 All right, so the next talk we've got coming up is by Michael Contario and it's how is the universe like a light bulb? So a big hand, please Good afternoon everyone. You're having a good EMF camp Excellent. So what I'm going to be doing is kind of a bit of a cross between a physics talk and a comedy show So who in here enjoys watching comedy? Hey Excellent. Excellent. Who in here enjoys watching physics talks? Hey Who in here likes neither? Excellent, you're all in the right place This is a bit of an experiment and as such I'm going to say what my aims of the experiments are out at the front Which is a good experimental practice. I did actually want to be doing a double blind experiment To see whether or not this was a good way of transmitting physics So I was going to try and put in a second event which was going to have the exact same title, but be contemporary dance But luckily that turned out to be too much fat, so you're all excused from that But what I'm going to be doing is I am going to be talking through some stuff Basically linking it through the physics. So things like how is the universe like a light bulb? or How is you might you might know this one already? This is an old joke. How is duct tape like the force? And the answer to this joke is it has a light side a dark side and it holds the universe together And another sort of comparison that you might make another famous one is how is a raven like a writing desk and There are a couple of almost canonical answers to this one of them is they're both inky and Another one is Poe wrote on both But because I'm coming at this from a physical perspective I think the answer is both bizarrely are made of exactly the same constituent parts and obey the same physical laws despite being really very obviously different and if you don't think they're obviously different then Yeah, there's no hope. I'm sorry. You're just gonna have to leave it there But there's so many things that are linked by the physics underlying them and I was a bit disappointed a while back I was reading the garden guardian education blog and they had a letter Well an email I assume that had been written in by someone who was choosing her a level subjects and she said I don't want to do physics because I've been doing physics and biology at GCSE and Biology just seems so much more relevant to my everyday life learning about things like stem cells And I think if we've got to the point where the subject of physics Which is literally about how everything in the universe works is not relevant to your everyday life Then we're doing something badly wrong Also, if you're doing if your everyday life requires stem cells When you're doing your GCSEs, then it's possible you might also be doing something wrong So I want you to put this together and kind of bring all of the different things together And also a lot of physics talks. They're all they're all about astrophysics all about particle physics and they're brilliant but there's so much more to physics and I wanted to kind of talk about some of the Almost nitty-gritty that often gets lost. So I hope you'll appreciate all of that So what we're going to start with is how is a roundabout like a space station? One answer that I have heard is a lot of Americans haven't seen either of these and don't honestly believe that they exist But no, it's one of that. Has anyone here driven through Milton Keynes? Yeah Did you enjoy driving through Milton Keynes? No No, I used to go there's a bus between Cambridge and Oxford that I've been on called the x5 and it for some reason It goes through Milton Keynes and all that you get all the way through is getting shoved to one side and shoved back to the other as you come out of the roundabouts and This To understand this you've got to kind of like we're going to use some actual technical physical terms here Because most of the time in real life we talk about how the speed Something is moving at but what we really care a lot of time about is its velocity Which is just a speed plus a direction direction is really important because if say I was wandering out outside And you said which way is it to the toilets and I said, oh, it's okay. They're only 300 meters away and Think of your direction. I am giving you not enough information It's the same a lot of time in physics. We need directions as well. And so technically the definition of acceleration Is a change in velocity so it can be a change in speed or it can be a change in the direction And so in when we're going around the roundabout because we're changing direction We are accelerating and there seems to be this weird link between Acceleration and being thrown about and feeling feeling being pulled somewhere So I'd like to do a bit of an experiment with all of you This is just a thought experiment. So it doesn't require you to move from your chairs And I'd just like you to imagine that after this talk You kind of went out. You had a fun rest of the EF and then you went to bed and then you woke up Bizarrely in what looks like a lift. You have no idea how you got there. Perhaps you party too hard at the bar tonight And and you are just there stood on the bottom of the lift and you think that's usual That's what normally happens. I'm stood on something. I can feel the ground pushing up against me. This is usual But since you don't know how you got there Something else might be happening. You might be out in deep space Where you're so far away from all the other stars and planets that the force of gravity is Negligible almost zero and all that's happening instead