Lawrence Krauss: A Universe from Nothing

for years our universe and how it came to be was really a mystery theologians and philosophers have filled in the gaps over the centuries but recent developments in science may give us a clearer understanding on the past present and future of the universe here now to tell us more about these developments Lawrence Krauss theoretical physicist and the author of a universe from nothing why there is something rather than nothing that's a great title I thought so welcome back to TV oh it's nice to be back remind people you were with us number years ago at the we did program in Waterloo yes at the yes please I space exploration right on the print the printer Institute and how are your arms today they're well actually they're pretty tired I just came in from Australia I'm a good straight man I'm just going to set you up all day long yeah so thank you for making the long slept from Australia to here today we're really grateful to have you and I want to know just off the top when you first published this book you've got the paperback out now but when you first published a universe from nothing what's our reaction did you get well I was actually surprised at the strength of the reaction the idea people were for me the idea was to explain the remarkable discoveries in cosmology about the universe in the last 30 40 years that tell us we might have come from nothing but the reaction to this to saying that we've sort of potentially answering this age-old question why is there something rather nothing was really strong people were offended because after all for many people it's kind of the last bastion of God and if signs of Fringe is on that area it's very terrifying and I was surprised enters not just from theologians but from philosophers in particular that this this philosophical question of can something come from nothing the fact that we kind of moved to move the ground underneath their feet really offended some people and you were surprised by that offense yeah I shouldn't be offended well I wasn't surprised by their theological offense because I was attempting to offend but but the philosophical one surprised me more so why'd you write the book well I wrote it because our picture of the universe has changed amazingly I mean these are some of the most amazing ideas and discoveries in human history and they've they confront common sense but they also give us a new sense of where we come from which is really what science is all about really the questions people ask I mean for me the value of science is sort of cultural it changes the way we think about our place in the cosmos it's not just the technology it's the ideas like art music and literature and what more profound idea than whether we could have come from nothing and and the fact that that the universe what we discovered is that the universe looks like a universe that could have come from nothing does that mean it did not it doesn't guarantee it but the fact that that's the case the fact that's that's even plausible is we're celebrating it would just explain what that means that it looks like it could have come from nothing well you know we live in a universe of four hundred billion galaxies each containing 100 billion stars there's a lot of stuff out there and it and its ever all common sense tells us that all that stuff couldn't come from nothing without some supernatural shenanigans it seems to violate the laws of physics but what we've discovered is that in fact it's possible in fact the total energy of the universe could be zero which is a first clue that maybe it could come from nothing that when you in in in in physics there's there's once you include gravity there's positive energy and negative energy and our universe appears as if its total energy could be precisely zero which is the first hint that maybe it could come from nothing that and the great discovery which is one of the real reasons I wrote the book this discovery that nothing is much more complicated than we thought that namely empty space you take a region of space get rid of all the particles and all the radiation and so there's nothing there that empty space weighs something and we don't understand why and so that wonderful mystery is worth talking about ok this is going to be the first time of many times over the next two days that I say to you I don't understand I need you to help me on this energy is zero I look all around there's lots of energy everywhere how can you say that the energy of the universe is zero well let me take you back to one of your favorite times high school physics okay so I throw a coin up in the air comes back down I throw it up faster goes a little higher comes back down if I throw up really fast it doesn't come back down as all long as we forget the roof and the rest of stuff well we teach high school students one way to calculate that we turn into accounting it turns out the energy of the coin has a positive piece we call it the kinetic energy and a negative piece which is the potential energy due to gravity it's actually negative and we add those two pieces up and if you make the positive piece big enough so the total energy is positive it'll escape without coming back down if the total energy is exactly zero where the positive energy from the speed is equal to the negative energy from gravity then it'll it'll just escape it'll it'll go up slow down never quite stopping so you see gravity has this negative piece and if you can balance the two the total energy can be zero and in fact what's amazing is it turns out we one of the things we've measured with our in fact one of the other great discoveries in the last twenty years is we've