The Greatest Story Ever Told ( ... so far) — Professor Lawrence Krauss, ISS2015

so I've told you a story about the universe and now I want to talk to you about looking inward and swell and and and as well as looking outward and how it's changed or how that's changed over the last 50 75 years and it's an amazing story it's a remarkable story that's not really appreciated and I want to I want to start you off to give you a sense so anyway I'll forget that quote but it's I do want to point out that the story of the rise of that what I call the standard model of particle physics is it is much better than any man-made myth and it's it as you'll see it's a sublime mixture of culture and technology and it's also suggests once again that not only are you insignificant which you are I hope we've got that out of yesterday but that in fact we are just a cosmic accident and it could have been quite different so okay so I want to start with the line which in the wardrobe how many people have ever read that well look at that see is everyone like it's a it's kind of a a con job it's really a religious story but but it's but simple that's a fun kids story but you may remember that that out that when the kids get shipped off to the professor's house in the country they find this wardrobe which is how they get to Narnia and it's an amazingly interesting thing if you think about the physics of it because you can go behind the Wardrobe it's just there but then when you go in the Wardrobe you've got to go get a whole whole new unit literally a whole new universe and and what I want to point out to you is it's actually conceivable that that's the situation we're about to be in in terms of terms of the experiments we do with small scales and you'll see so we are we are potentially about to open a wardrobe that is similar and I want to start though way back I want to take this is a story that's over causing over here all of human history so I want to start back with this guy here does anyone know who this guy is and he classically trained I'm not Aristotle stop softy said so you get your in close the other one played oh that's right Plato Plato I mean they were all you know classical philosophers and and better or worse in some ways and others but Plato was quite interesting to me when I was a little bit younger than you well know yeah a little bit younger in high school because I was forced to read Plato in high school and and I remember the Plato's Republic and there's a great story in there it's parable of the cave and it had a lot of impact on me and it's interesting you'll see it's kind of relevant so so Plato imagined that really when we're looking at reality were like people in a cave that are just looking at shadows of reality and so this is from my high school textbook from probably from the 1950s so this is this is uh so he imagined that the people of humanity was kind of like tied and shackled look at only the shadows of reality only to see the shadows on a wall and enter the job of the philosopher he said or the mathematician was to somehow interpret the shadows and understand the underlying reality underneath and that's quite poignant as you'll see this is a this is also timely because it's interesting to see the 1950s that the people being shackled involved having sort of skin Grantley clad women in Chains which sort of would be inappropriate now I think but um and should be inappropriate but let us think about what it would be like if you were such a philosopher or mathematician in such a world if you could only see the two-dimensional shadows of a three-dimensional reality let's say for example if you were if you were living in such a world you would say there's no such thing as length length is because length is not constant objects change their length all the time you could see a the shadow of a ruler on the wall at one moment and then a little bit later see the shadow the same ruler and it would have changed its length so you would say there's no such thing as length and that's if you were just the common person but if you were the philosopher mathematician you'd think about this and say no no no no I understand what situation is what really the world isn't two-dimensional the world is three-dimensional you know see if I can do this no I don't think I do it very well but with the lights maybe um so here can you see my fat of my arm there right so that's the shadow of my arm but of course if I rotate my arm the shadow of my arm gets smaller I'll just show you the picture so let's say there's a ruler and and and the light is coming from behind and the rulers there and I get the shadow and if I were to rotate the ruler and in another dimension which the mathematician could imagine actually existed even though you couldn't see it then he'd say really what we're seeing is of course the projection the cosine or sine of that length if you want to if you want to think about it so we're seeing the projection on the x axis of the ruler and so in the real world there really is something called that you can call linked that is constant and unchanging but our perception of it is just the fact that we are only seeing literally the shadow of reality ok so that's the kind of thing the mathematician philosopher would would have to do at that time and by the way Plato said that if you really were a mathematician you ever and and and if the philosopher was ever taken to the outside world and actually shown it and then came back to try and talk to people what was actually happening he'd be basically put in a lunatic asylum because no one would but no one would believe it or listen or understand and and sometimes I feel that way myself when I talk about some of this stuff to the public I did last night I felt that way when I was on a TV program anyway um ok so that was that that's uh we're jumping I'm going to go all the way from Plato and and that and I want you to keep that in the back your mind ok because we're in it that concept will come important to us later to this guy who's this guy anyone know Michael Faraday the greatest experimental physicists of the 19th century another hero of mine he's responsible for basically everything in this room electromagnetism as a as a as a tool to operate everything we see and all the tools and and all the motors and basically everything that runs modern civilization he he there's two things I show you about one is very important to which is more valuable lesson learned from Michael Faraday's two always suck up to your professors because he started life he had no formal education he was he his family's poor and he I think he stopped school at age 10 or 11 and was apprenticed to a book binder when his apprentice for about seven years and he attended the lectures of Humphrey Davy who was the head of the Royal Institution in London a famous chemist you may have heard of his name and he attended those lectures and he took beautiful notes and then he bound them in a book and he presented them to Humphrey Davy said here are your lectures in a book can I be your assistant and and Humphrey Davy said yes and in fact Maxwell day became moved up to eventually become the director of the institution and as I say the most famous and best experimental physicist of the of the 19th century he also was doing all these experiments with on electricity and magnetism and and it was rather esoteric I there's very many apocryphal stories none of them are probably true but there it said that the Prime Minister of England came into the his laboratory and looked at all this useless stuff and said of what use you know is any of this stuff that you're doing and Faraday said it's so useful that one day you'll tax us for it and it's absolutely right because the every time you plug things in the wall and use electricity you get taxed now but at the time it was just it was a new world trying to understand the nature of electricity and and relate something that in fact was not it was sort of clear but not so clear you've all undoubtedly because your of your interests and physics played with magnets when you were a kid okay magnets you've all played with static electricity okay and hung balloons on a wall and all the rest it was clear it became clear by the time a Faraday that there was a relationship between electricity and magnetism if for example you took a charge and moved it as you know you produce a current and therefore a magnetic field around current and that that was known so moving charged produced a magnetic field pretend therefore it proves to a force of another magnet so that was known and what wasn't well therefore people tried for the longest time say well if a charged a moving charge computes a force on a magnet can a magnet produce a force on a moving charge I mean well in fact the magnet could produce a force in between charge sorry could a magnet produced a forest could on a static charge could a magnet somehow produce an electric force because a moving charge produces a magnetic force could somehow you do something to a magnet that would produce an electric force on that charge and people tried for a long time to do that and Faraday was trying and wasn't able to do that brought very strong magnets next to a charge and it wouldn't do anything next to a charged body and and but then one day by accident when he had a wire and another magnet and the magnet was brought up to see if any way you could induce a current in that wire namely a Bruce electric force and and then he turned off the other magnet and notice when he turned off the other magnet suddenly a current flow flowed in the first magnet and he discovered something you probably all learned maybe electromagnetic induction the fact that indeed you can produce