Echoes From The Beginning: A Journey Through Space And Time

your patience let's see I'm waiting for my images to show up before I start to talk hopefully my image will show up before I start to talk there we are okay good what I'm here for is to give you a sort of an introduction we're going to have a discussion about open questions in cosmology in a few minutes but I'm going to give you an overview of our current picture of the universe and I figured since we're in New York I should begin by telling you these are stars and you may not have seen them before they're at night they're up there and if but if you go in the country you might see this kind of picture this a globular cluster and the stars are absolutely beautiful but what we've learned in the last 25 years is that as beautiful as they are they're really just the tip of a vast cosmic iceberg and the really important stuff is the stuff between the stars and we are just beginning to learn about that stuff and there are huge mysteries that are related to it and I want to I want to set the stage by explain to what we know and most importantly what we don't know about the universe so I always begin with this guy who gives me great faith in humanity now this is Edwin Hubble he he began life as a lawyer and then became an astronomer so there's there's really his hope for everybody and he changed our picture of the universe yeah tremendously and we're going to be talking about history a little bit so I just want to point out to put in perspective his greatest discovery which i'll talk about in a minute has to do with with the way the dynamics of the universe but about a little over 80 years ago when the first large telescope Mount Wilson was built he he resolved a big problem when people looked out in our galaxy and by the way at that time 80 some odd years ago there was one galaxy in the universe that was it our Milky Way galaxy and when you looked in with telescopes you saw some fuzzy things that we called nebulae which is Greek for fuzzy thing and there was a big debate about what they were and with that telescope he was able to resolve the fact that in fact these nebulae many of them were in fact other Island universes other galaxies we now know that there are 400 billion galaxies in the observable universe and 80 years ago we knew of one so it's we're we're like the early map makers in fact one of the map makers is here and we're going to talk on stage about this stuff and we and it's therefore not surprising that our picture of the universe is dramatically changing all the time it's a very exciting time in cosmology but the discovery that he made that that made him famous of course was that the universe was not static and eternal up to that point scientists that was the conventional wisdom in science that the universe had been around as it was more or less forever and he convinced the world that it wasn't by an observation which he made these are not sperm these are galaxies and and what he what he discovered was that as we as he looked out from our galaxy here at other galaxies they're all on average moving away from us and those that are twice as far away from us are moving twice as fast those are three times as far away from us are moving three times as fast etcetera everything is moving away from us and this obviously tells you that we are the center of the universe okay now that's what it naively would suggest when you look at it but it doesn't imply that it implies the fact that the universe is expanding uniformly and and there are lots of different ways I've tried to to demonstrate this to people but I think the only way to really see that this implies the universe is expanding is is to get out of our myopic position where we are in fact the really the best way is to get outside of our universe and look in and so what I've done here is that is to draw a two dimensional universe where we're outside of it easily enough and we're looking at a university now each I put each of the galaxies a nice uniform distance apart at some time t1 and now if the universe is expanding all those galaxies are a little bit further apart at some later time so if you were standing outside the universe it'd be obvious that the universe was expanding but what would you see if you're in that universe well pick a galaxy any galaxy that one there and to understand what it would look like from that galaxy I'm just going to superimpose this image on top of this one placing this on top of where it was before and what do you see you see exactly what Hubble saw every galaxy is moving away from that one and those that are twice as far our way has moved twice the distance at the same time those are three times as far away three times etc and the point is it doesn't matter where you are any place you are you see exactly the same thing everything is moving away from you so if you're a pessimist there is no center of the universe and optimist every place as the center of the universe but what it really means is that what Hubble saw tells us that the universe is expanding and that is profoundly important because it changes cosmology and it's really one of the reasons we're here because if the universe is expanding yesterday was a little smaller than it is today and the day before a little smaller and if we work backwards at one point a time that we now know about 13.7 billion years ago all of the observable galaxies in the universe and all the matter associated those with those galaxies was contained in a region smaller than the size of a baseball and that means to understand that universe we don't just think about astronomy but in fact about the physics of the very small and if and what what really this this is a famous alchemy symbol for called the Ouroboros which is a snake eating its own tail and that really sort of represents cosmology because the very biggest scales to understand the universe of the very biggest scales we really have to think about physics at the very smallest scales because of the earliest moments of the Big Bang it was the physics of the very smallest scales that determined what would happen and those are the some of the things were going to be talking about in the panel later now this is Hubble's data I'm not supposed to so graphs here but I lied I'm doing it this it's important to see this because it gives you a sense of how cosmology has changed and also one of the reasons why he was such a great scientist in fact because he knew to draw a straight line through this data set but this is velocity versus distance and he saw that objects that are further away from us are moving faster he interpreted this to be now he did something very important he got the answer wrong by about a factor ten and that's a tradition we've tried to continue in astrophysics and but it is the reason he did it was not that he wasn't a good observer but it's very difficult to determine how fast the universe is expanding in fact it's taken us 80 years to really get this down pat because it well it's easy to measure velocity it's hard to measure distance velocity is easy to measure and in fact these two Cowboys know how to do it they're on the plane and one of them is turn the other and says 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 so we we see galaxies and moving away from us and we know they're moving away from us because we see the light from those galaxies stretched out by the Doppler effect and the long wavelength end of the radiation is the red end of the spectrum so when objects are moving away from us we say they're red shifted and what we found is that objects that are farther away are red shifted more than objects that are closer but the big question is how do we know they're farther away that's the hard part how do you measure distance velocity is easy distance isn't so easy in order to measure distance you have to what we've tried to find is something called a standard candle an object whose intrinsic brightness we believe we understand like a hundred watt light bulb I could measure the distance to the back of the room if I turned off all the lights except for 100 watt light bulb but if I had an old-fashioned camera older than many of the people in this audience used to have a light meter if I saw how much power was coming into my camera and I knew it was onto a light bulb back there I could work out how far away the light bulb was so if the universe were populated by hundred watt light bulbs we'd be fine but it's not and we have to look for the equivalent something whose brightness we understand we look through a telescope and see how bright it appears if we know its intrinsic brightness we can figure out how far away it is and that's the hard part of measuring distance and that's been very hard for 80 years and in fact what we now have is a great standard candle and the first image I showed you was this picture one of my favorite pictures it's the galaxy far far away and long long ago and and and this is a bright star and now this star is as bright as the center of this whole galaxy and you would therefore think that what it is is just a star in our galaxy that got in the way the picture but it isn't it's a star in the edge of this galaxy and it is shining with the brightness of ten billion stars what happened well it's a star that's just exploded it's a supernova and supernova don't explode very often fortunately for us they explode about once per hundred years per galaxy but they do explode which is important for all of you because every atom in your body almost was once inside an