Bright futures in a dark universe | 91TV
Transcript
- Clare Burrage: Thank you very much. Thanks for the really lovely introduction, and thank you
- all for coming this evening. I want to start my talk by giving you a very brief history of
- our universe. So the universe that we know, we think began with a big bang explosion and that
- made everything very hot, very dense, and it set our space time expanding. So points and particles
- are moving apart from one another. As the universe expands, all of those hot, dense particles that we
- produced at the beginning, they begin to cool, and slowly we get the first nuclei forming,
- the first atoms, and then they combine to give us the first stars, and eventually galaxies
- form. What you would expect at that point is that everything is very far apart, everything's nicely
- tied together. So gravity on the larger scales of the universe is really the only game in town,
- and gravity likes to pull things together. So what you would expect from this expanding universe is
- that expansion maybe stabilises, maybe starts to slow down, maybe even things start coming
- back together. What you don't expect is that that expansion suddenly starts speeding up.
- Yet that is what we've seen recently, cosmologically recently, so in the last
- few billion years, we've seen that expansion of the universe start to accelerate. So things are
- moving apart from each other, galaxies are moving apart from each other, and they're moving apart
- with ever increasing speed. Now, this is quite a tiny acceleration. The current value that we
- measure means that those galaxies are moving away from us, and it takes them 20 years for that speed
- to increase by one kilometre per hour. Okay, so very, very tiny acceleration, but it's there and
- it's dominating the expansion of the universe that we see. Yet so we have really, really
- good evidence that this is happening. There's such good evidence that it won the Nobel Prize in 2011,
- but we have no idea why this is happening. There's nothing in our standard models of particle physics
- or gravity that explain this accelerated expansion that we see. Okay, so when we have a problem, when
- we have a puzzle, the first thing, and we don't know what it is, the first thing to do is to give
- it a name. So the name that we give to whatever is driving this accelerated expansion is dark energy.
- Dark because it's not giving off light, and energy as a physics word for unidentified stuff! So the
- dark energy is what's causing the accelerated expansion, and what I do in my research is to
- try and figure out what this substance is and how do we figure out what that is and how do we test
- our theories? So what I want to talk to you about for the next roughly 40 minutes, I'm going to tell
- you a little bit about how I came into physics, a little bit what physics was like at school, and a
- little bit about what physics is like in schools today. I'm then going to tell you a little bit
- about the projects that we have planned as part of the Rosalind Franklin Award. Then finally, I'm
- going to come back to talking about dark energy and how we might go about figuring out what it is.
- The reason that I wanted to start by telling you a little bit about my journey into physics
- is I think there's often an expectation that if somebody is doing the kind of job that I'm doing,
- if you're lucky enough to get to figure out what on earth is all this weird stuff that's
- happening in the universe, that you must have wanted to do that, you must have been dreaming
- of doing this ever since you were a kid. In my case, that really, really wasn't the case. So
- I went to a fairly average state comprehensive, and my memory of physics at school is of always
- managing to pick the broken piece of kit out of the cupboard and with some fairly uninspiring
- lessons! So just to tell you, give you an example of one of those, and this is one that actually
- worked. What we've got on the slide here is a demonstration of an experiment. So what we've got
- is a metal rod suspended horizontally, and we've got a series of drawing pins attached to that
- rod with Vaseline. Then what you do is you get your Bunsen burner, you heat one end of the rod,
- the rod heats up and slowly the Vaseline melts and the drawing pins fall off. Okay, so there's some
- sensible physics there, right? Heat transfer in metals. There's nothing wrong with the experiment
- itself. The problem is, if you're using such a thick metal bar, that that demonstration takes
- up the majority of a 75 minute physics lesson! So you can see maybe why, at this point in my life,
- I thought physics was about as exciting as watching paint dry. But I was lucky. So around
- the end of my GCSEs, I was thinking, obviously as you do, what you want to do at A-level,
- what you want to go on to do afterwards. At that point in my life, I thought I liked maths,
- I thought I was going to go on and do maths for my degree. I was going to have a nice, stable,
- well-paid job, maybe as an accountant, very cool as a kid! What I learned was that if you wanted to
- do maths at university, you needed to do physics A-level. So, oh, for goodness sake. What happened,
- and the really lucky thing for me was that around this time, a really great physics teacher joined
- our school. This is Mrs [?Mageean 0:05:31] in the middle of the slide, this is Mrs Mageean,
- this is me. She joined, she was a specialist physics teacher, and I think what I've realised in
- hindsight, is that the problems I was having with physics teachers at school is that we didn't have
- specialist teachers, and the teachers we had would rotate through very quickly, through the school.
- So we had a specialist teacher join and she was really, really good. I went to her and I was like,
- 'Please, will you stay for the next two years if I'm going to do physics for A-level?' Amazingly,
- she promised that she would do that and she stayed, and my A-level experience was much,
- much better. That was the start of my slow drift into physics. My experience in that way is not
- unusual. This is a headline from The Independent last month, based on a report from the Institute
- of Physics that says more than 700000 GCSE students in state schools in this country
- don't have a specialist physics teacher. That's a quarter of state schools in this country that
- don't have a single specialist physics teacher, and that really that really just breaks my heart,
- because we know that students in schools that don't have specialist teachers are much, much less
- likely to go on and study that at A-level. If you don't have somebody who can tell you why this is
- fun, what it is that physics can do for you, what you can do with physics in the rest of your life.