an electric force on a charge with a magnet but we have to do it is you have to have a changing magnetic field if you turn a magnet on or off you'll produce a current in a nearby wire because the magnetic field that turns on or off will produce a char a electric force on a charge that will cause the Freret to flow and this was very important but before he did this faraday there was a great virtue of faraday not having been trained in school he said there was only one he only ever written down one equation in his whole life and and therefore he didn't think mathematically he thought pictorially and and people know that charges had forces of other charges and in fact you could write down the law of the force law between electric charges looks as the same as the force law of gravity but for Faraday he needed to happen on intuitive picture so he invented a concept which Newton before him had not and and this was the question Newton remember you may remember he's a hypothesis non Fingal I'm framed no hypotheses Newton was asked how does the earth know where the Sun is to fuck to go around it I don't know but does and and and so I was a real problem and the same thing was with electric charges at Faraday was think about how does an electric charge know on another electric charges there but Firday invent a concept that was useful to him it's just a toy model for him and was his idea that around every charge was an electric field he called an electric field and in any said well I could picture it let me imagine the charge sitting there sets up through space these field lines and the number of field lines is proportional to the charge the more bigger the charge the more field lines that are going out of it and then if I bring another charge nearby it the reason it knows to respond is that it feels the field lines that are over here this charge is set up a field throughout all space so this this charge here just interacts with the field here in fact you can make pictures of it two charges each having their few lines of field lines repel each other if they're the same thing and the positive field lines go to a negative field line so positive charges have field lines going out of them negative charges have field lines going into them and you could draw these pictures and what's amazing is you could say well if I place another charge down right here I can determine what it's going to do just by looking at the field line the charge is going to move in the direction of that field line and what was amazing is this gave exactly not just approximately exactly the right answer just by pictures you could do the answers by adding up electric fields and doing vector mathematics which you could all do but you didn't need to and he didn't do it he the picture is what mattered to him so he invented this mathematical crutch of this of this of these field lines and just a mathematical nicety that was useful to him and then he went on and did the experiments which established of course everything today because electromagnetic induction is the basis of motors and power and lights and everything you see changing fields producing electric fields producing currents so on when when water goes over Niagara Falls in Canada and turns a turbine which has a magnet on it and and sorry there's a magnet and the turbine turns with wires on it those wires are moving in a magnetic field they produce a current and that's how you get power great so it's kind of interesting but no one so there was this new relationship between electricity and magnetism and ultimately that relationship was shown to mean in fact one person's electricity is another person's magnetism electricity and magnetism are not different things at all they're really the same thing it just depends on your point of view for example if you're at rest and that magnet is moving with respect to you okay you experienced an electric force causing you to accelerate but if you're moving along with that magnet you'll see it as a magnetic force so one person's electric you'd see this both of you did see the same force but one person's force that they call an electric force was another person's force that you call a magnetic force and it depended upon your frame of reference okay hold that here the next major step was done by this guy who's this guy who Maxwell my real hero he was the greatest theoretical physicist of the 19th century he was dead by the time he was almost half my age but nevertheless in that time he established the greatest unification perhaps in all of physics but certainly the first great unification all the physics the theory of electromagnetism he showed that there was a complete if you wish symmetry between electricity and magnetism and he was able to put mathematical bones onto the onto the framework that that Faraday had established and Maxwell showed in one of the best most exciting calculations you can do and we're do it for you here but I don't want to I don't want to take the fun out of your undergraduate physics teachers because for me this is one of the my favorite calculations you can do as an undergraduate and for all I know some of you already have done it but he could so so he said look there's this big question well forget the big question for the moment he was able to show that there was this complete symmetry if you think about it the words I just gave you gave away the symmetry so there's electricity and magnetism a changing electric field produces a changing produces a magnetic field a changing magnetic field produces an electric field with the fields just being these mathematical inventions but Maxwell asked himself the following question by completing the mathematics of this he realized what you could show was okay if that's really true then there's a brand new phenomenon in nature because let's think what happens if I shake an electron back and forth shake an electron back and forth well of course it's a current okay it's a changing electric field so that produces a magnetic field but that but if I constantly am changing the electric field then it produces a changing magnetic field one that grows and one that's gets smaller one the group but that changing magnetic field will then produce a changing electric field which then produces a changing magnetic field with temperatures a changing electric field and he showed if you jiggle a charge there'll be a disturbance in fields that move out I probably have it here he said if i Dickel a charge I can imagine these fields moving out because the changing electric field his changing magnetic field etc center etc and he said okay there's something really important here how do I know I can calculate the speed of which that field moves out and that's the calculation that's so wonderful you can try it at home tonight if you want if you haven't done it or you can wait to your undergraduate a senior undergraduate probably he'd the way we could determine that the strength of the force between two magnets is is we measure it and there's a force constant so we measure the constant that tells you the strength of magnetism and we measure a call incident that measures the strength of the force between two charges those are two fundamental constants of nature measured them we plug them in when you solve the equations you plug in the strength of electricity and strength of magnetism what he was able to show is that of course the changing electric field and the change in magnetic fields produce each other in a way that depends upon the force those two those two strip for the strength of electricity and the strength of magnetism so we use actually they do the calculation when you jiggle a charge how fast will that disturbance move out and it depends on two fundamental constants the strength of electricity and the strength of magnetism if you just gave him those numbers he could calculate what that disturbance would propagate at and so could you it's it's a beautiful calculation and relatively simple and of course what did he find out he plugged in the numbers from the strength electricity in the strength of magnetism and he got a number like 3 times 10 to the eighth meters per second which should be familiar to you he got the speed of light and what that told him and what that showed was now people knew what light was light was an electromagnetic wave because from this fundamental calculation you can show if you shake a charge you will produce a disturbance in these fields that propagates at the speed of light and then Hertz was able to do the experiment to show that's exactly what happened shaking charge here would produce get you know light up a light bulb does you may have seen in physics classes over there but the important thing is that this was a fundamental calculation of the speed of light and it also did something else it if you think about it it was amazing the fields that were invented by Faraday were just in his mind because he couldn't do math or he couldn't do algebra you could do pictures and they were just an eventually human right but they are as real as anything what Maxwell showed is those fields are not just in a figment of your imagination the fields themselves you don't need the charges anymore that they produce disturbances in the field and the disturbances the field are so so important that you can see me because of it okay and therefore these inventions of the mind were real electric magnetic fields were absolutely real and there were different manifestations of the same thing the first great unification in physics two seemingly different forces electricity magnetism were shown to be so integrally tied together they were really different manifestations of the same thing and they were taught what tied them