it would quickly remove itself from our horizon so it's a space that you're creating universes that aren't part of our universe so it's not too surprising you don't see him okay and that's perhaps a good confusing way to end this life thank you very much [Applause]

Channel: The University of British Columbia

Views: 89,913

Rating: 4.7129631 out of 5

Keywords: IKBLC, earth, space, space exploration

Id: LQL2qiPsHSQ

Length: 77min 35sec (4655 seconds)

Published: Tue Mar 06 2012