is you would be floating apart from the fact that your rocket ship is Constantly accelerating in one direction. So to you it feels like there's gravity pushing you away from that But then if you're in the lift Something bad happens the lift cable snaps The lift starts falling down and you start falling down at the same rate as a lift You lose contact with the floor and just floating floating there is a lift plummets heading towards What seems inevitable at this point? You're probably hoping very much that you are actually in the rocket ship and in fact all that's happened is a rocket ship has Stopped accelerating leaving you free to float around in zero g and it was this kind of equivalence between acceleration and gravity that caused eyes That caused Albert Einstein to actually come up with his general theory of relativity, which is basically Theory of relativity number two the first one was special because it didn't involve gravity Why that makes something special is an answer that is Lost in the midst of time so so When Einstein did this He realized that actually gravity did more than that. Oops. Sorry. I managed to put my slides on He realized that gravity did more than that because in theory of relativity he linked space and time and in the General for it theory of relativity. He put gravity into the mix and that warped space-time Which is of course a really poor naming system by I'm saying he's literally just taking space and time and Ram them together. I wonder whether or not Einstein was at the time. He was thinking about this getting slightly hangry Because and perhaps he shouldn't eat an a ham bread, which I'm sure is what he would have called a ham sandwich So he's got all that and he's put it all together And oh one thing you might not know The mathematics of relativity gets very complicated and Einstein was the master of the humble brag Because he said no matter what your problems are with mathematics. Do not worry for mine are far greater I'm not I'm not struggling with that low-level mathematics I'm struggling with the really epic mathematics So he did that and he through this he wrote some equations Which were basically the called Einstein's field equations and some of these describe kind of how the universe changed over time and Einstein actually during this was an awful awful scientist Because the results that came out of this Were not what he wanted. They basically said either Well, they basically said all of the matter and energy in the universe will effectively be pulling Back inwards and so the universe will be up be shrinking or if it was already going outwards That would at least be decelerating come back in and Einstein didn't like that So he put in what we put call in physics and a very technical term a fudge factor He had literally no idea what this was. It was just because he wanted the universe to be unchanged and Eternal he had no explanation for that. He later called it his greatest mistake But we'll come back to that later as to why it might not actually have been his greatest mistake But the thing about this is that we've kind of gone a long way from our initial point, which is that Acceleration and gravity are completely linked in a lot of six situations you cannot tell a difference between them and these this picture of space stations is actually One that was kind of drawn for NASA as a suggestion of what future space stations might look like As you can see their long cylinders. They're pointing towards the Sun to all the pickup things solar power But what you can't see because it's still picture is that these would be rotating And so you'd have basically exactly the same situation as a car going around the roundabouts You would feel yourself as you're just going constantly round the roundabout pushed out towards the side And that is what you would feel inside the space station So this theory of gravity doesn't just link roundabouts and space stations But also links them to something that I'll come back to later, which is just the fate of the entire universe So the next one starting again a little close to home. How is a street lamp? The opposite of light from a distant planet Now this is a very specific type of street lamp who here recognizes a street lamp can tell me what element is used in it Sodium yes, this is a sodium street lamp to those of you who are watching earlier cat was talking about Sodium lights being used in film special effects and the reason that they were used is because they put out Technically a few but only what very very close colors of yellow light and the reason they do this is Down to quantum mechanics and I realize I'm pushing it a bit in that I'm only about 15 minutes into this and I've already gone through relativity and quantum mechanics Which is kind of like the big theories of the 20th century But it's not as complicated as sometimes it can be made to sound you can have lots of people talking about Shrodinger's cat and is it half dead or half alive or is it both dead and alive until you look at it? And there's lots of quantum weirdness like that but the thing about quantum physics is We've tested it really rather well and We know that it's weird, but effectively we know how weird it is we can quantify that weirdness and that means we can use it and You can use it for example To tell us what will happen when you press electricity into a sodium light and what we've got there is I've got one equation for us, which is the Shrodinger equation Which is kind of the key equation of quantum mechanics. Don't worry. There aren't many equations