together was light light is the thing that tied together electricity and magnetism and light was a manifestation of that okay let's move on who's this guy everyone knows to that guy okay Albert Einstein now I get letters every day from people who um who tell me that they have a new theory of everything and want me to explain it want me to read it which I don't do and and they and then what and the standard line I get a lot is you know most people most my friends think I'm crazy and people I give this to think I'm crazy but everyone thought Einstein was crazy so they figure that if people fill out lines down was crazy and people up there was crazy they must be Einstein there's some kind of transitive thing there and but more important they say I have shown that all everything we now know is wrong all of the signs that we now know is wrong my theory is right and that's exactly and just like Einstein I'm revolutionising physics and then of course when you read that if ever anyone ever says that to you you can stop listening because that's exactly what Einstein didn't do the biggest misunderstanding about Einstein and the revolution that is relativity is that he somehow did away with the physics that went before me it was exactly the opposite why because if physics ends that the test of experiment today no matter what we learn about physics in the future it'll always be true so there's no way the physics of the future can ever say that the laws of electromagnetism are wrong because we've tested them in laboratory whatever we learn at the extremes of scale on the largest scales that you are the small scales the universe electromagnetism is still going to work because we've tested it now what happens to that theory when you go to small scales or law large scales may change but in human scales it'll always remain the same okay so what Einstein did what the brilliance at Einstein did was to take two things which were mutually inconsistent two results which were done by experiment which so they are both true but they are both mutually inconsistent and say how can how can I live with that the two results were the following Galileo as you all get subjected to in introductory physics class showed that you can't tell whether you're moving or standing still as long as you're moving in a constant velocity there's no difference there's no experiment you can do in this room that'll tell us whether we're moving you're standing still in fact lessor people than you think we're standing still because we are but of course you know that we're really moving at 30 km/s around the Sun as I do this lecture and between the time of the lecture beginning the lecture in the end we'll have travelled several thousand kilometers around the Sun so we're not standing still but it doesn't matter because we're relatively because it there's the curvature of the Earth's orbit space law small let's go we're moving in a straight line at constant velocity similarly if you throw up a ball an airplane and the windows are closed and there's no turbulence or train you you probably those of you yeah if you're not in the States trains may be better so it I don't know if you've ever had this experience of being on a subway train system and and or our train station and being sitting in your train and look at the train next to you and it starts to move relative you and for a moment you don't know whether you're moving in there moving until you start to feel the tracks okay and it's true there's no experiment you can perform is it not a zip zilch just say that you're moving or maybe the earth is moving in you're standing still and the train next to you is going by so that's Galileo basis of all of physics that result there's nothing more solid than that result well there's maybe just things just too solid that's one then you come over here you got Maxwell and Maxwell said I shake a charge and uh and there will be a light ray traveling out at the speed of light the speed of light which is determined by measuring the force of electricity and the force of magnetism those two things are mutually inconsistent most people don't even realize they were perhaps but Einstein did now what did Einstein do Einstein didn't say well okay I'm going to throw it all out okay Maxwell's wrong or Galileo on one of them has to be wrong because they're inconsistent now how are they inconsistent okay well so here's Galileo we're going along and this example I first developed of my daughter was very young so it involves projectile vomit so she was just infinite at the time and so I'm driving along my car and say I'll use American units because they're easy for me at the moment but it said we should never use miles but I will I'm driving on a car 30 miles per hour okay my daughter's in the backseat and she end and she projectile vomits and hits me in the head now the vomit goes to the back seat to the front screen it's a 10 miles per hour okay so relative to me the bomb hits me 10 miles an hour now what what about someone on the ground somewhere the ground sees my car going it's at 30 miles an hour since the vomit hit me go from the back of the front at 10 miles per hour in the car and therefore how fast is the vomit going with respect to someone on the ground 40 good baby physics okay great but let's say my daughter is a 21st century child and instead of playing with instead of a prediction of vomit she's playing with her laser beam and she decides to point her laser beam at the back of my head I almost blinded you there Chris but okay then what happens well so I'm traveling at 30 miles per hour she shoots the laser beam at my head and the laser beam comes to me at the speed of light okay so in relative meets be like but someone on the ground sees the laser beam in the car okay and the and in the car the laser beam therefore must be going at the speed of the car 30 miles per hour plus the speed of light according to Galileo okay but that's impossible says Maxwell why because if that were the case when this person saw the laser beam get turned on they would measure the light ray as going at the speed of light plus 30 miles per hour but remember the speed of light is determined by two fundamental constants the strength of electricity and the strength of magnetism therefore if the person on the ground sees the speed of light to be different for that moving laser beam then that person will measure electricity and magnetism to be different than the person in the car but Galileo says no because the person the car must always measure the same laws of physics of the person on the ground okay and therefore you can't have your cake and eat it too Galileo and Maxwell cannot be true at the same time because if they were people someone on the ground would measure the strength of electricity and the strength of magnetism to be different than someone in the car that was the paradox I'm always amazed it's never really explained that way because what we do to students and this is one of the awful ways that science is usually taught in high school is that you write down and I'm glad I don't have a blackboard here right someone writes down the speed of light is constant for all observers and it's like you know it's like some religious dogma that you write down you're supposed to believe why because Einstein said so well no one should believe anything because Einstein said so or because I say so or anyone says so Einstein was driven to that not because he said the nice thing about nature but he thought to himself how can I make Galileo and Maxwell consistent the only way they can be consistent I mean a lesser person want to said well there's no way but what I say says well you know what maybe they can be consistent if they both measure the same speed me with respect to me in the front seat of the car and that person on the ground with respect to them doesn't sound too crazy but of course it is crazy because how can they be the same speed if one person is moving with respect to the other well what Einstein said is let's think about what speed is speed is distance traveled free at a time so maybe that person measures speed to be the same as this one because their distance and their time measurements change so maybe maybe nature adjusts itself so that not that the distance that I measure over here and the time I measure here is different than the distance and the time I measure here it's the only way to make those two things consistent so in an incredible leap of courage what he said is instead of giving up all of the classical physics that went before him he would say the two things have been measured by experiment are both right but if they're both right space and time have to give and the consequences of course of that are threefold the three consequences of making the speed of light a universal constant which is the fundamental principle of relativity but it's not a principle based on Revelation it's a principle based on those two observational facts are the following lengths contract if if the speed of light is can be measured by all observers to be the same regardless of the speed with respect to the light ray that if I take this laser pointer and I'm moving very fast with respect to you and say it's 10 centimeters okay if I'm moving very fast with respect to U with respect to me it's 10 centimeters you will measure to be 6 centimeters now you might say a big misconception is you'll say well that's just you measuring it to be 6 any words no it is 6 centimeters to you it is every experiment you could ever do on this would tell you at 6 centimeters every experiment I would do on it would tell me it's 10 centimeters and we're both right okay the next one simultaneity changes if lightning strikes here and