exploding star because that's where all the heavy elements on earth were made in exploding star so you really are star children but they don't explode very often and therefore you might say how can we use these things and and the other thing I want to point out is that the amazing thing about the universe is that it's big and it's old and therefore rare things happen all the time and if you hold your hand out at arm's length and held out about a dime-size hole and looked at a dark spot in the sky if you had a telescope that was powerful enough you could see about a hundred thousand galaxies and if you work it out once per hundred year per galaxy a hundred thousand galaxies on a given night you would see ten stars explode you would expect and astronomers do that they actually make apply for telescope time and say tonight I'm gonna see ten stars explode and they might see nine they makes eleven it might be cloudy or whatever and we can use these objects in fact these are new standard candles and we can actually see them explode in real time here's a little movie of a star exploding in a distant galaxy can it it they remain bright for about a month or so we can measure the brightness and from their colors we can tell what kind of exploding star they are and a certain type of supernova has become a wonderful standard candle that has allowed us to measure the expansion of the universe and here's a new Hubble plot you can see how much better we do this is of course also after the important mathematical discovery that on a log-log plot everything is a straight line but in a case we now can measure the Hubble constant to about ten percent as opposed to about a factor of ten and that may not sound like much but it's really been important and it's been important because it turns out if we want to determine the future of the universe we have to understand the expansion rate because as Einstein told us with his general theory of relativity which governs the dynamics of an expanding universe we think and we'll talk about to what extent it may or may not ultimately discover those dynamics but if it does then the neat thing about general relativity is it tells us that matter curved space energy radiation matter can curve space and cause it to dynamically respond by expanding contracting etc and that means we live in one of three types of universes so-called open closed or flat universe the geometry of those universes are different and now of course these are two-dimensional images it's a lot easier to draw a two dimensional curved universe than a three-dimensional one which is why I have it here but what really got us interested in why we wanted to know and why in fact became a cosmologists from originally doing particle physics is it turns out that well that what's really important about these universes is in a closed universe if it's full of matter alone it will expand up to a certain point and then contract into a reverse of the of the Big Bang Big Crunch if you want so I closed universe would expand and then contract an open universe would expand forever to find out rate and a flat universe was just the boundary between those two which would almost stop but never quite stop and the real question in cosmology over the 20th century was what universe do we live in that's what we wanted to know in order to know that there's two things we have to know how fast the universe is expanding measuring the Hubble constant and how much matter there is because we wanted to know whether it was enough matter to curve the universe and close it in a closed universe literally if you look far enough in that direction you'll see the back of your head okay and so the idea was to try and determine how much matter there was measure the expansion rate and determine if the universe were open closed or flat and then we would know whether our universe ended in a in a bang or a whimper okay now we have been able to do that and that those are the things I want to talk about in the next few minutes we've been weighing the universe to determine how much matter there is we now know how fast the universe is expanding how much matter is there how do you weigh the universe you stand on the shoulders of giants this is a an old guy named Tycho Brahe hey whose work eventually allowed Nutan to develop his theory of gravity and eventually allowed us to delay the earth and the Matt of the Sun and our own galaxy but nowadays in fact we use gravity to weigh the universe in a slightly different way and I just want to show you a picture which is worth a thousand words in this case this is the way we can actually and this is only been possible in the last decade or so determine how much matter there is in the universe by weighing the largest objects in the universe this is what most galaxies hang out in clusters this is a picture one of many Hubble like pictures which are really amazing every point in that picture is not a star but a galaxy and every galaxy contains roughly a hundred billion stars so every one of these has billions of stars in it maybe with civilizations around them long ago gone because these images are these objects are billions of light-years away many of the stars no longer exist and the but the interesting thing about this cluster of galaxies these are this clusters are the largest bound objects in the universe if we can weigh them we can weigh anything and this picture allows us to weigh this cluster because you know you don't do a rocket scientist to see there's something weird about this picture there all these blue things and this is an image of something in Einstein first predicted in 1937 but said we'd never observe because he underestimated observers which is easy to do it's a phenomena called gravitational lensing Einstein told us that mass curved space and if I have a big enough mass and I have an object behind that big enough mass emitting light the light will Bend around it and that light can be magnified just as the light going through my glasses is magnified so I can see all of you or if I had a very irregular surface like a crystal goblet if I looked in it I'd see many different images of all of you and that's exactly what's happening here we now know that each of these images these blue things are different images of a single galaxy located billions of light years behind this cluster and the light from that galaxy has been magnified and distorted so we see many different copies of the galaxy due to gravity now it's a beautiful phenomena but it allows us to weigh the cluster B we know how general relativity works and we can ask how much mass is in this system and where is it distributed so we can see this this image and here is the the inversion of this image to determine where the mass is in this system where each of this little bumps is is where a galaxy is but what you see first of all very importantly is that most of the mass by far the majority of the mass in this system is not with the galaxy's honor it's between the galaxies it's stuff that doesn't shine and we now know that almost 30 times as much stuff in the universe is out there and is dark it's compared to all the stars and all the galaxies and everything we can see 30 times as much stuff and physicists with their great linguistic perspicacity if called the stuff dark matter okay and one of the big mysteries is what is this dark matter and one of the things that makes it really exciting is that we realize there's too much dark matter to be made up of normal stuff for argue I don't have time to explain the arguments but we know pretty for very good reasons to believe that that dark matter is not made of protons and neutrons and the same stuff that you and I are made of it's we think it's made of some new type of elementary particle created in the earliest moments of the Big Bang a part elementary particle doesn't interact with matter like you like normal matter does and what makes that interesting is that we don't just need telescopes there to for to find it if it's uniformly distributed in galaxies like our own galaxy it's in this room it's going right through your bodies as you doze off during this lecture okay and that means we can build detectors to look for it in fact there are detectors underground around the world like this one which has a block of germanium cool to very close to absolute zero and most of dark matter particles are going right through this thing without ever knowing it's there but every now and then one may bounce off it we hope depositing a little bit of energy heating the whole thing up so we can measure it and then we could try and determine maybe what this stuff is made of but what but to go back to that other picture what we've been able to know in fact physicists whenever they have an important number give it a Greek letter and so we call this thing Omega and what we've been able to measure is Omega is 0.3 what does that mean Omega tells us how much matter there is in the universe compared to how much matter we need to have to make the universe just closed on itself if I make is 1 the universe is flat make us bigger than 1 the universe is closed and if it's less than 1 it's open so we seem to have discovered with great accuracy that we live in an open universe that big holy grail of cosmology looks like it's been finally solved we live in an open universe but there's a problem first of all a theoretical problem theorists knew that the universe couldn't be open Omega has to be one we knew that why because Omega 1 is the only pretty number and so we figured it had to be 1 