here But basically on the right hand side. You've got the energy of a state and on the left hand side the far left bit you've got basically some fundamental constants the mass of whatever it is that you're looking at and a Mathematical operator, which some of you may or may not recognize and that's kind of that's kind of just a quantum mechanical way of looking at something's motion The v-term on the other hand is a little bit more It basically says insert the rest of physics here All of the rest of the physics is basically combined into that one v-term there This is actually a great frustration to some people Because obviously the rest of physics includes gravity and we still haven't worked out really how to properly Get that in there. We can't get relativity and quantum physics to play nicely together But when we're looking at that that's that's everything when we're looking in a solid That's basically saying look at the effects of all of the other surrounding atoms the electrons in that the electric fields We put across things Basically and inside a particle inside of an atom in the center It's all of the forces a strong and weak force which are involved inside the nucleus in various cases but mostly it's going to be electric and magnetic fields and That is what's going to change things inside our sodium light Well, there's a funny outcome of this equation, which is basically that we have very few Specific energy levels for things. This is in fact why quantum mechanics gets its name It comes from the word quanta which effectively translates as bit of stuff and So in quantum mechanics, we have only very specific sizes of stuff in this case It's the energy of the electrons inside the sodium light They sit in very specific energy levels and when we jump up when we when we give them some power by basically switching the current on What the electron will jump up to a higher energy level and will then fall back down again some random time later And when it does so it's got to give up that energy somehow and how it does that is by emitting a Particle of light or a photon and it turns out that the color of the light that you see Depends on the energy of this photon and because we've got just one size energy gap We get one specific color of light coming out of our lamp and So so why do we why do we even use this in lamps and the answer is because we're cheap this light this color light is actually picked up really well by our eyes and Because it's doing going this way Basically most of the energy that we put in through these lights are coming out as the light And it means that we can use less energy in order light Our streets at night and we can still see really well But you might wonder what has that got to do with light from distant planets? And it answers the kind of the opposite and we have to we have to take a step back and look at distant stars first So in these distant stars, we've got huge giant balls of plasma and light is being produced in the center of the star And it's kind of making its way out. It's being absorbed. It's being re-emitted loads and loads of times But eventually it's got to come out past the outer bits of the star and there are some Gases there as well and we have exactly the same situation We have gases with specific energy levels, but different energy levels because they're different Chemicals the electrons inside them are bound to the nucleus differently So we get we can see when we look at these distant stars We see a big spectrum of light just as we see from the Sun But there are some gaps Because basically what's happening there is light is coming out of the Sun, but it's trying to get through this gas It's coming out towards imagine you are now representing Earth a Lot of pressure on such as more people, but don't worry And I will be a distant star And now there's gas in front of me and as the light goes into that gas some of it gets absorbed It's a right energy to actually make an electron jump up an energy level. It precisely matches that gap But then when it gets re-emitted it can get Mitted in a completely different direction to what it was coming from originally. It was coming at you But now it might instead be going in that direction It might be going back into the star it might be going somewhere else And so most of the light that was coming at you of that particular color that is being absorbed Will never reach you and so we see these gaps in the spectrum These dark lines where we'd expect normally to see a color But we can go one further than that Because we've been detecting exoplanets recently Have any of you seen the news about all the exoplanets that the Kepler mission have been detecting? Yeah, one of the ways that that's been done is basically just the planets passing in front of The star and blocking out a tiny tiny bit of the light that's coming towards us And we actually have sensors which are fine enough. We can actually detect The dimming as the planet passes in front of its star But even more than that When a star passes in front of the planet passes in front of the star So does the planet's atmosphere and that's made up of gases as well And so some of the light will be absorbed by the atmosphere and again scattered in lots of different Directions, so it won't come to us. So what we're seeing is not just dimming of light Due to the planet physically blocking the light We're also seeing some dimming because of the light going into that planet's atmosphere and then being sent off in a different direction And the frequency and hence color of that light