lightning strikes there at exactly the same time for me and you're running with respect to me you will say lightning struck in one place before the other place if you're running in that direction and say lightning struck in one place before the other place and we're all right and ein said so that's the case because we can never be more than one place at a time I know what happens with simultaneous for me right here anyone else who's standing right beside me has got to see the same thing but what happens in different distant points I can only find out about by light and what I infer from measuring that light will be that that event happened earlier than that event for me or later and less late for you and the last thing is time dilation the very famous effect the basis of science fiction movies which is really true that my wonderful apple watch will if I'm traveling fast with respect to you will be taking more slowly something we measure every day in undergraduate physics laboratories around the world if I'm moving with respect to you my watch ticks more slowly than yours now so those are the three consequences of relativity but the next where I presented this picture for you because it should jog your mind so what does this imply well here we are in this cave and we in this cave we see that we measure that if you're standing still with respect to me your rulers 10 centimeters long if you're moving with respect to me you ruler six centimeters long so there's no such absolute thing as length right wrong because we have the philosopher mathematician now natural scientist and it was actually Einstein's math teacher one of the few teachers who liked him Hermann Minkowski in 1908 who said you know what Einstein your theory tells us that really we don't live in a three-dimensional universe the hint for space 5 self and time by itself are doomed to fade away into mere shadows and only a kind of union of the two will preserve an independent reality we live in something we now call a Minkowski space where space and time are tied together and we now understand that in that space when I'm moving with respect to you my ruler is rotated in a general kind of way it's rotated in a four dimensional space every time we look we only see three dimensional slices so sometimes your space turns into my time and sometimes my time turns into your space and as the rotations a little more complicated in Mackowski space but the idea is exactly the same we have this quaint little notion that when we're looking out of this room we're capturing everything at the same time but we're not when I look at you the light from the people in the back of the room was emitted earlier than the light the people in the front of the room every time I take a picture I think a 3-dimensional slice of four-dimensional universe a four-dimensional universe of three dimensions of space and one dimension of time so when I take a picture it's actually spread out in time it's not an instant it's spread out in time because the people the back room the light from them had to leave earlier than the front so when I take it I'm taking a 3-dimensional slice of four-dimensional universe of space-time and in fact what you can show is when you consider that rotation in four dimensions there is something that's absolute in fact the theory of relativity really should be called the theory of absolutes because space and time are relative but space-time is absolute there's a four-dimensional length a combination of Delta x squared minus delta T squared the time difference between two measurements that quantity is called the four-dimensional space-time and that quantity is measured to be the same by all observers so we in a four-dimensional space there really is something universal space time and we were driven to this incredible realization that we live in a four-dimensional universe just as Plato would have imagined that philosopher back 2,000 years ago would have a mat discovered for people that they live in a three-dimensional universe when they saw length contract and it all came from these quaint little experiments and jumping frogs that Faraday's started to do led us to the beautiful unification in physics now in the 20th century we had the unification electricity magnetism but that very unification implied the unification of space and time ok good that was great then all hell broke loose the universe was coming together pretty well for dimensions electricity magnetism but then everything started to change first of all in 1950s we started building elementary particle accelerators and started smashing particles against each other and what did we discover every time we ramped up the energy and smashed particles together we produced more particles new particles and more energy new particles it looked like there were an infinite number of particles were there any fundamental particles what was fundamental if every time you smashed one particle to another you produced other particles were there anything truly fundamental particles and a lot of people said no maybe may it's kind of a Zen thing maybe every particle is made up of every other particle it was stupid but people were desperate so you know every time we with cloud chamber as we RAM particles together and see new tracks and we discover new particles and it was all depend on the energy so it looked like there were an infinite number of elementary particles first the next great discovery was it left doesn't equal right one of the most common-sense things what we grow up to understand is that left and right are an anachronism they're an invention that we use to tell you to tell ourselves how to go from somewhere to somewhere else I have to remember which is left because I put my watch on that hand so I can always remember which is left and and but it's not a fundamental about left or right I mean no one thinks that the laws of physics on the left side of the room are different than the laws of physics on the right side I'm never that's the left side room is different than the right side room the right side the room has one person sitting in it over here the left hand side has maybe 20 people sitting there's no doubt but that's an accident of our of the circumstances in this room so we could tell left from right you know that's how we can be at directions because the building is on the left it's not on the right but that's it accident no one thinks there's some fundamental difference between that now and there isn't there isn't in all the physics we could normally measure and though in the way light behaves and gravity behaves and all the rest left and white or just some mention and it's an important convention something you should think about again I learned from Richard Feynman and who gives a wonderful example somewhere but try and think how you would give directions to someone on Mars who didn't know what left and right were okay tell him how to get to their corner of corner store when they landed okay try and think about it see if you could do it okay have fun tonight with that anyway two young guys discovered these are love these payments I use them we all know that is differently the left hand and right hand but again that's an accident you can't turn your left hand into your right hand it doesn't look the same when you do that right and this is a wonderful if this is a wonderful cave not even a painting that done about 30,000 years ago deep inside a cave in Germany this is the kind of thing that when I spend time thinking about some at 30,000 years ago some adult took a child to deep into a cave in Germany put their hand against the wall and spray paint over why who the hell knows did that you know it's a mad and just but they did it thank goodness and we now have that impression but of course if they did the other hand it would be different so those those are different but that's just an accident but what was discovered by these two really young guys who weren't much older than you are now a little bit TD lien and Seon yang in the early 20s was that in fact if you looked not at the force between electrons or the force between planets but there was a new force called the weak force and I'll tell you about the weak force the weak force is responsible for us being here it's responsible for the nuclear reactions that power the Sun and it was only begun to be discovered in the 1930s in nature the reak force and and and and what was once like they realize it look when you look at the weak force there was a puzzle and the puzzle could be solved if the weak force distinguished left from right and the way you did it was in fact they proposed an experiment if you have a neutron and the neutron decays as I'll talk to you about in a second because because the weak force the case and the protons electrons and it turns out other stuff and they show that look if they were right if you took a neutron and spinning so neutrons spin like all like many elementary particles and you put in spin axis here and it's a cade protons electrons would go out but in fact they wouldn't go out uniformly you could tell you could determine an absolute left from once you set the neutron up then the decays would be dipped it wouldn't be the same number of protons going or going off in that direction as that direction you distinguish left from right that's what they proposed and madam Wu an experimental physicists at Columbia did the experiment this was back in the days when you could make a proposal and then do an experiment at the weekend later which she almost did so 1955 they proposed it she did it discovered that in fact that weak interaction is distinguished left from right and in one of the only times it's actually happened the Nobel Prize will was