and there's a big problem because none of the observations told us it was 1 and so there's a big problem as as we finally got this number down pat it caused a big puzzle but now there's another way it turns out we can measure the geometry of the universe instead of adding up matter and comparing it to the expansion in the universe we can actually measure the geometry of the universe directly and we can do it using one of the strongest tools in cosmology that we'll talk about in fact Lyman pages here is one of the people directing one of the programs to look for this stuff so the question is how would you measure the geometry of the universe well the question you can ask is how would you measure that the earth is curved if you couldn't go around it you couldn't sit in a satellite and see it well very simple you draw a triangle and then you ask a European high school student what's the sum of the angles in the Triangle and then they tell you 180 degrees ok and you say ok you learned your geometry from Euclid but in fact on a curved surface like the surface of the earth I can draw a triangle that's very different if I take a triangle why I go along the equator make a right angle go to the North Pole make another right angle come back to the equator I now have a triangle with three right angles and three right angles adds up to 270 degrees so if I could draw big enough triangle on the surface of the earth and see that it differed from 180 Riis I know that the earth is curved it turns out that that thinking works exactly the same for a curved three-dimensional universe if we could draw a big enough triangle and measure the angles we know whether we lived in open closed or flat universe and that's what we've been able to do in the last 10 years or so we've done it using this great observable in cosmology that's really turned cosmology into a precision empirical science it's called the cosmic microwave background radiation the afterglow of the Big Bang it was discovered by accident in New Jersey of all places about 40 years ago by two people who really didn't know what they were doing but we won't go into that it's the afterglow of the Big Bang and what is it well when we look out at galaxies that are say a billion light years away we we're doing cosmic archaeology because we're looking at them as they looked a billion years ago now given that you'd think if the universe is 14 billion years old or so if you looked out 14 billion light years shouldn't I see the Big Bang the answer is yes if you could but you can't and the reason you can't is well the same reason I can't look outside this room the wall is opaque I can't see past the wall and if I look out the universe earlier in earlier times the universe was hotter and hotter and hotter and at a certain time the universe was so hot when it was a hundred thousand years old it was so hot that the universe was three thousand degrees and at that temperature was hot enough so that hydrogen which is the dominant stuff in the universe gets broken apart into protons and electrons charged particles and it becomes what's called a plasma and a plasma is opaque to radiation so we can't see past this point because the universe is opaque here now let's run the film forward the universe is cooling down and it gets to a point when it cools down to 3,000 degrees Kelvin protons capture electrons become neutral the universe becomes transparent and just like this room I can see all the way back to the point where the universe was opaque and what I would expect if there was a big bang was to see radiation coming at me from all directions at the point when the universe first became transparent and that radiation was 3,000 degrees in temperature then but it's been cooling down and we would expect it to be about three degrees and that's the cosmic microwave background radiation that's been discovered and what makes it so neat is if we look at that radiation we get a picture of what the universe looked like when it was only a hundred thousand years old now pictures so profoundly interesting it's already two Nobel Prizes have been given for it but for our purposes there's one distant scale that matters on that picture and that's one degree across why one degree well that's about a hundred thousand light years across now Einstein tells us that no signal can move faster than speed of light and that means if this is a hundred thousand light years at the time it's getting so scared that it's shaking that the time the universe was a hundred thousand years old guys back there stopped drinking okay then then no information could travel from here to here that's if I send out a light beam it can only travel that far at that surface that means nothing that happens here can affect anything that happens over there and that's interesting because let's say I have a lump of matter that's that big well it knows it's a lump it should it should still start to collapse and then I'll heat up and pressure will respond then all sorts of interesting things will happen but if I have a lump that's this big it doesn't know to collapse it's like wily coyote when it goes over the cliff okay doesn't know what coaching because light can't travel across it and gravity can't even travel across it so it doesn't know what should collapse are the largest objects that will have significant you begun to collapse at that point are one degree across or so that's the ruler because if we look out at this known distance we have a ruler it's a hundred thousand light-years across and we look at it we say what's well if the universe is flat light rays travel in straight lines and that means the angle I would expect to see on a roll or a hundred thousand light years across at that point would be one degree but if the universe is open then light rays diverge as we go back in time and I expect to see the ruler would look smaller it would only subtend say half a degree on my eye if the universe is closed the ruler will look bigger because light rays converge so all I have to do is look at that image and say what size are these lumps are they half a degree one degree two degrees across and that's the type of thing that we've been just begun to be able to do in the last decade one of the first experiments to be able to do it was on on the earth in fact in Antarctica it was this is a microwave radiometer this is a balloon and this thing was taken away above the earth because it's looking for a background it's three degrees the earth is much hotter than that so you want to get above the atmosphere and this balloon went around the world which is easy to do in Antarctica and it in fact right here it's really easy to do but here it took about two weeks to go around came back to where it began which is why this experiment is called the boomerang experiment and it took an image of the microwave background radiation and here's one version of this image where the original picture is put on top that this is just to demonstrate our cosmic myopia because you know during we've evolved and I'm allowed to say that because I'm not in Ohio we've evolved so that our eyes detect visible radiation and if however we evolved to detect microwave radiation day or night we look out and we'd see that microwave background radiation and these hot spots and cold spots and that radiation are the lumps and the question is how big are they well this is these this is the a different false color image of this these are images of a universe created on a computer if we live in a closed universe the lumps average lump should be this big we live in an open University average lump should be about that big well this is bigger than these lumps this is smaller than these lumps but just like Goldilocks if we live in a flat universe it's just right and I think I have I hope yes the much better image taken with the W Maps satellite which Lima page we'll talk about which shows us we can do the same thing over the whole sky and and it turns out we can do a much better much more accurate analysis and we find out two great precision that the universe is flat now there's a problem if you've been awake we prove the universe was open there was enough matter to make the universe flat we've now proved the universe is flat where's all that extra energy we only have 30% of the amount of stuff and to make a flat universe but we live in a flat universe where could that extra stuff be well it could be right in empty space this is a picture of what empty space really looks like it's not so empty due to laws of quantum mechanics and relativity empty space is a boiling bubbling brew of virtual particles that pop in and out of existence in a time so short you can't even measure them in general and you might say well that's like counting angels on the head of a pin or something you can't see their effects directly but their indirect effects are profoundly important in fact this is a picture of what space inside of a proton looks like these particles are popping in and out of existence and they're actually responsible for most of the mass of a proton most of the mass of your body is not due to the quarks that are sitting in the protons but due to these fields that power popping in and out of existence so they're vitally important now if empty space has stuff in it like this popping in and out of existence and it can give mass to the proton maybe empty space can have energy and we can ask the same kind of physics that tells us this how much energy does a gift empty space we do the calculation we come up with the worst prediction in all