depends on what's inside that planet's atmosphere And so we can tell what's there Okay, I don't think you're excited enough. We can detect Atmospheres and planets in other solar systems by the light that it's blocking from a distant star Forget jet packs. We are living in the future now and We're hoping that we actually be able soon to recognize some of some of the molecules or compounds That we associate with life as well all from just a slight dimming of that light being captured from the light from the star being captured by those molecules and emitted in a completely different direction according to the rules of quantum physics and I think this is a really exciting bit and it's all coming from this key equation of Quantum physics So I think that's pretty awesome, and I'm looking forward to seeing what comes out later So next one. How is the sound of formula one? like light from distant stars And for the sound of formula one, I don't mean the sort of sound which involves lots of rich people sponsoring teams and Money possibly being used in dubious ways What I mean is the sound that you hear while stood next to the track and I want to recreate that sound here So what I'm going to do is I'm going to point sweep across the entire audience And what I'd like you to do is I'd like you to make the sound of a formula one car Going past on a count of three one two three okay, and So what we've got there is the Doppler effect. This is something which I'm sure most of you will recognize and Be able to talk about but I am aware that for some people in here Some people might not have actually got to this point in school and for some people I know GCSE or O level physics was a long long time ago So can I have a volunteer, please? to come on the stage It's okay, you're not going to have to do anything complicated Down there, please come to the stage big round of applause for our volunteer, please Okay, thank you, sir If you could just take one end of this slinky and just take a few steps back. So we've got it vaguely taught So I'm sure most of you aware that sound is vibrations in the air And what I'm going to be doing is I'm going to be using this slinky to represent those You can imagine kind of like each ring of slink the slinky being a Molecule inside the air and when I'm talking and it's coming out the speakers What's happening is we're getting a vibration back and forth and some in some places The slinky is getting tight the slinky wings are getting closer together and in other places They're getting stretched out and that those compressions and stretches are traveling down the slinky They're also getting reflected at the other end there at Sarah, which we know is a function of waves of which sound is one But that's fine if I'm just standing still, but if I start menacingly approaching Sarah All of as I'm pushing this back and forwards You'll notice that the areas of which I'll do that again as I'm getting closer the areas of bits which are Squished together are getting closer to each other and the areas of stretch are also getting closer to each other Whereas if I'm doing that while I'm reversing They're getting further apart Thank you very much a big round of applause for volunteer And so Basically what we've got there is a Doppler effect in action as I was moving closer to the person who was here in the sound The sound waves were getting squashed together or we call the wavelength Which is equivalent to the gap between the squished together regions was getting smaller the Frequency of those getting to our receiver was getting higher and the pitchers sound goes up Which in the case of the sound the formula one is the knee Whereas when they go past we get them spreading the waves spreading out the frequency going down and we get the album again technical terms But what one interesting thing is that you get that weird continuum between them. It doesn't just go knee Alme it goes knee Alme and slides along the way one way I've heard of Explaining this is this only happens because the F1 car Doesn't hit you and this is because when it's coming almost directly towards you It's speed with the we're back to directions being important again All all of its speed is in towards you and so that gives you a higher pitch But as it's getting closer to you Lesson a smaller and smaller component of that speed is actually coming towards you. It's going past things going past You don't change the frequency And so as it's going down there getting close and close to you the amount of which the sound is Doppler shifted Gets smaller and smaller and smaller and then as it's going away from you the opposite happens as it gets further and further away the Doppler effect gets bigger and bigger and bigger and the frequency goes down even more but This means that when you're watching all the kind of like old films and kind of looking at World War two documentaries The scary sound of the bomb falling is not the one that you think it is The scary sound of a bomb falling is not the one that slides It's the one that is just a whistle which sounds exactly the same As you're hearing it because that means it's coming directly towards you and this sort of thing happens happens for a lot of different waves Including light because light is an electromagnetic wave It's got oscillations in the electric field in one direction and in the magnetic field basically at 90 degrees to that direction and It can have the Doppler effect It's not the same way But the reason you don't see it when our projector screen is wobbling back and forth is because light