carried out correctly the Nobel Prize was supposed to be for the greatest development in that field physics or whatever in that field in the last year never happens and many friends win the Nobel Prize for work they did 50 years earlier okay but this time was so amazing the notion that left and right were different were so crazy these guys won the Nobel Prize in a year after they did it when they still looked like they couldn't yet shave okay then we got this guy who's this guy richard fineman of course I couldn't give a lecture let's aqua richard fineman richard fineman then showed that there was something even curiouser was first actually demonstrated by Dirac but fine was the first one to give an argument for this okay fine Minh won the Nobel Prize for developing a quantum theory of electromagnetism electromagnetism as Maxwell has shown if you shake a charge you mitt light and that's electromagnetism and you can work out the interactions and you can all wear the equations on a t-shirt that tell us everything you need to know about nature Maxwell's four equations tell us how electromagnetism work and that's true on the macroscopic level but on the quantum level it turns out that we now understand forces the force between two electrons as due to the exchange of virtual particles that they're actually particles at the basis of light waves those particles are called photons as you know and so Fineman developed helped develop the mathematics and described the theory of electrons interacting with photons and the way two electrons would know to be repelled by one another was not that this electron would set up a field necessarily but the way we think about it from a quantum mechanical perspective is this electrons going along and it emits a virtual Photon namely a photon that you can't see that basically if you ever tried to measure isn't there that virtual photon would be absorbed by another electron and that would cut that with what would tell the kick that electron away so the two electrons would repel now what are virtual particles well virtual particles exist because of something called the Heisenberg uncertainty principle the eisenbergers Earnie principle says as I like to say the same thing as the white house and Corporate America if you can't see it anything goes and so the quantum mechanics tells us it's exactly this about case on scale smaller than you can measure anything and everything happens even things that seem classically impossible and what the Heisenberg uncertainty principle says is that there is there are certain quantities that you can't measure exactly certain combinations of quantum quantities one of them is energy in time if I measure a system for a fixed amount of time I can only measure its energy to a certain accuracy to measure more accurately I have to measure it for a longer time well that's the point so when this electron emits a photon and emits a photon with some energy well that violates energy conservation because you can't just have a electron sit there and suddenly emit a photon that has energy where did the energy come from that's not possible except quantum mechanics says long as you can't see it it's fine so the photon goes long it violates conservation energy but now you're measuring the system and therefore if I measure it for a finite amount of time I can measure the energy act received and a finite amount of energy and that means the photon us to disappear before I can measure it that accurately so if I met a very energetic photon that in that photon has to be absorbed really quickly because it would violate the conservation of energy otherwise and that's why electromagnetism is a long-range force because a photon is massless to answer your question and therefore it can take up an arbitrarily small amount of energy therefore when I have an electron over here it can emit a photon that can travel all the way to Alpha Centauri four light-years away before it gets absorbed because in the process it can take an arbitrarily small amount of energy and I never be able to measure the energy of this electron accurately enough over four light-years or four years to know that that electron that that there was violation energy so that's why that's why the only long-range forces in nature are the ones that have massless particles that that are responsible for the exchange and Fineman did the did the theory the mathematics of this and there were many problems of the mathematics which I'll talk about but he he worked them up but one of things he showed is okay these are called Fineman diagrams and he said okay well I can think now of understanding interactions in particles particle a is moving along and then emits a photon is absorbed by particle B but of course the interaction could happen the other direction particle B can emit the photon before and and be received by particle a there's no and if you want to calculate the total interaction you have to consider all possibilities be emitting a to a a minute B and all of those possibilities in between but he said okay well here let's just think therefore what can happen to an electron well an electron is moving along but remember the Heisenberg uncertainty principle electrons moving along let us be light who do then Hey I'm a quantum particle I'm going too long faster than speed light okay nothing stops that nothing stops the electrons going faster in light as long as it does it for such a short time you can't see it so I get electron okay good that's that's allowed in quantum mechanics but then there's a problem because relativity tells us that if you're moving faster than light in one frame in another frame you would be observed to be going backwards in time so really for another frame if you if there if that would happen another frame then the electron we're moving forward in time go backward in time for a little while and go forward in time that happens but then let's think about what that really means and finally said well imagine you're looking at a he used the example of a bombardier in the worid looking down and you see one road going along and then you're travelling along here you see one road going along and then suddenly you see three roads and then you suddenly see one road again well what happened you saw the road did it turn back okay was really one road doing that all along but he said that's what if you're thinking about measuring things if this is really true and you look at this in this frame you start with one electron but what does an electron that's going backwards in time looked like well it's a negative charge going backwards in time but that is mathematically equivalent to a positive charge going forward in time right if you're traveling if you're following the flow of charge then elect a negative charge moving backward in time is the same as a positive charge moving forward in time and therefore we said if you're going along for the observer in the other frame it would look like this electrons moving along then at this point out of nowhere an electron is emitted and suddenly a particle that looks exactly the same as an electron but has opposite charge is emitted and then at this point this particle with opposite charge and this electron annihilate each other and then you're left with one electron left over so just by applying quantum mechanics and relativity together we now know that suddenly empty space isn't empty as I told you suddenly not only does this imply that for every particle in nature there must be a particle with equal equal and opposite charge in the same mass the antiparticle anti particles are required just by the combination of relativity and quantum mechanics the two are inconsistent unless and which is what Dirac and first really shown without unless you allow for the existence of antiparticles first and but then secondly particles and antiparticles can pop in and out of the vacuum again as long as the extra ones get rid of themselves in a time scale so short you can't measure it but this says particles can pop in and out of existence and so you not only have virtual particles but you get virtual antiparticles the world suddenly became a lot more complicated because gotten not on now not an infinite but particles you got anti particles but you have anti particles and and that's this is the reason they exist ladies and gentlemen and you now know why you could have predicted it if you thought about logically what I said to you the first part of lecture you now don't feel bad he didn't because of course a lot of people could have predicted it and didn't for a long time so this is why empty space has energy and this is why inside protons virtual particles are popping in and out of existence and they can affect the properties of protons and we now know that those virtual particles they're because we can measure them indirectly okay next when I was in high school I learned something amazing that I'm now going to tell you and when you get as old as me you can tell people your age and say that when I was in high school someone told me this and it was amazing I hope it's amazing you you are made up of mostly neutrons there's one written most more neutrons and protons right and the atoms in your body but neutrons are radioactive if I take this Neutron here and hold it it lives ten minutes that's the let radioactive lifetime of a neutron now that should shock you because you've been here for more than 10 minutes as you've been painfully aware but the neutron actually in 10 minutes will decay as I told you with decays into proton an electron called in this picture of beta - and it turns out a weird new particle called a neutrino my favorite part particles in nature in ten minutes so why are you still here