measured the geometry of the universe Einstein told us that space is curved in the presence of matter and one of the big questions of cosmology the 20th century in fact was what's the curvature of the universe is it so-called open closed or flat flat being the boundary between a universe that closes on itself and one that's open and it turns out that we've discovered the universe is flat as we theorist new for me reasons we may talk about it is not but the University the universe is flat in the three-dimensional sense it's not flat like a pancake it's flat like it's the universe you always thought you lived in where the x y&z axes are perpendicular and main perpendicular well what's amazing as it turns out in a flat universe the energies add up to be precisely zero the energy of every galaxy all the galaxies are moving away from us Hubble discovered that in 1929 everywhere we look all the galaxies on average are moving away from us if you measure their speeds and then you work out the attraction the to add up to precisely zero an amazing discovery that that confirms this notion that not only is universe flat and mathematically beautiful but begins to give this inkling that maybe maybe maybe we could come from nothing ok but let the record show you're talking physics not English here absolutely physics not English well try to make the tooth balance if you're talking physics not reality in reality there's lots of energy here but it doesn't talk like realities physics is reality but you know when we look on earth yeah there's lots of energy and it's a really weird concept and throughout our discussion I suspect we may violate common sense and the point is why should the universe at bay our common sense we evolved on the savanna to avoid lions and you know we didn't we didn't evolve to understand quantum mechanics and so one of the great things about science is it forces us to refine our idea what's common-sense it forces us to have our beliefs conform to the evidence of reality rather than the other way around the universe may not be like we'd like it to be but it doesn't really care why is defining nothing considered so controversial in your business I don't think it's so controversial my business I think well look because we change the that we change the notions I mean well actually we've begun to define the notions what is nothing well I think the idea of nothing is the absence of something right but that makes nothing a physical quantity not a philosophical one because something's physical then the absence of something is physical and as I say when when you think about that well what's the absence of something the simplest version of nothing you might be empty space just the nothing of the Bible an infinite dark empty void but as I have been mentioning that empty space is actually quite complicated when we put together quantum mechanics and relativity two of the foundations of 20th century physics we put them together and we find out that empty space is actually a boiling bubbling brew of virtual particles popping in and out of existence every second so quickly you can't see them in fact if you try to measure them they're not there but they have an impact that we can actually calculate and predict and it in fact it produces the best predictions in all of physics it explains why the atoms in your body behave the way they do in fact why your body has mass so we know that that that prediction is true even though we can't measure those things exactly but that changes the ground rules it says that empty space is really complicated now some people say well if there's virtual particles there it's really not nothing but there are no real particles you try and measure things there there's nothing but those virtual particles can give space energy and in fact we discovered to our great surprise that won the Nobel Prize two years ago that empty space has energy and if you put energy and empty space then it's really strange because it's not like the normal energy that you and I it's not gravitationally attractive it's actually repulsive and we discovered the expansion of the universe is not slowing down like any sensible universe to do it's actually speeding up it's getting faster and faster and that's because it's dominated by the energy of empty space but it actually gets a little more interesting because you might say well look that's not nothing because there's still space and I say ok but it turns out when you apply quantum mechanics to gravity then even space itself can pop into existence from nothing space and time can spontaneously pop into existence you whole universes can pop into existence and most of them will disappear at a timescale so short you would know about it the worms that can survive for a long time have zero total energy and so you're beginning to see the threat here and then it goes to another stage which you may get to where it turns out Yusei may say okay we'll look you've got no space no time no particles no radiation that's a pretty good approximation nothing but there's still the laws who created the laws and and what we've discovered as we think about these things in the last 10 years or so and again this is this is speculative but it's based on everything we know of in particle physics right now it's quite reasonable to suspect that even the laws themselves came into existence when our universe came to existence there could be many different universes and each one of them the laws of physics are different they spontaneous arrives when the universe arises so you got no laws no space no time no particles no radiation to me that's nothing all right let me follow up with I thought the first big surprise for me in