is very very fast Basically what you need to get to an appreciable fraction of it in order to be able to see it So so we don't have anything really here that is going to be going fast enough on this planet to be able to see it But we can look at these distant stars and we can look to see whether the light is Doppler shifted But compared to what? How are we going to tell the difference between light being changing frequency because a star is coming towards us or light that was just that color when the star emitted it anyway and This is where all of the spectra that we were just talking about come in useful Because when we were talking about the sodium lights, it wasn't quite just one yellow line it was a few different types of yellow which were very close together in frequency and so they have very specific gaps between them and So we can look at the light that's come from these distant stars and look for those patterns in the light That has been absorbed by the gases around them and so we can therefore measure Whether or not they're moving towards us or away from us and a guy called Edwin Hubble in 1929 did this and noticed that For basically every star in a galaxy that was not our own The light was being redshifted. It was moving towards a red end of the spectrum Which is the same as going to a lower frequency and so the objects were moving away But more than that he discovered that the further away This galaxy was The faster it seemed to be moving there was a linear dependence Between these two things and we call this Hubble's law. He wasn't actually the first one to notice this Actually, there was a guy called George Lemaire Who actually published results about this two years earlier? But he had something of a disadvantage He was French That wasn't a disadvantage the disadvantage was and he published his paper in an obscure French journal Which meant that suddenly French wasn't really being read as much in scientific journals by that time and So people just didn't read it Whereas Edwin Hubble's paper on it got distributed and science is all about not just getting your results But sharing them with the wider scientific community and so poor Lemaire, not only Did it did he not have his paper read it was later translated into English and the translator left out Some of the key bits about this because well, we don't know But possibly because they matched what Edwin Hubble had already published in English And so even then he didn't get the recognition for actually discovering this first But going back to the idea of Hubble's law It does just look like all other galaxies just really hate us and have been trying to get away with us Basically, if you rewind time back, they've been trying to get away from us all the way back until a Point where it looks like they were basically on top of us And this was some of the first evidence for the theory of the big bang The idea that the entire universe basically started in one point and has been expanding from there ever since But There's still another few twists to this tale, which is that one inside this we've looked at the acceleration and we've been measuring it over time and We expected based on Einstein's theory of relativity that the acceleration if they are going out The acceleration must be decreasing because of all the mass and energy pulling everything back inwards But when we look at the measurements, we don't see this We see I'm not entirely up to date with it We see as I believe we're still a small acceleration out the universe is expanding faster than it should and so Einstein's cosmological constant the fudge factor that he put in his equations it turns out We needed that but we needed it a bit bigger than he put it it put it in there and there were lots of Competing theories as to what this actually is and some people say it might be the energy of the vacuum In quantum physics your ground state has some energy and it might be this which is causing space to expand But there's a slight problem with that and that's From particle physics measurements We've got quite a good idea of how big this should be and if we compare that to the size of How big it should be for? Astronomical purposes There's an error of 10 to the power 120 That's a one with 120 zeros after it Which is really? rather embarrassing and we don't know why we still don't know what this is and There are lots of theories going around but And eventually we just don't know this is still an active bit of research And so we've come a long way from the same effect Which gives us a sound of F1 cars going past an ambulance siren is it going past? to What is now one of the biggest? mysteries of the universe Why is it accelerating? And that we still don't know Okay, how are you all how you all doing you all following at the moment? Yeah, yeah, that's good. Um, well, I'd like to say we've gone through some of the biggest bits of science there But now for this next bit. I am actually going to get you all involved Because I have here a set of elastic bands and I'm just going to throw these out vaguely towards you I might need some help going to the back And if you could all just grab one of these pass them on and share them around that would be brilliant yes, you can just pass those all around because What we're moving on to next is how is an elastic band? like a fridge and For this I'm going to be asking all of you to take the elastic bands and make your own observation So those of you who've got them what I'd like you to do is I'd like you to take the elastic band in two hands and hold it up So that