if the particles that make you up should decay in ten minutes an amazing accident the neutron the difference in neutron proton mass is one part in a thousand the neutron is just one part in a thousand heavier in the program they're almost exactly the same as in fact the mass of the neutron is almost like almost exactly the sum of the mass of proton plus electron with a little bit of energy left over that's why you're here because what happens a free Neutron decays but then I let a neutron fall into a nucleus what happens when it falls into a nucleus loses energy that's what getting bound into it listen if you jump from the top rope just to kill yourself because his lectures driving crazy you fall down here you'll lose energy in the process before you topple on to this poor people who feel that energy released on their head okay so the neutron loses energy to fall simplest but what did Einstein tell us Einstein told us e equals MC squared if the neutron loses energy when it falls in a nucleus it loses mass now it's no longer heavy enough to decay into a proton plus electron plus a neutrino so if you stick neutrons and nuclei they're stable for that accidental reason that the neutron is just heavy enough to decay in the real world but you put inside a nucleus they can't decay anywhere that's why you can build a comic nuclei that's why stars can make atomic nuclei that's why you're here because that's how you can build up things from hydrogen to helium to carbon nitrogen oxygen iron and everything else you just ate okay a wonderful amazing fact and the force there's as as in fact Enrico Fermi another one my heroes the last great physicist who was both an equally good experimentalist and theorist doesn't happen anymore because both fields have too much intellectual baggage to be an experimentalist you have to become an expert and all this stuff takes a lifetime to be a theorist you have to learn all this mathematical stuff that takes a lifetime and and but Fermi was able to do both and Fermi came up with a theory of that which was an idea of that called beta decay and which he presented in it it was theory and the neutron decays and in his theory into proton and electron and neutrino and that it gives the right answer etc right there's a problem with the theory however and it was recognized the falling well the weak force neutrons decay in fact to go back here at a point and at one point suddenly you haven't looked the neutron and then suddenly a proton electron neutrino come out at that point so the weak force has a range that's incredibly short you don't see a neutron over here and suddenly a proton electron and neutrino appear over here whatever causes that interaction happen happens over a scale much smaller than the size of an atomic nucleus okay and so people say well look you know we got this great theory quantum theory of electromagnetism that works it's the best theory in nature still the best theory in nature quantum electrodynamics allows you to predict to eleven decimal places are better fundamental quantities that you can measure there's no other theory in the universe that we have that allows you to take fundamental quantities and predict answers to eleven or twelve decimal places and get the right answer this is the best theory in nature and it what didn't take a rocket scientist a lot actually took about 20 years for sort of say well look you know maybe maybe if this theory works so well I can maybe make a full good quantum theory cuz Fermi theory was just an approximation I can make a quantum theory of the weak force by having the neutron which turns out to be made of quarks but that doesn't really matter decay into an electron and a neutrino but to be a particle exchange because all forces in nature in the quantum world and due to particle exchange but why why would the weak force be up and over the size of a nucleus well giving you the ammunition it give me the answer anyone okay I'm not going to what it has a big mass that's right because I told you that if you carry a lot of energy you have to disappear really quickly a photon doesn't have to disappear very quickly because it's massless that's why you left compact in long ways if you have a forced carry that's very massive then whenever a virtual interaction occurs asked to emit a very massive particle a lot of violation of energy right there it better disappear very quickly okay so I can make a quantum theory of the weak force that was looked the same as the electromagnetic force but I have a a a heavy carrier great the problem is nonsense ensues what happens I'll go back for a second if you try and do the mathematics of this this is the best theory of nature predicts everything all right this predicts everything is infinite that's a slight problem and and the problem is that this theory just doesn't make mathematical sense now I want to just spend a little bit of time on infinities because there's not fascinating mathematicians love infinities physics don't like infinities this is Hilbert the greatest mathematician of the end of the 19th century really part of the 20th century and he he gave a wonderful example which you've haven't heard you'll hear and if you've heard you'll hear it again something called Hilbert's hotel to show how ridiculous infinity is let me give you an example so has anybody ever been to Las Vegas yet not yet oh so you have interesting okay well they're these infinitely big hotels so let's say you go to Las Vegas an infinitely big hotel and and and you go in and and let me just label number the rooms the hotel one two three four five six seven eight nine ten up to infinity and I go to hotel I get in one in the morning and I go in I say can get I can I have a room and the room keeper says that's full all right okay I'll go somewhere else no no no I can we can fit you in how well it's very simple I'll take a person from room number one and put them in room number two room number 2 into 1 or 3 etc etc etc and now we'll number 1 is empty I just move everyone over 1 well it's infinite you're allowed to do that right that night that doesn't seem to bother you enough let's say you have a Catholic family it's infinitely big and you and you and you wanna you and your children want to go into the room in the hotel and say say I want to and this is faux but oh no I can accommodate you I just drew will the person room number one into room number 2 the person from number two in the room number four room number three into the room number six and now only the even number of rooms are occupied but of course they're an infant number of odd integers so we can fit your family ok begins to bother you let me give you an example that's that's an artificial example let me give you another example of something that's actually relevant in physics let me ask you the following what's this and if you know the answer don't tell me you can only answer if you don't know the answer ok what's the sum of this series the simple answer is infinity so say very good no okay yeah yeah see I knew that we someone have to prove they knew the answer ok the answer to this first of all we can we can write down that series in weird ways we can call the sum of here's that we can label it as a function the Riemann zeta function which is the sum from n equal 1 to infinity of n to the minus s and if s is minus 1 then this is the sum of 1 to infinity of n which happens to be this series so the Riemann zeta-function we can we can define a generalized function where s is the exponent here and in if s is minus 1 it's this number then we can do something fancy and say well we did this s could be anything not just a integer but a real number maybe it could just be a complex number and then I can rewrite the Rhianna zeta function in some weird way which we can do and then we can do the answer we can say what is the sum of that series if what is the Riemann zeta function of s of minus 1 and the answer is as the young man who had to shout it out - 112 now this should bother you because in fact every number in this series is larger than 112 and every number is positive for the sum is minus 112 maybe I'd say that's just a bit of mathematical wizardry it's irrelevant well maybe it is but the interesting thing and I won't tell you now because I was think of doing it but I'm is this this sum is the reason why string theory requires extra dimensions turns out string theory as was originally defined had a series that appears like this in it they gave nonsense ah well it sorry in the series it was times a number which became infinite and you would sum it up and get in infinity unless the two other numbers were just set up so this series which is minus 112 will cancel another series which is plus 1/12 and those two numbers depend upon the dimension of space-time and it turns out string theory requires if you don't have weird other things 26 dimensions of space-time the reason string theory requires 26 dimensions based on is to cancel things because of some of that series is minus 112 so if you think it's just mathematical shenanigans maybe it is but it's responsible for the fact what the reason that a lot of physicists began to think the rector dimensions in nature because of this 1/12 had to be cancelled okay so maybe it is just mathematical shenanigans but infinities are crazy and and the and the main point of this is if we want to come up with sensible physical results we have to get rid of the infinities okay how can we do that well coming to the climax which is good excellent those of you who live in cold climates I've talked about this in the other day what can experience the fact that when it suddenly gets cold there icicles on a window and we can see the icicles on a window if