of physics we predict about a gazillion times as much energy in empty space as there is in all matter in the universe and that is pretty worrisome now a long time when I was a graduate student this problem has been around for a long time we solved it very simply in our minds we said a miracle occurs and somehow we get rid of all that and the energy of empty space is zero that seemed about the only sense of a way of solving the problem but physics isn't empirical science and what if empty space has energy well general relativity tells us that if you put energy and empty space it's not gravitationally attractive like everything else it's gravitationally repulsive it produces a repulsion and what would that do if I put energy and empty space here in the universe what would it do well the University of was expanding instead of slowing down with speed up and about eight years ago people used those supernovae to try and measure the velocity of supernovae as a function of distance away from us and in a sensible universe that we should measure something to look like that as universe slows down if was accelerating if it was dominated by the energy of empty space it should look like this 1998 a remark of two different groups found a remarkable result this may not look that remarkable but in fact here's this Hubble curve I showed you earlier and if I just for fun draw a straight line through this and try and make it horizontal here if the universe was slowing down these distant supernovae would fall along this curve and they don't they're above the straight line and what does that tell us it tells us that the expansion of the universe is speeding up and just for fun if we try and fit that curve what do we get we get 70% of the amount of energy needed to make the universe flat must exist in empty space that's exactly what we were missing so everything holds together with this cockamamie universe that we don't understand at all the universe is dominated by the energy empty space we don't understand why it's there we don't have the slightest understanding why it's there and if anyone comes out and tells you they do especially if they're a string theorist you shouldn't believe them sorry Brian wherever you are but uh but we think one of the things that makes the most something what's so exciting about we don't understand it but we think it's related to the physics of maybe the beginning of time which is what we're going to talk about in the panel among other things and so measuring it and trying to understand it may give us important information about how the universe began and it will ultimately determine our future and I want to have a New York poet here so I quote Yogi Berra who said the future ain't what it used to be and it turns out our picture of the universe's future the universe is vastly different and maybe we'll talk about it maybe we won't but I just want to point out that that's where we're at we live in this cockamamie universe we if you take away everything we see the universe would be largely the same we are completely insignificant everything we see all the stars and galaxies planets aliens everything take away them we are just a 1% bit of pollution in a universe that's dominated by dark matter and dark energy and we don't know the make up of dark matter and we don't have the slightest understanding of the energy so it's incredibly exciting if you're a theorist and incredibly challenging if you're an experimentalist and I don't know what the future is going to bring but I do know that every time we open up a new window on the universe it surprises us and we have a lot of new windows that are going to open up and the large scale we have next generation Space Telescope and other proposed experiments that are gonna try and probe dark energy on the smallest scales in fact this year a new huge particle accelerator is turning on in fact it's very month in Geneva Switzerland because we don't have enough money in this country to spend for these things and it is going to turn on and Pruce the highest energy collisions that have ever been observed on earth through trying to recreate the earliest moments of the Big Bang with incredible detectors built underground the Gothic cathedrals of the 21st century and the information about the beginning of the universe may come from the websites telescope it may come from the Large Hadron Collider with that Earl Burroughs understand the universe and the largest and smallest scales so to end this little introduction I want to just say two things okay first you are completely insignificant and secondly it turns out the future is miserable but you should not be depressed because with the new with with our telescopes and our accelerators we have been as you can see in the last years changing our picture of the universe more than we could have imagined beforehand and so instead of worrying about the future and our and our insignificance in it we should really revel in the fact that we living in the middle of nowhere in a remote corner of the universe have an intelligence and endowed intelligence that we can use to understand the universe and so instead of being depressed we should enjoy our brief moment in the Sun thank and to see you know yesterday Lawrence didn't know a thing but he did say to comfort in last night I think it and sort of learned all that over night I want to invite our panelists come on up invite our panelists to come and take the chairs we have for the next 45 minutes we're going to pick up where Lawrence left off and talk about those first few instances at the beginning what happened at the beginning how do we know what happened at the beginning what is the beginning all about was there something before the beginning you know well and we have a distinguished panel of experts we were going to talk to us about it let me introduce them sitting right next to me is a Lyman page he studied the earliest universe by measuring the imprint left on the cosmos by the Big Bang the Lawrence talked about the microwave background radiation Lyman Paige studies that he is a physicist the Henri de Wolfe Smith professor physics of Princeton University welcome to the panel great to be here now what is the significance of all of this and where does it fit in history and then cultures trying to discuss where we came from and where we're heading and that's why we invited Helle crog he is one of the world's leading historians of cosmology he's the author of several books about the history of physics and he comes all away from Denmark from the department health history of science department at the University of Aris in Denmark welcome and elegant craic now now Lawrence talked about the Big Bang Theory and how everything started for the Big Bang but that may not be the only ideas about the idea about how the universe started so Paul Steinhardt is here to talk about those first first few microseconds and other possibly other competing theories he is a theoretical physicist he is one of the architects of this inflationary model which says that the universe began as this rapid accelerated expansion surely after the Big Bang and he is the Albert Einstein professor of science and professor of theoretical physics at Princeton University welcome to the panel Paul ok and of course Lawrence will be here to kibbutz whenever he can about what we're talking about hopefully he'll he'll stick around I'm sure he will have some great information to add but I want to ask you a Paul Steiner about universes about the one of the problems the big problem that they were outlining at the end of their talk was how does something come out of nothing how do we have a universe that comes out of nothing or did it not come out of nothing well that's a fundamental question which challenges everything we know about physics because we know of no phenomenon in nature where say the things come in and then nothing comes out or you begin with nothing and then something something occurs so we don't we know of no phenomenon in nature which has this this this property that we observe in our everyday world so it's a it's a theorists are really speculating that somehow something is special about the Big Bang that's different than any other phenomenon that we've seen when they had this idea of a beginning for this very reason that's there are some of us that think that maybe that's the wrong idea the Big Bang is not the beginning but there's something that comes before and there's actually trace things back such as well one of the idea is that would that's that some of us have been thinking about is that in fact there was a whole universe evolving before the bang a universe that went through the same sort of history as we've observed since the bang it continued this way of ollying for a period say a trillion year then the sequence events occurred where after it sort of emptied out of all the matter and radiation that it is it had expanded enough that the matter of radiation was almost perfectly dilute due to the acceleration that that effect that Lawrence mentioned suddenly gravitational energy is transformed into new matter and radiation which begins a new period of evolution this could repeat itself in a cyclical way so maybe the Big Bang is not the beginning maybe maybe it's a transformational event and that it and that the the evolution of the universe is cyclical so those up over and over and over again that's right so they of course people are going to say what happened before that okay before the sick cycling began well is this you can't get away