it's just touching your face here like some sort of natty moustache And like you very quickly, but with a bit of a gap of time in between them stretch it out really quickly and Then relax it really quickly stretch it out Relax it and just feel what it does. What does it feel like on the top of your lip? Well, when does it get warm? When you it gets warm when you stretch it what about when you let it relax What was that? And when you relax it it gets cold and bizarrely this effect is down to One of the most fundamental rules of the universe and time So who here has heard of entropy before? Yeah, yeah a few people few people Entropy is a quantity we like to define in physics Which is always increasing inside an isolated system and That's a very important bit of the rule entropy always increases inside an isolated system and entropy can be thought of as a measure of disorder but more accurately almost like the number of ways that you can do something so There's kind of a lot of people like lots of people say or Entropy means that things just naturally get messier So for example, I shouldn't need to clean my room. It'll just get messier anyway To which the fundamental floor is your room is not a closed system And so you can't use that excuse for exactly the same reason if you're a creationist you can't say that entropy always increases This proves evolution because evolution obviously things are getting more ordered We've gone from final final audio goop to the fine specimens we see out here today And they say oh well, that's more that kind of happened You've ignored half of the rule. You cannot ignore half of the rule. That would be like me saying The rule is you can drive at 70 miles per hour on a motorway And then proceeding to drive through the center of town at 70 miles per hour It doesn't work And yes, some people still try and use this as a result but going to the elastic bands Basically the reason it heats up is because we need entropy to always be Increasing so the first way that we've got entropy inside elastic band is it's got lots of long fiber chains inside it And these are all wiggling about in space In lots of different directions and when the elastic band is small They're wiggling around an awful lot and basically there's lots and lots of ways that they can wiggle and the elastic band be small Which means that in this state they have high entropy But when you put it taught all of those bands line up nicely And then there are only a few ways you can do that so their physical position has low entropy But there's more than just how the change Chains can wiggle. There's also How they can jiggle because none of these chains are stationary. They're all moving all the time and If things are moving faster They're again, they've got they've got many more ways in which they can achieve this and so Moving faster means that you have a higher entropy So when you stretch your elastic band All the entropy based on how the chains are aligned goes down But it gets warmer all the entropy based on how they're moving goes up and Basically when you're letting go exactly the opposite is happening. You're still ending up with a net increase in entropy But you had to put energy in To heat it up. You'll get kind of getting a pull out That could elastic bands can pull things they'd be giving the energy to that And so they've got to lose energy and cool cool down as well And so you've got all of this going on but there's a little bit little bit more There's also just how they're losing heat to the outside world. This is my last equation So which I'm sure you're glad and this is a really simple equation for change in entropy Now on this left hand side we have ds s is entropy and so ds is the change in entropy And on the right side. Oh, I've got extra d on here. That's nonsense that equation That is actually a nonsense equation I do apologize that that d on the bottom has snuck in and shouldn't be there the bottom of that equation should just say t So because dq is the amount of heat flowing into a material That's positive if it's flowing out of material. It's negative and t which should be on its own on the bottom And I'm going to have words with that d later Is the temperature of that and so as you can see he goes in the entropy increases He goes out the entropy decreases But the amount by which it does so is related to the temperature of the body and this basically explains why When you've got a hot thing and a cold thing together the hot thing gets cooler and the cold thing gets hotter because the hotter thing higher temperature there measured of course in Kelvin and The colder thing has a lower temperature. So for the same amount of heat moving there'll be a greater change in entropy For the colder object. So as the heat moves to the cold object overall Entropy will increase. There's a bigger change for the colder object same amount of heat lower temperature So that's great and that explains kind of heat flowing, but a fridge doesn't really do that It'd be kind of a rubbish fridge if it did And in a fridge we've got a cold area inside and he is removed from that and dumped in the hotter area outside So how are we going to getting an increase in entropy and this equation shows that as well because Crucially a fridge again is not an isolated system It's plugged in and so we can get certain so when we're transferring heat We can create some extra heat basically by using some of the electrical energy. We're getting flowing in so the energy that goes leaves from the inside the fridge and The energy that comes out the