you've never seen them they look like this they're beautiful because we're standing outside the window over here looking at them prettier now if however you lived on one of those icicles the world would be very different for you if you lived on this particular icicle that direction would be very different than all the other directions wouldn't it if I'm not icicle your universe would say we have this a preferred direction in nature okay nature is such if you only live them that on that icicle just like living in their cave you live that icicle One Direction would be different than all the other directions now that's an accident of your circumstances we know then the real world doesn't matter all the icicles pointing in the Civic different directions are the same but if you lived on one of them it would pick one direction to be different that's the phenomenon of spontaneous symmetry breaking we call it what it means is the real world has a symmetry it doesn't no matter which direction you're pointing but when you actually get a manifestation of nature one direction is different than the other for example in this room there's spontaneous symmetry breaking that direction is different than that direction because I can go out the door in that direction can't go out that door but that doesn't mean it's just an accident of our circumstances now mr. Higgs and a few others point out the following if there is if we live in an icicle if the universe is an icicle and there's a background field that's invisible everywhere in the universe but some particles interact with it differently than others then the particles can initially be exactly the same but end up looking different it's like swimming in molasses if you swim in water you can swim very fast if you if you if you jump into a pool of molasses you looked at you you'll swim pretty slowly and probably other things will happen - but you look some pretty slow now you will feel heavier in that molasses another example take a car if you've ever had a flat tire and you end you want to push the car off the road it doesn't get you can push it until you at the side of the road which is mud and then you can't push it anymore the car suddenly becomes heavier well it doesn't becomes heavier there's just more much more resistance when you try and push it through the mud right but it acts as if it's heavier what higgs another citizen maybe there's this background field in nature and some particles interact with another particles don't and let's say photons don't interact with it so they go along directly but let's say particles like the force carriers of the weak force interact with it and try to get through and they act like they're heavier so really in a fundamental way the particles are both massless the weak particles that convey the weak force only act like they're massive because there's this background field and if the weak particles that convey the weak force are really fundamentally massless at some fundamental physical scale the mathematics of their theory is identical to the mathematics of electromagnetism and all the infinities that disappear and so the second the third great unification of physics is to say well maybe the theory of the weak force in terms of their three particles that can create a weak force two charged ones in one neutral one looks identical to the theory of complex dynamics if you assume they're massless particles and there's this weird field that makes these massive that these interact with well that's fine but inventing a weird field is like religion if it's invisible it's like God right but in physics if it's going to be relevant you've got to be able to test it well before we talk about that let's go back to this it was recognized that look if these if these things look the same maybe they are the same maybe all of these are different manifestations of the same force just like electricity and magnetism which look different are really you know one person's electricity is another person's magnetism maybe at an underlying scale these are all part of a unified theory where the same force but because these have a different interaction strengths with this background field they end up looking different so this one theory of two forces the weak force and the electromagnetic force is really a single theory call the electroweak theory their unified together and it's an accident of nature that this begins to look different and then it was up to these gentlemen to show the mathematics worked out exactly right sheldon glashow who did it during his PhD thesis in 1961 Steve Weinberg who did in 1967 and Abdul Salam around the same time said look maybe there's a unified theory of the electric magnet or weak force the electric and weak forces and they're all manifestations the same thing and the proof of it because they were the first ones to put the meat on this picture is that there'll be three particles here and because of the same force they'll have very characteristic interactions with matter that you can measure if you could just build an accelerator big enough to detect them they'd have to be there and I can tell you exactly what the mass is because I can tell you how big the force long-range forces and they wrote down the mathematics of it and in 1979 they won the Nobel Prize for producing the next great unification we had electricity magnetism now we have electromagnetism unified with the weak force now so there's a few things missing here first of all they wrote down the theory but no one ever actually showed it work mathematically that the actual theory could get rid of all the infinities these guys showed you get rid of all the infinities this guy did it when he was a graduate student Gerardo Tufton is most and its thesis supervisor and 20 years later they won the Nobel Prize for actually because no one you know when Weinberg ed wrote down his theory in 1967 and have precisely zero citations until 1971 no one cared about it until these guys proved the theory made mathematical sense that the infinities really did go away if saunt any asymmetry have baking happened and they won the Nobel Prize then yet these guys and they showed okay you got the week you get the electromagnetic force that there's one other force in nature the strong force the force holds quarks together and they showed that it was exactly the same type of mathematical theory could explain that phenomena if some and in fact that theory would predict something even weirder that if you took two quarks and brought them together the force between those quarks will get weaker the closer they got completely non-intuitive but quantum mechanics makes it happen they'd call that asymptotic freedom they said if the same kind of mathematical theory called the gauge theory explains the strong forces explains the others then because of its form quarks the force between quarks to get weaker the closer they get and what do you know the 1980s people began to measure things and discovered the force between quarks gets weaker and in 9 2004 these guys won the Nobel Prize in Physics for that and they're the ones who allowed that picture of what happens inside a proton to be actually calculated because they have the theory called quantum chromodynamics electrodynamics is a theory of electromagnetism quantum chromodynamics is a theory of the strong force so now we have quantum theories of the three of the four forces in nature everything works out all the infinities are gone you've got theories that work completely and explain every phenomena we've ever observed in the laboratory but there's a problem the problem is well so this is what we got one type of symmetry every observation explained and it led us by the way - it made physicists particle physicists even more obnoxious than they were before because if we were convinced were on the verge of understanding absolutely everything but there was one little bit of in this house of cards that could make the whole thing fall down you it was based on this invisible field that no one could measure or no one could measure up at that point so the whole edifice could fall down if that field was just didn't exist how do you find such a field very simple you spanked the vacuum sadomasochism in physics is everywhere because quantum mechanics tells us that for every field there's a particle and if I spank the vacuum hard enough at a specific point meaning if I dump enough energy in the vacuum at a specific point I can kick a real particle out if there's a background Higgs field if I put enough energy in a single point I can get a real particle out and I'll produce a particle associated that field now the mathematics told us that particle was probably pretty heavy so he built accelerators in 1970s and 1980s and then we were building an accelerator in the 1990s in the United States that would find it we thought but then Congress and their infinite wisdom said we can't afford anymore it's five billion dollars it's a lot of money so the amount of money of maybe the Iraq war air conditioning in the Iraq war in a week okay but then they thought was a lot of money so they cancelled it but then the Europeans built an accelerator and said look if this is empty space the particles interact with it giving the mass we could turn the picture around and say if we smash two particles together with enough energy we can reduce the particle that was responsible for the Higgs field so let's build accelerators in this case build a machine that will accelerate protons around in one direction and antiproton and protons protons around one direction and protons around another direction and accelerate them to 99.9999% of the speed of light so they get pretty heavy and then smash them together maybe