with that answer it so we're toying with this crowd I can see it that's right well I mean there's two logical possibilities there was some beginning but it wasn't the Big Bang it was some event that occurred many cycles ago or one of the interesting ideas is that it could have been cycles forever like or that are constantly number cycles is our concept is time is wrong that's right that's that's that's right so that we have to we have to change our views of things and and and these and this leads to two different pictures of where everything in the universe came from where all the structure we see in the universe came from that we can actually distinguish experimentally how long is busted here let me get it fix them yes I want to emphasize that we need to be very cautious with the terms that we use and that there is a whole lot of difference about speaking of the origin of the universe that the universe has existed for a limited span of time and then to speak about a universe which came into being or even worse a created universe because these words are not the same I sometimes I like to phrase this philosophical insight which is quite trivial really by saying that we know that the universe has an each of approximately 13 billion years and yet it has always existed this is a true statement there's a no contradiction between these two parts of the sentence tell me why because the term always refers necessarily to time it's a temporal concept and to say that the universe has always existed merely tell says that we cannot have a concept of time without a universe so time began at the beginning of the universe yes I mean whatever model or view we have of the universe because the universe is everything physical including time and space then the the claim that the universe has always assisted is true a priori alarm for the moment the defender of the Big Bang and say two things it responsible said first of all as as unusual is to imagine a universe beating from nothing in fact it's not so crazy because one of the reasons of flat universe is so pretty for theorists is if you add up the total energy of a flat universe it dad's up to zero and that's one of the read many reasons why all of us Paul even a decade ago probably would have argued that the universe was flat because if you're going to imagine a universe began that began with nothing a good value for the total energy is zero now how can the energy add up to zero well it turns out gravitational energy can be both positive and negative and a flat universe is one in which the energy balances the positive energy of motion is balanced by the negative gravitational attraction and the two add up to zero and so it is possible to imagine a universe that began from nothing it's and and then with regard to the time question that's not only a philosophical question is actually a physics question and it could all it could be from a physics sense that time literally began at the Big Bang because general relativity at least tells us that space and time are related to the matter and it as they get very very dense we know the laws of physics as we now understand them break down and it could be the time itself wasn't a relevant quantity at the beginning so the answer to what happened before the Big Bang is it's not a good question not for you for me as a panel moderator I think it's a great what yes Bhopal so just to clarify when I was talking about the cyclical idea I wasn't arguing that it's logically impossible that the Big Bang was the beginning it just baby physically incorrect there may actually it may actually be that the structure of the universe as we see today was not created by events that occurred after the bang but it was actually created by events that occurred before the bank and we can actually see the evidence of that through the kinds of measurements that Lyman and his colleagues are attempting to make and then we wouldn't be able to answer the question whether it was one story or the other story whether the Big Bang was the beginning of time or not well I mean let me ask you good you want to pick up on that or yeah I want to bring your props in right go get to them in a second yeah so the amazing thing that's happened in cosmology in the last say 20 years is that you can have these discussions that were that you've heard about in these notions from Lawrence and they're based in measurement that's the whole new thing and they're based and and so Lawrence showed you a couple of pictures and what I like to do is just take a step back give you a sense for them and give you some idea of how it can be so confident of of what we're what we're talking about and that we can and how these questions are posed so if you can put up this first picture of the Hubble Deep Field the Hubble ah wonderful ok so let me let me stand over here so I can point so Lawrence showed a piece of this and what I wanted to what I just wanted to to give you a sense for is what what we study in cosmology in the sizes you heard a few numbers right you know the moon right you can drive a good car to the moon it's only 250,000 miles away or about a light second right in the Sun is about eight light minutes okay so in each one of these guys here that you can see are a hundred billion suns ok so so that's a large number right so one way to remember it is Bill Gates has a dollar for every star in our galaxy in the Milky Way okay so here so and now this is this is a huge this is a big picture right and that's and that's all light that picture is one fiftieth the size of the full moon okay so take 50 of those to make the full moon now if you then go and count up all the galaxies if you did this over all the sky was the other number that that Lawrence told you is about 400 billion so maybe you know that was the height of the Internet era so it's the same number right of galaxies in the observable universe okay so that's the first thing and remember those are those are those are just pictures you know these are little agglomerations of mass each one in galaxies each one 100 billion suns okay so now let me wonder if you can put up the egg and I want to good so this is the pitch the last picture the Hubble was relatively recently you look back you know billion billions of years this is if you look back 13.7 billion years right and you could see the first picture was in light that you see like this you know just like the lights in this room just like what you see looking through binoculars this picture since it's the universe you trace it back through what Lawrence told you since it was so much younger and so much more compact it's an older these lightweight let's forget the compact form it we'll get back to that these since it's so much older the light from here is not an optical wavelengths but it's at millimetre wavelengths so here's a way to think about this and this is the stuff so this is an image of the sky I'm going to show you what would we know today that's at millimeter wavelengths what is it Razors a TV a typical TV station is at centimeter wavelengths a few centimeters like some of the TV stations broadcast elements of it at centimeter wavelengths so here's the picture I want you to get from that what is that that's if we take the whole sky and we're at and we plaster it flat on a screen so this is what you should be thinking of so this is a beach ball of the whole universe that light is Lawrence told you it's from the edge of the universe okay so it's like so this is the picture those 1-degree spots she was talking about are all the blue and red spots on here these are tiny variations in the intensity of power from when this radiation was emitted so just a few hundred thousand years after the Big Bang so this is so the picture then to have is that this is looking back to the edge of the observable universe all those galaxies are happening or took place and or you see them inside the speech ball what's on the outside of the Beedrill okay so great so so the outside of the beach ball is more beach ball okay so the universe let me past you so I have a couple of these that can pass these around we're gonna take a way of just really yeah let's look at so the universe oh the picture here and these and these guys cannot pass this back okay the universe now is in our we're thinking about is infinite okay and it always has been infinite we owe and went so that's what I want to get back to the compact right the part we see that beach ball inside that beach ball was more compact you know down to the grapefruit size early on but there's but what happens is this radiation such as the speed of light it travels the age of the universal reaches us carves out a piece of the universe that's accessible and that's what we call the observable universe so when we think of space it's it we think of it as being infinite and we just access access a small chunk of it thank you okay great is that yeah thank you good Helen let me ask you this is a question that's been asked by the Greek philosophers basically we're talking about the same question where did we all come from right where we headed because that's what this is this ball is going to talk about yes that's relating a course to man's place than universe or the role of humanity compared to the universe as such and that was part a very important part in early cosmology but as we heard in very that directly expressed we are totally insignificant and I'd like to enter at just two small saying that this sort of insight or recognition that not only humanity but also the earth is an insignificant