the book which was I always thought that physics and certainly my business is all about the Y and you tell us quite early on in the book you're actually not really into the Y you're into the how yeah sure you have kids playing the diff yeah okay you ultimately know the only answer to the why question is what is because go to bed why because because ultimately you know why presumes purpose if you think about it it presumes purpose but what if there isn't purpose whenever we say why we really mean how we say let me give an example which I use in that in the preface of the of the paperback version because people were asking these questions so Kepler you know there used to be six planets okay and Kepler had a great explanation for why there are six planets maybe there's progress hundreds of years ago hundreds of years ago because God intended to be that way because there are five platonic solids beautiful platonic solids based of these regular polyhedra and he said oh look you can fit the five platonic solids and you could put the orbits of the six planets each of them outside a platonic solid and there's a beautiful mathematical reason why God the mathematician would create this universe so that was a why answer the question but of course it was completely wrong there aren't six planets there are nine planets to me they're always going to be nine planets Pluto always give an account please yeah my daughter did her fourth grade project on Pluto and I'm not going to give it up so easily but the point is we we know there are lots of solar systems now and all lots of stars and and what we really care about is not why are there nine planks but how are the nine planets it is our solar system unique or there are lots of solar systems with many planets and how did their you know they all have rocky planets on the inside and gas plants on the outside we want to understand our origins so the real question is how are there nine planets this question why where the six planets is really irrelevant and so when you think about it whenever we say why what we really want to understand is how things came to be and if you would insist on why then you're assisting on purpose but everything we know about the universe if when we look out tells us there's no evidence of purpose now I want to be before we get lots of you get lots of mail I want to indicate that doesn't mean there's no purpose then maybe there is some purpose it's just no evidence that there's any purpose you haven't figured it out yet no it's not that there's no evidence the universe behaves just like a universe that had no purpose now to me a universe with that behaves as if it has no purpose and one with no purpose are effectively the same thing so God is redundant but but we can get into that yes don't get ahead of me yet okay you show me a Kepler I'm going to raise you and bring you a Doppler okay what's the Doppler effect well the Doppler effect you know I there's a cartoon I like to show it has these two Cowboys on the plane looking at this train and one says you know I love hearing the lonesome well the train whistle as a magnitude of the frequency changes do the Doppler effect but the Doppler effect is this famous example if you hear on ambulance in Toronto when a car and ambulance or train is coming towards you the whistle sounds higher when it's moving away it sounds lower that's because sound is a wave and in front of the Train the the waves get compressed and that means their wavelength gets smaller their frequency increases they get stretched out behind the train it turns out for very different reasons the same thing happens to light so we look at stars and one of the great discoveries of the 18th action was 17th but 18th century and then in 19th century was its star stuff is the same stuff as Earth stuff we look at the light emitted by stars and it's the same set of colors that's submitted by hydrogen gas here in the laboratory telling us that stars are made of hydrogen in fact helium was actually first discovered in the Sun before was discovered here on earth by looking at that spectra so we know stars are made of the same stuff but if the stars are moving away from us all those frequencies of light gets stretched out by this effect called the Doppler effect and it gives it it tells us that we can measure the speed of stars and in fact stars and galaxies and the you are and the universe as a whole because if we measure the galaxies moving if we can see bright enough stars we can we can look out and see the whole expansion the universe that's what in fact Hubble discovered in 1929 is that these galaxies and by the way this is really interesting to point out in 1925 when Hubble sir started doing his stuff the universe consisted of one galaxy a single galaxy our own surrounded by an infinite empty space that's a human lifetime ago that's 83 years ago or so but so it's amazing to think that a single human lifetime we now know there are 400 billion galaxies we're like the early map makers we're just beginning to understand the universe on larger scales which is not therefore surprising that we're surprised all the time because we keep understanding universe and larger scales and it's more amazing than we imagined doesn't it drive you nuts that you're not going to be around hundred years to to know exponentially so much more than you know yeah of course it does but on the other hand it's an exciting time to live in it's an amazing time our picture has changed completely of the universe so I'll live with that for and and I'll live with and I'll be happy with the surprises I'm getting every day it's a fraction of what they're gonna whoever you are a hundred years from now what