with enough energy to produce the Higgs particle producing the most complex machine that humans have ever built it's this tunnel is 26 kilometers around if you go to Geneva the airport there you won't see anything you'll just see farmland because it's deep underground it goes underneath the Jura mountains here and and protons are accelerated 99.999% of speed aligned that direction 99.9 percent the speed of light in that direction they smash in a few places and by the way they go through that this is the French Swiss border they cross the border maybe ten thousand times a second without passports and and and and they and it was hoped that they might produce the particle that was a manifestation in the Higgs field and this is an observation in July 4th 2012 they discovered that the reported the cover of 50 particles of more or less that looked like a Higgs and and sort of sounded like a Higgs and if you walks like a duck and it quacks like a duck maybe it's a duck and in fact how do you know well remember that because the Higgs particle gives gives mass to other particles Biggs field particles that are heavier must interact with it stronger than articles are lighter and therefore if the Higgs particle is there and it's going to decay it's going to k preferentially into heavier particles can interact more with them than light particles so it's interactions are prescribed by the standard model and in fact you can look at all the different kind of decays of this particle we can predict what they would be in the standard model and this was the early results and they were all more except for one was a to Sigma way but now is is is there but two sigma differences happen all the time now we know we've discovered the Higgs particle the standard model of particle physics is complete starting with Plato going through Faraday and Maxwell and Einstein and Fineman and all the rest we took this incredible theoretical edifice of staring at a screen and realizing that what we see the world we see is just a manifestation of a deep underlying reality and now we see that if in a sense we are all living on an icicle we the reality that we see our existence our mass is an accident of the fact that this background field exists the fundamental particles in nature are all massless and what makes our reality possible is that we're living in a tip of an iceberg now we aren't done and I'm almost out of time I went slower than they thought I would I like impressionist painting but the thing about impressionist painting is it's great until you get really close to it then looks crappy and there was something interesting about the about the forces of nature we measure the three non-gravitational forces of nature the strong force the weak force and then like a magnetic force they have different strengths as manifested at our at our scale but one of the interesting things is I told you the force between quarks gets weaker as you get closer together that's equivalent in quantum mechanics are saying the force gets weaker as the energy scale of which you explore it gets bigger and it turns out the strength of the other forces change too and it didn't take much smarts in nineteen seventy four or five say look you know although there these two have already been unified by the single theory but since they all come together if you go to a really high energy scale or a really small distance scale maybe they're all the same force maybe not just electricity and magnetism and the weak interaction you divide but maybe they're all unified in some grand unified field clear and in fact the problem is it's wrong doesn't work we didn't know the exact strengths of the forces in 1974 but we measured them now and when you extrapolate them using the known laws of physics and the known particles in nature at some scale 16 orders of magnitude higher in energy than the mass of the proton or 16 orders of magnitude smaller in scale than the size of the proton they don't come together but if there's a new symmetry of nature supersymmetry then it and if it's manifest at the scale of the Higgs it predicts a whole bunch of new elementary particles in nature they change the weight the way those forces change and in fact if you put supersymmetry in they all come together at a single point a single point at a scale that's comparable by the way to exactly the scale where inflation might have occurred and so it all is beginning to smell like it might be there except if there are a lot of new particles at the electroweak scale we should see them in the Large Hadron Collider we haven't that's what we've turned it on again and increase the energy it's now running and it may tell us if it discovers these particles that were on the right track to a unified theory that might predict a theory of inflation that ultimately might predict those extra dimensions that I talked about and they actually universe as I talked about yesterday okay they're not there what if the Justin Hicks is measured and nothing else when the Large Hadron Collider turns on well maybe it's some mentor fundamentally wrong or maybe they're just a little too heavy maybe we have to build another machine but it's gonna be a lot harder to build another machine because he can't go to Congress or the European Union or whatever say guess what guess what we turned it on and we didn't discover anything give us more money okay it's hard maybe we'll continue we've waited 40 years 50 years from the time of Higgs to the time we measured the particle during that time we came up with lots of theories most of them wrong probably if we don't build another machine we could be into another 50 years of sensory deprivation we'll see what happens at the Large Hadron Collider so what I want to conclude with is that in my opinion the Large Hadron Collider is humanity it's his best the Large Hadron Collider machines like it or the Gothic cathedrals of the 21st century Gothic cathedrals when the most complex machine devices buildings ever made in Gothic times they celebrated the glory of God they were beautiful etc they were built by thousands of artisans over centuries working together to make a beautiful thing the Large Hadron Collider has these amazing detectors that are gone gatchoo and in size built by thousands of physicists over decades each of the physicists speaking dozens of languages dozens different religions but they have to design machines that are accurate to the nearest millionth of an inch to make it work and it works it's an example of the fact that science as we can see in this this auditorium is universalist is global it doesn't matter whether you're chinese or japanese or news from new zealand or from the united states or from singapore or wherever we speak the same language and it doesn't matter what our cultural backgrounds are or our language or our religion we can work together to find a common reality it's humanity and it's best there's there I am that makes even a better sure of it let me give you an example of how hard this is though what they have to do every second the Large Hadron Collider every second enough data is generated to fill more than a thousand one terabyte hard drives more than the information all the worlds elaborate libraries every second that Sheen runs we have to figure out ways to manipulate that kind of data the machine itself is 26 kilometers around at a temperature of almost absolute zero with a vacuum better than the vacuum of space there are fewer particles in that in that tunnel than there are if you go out into orbit among the earth the unbelievable requirements that were on this machine in order to make it work make it the most complex thing that's ever been built but it's built but the last thing I want to end with then is if this whole theory is right and appears to be we are just here by a cosmic accident the fundamental universe doesn't look at all like the universe we see and if the higgs field in the early universe hadn't frozen in place we wouldn't be here so much for planning and design so we're here by cosmic accident I won't go into that anymore the last thing I want to say that is we are actually at this point with the Large Hadron Collider about to turn on again to see when we open that thing if all the forces nature are unified and some people have argued that unification may imply that four dimensions isn't all there is that when we turn on the Large Hadron Collider will actually see five six seven or eight dimensions at very small scales maybe we really will open the Wardrobe and find a whole new universe inside I don't know but the great thing is you're young and we'll find out in your lifetime and maybe some of you will help us open the Wardrobe thank you very much Thank You Lars

Channel: The Professor Harry Messel International Science School

Views: 103,127

Rating: 4.6830187 out of 5

Keywords: Lawrence M. Krauss (Academic), Physics (Field Of Study), Particle Physics (Field Of Study), iss2015, Sydney (City/Town/Village), Australia (Country), Harry Messel

Id: wMI-ot-n-aw

Length: 81min 37sec (4897 seconds)

Published: Wed Sep 02 2015

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Apologies: the first 35 minutes have no footage of Lawrence himself due to a technical glitch!

The story of our understanding of particle physics, from the atoms of the ancient Greeks to strings and hidden dimensions — it's one of the most staggering achievements of the human race.

Professor Lawrence Krauss, Foundation Professor of the School of Earth and Space Exploration at Arizona State University and director of its Origins Project, speaking to students at the 38th Professor Harry Messel International Science School, ISS2015: BIG — The University of Sydney, Australia, July 2015