place and universe is sometimes known as Copernican principles because in a certain sense it goes back to the same sixteenth century and for a very long time it has been a paradigm in scientific cosmology that the earth has snow is no privileged place that the time that that we live in is not privileged and that human observers are not privileged but as you may know some of you may know for a couple of decades a new controversial point of view or principle named the entropic principle has created a lot of discussion in cosmology and physics and elsewhere and this principle although it exists in many different versions tell us essentially that that human observers are not insignificant they are all important the name and tropic is after all derived from the Greek name of humans and well there are different points of view with regard to the entropic principle but some people including Marty Rees take it very seriously other people will say that it's not true signs it has no explanatory power and it's a worrying return to philosophical and even see logic exploited again a little what years are you saying that the fact that anything is here the anthropic pissed we the reason anything is here is because we are here to observe it a call they make it happen yes indeed according to the so-called a strong version of the entropic principle the existence well not necessarily of humans but the existence of beings being made up of carbon atoms in some advanced combinations can't be said to be the reason for the existence of the entire universe all right at that of course simpler if you think of the possibility of many universes which many of how I get it to that yeah and it's currently in physics we think it's quite likely there many universes then you can imagine and so it's it's a little less mysterious if you put it that way because they say well in each universe say the laws of physics could be a little bit different or the initial conditions could be a little bit different and it turns out of course unless things were just right so you could have galaxies if you didn't have galaxies you couldn't have stars but if you didn't have stars you would have planets if you'd have planets you would have astronomers and so it so the fact that we're here just validates that the laws of physics have to be able to produce astronomers it's like an intelligent fish asking why is the universe made of water if it wasn't the fish wouldn't be there to ask the question so it's it's a little less mysterious if you put it that way and then and so the question is is there any fundamental reason why the laws of physics are as they are or could there be anything and they just are as they are because if they were any different we wouldn't be here to measure it and that's the current debate that's happening in physics largely because of this energy of empty space which is so weird that has caused some physicists to go crazy right but actually I move down an aisle phone actually it's more than that that made it really ties together this whole story that beach ball that Lyman is showing in having has in his lap there that pattern has two possible explanations one that arises if the is that if the universe has a beginning if that's if that happened through point seven billion years ago was the beginning then the only way we know how to make that pattern and make the flatness and the smoothness of the universe BC is to have a period of inflation and the original idea is that what inflation did it took an initially chaotic universe and made it everywhere the same inflation for people don't understand inflation there's some rapid it's a period like the present day acceleration but at a much more rapid rate that I would have heard shortly after this beginning and would have taken some random distribution of energy smoothed it out and then this inflationary energy would have decayed into the matter we see and that's how we got to be the way we are and it would have left because this is decay of energy occurs through a random quantum process it wouldn't have occurred everywhere exactly at the same time it would have left some regions hotter or cooler than the others producing a pattern which agrees beautifully with the measurements in that beach ball that is so that is one possible explanation but along with that I but there's a surprise like sort of kicker with that idea which is that it doesn't do quite what we thought it doesn't make everywhere the universe the same once inflation starts it never really stops there are always due to rare quantum fluctuations some pieces of the universe that continue to inflate so in fact what really happens with inflation is that it inflates AB large piece of the universe part of it decays into matter and radiation leaving a pocket of stuff ok well the rest of it B continues to inflate then another decay process occurs another pocket universe occurs which contains stuff another one another one so you get this multiverse picture and one of the problems or issues is these different pockets have different physical properties so for example we point to this map and we say the universe is flat ah inflation flattens the universe but actually there's an infinite number of these pockets in which the universe is not flat an infant number which are so we end up with this idea there's different possibilities for the universe for its flatness or not flatness or for its physical laws so the reflection leaves have your cake and eat it then you can well it's not well I I view it a problem I view it is I mean I call this the unpredictability problem because it means that you thought you had a theory that explained the universe but actually it produced many different universes other than the one that you see in addition to the one that you see instead of simplifying it actually made it more come well admit in fact the deposited now it may change the nature science because you got asked it you know instead of a theory of everything it's a theory of anything right and and theory of anything is it science I mean if you could explain anything you can see then you could never falsify it and that's a big worry it's a big worry in modern physics something that I just want to follow up on on how then Lawrence's comments I mean the the thing the reason you can talk about these wild things and and anyone will listen are their scientists is you can make measurements right and that's and the thing is multiverses no one knows how to make a measurement that can say whether that is true or not the only way to get at that is to follow through and make some prediction which has an effect on the universe that we see the anthropic principle same thing there are no predictions and so for making headway and this is this is a philosophical you can see were very different for making headway you have to make models that make predictions and again the key thing with this like with it with this measurement is since we can measure the sky so well now measure this this cosmic microwave background radiation we can measure it so well we're on the verge of of making measurements of detailed predictions of say the inflationary model of the universe it says the sky has to act just like this and and we in fact are seen that another way this is taking Lawrence's picture when we look at these hot and cold spots these are pictures of the quantum mechanics of the early universe written a large across the sky and by looking at them in detail we can start to sort out these these various theories and it's it's it's stunning that's what keeps us all up at night doing this it's really exciting and it's it's it's happening so is there any way to actually settle which picture is corrected you said now we can test out some of these things I would like to say that yeah right that the alternative iris mentioned the cyclical idea does not lead to this multi universe picture so really what's at stake is not just a question of is it inflation or a cyclic model or a quest to know whether there was something before the Big Bang but are we going to be forced to this idea of multiverse and we can't we can only understand a small section of the universe and anything was possible this kind of science or pseudoscience or are we going to be led to an idea of a unified universe and so that's also at stake what why do we believe is that you brought up the multiverse why should we think there is such a thing well Paul already mentioned that that the best ideas we have or at least one of the best ideas we have the early universe naturally predicts many other universal it predicts that phenomena in fact it's kind of philosophically almost like returning in the steady state universe and the largest scales if this picture is true on the largest scales at any instant there's always some universe being born and another one maybe but wouldn't we feel the effects of another universe no we wouldn't and could we be in the middle of one or no and so the question is is this philosophy and I want to get back to Lyman's point it isn't it's actually physics because for the following reason let's say we actually had a theory which we don't have but let's say we had a theory that actually predicted the mass of the proton the mass of the electron why there are three generations of elementary particles while there are four forces in nature all of these things but it also predicted that there had to be this phase of inflation in the early universe well we would make a hundred predictions that we could measure and test and one that we couldn't