you know is a fraction of what he or she didn't and but I'm happy that what I know it was a large lot greater than what was known on the forest what about the mist well you know and although my friend Cormac MacCarthy says I'm a pessimist but that's no reason to be gloomy let's bring up control room if we can amid LePage to here the image of the standard candle and there it is okay to measure distance you use what you call a standard candle what is that okay look it you know we we want to measure distances in the universe to see and how the universe is expanding to frame the universe but we don't have tape measures that are long enough to get the distances between stars are amazing the distance between us in the nearest stars four light years takes light four years to get to the nearest star the distance across the Milky Way galaxy is a hundred thousand light-years and the distance between even the nearest galaxies in our own millions of light years so clearly we have to figure out how can we measure distances and we use physics of course and one of the ways to measure distance oh I can measure distance in the studio it wouldn't be good TV but if I turned out all the lights but one in the back of the studio and you and I are both old enough to remember light meters on cameras okay if I had a new that was a hundred watt light bulb and I had a camera here and I looked and I saw there's one watt of light coming in the camera and I know light spreads out a certain way I could work out how far away that light is okay so if the universe were populated by a hundred watt light bulbs are you fine but it's not so we look for what's called a standard candle something whose intrinsic brightness we believe for many reasons we understand and then we look at say a distant galaxy and say how bright is that object how bright does it appear in that galaxy and then we work backwards and we figure out how far away the galaxy is and that's the hard part that's why Hubble got the answer wrong in 1929 and what's really amazing is that we found what we think is a really good standard candle in that image you showed it was a bright spot and it was as bright as the center of a whole galaxy was which contains 10 billion stars it was a star that just exploded the brightest fireworks in the universe a supernova explosion and when stars explode they shine briefly with the brightness of 10 billion stars and that object out there which looks like it might be a star in our galaxy is actually a star in that galaxy that's just exploded a very particular type of exploding star called a type 1a supernova and for reasons that we probably don't need to go into here it turns out that that's a wonderful standard candle that observers have been able to use to peer out because supernovae are so bright you can see them across the universe we can now measure distances across the universe now what is equally amazing to me is that supernovae occur very rarely it's fortunate for us that stars don't explode more often perhaps but it's fortunate for us that they explode stars explode about once 400 years per galaxy so how can you study these things if it's once per hundred years for galaxies often say well you can assign a graduate student each galaxy 100 years about the right time for PhD you've got to just do the sky well they're cheap you get new ones but we don't need to do that because the universe is big and old and so rare events happen all the time if you went out tonight outside of Toronto and in a place where you could actually see the stars and held up a sort of a hole in your hand a dime-sized hole and looked out within a region of the sky where there were no stars with one of our biggest telescopes on earth today in that region you could see a hundred thousand galaxies if you work it out once for a hundred years for galaxies on a given night you're going to see a few stars explode and observers do they apply for telescope time they say tonight we're going to see a few stars explode and they might see one that might see two might be cloudy but that's how we can study these objects and those objects have been used to measure distances and therefore from their spectra also the speeds of the galaxies are in and allows us to map the expansion the universe and discover that it's speeding up it was that measurement of those supernovae and the speeding up of the universe that won the Nobel Prize I can see why it would be important to know distance in the way you've just described it but you also want to know the weight of the universe and I'm a little murkier on why that's important to know well because in fact I Stein tells us that that space is curved in the presence of matter and what we want to know is the curvature of space just like for example if we wanted to if we want to know how fast you have to send something up Canada you know I know recently sent up a satellite the other day and and if you want to know how fast you have to send something up to escape the earth you also need to know the mass of the earth and similarly if we want to determine the future of the universe and which depends on its we thought on its geometry you want to weigh the universe you want to know what the total mass of the universe is to know if those speeds are fast enough to keep things going I mean the reason I got into cosmology as a particle physicist is I wanted to be the first one to know how the universe would end it seemed like a good idea at the time and and if we know the speeds what we got to know the mass because then we'll know if the speeds are fast enough to keep things expanding out now it turns out all that's changed due to the energy of empty space but we want to weigh