back of the fridge As heat is not the same amount more energy is coming out So we can put a bigger DQ and we can overcome the higher temperature of the outside and still keep entropy increasing and This in fact all the way around inside the fridge entry is always increasing you've got you start off inside the fridge You've got cold fridge You've got a cooler refrigerant it now in the back heat flows from hot to cold increasing entropy then you let that Then you let that go through a Comfort, excuse me then when you've done that you your heat your Your your your now slightly warmer fluid goes on the back and is compressed is getting compressed into a smaller space Which means there are fewer ways all the particles inside it can be arranged and so that would normally be a lower entropy But to counter that it heats up higher entropy. It's now at the back of the fridge It's now in the little wavy bit of the back, but now because it's got hotter It's hotter than the outside Heat flows from the hot to the cold increase an entropy and finally it's allowed to go through an expansion valve and Spread out it spread out more space more ways of actually being able to have the particles in it arranged and Higher entropy there and it cools down as it does so and so all the way around we've got this fundamental increase in entropy and You know as a physicist that's really really weird Because normally in physics things that go happening in one direction Happen in the other direction all the laws of physics basically apart from this Look the same depending on which way round you look at them in time. This is the only one that seems to have a direction and This has led lots of people to start pondering on whether this it gives you the meaning of time The only problem there is basically what you've got is Physicists talking philosophy, which is never a good plan Although I am willing to do it with a few pints inside me if you see me at the bar later But when we've got one of these weird lacks of symmetry, we should start looking for more because they're interesting places and one other fit place that we get them is in matter and anti matter perhaps because Inside when we have energy in the vacuum. I was talking about earlier Sometimes that can spontaneously cause some matter to be created and for you get a particle an anti particle at the same time Normally these then meet annihilate Done. That's fine. We've not changed anything But we expect that the big bang Equal amounts of this matter and anti matter to have been created But you look around and we're all made up out of matter You can tell because we're not basically exploding when we come into contact with anything else and so Like we've got this weird difference between matter and anti matter and this again is a current research project Partially at CERN where they're just trying to work out where it is that there's a difference between matter and Anti-matter that actually allows anything to exist at all So we've gone through an awful lot of physics We picked up quantum physics. We picked up general relativity and we've picked up the contact concept of entropy And these are all kind of like always the fundamentals of what we've got to work with And so we're finally ready to go to a grand finale how is the universe like a light bulb and I kind of jumped over a bit earlier Where I was talking about lights coming from stars because I said you get a whole different colors loads of different colors of light and I didn't really explain how that happened how we had the entire spectrum before it was absorbed by the gases surrounding it and so The reason I didn't say that is actually in some ways. It's quite complicated but it wasn't that we look at the light coming out from the stars and we look at the ideas of entropy and likelihood of various things and With the entropy we've said things go to high entropy things go to more disordered whereas more different ways of doing it and With light as you get into the higher energy light the higher frequency UV rays and so on Then there should be more ways for that to be happening caused by the jiggling around of all of the plasma inside the Sun But and so in that case we should expect to see a lot more of it We should expect basically to have the entire planet irradiated by UV rays and none of us existing at all Bizarrely, it's the fact that this doesn't happen that physicists have called the ultraviolet catastrophe Yes, yes physicists again bit poor at naming things often and basically we didn't know why it was that this didn't happen until Max Planck basically Looked at the shape of the emission This is an example of the sort of shape that we get from the the emission spectra of Stars and saying well at the high frequency. Why do we get this tail off and he basically said let's go back to quantum physics It was a back to it basically was a new thing around then he was kind of just making it up And said well, let's assume that there's a probability of getting things which goes down as the energy quanta involved gets bigger and other people said to him Why that? Why would you do that? And he didn't know but it worked and He literally like normally I teach physics sometimes and to my students I'm always very keen that they write out there working in their explanations I wouldn't have accepted it just works normally the only reason we were it was really accepted by then is because it gave us graphs like this. This is some experimental data and Basically the error that the line that's going through all of these points does it so