that there are other universes and so we pretty well believe that those other universes are out there it could also but the key point is that it's good that these models also and one of the things that sort of the theory that Paul's promoting versus inflation it does some of these things do predict measurable differences in those in that pattern of dots and so we're not guaranteed by any means that we're going to be able to settle this but there's great excitement about the possibility that by measuring that pattern of dots or even looking for something even more interesting called gravitational waves from the early universe we may be able to distinguish these pictures we don't know what the future is going to bring which is why it's interesting stay tuned yeah but we need to keep looking question here yes sir hi just first a quick clarification question for Lyman in terms of could use as the beach poles are running around the audience here we explain the apparent discrepancy between the beach ball and the picture in terms of the for example the large stripe without registration things like that so that's my first question sharp audience yeah okay sure so so yikes Oh universe on the loose here we go hatred peril yeah yes that one so we're in the galaxy right and we have to look out to the galaxy that picture that we splash around has the galaxy subtracted this one because we're right in the middle right looking out we have to look out to the galaxy so this this red ring around here is looking out through the gallery our to our galaxy the Milky Way okay right second for the panel um in terms of the kind of many universes theory that's recently kind of cropped up could you relate that or not relate that to when people first realized that superposition existed and one sense was let's different states collapse Super's in collapses to one state or the other obviously Everett another said no maybe they don't collapse maybe two universes you know so when we observe something and it looks like this beam was split and it went to this way and that way and then it it it collapsed one way or the other no Everett said no two universes were created upon that observation that the observation itself created now two strands two streams can you relate the two or do you find them completely different and finally all right ways anybody know what he's talking about okay maybe a few people Laurence Illustrated oh yeah okay so that unfortunately there's many different ways of talking about many universes and physics and and then this is actually different the quantum mechanics is really fascinating because it says that on small scales the universe is really crazy and objects can do many different things at the same time too bad you don't like it too bad that's the way it is and it turns out when you actually measure it you find out well no was doing one thing what what the picture he's talking about it suggests is when you measure it yeah you force it to be doing one thing but in fact every measurement because the object was doing many things every measurement forces you to exist on what what's called one branch of many universes and in a different you know had you had the quantum mechanical measurement come out a different way you would come out with a different number and in a different in a different universe be asking the questions and I would be answering them and and and it's just there are many many universes and we're always measuring on every time we look out we create a new universe it's a it's a weird and crazy picture to try and understand quantum mechanics but it's very different than this picture this picture has many physical universes in the same if you wish the same quantum mechanical branch of the wavefunction oh my Cara thank you yeah well as is the idea of inflation necessarily that matter has moved at speeds perhaps grade in the speed of light or that the way we measure has changed that the ruler has changed well so when we talk about inflation it fits in this idea of expansion like the Hubble expansion that Lawrence described except that the rate of expansion is increasing with time so for example imagine a situation where the universe doubles in size every 10 billion years that's roughly speaking what seems to be happening in the universe right now so space stretches by a factor of two in every direction every 10 billion years so something which a distant galaxy which is now say a million light years from now will and 10 billion light years be twice that and another 10 billion light years twice that again so it's gone twice as far in the next 10 billion years as in the first and then another 10 billion years it goes yet twice as far as that so it's it's separation from us that's picking up with time if you could imagine that situation if it continues over time it ventually dilutes or spreads out all the matter in the universe to the point where the universe becomes essentially empty this is what's happening in the universe in the future at a rate of doubling of about every 10 billion years now the idea of inflation is that there was another thing just like dark energy it was short-lived it eventually decayed into matter and radiation but before that happened it was also causing the universe to double in size but not once every 10 billion years once every 10 to the minus thirty fifth seconds okay so in just an instant of time 10 to the minus 30 seconds so one with you know I'm sorry a decimal point and you know yeah they say 30 zeros in a 1 or something like that and that instant of time it could have doubled as much as a hundred thousand times well if you take something the size of a proton you double the region the size of a proton you double it a hundred thousand times you get to a region which is much greater than anything we've been able to see in the universe up to this point we know why that some you would decide to do that well with you know we might suspect to be like opening a soda bottle it's only the fizzle comes out and it settles back down again is that the inflation of the bubbles coming out well it's not required that so the idea that there's a beginning doesn't require inflation doesn't require we have to add in something just like we have to add in something to explain dark energy we have to suppose that in order to explain the universe we see there had to have been if it was a beginning right the only way we can get this smooth universe is to suppose there was such an element in the universe that on the one hand causes inflation and the other hand decayed away so this is a mathematical theory it's in serious I thought it's not just added for cosmology we should we should say that you know we're not just inventing things because we that that particle physics tells us that there were lots of things called phase transitions in the early universe the nature of the universe change the forces that we now see that look very different we know that at least two of the forces that we now see that look very different the weak and electromagnetic force were once when the universe was about a millionth of a second old look very similar we we think that three of the of the four forces probably look very similar at a time around 10 to the minus 35 seconds and when a phase transition happens just like when ice water turns ice you could trap energy and and that trapped energy if it happened in the early universe could produce inflation so there are kind of natural mechanism it's not just something we're okay what every other hello we should be a little bit cautious because to get the inflation we need it can't just be any old phase transition it turns out has to be very finely tuned salutely but and that's a big issue as to why would be so finely tuned so it's not going to so there's some of the ingredients you need naturally but they have to be just so I understand how you have to be careful about talking about inflation with the price of oil and stuff exactly right there was a a little bit right the I think the picture most of us have of the Big Bang is is absolutely not one of mass being thrown out from some beginning that's just that's not it like a much a much easier way to think about it is well of course all the math we know today was in proton you know even protons or quarks before that but as as you can think of these galaxies as markers of space it is the space that the currency of inflation of all these models is space is space that's changing its space sets that's accelerating it's a hard concept is very hard concept of space and matters at rest it's a mat matters at the right that's really weird because in general relativity you can be arrested moving in the speed of light at the same time yeah your arrest locally but some other regions moving away from you at the speed of light it's great you know it's just the way it is just goes yeah okay question sir yes I was going to ask a question from the the visitor from Denmark when you talk about the I think you called the entropic principle and it relates to what the the first gentleman asked the concept that sort of you know that you really don't know if there's universe behind you until you turn around the wavefunction collapses and you're able to observe something so can you expand upon what you were talking about in that principle and how that interacts with that concept I don't know how the entropic principle relates to the quantum mechanical principles but in a certain sense the entropic principles can be said to be merely a principle of consistency that everything that