the universe to determine the geometry of the universe and I actually would have thought when I was a graduate student that we'd never get there in my lifetime so we know I don't have to wait for those people 100 years from now what's amazing is we have weighed the universe and and the answer was wrong what we discovered by we can weigh systems of galaxies the largest bound objects in the universe are called clusters of galaxies there may be ten million light years across if we can weigh them since anything that can fall into anything will fall into a cluster then we can weigh the universe and we weigh them using gravity because Einstein told us at mass curved space and we can actually use those large clusters as lenses if there's a light source behind a cluster the light from it can come around and be lens just like my my glasses magnify things and we've actually measured this gravitational lensing phenomena which Einstein by the way said it would never be observable but he underestimated observers and we've weighed these systems and we found that there's only thirty percent of the mass needed to make a flat universe and that was a big problem because as I say theorists like me knew the universe was flat because it's the only mathematically universal universe and we were there for sure the universe was flat but here these observers kept coming up with only 30% of this stuff needed to make it flat but then what we've discovered and we can talk about observation is that the universe actually is flat and the rest of the 70% of the energy in a flat universe comes from the energy of nothing back again full circle here okay two more thing we got about five minutes to go and I want to touch on two more things you physicists have a habit of wanting to put a Greek letter on so many things yeah makes it sound scholarly is that what you do with it I think so I I don't know Megha Omega is okay I make it was the holy grail of physics in the 20th century what it is is basically a represents a number that represents the ratio of the actual density of the matter in the universe divided by the density of a flat universe so if Omega is less than 1 the density is less than a flat universe that makes it open if Omega is greater than one more it's closed and what we discovered when we weighed galaxies was Omega was 0.3 30 percent of the energy needed for make a flat universe that's what caused people like me headaches because we wanted Omega to be 1 and by the way if Omega is 1 then the total energy gravitational energy of the universe is 0 that's another reason why it's so beautiful and here we were getting a factor of 3 less than we imagined and of course there's a loophole if you weigh galaxies and clusters because you're weighing the total amount of energy around galaxies what if there's energy where galaxies aren't what is where galaxies aren't nothing I can't cope it's hard draw the loops they're in your in your pen ultimate answer you dropped a little something and I should follow that up in our remaining moments here which is you started by trying to explore how it all ends how far have you got in that exploration well of course the nice answer is this kind of like Charles Dickens Christmas story I can tell you how the aunt what the end might be but I can't tell you for sure what it what it will be because we don't know the nature of the energy in empty space we don't know what's causing it but if it remains constant which is the best guess then the future is miserable that's what I can tell you so so much for the far future because what will happen is the Alexei's we now see will be moving away from us faster and faster and faster and in the far future they'll actually be moving away from us faster than the speed of light it's allowed in general relativity and the rest of the universe will disappear in a mere two trillion years which may not seem like a long time or maybe compared to this interview it won't seem like a long time but but in two trillion years all the rest of the galaxies that we can now see will have disappeared and I find that poetic because in fact you know there's still be stars in two trillion years and and and they'll therefore be planets that can be around those stars and life forms that can exist around those planet in those planets and they'll the astronomers will arise ultimately and they'll learn the laws of physics and quantum mechanics and relativity and they're build telescopes and when they look out they'll see the universe we thought we lived in a hundred years ago because they'll see a single galaxy surrounded by vast eternal empty space and all evidence of the Big Bang will have disappeared and they'll they'll poetically come up with a picture which is the false picture we had a hundred years ago say poetically it sounds kind of depressing actually well maybe but it's kind of nice fullcycle and and and and therefore in fact it's not depressing because you talked about being depressed about observers 100 years from now we can be excited that we're living in this time in the universe we can see when what we can see in the far future it'll be much worse so there's reason to live Steve I always Lawrence always well if if only because we need to hear the second half of this interview which will be coming up tomorrow night and I want to thank you for setting the table for tonight and we want to remind everybody that Lawrence Krauss will be with us again tomorrow night and we hope you can join us for that to support Ontario's public television donate at TV org

Channel: The Agenda with Steve Paikin

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Length: 26min 13sec (1573 seconds)

Published: Wed Jul 03 2013