well that The predicted line which is from his theory goes for it so well that we basically can't Distinguished between the two and so this was brilliant and men that we actually were getting somewhere but Still kind of unsatisfactory so It took a little while of quantum physics actually coming in before this was kind of Accepted we talk about all the different energy levels and this kind of basically eventually all worked but this data isn't from a Sun or a star This data is in fact something which is very very similar to that which was developed and discovered by Arno, Penzias and Robert Wilson in 1964 they built basically a radio telescope and Wanted to take lots of measurements with it. They were good physicists They they cooled down the sensors so that things weren't jiggling about in there so much so they'd have less noise inside it But no matter what they did they got some constant noise And they did everything they could think of they they pointed the antenna all in different places. They still got this noise They tried doing it during the day tried doing a night same noise They tried doing it all different times and unlike many experiments They had to clean out what was referred to as Dialectric material which had been left in the hall of that antenna because some pigeons had been roosting inside it and They cleaned that all out and they still got Some noise and they couldn't work out where it was and then this is where we see how the world of real physics Is very different from school because basically what they did is they phoned up their colleagues nearby and said We don't know we've got a signal we need to get rid of it so we can do our experiments do you know what it is and They go in contact with contact with some physicists nearby lab who were very very disappointed in order to get this phone call because their reaction was ah I Think we think we know precisely what this is This is the remains of the Big Bang This is light that has been bouncing around since basically shortly after the Big Bang and As the universe has cooled it's shifted Basically, this is a spectrum for the universe of a few Kelvin a few degrees above absolute zero And that is what this particular one is it's exactly the same shape as you get from Stars and also from things like a filament light bulb But when we were doing this Yes, so this was an amazing result and they won Penzias and Wilson won the Nobel Prize for this Which I think is brilliant not only because it's an amazing discovery But what they won the Nobel Prize for is basically being physicists who did everything right? They try to remove all the sources of error in a measurement. They went through it nice and systematically and then They asked for help and then they finally found something a very which someone else would come up with independently which matched and so I Think this is a wonderful place for us to be at but it's not the whole story because this isn't actually their original results This is some later measurements taken by NASA and in fact if you oh one of those things I there were a couple of ways of thinking about this That basically the shape is the same for black bodies, but the position of the peak changes depending on temperature So one way you can think about this is it's this temperature because universe was originally very very hot and has cooled down since But another way of thinking about it is going back to our formula one cars and our Doppler shifts from different distant stars You can think of this as a light originally basically being having a lot smaller wavelength and gradually being stretched out as Time has gone on and moving towards the left-hand side of the graph And so we're now a point where we've seen the universe You see how it's like a light bulb, but no matter how good of some results are As soon as you start looking deeper You're likely to find something else and this is a W map project This is looking basically at the sky and looking in all distant different directions and these colors are basically Slight differences in the temperature that we get from that nice graph in different, but when we look in different directions Obviously red and yellow is hotter kind of green and blue is colder and these are all on the order of 1000th of a Kelvin 1000th of a degree Temperature difference, which is quite a bit when you're looking at just kind of 2.7 Kelvin to start with and This is where we are now and we're wondering whether or not this is kind of an imprint of fluctuations in the early universe which basically meant that there was actually a way for things to start coalescing rather than being forever a diffuse Equal throughout the entire universe just set of matter for things to start coalescing and forming Stars and galaxies and planets and eventually all of the processes that led to people and the modern world today So I hope you've enjoyed this I hope you feel like we've come a long way and we've started from things that you are used to And I hope you enjoy the rest of emf camp One thing that I need to put up beforehand is all of the wonderful people who made all of the figures and images I used throughout this slide attribution is very important, especially when you see science images on the internet Please make sure they're attributed to who made them But so just two questions to evaluate Do you all think you've learned something? Yes, excellent, and have you enjoyed doing so? Yes, well, thank you very much. I think we can call this experiment an excess success Thank you very much and enjoy the rest of your camp