we observed and that we know exists they have to be consistent that with our being and if that is the case the entropic principle is not very interesting it's it's almost a rather trivial observation and as it was indicated the the the standard test whether a statement or a theory is scientific or not is that it leads to a certain kinds of predictions and that these predictions are testable and I think it's generally agreed that the entropic principle which has been on the scene for certainly well 40 years or something like that has not resulted in testable predictions and from that point of view it's really surprising that this principle is still taken very seriously I remember when it emerged and became an issue I saw that it would well that's the sort of silly ideas which come up and they would probably evaporate next year but this did not happen it's also why let's hope let's hope next by next year yeah but it's really it's really dark energy that's so inexplicable the only act right now unfortunately the only good explanation of why it's there at the value it is is an entropic one now it's it's not very satisfying but it's it's forced a lot of physicists to think that maybe that's the explanation and again I agree that I hope it I certainly hope it goes away but if I'm a very brief No so you want it you'd like to take that you'd like to find an explanation does away with the whole anthropic well the dark in the whole reason for doing science I believe is that you have to have predictive power the measure the currency or the measure the validity or power of the the value of science is its predictive power because if it doesn't have that it just blind faith that's only doing some other activities you're doing some other activity right is not please you have to make a prediction and you have to test it or else you just believe it on faith and right outside neat thing about science is that most theories are wrong I mean if they weren't it'd be easy anyone could do it great I think it's always important to have alternatives because they help focus your attention on how to how to what test to do to McGrane to gain more confidence about which theory is right and they also help generate new ideas new ideas wouldn't webpage so you that's just not family theories until you come up with the right one you say let's try this one let's test it out and knock it down let's go to the next you want you want so you want predictive power yeah that whatever the gorilla in the room right is this is dark energy there is no I mean first it was found as by measurement and there is no theory that predicts it in any fundamental way and talking to theorists the problem is also why is there so little of it right yeah there should be a lot more of it first we don't know what it is but there should be a whole lot more of it yeah right with that correct there should be a lot more nothing you should get a lot more done yeah yeah and it's and you guys got your hands full I they got and by the way that's a big question I we talked about earlier why why is there anything at all is another you know interesting our way we want to go into it now but if that's another fascinating question we really don't yet have the answer to do we know why time moves in this direction and that another well sometimes moves in that direction but it's a serious question doesn't time the arrow doesn't have to go on that it's a very philosophically fascinating question a physics question that's still I mean we have good ideas at some level about it but it's a time is a really slippery concept now I would like to well to protest and at least to your number here and and to to to argue that even in cosmology which is an extremely ambitious science probably the most ambitious science of all but there are questions which cannot be answered by the cosmologists all the physicists simply questions which are not within the realm within the power of science to answer it may be because they are meaningless or it may be because they are best answered from other points of view by philosophers or for that matter pious theologians and the famous or infamous question or why is there anything at all rather than nothing which is a I mean this is admit a physical question theologians have answers to that but it is not a scientific question although I actually disagree there I think one of the most one of the things that got many of us theorists into cosmology was try and ask that quit it's amazing that I think that physics with our understanding of what's called grand unification suggested you can understand how a universe which basically should have ended up with nothing actually ended up with something how matter was created of enough yes but you that's a person you are using the term nothing right in a shaky and wrong sense we I mean it's it's very important to say that that zero energy is totally different from nothingness nothingness is a metaphysical concept to which no physical observable or any measurable property can be assigned okay it's very nature and for this reason it cannot be part of physics yeah is about us sorry we score a few points on that one like we're here for one more question whoever has the mic go ahead guys Dano just speak up yeah I go oh two question let's go one at a time okay so long it takes to answer these questions first can you tell me the exact name of that Big Bend project in Switzerland and also is it a worldwide effort or is how much is NASA involved in this project well actually it's not a NASA it's actually the Department of Energy and it's called the Large Hadron Collider the LHC it's an accelerator and it is a truly international effort which is really I think it's a really important to stress that it's amazing to me it's an effort each each of the experiments of that Large Hadron Collider involves thousands of physicists from hundreds of countries speaking with dozens of languages designing machine that that that's bigger than a Gothic cathedral each of those detectors has more iron than the Eiffel Tower that have to fit together with an accuracy of microns to measure events that require so much information that each event which happens a million times a second the LHC will generate terabytes of information and that we are trying to analyze that it is truly an international project and it demonstrates to me one of the greatest aspects of science that that you know we can work together and when will the first experiments happen well the first its I was just there last week and and the machine is almost cooled down the first the the beam is being set up and in the month of June the beam will begin to get going and the first collisions test collisions should begin to be and what and what do they collide with well they'll begin to climb by the fall we won't have day what things will they collide together protons going around 26 kilometers this direction in 26 kilometers this direction will collide at four different places producing little if you wish little mini big bangs recreating the universe as it was about a millionth of a millionth of a second after the Big Bang there was there wasn't fear that a little black hole could be created yeah let me tell you that's not a problem because as as energetic as those collisions are you know the universe nature is a lot more powerful than we are and more energetic cosmic rays are coming down and striking the earth every second that are produced at the LHC and particular the moon so the fact that the moon has been around for four and a half billion years with cosmic rays my barding us makes us pretty confident that the accelerations that are happening at the violation I got time for one more question than we have - who's got the mic close by raise your hand okay if the universe is expanding and the mass is separating from each other at a mix at a rate of acceleration that's continuing won't they reach the speed of light separating each other and then what will happen in fact that's one of the things I didn't get a chance to talk about but in fact objects in any universe in fact even if the universe isn't accelerating there are always regions that are moving away far faster than the speed of light now you learn in school that that's not possible but that's because we lied really you have to be like a lawyer and parse a little more carefully objects can't move through space faster than speed of light but space can do whatever the hell it wants and and in fact so in such a universe and this is really fascinating in such a universe the longer we wait the less we will see because objects that are now moving away from us less fast than the speed of light will one day be moving away from us faster than the speed of light so in such a universe eventually everything that isn't bound to us now will disappear and the universe become cold and dark and empty Wow well that's that that's the take-home message you guys can do whatever the hell wants to thank you okay Lawrence Krauss Paul Stine hotel defrag you

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Rating: 4.7425289 out of 5

Keywords: Echoes From The Beginning, A Journey Through Space And Time, Universe, cosmic microwave background, CMB, golden age of cosmology, astronomers, dark energy, big bang, origin of time, Do we live in a multiverse, multiverse, Big Idea Series, John Templeton Foundation, New York City, NYC, world science festival, World, Science, Festival, full program, 2008, Big Ideas Series

Id: qRHLoEbOlSI

Length: 77min 20sec (4640 seconds)

Published: Mon Aug 18 2014