- It makes so much sense that you wouldn't think it was interesting and you wouldn't go and study it,
- and that's a shame, that's a shame in and of itself. It's also a shame because it compounds
- other problems that we have in this discipline. We know that there are demographic factors that
- correlate hugely with how likely you are to be a physicist. We also know that there
- are really strong stereotypes about what a physicist looks like in this country.
- Those stereotypes are that you're very likely to be male, you're very likely to be white,
- and you're very likely to be comfortably off. Just to be clear, because unfortunately in 2025,
- these things still need saying, your ability to do physics is not dictated by your gender or your
- sex. It's not dictated by what your parents did for a living, where you're from, what your accent
- was, what religion you are, what ethnicity you are, or the colour of your skin. Okay,
- your ability to do physics is not determined by those things, but your opportunities might
- be. If you're already feeling like maybe you're not going to belong in this subject,
- in that classroom, or maybe it's not a subject for people like you, then if the teaching is also
- boring and the subject feels hard, why on earth would you bother going on to study this subject?
- So, unfortunately, it's not within the scope of the Rosalind Franklin Award for me to solve all
- of the problems with the physics recruitment crisis. What we are going to do is to try and
- do some things to bring the joy and excitement of physics to school students, and to do that in
- spaces where we can also try to tackle some of the stereotypes about what it means to be a physicist.
- So the first one that I'm going to talk about is the 'I'm a Physicist' girl guiding badge that
- was set up as an initiative between Girlguiding Nottinghamshire and the IoP East Midlands branch,
- and in particular by my amazing colleague Becky Dewey, who is here, and Becky is a physicist who
- works with MRI to study hearing and balance. As you can see from the pictures of the figures on
- the badge, physics is so many things. It's so much more than what I do, looking out at the skies. It
- goes from that to the subatomic, to understanding how the human body works, to making sense of the
- world around us. That's what we want to take into these guiding groups. So there are four parts to
- the badge, four things that they have to do to get their badge, to say that they're a physicist. They
- have to experience some fun activities, some fun little physics activities. They have to create
- something so like a musical instrument or a lava lamp. They have to do an investigation to ask,
- what if I do this, what if I change this, what happens? They have to either meet a physicist,
- or visit, or take part in a physics activity in their community. Up to this point, there have
- been 50000 badges awarded so far, and they've been awarded all over the world. If you're interested
- in finding out more about what this badge is, maybe taking it into a Girlguiding group that you
- know, or you just want some really cool physics activities to do at home, this is the QR code
- for you to go and look all of those up. So it's been done all over the world, it's also been done
- all over the UK. If you were to zoom in on this map, you'll find that there are places in the
- UK where we haven't reached, where there's lots and lots of people and maybe not very many badges
- that have been done. So what we're going to do is to make it really easy for guide leaders to
- do this badge with their groups, to offer them training, offer them support, offer them boxes
- of kit for the experiments, and to make it really easy for them to meet physicists in their local
- communities. The other thing that we're going to do is expand the work experience week that we run
- at Nottingham. So this is an initiative that was set up by my colleague Ed Copeland, who is here
- in 2017. We bring A-level students in, a cohort of A-level students that are majority female to
- experience all of the weird and wonderful things that happen in an academic physics department,
- but more importantly, to build the connections, to build the relationships with each other, to
- find other people who like physics as much as they do, which they're not necessarily getting in their
- lessons at school. So, coming back to my story. I was lucky that I did get those opportunities, that
- I did have those teachers and that support to help me on my journey, and to find the love of physics,
- and the love of figuring out what on earth it is that the universe is doing. So we're going
- to come back to dark energy and how to find it. So what we said was that the universe is expanding,
- and relatively recently that expansion has started to accelerate. We don't know what the reason for
- that acceleration is. As we start to dig into that, we realise that we generate yet more
- questions. So the expansion is accelerating, why is that acceleration really small, why isn't it
- huge? Because the theories of physics we have do actually make a prediction for us that the
- universe, the expansion, could be accelerating. The problem is that, that acceleration is so
- huge and starts so early, that you would have ripped galaxies apart before we'd have time to
- form people and planets. So that's wrong, that's not what's happening! So something is wrong with
- our theories there, there's something there that we need to figure out. So the acceleration is not
- massive. If it's not massive, why is it small but not zero? That's also weird. It's not huge,
- maybe it's just been cancelled out, but no, it's not been perfectly cancelled out, there's
- something left that is driving this really, really small acceleration. There's also some evidence in
- recent years, tentative, but that perhaps whatever is driving this acceleration of the expansion of
- the universe is not constant, maybe that's also changing with time. That's also then something
- that we need to figure out what is going on. Now to try and make sense of these questions, people
- come up with new theories, new models, and very often those models introduce new particles and new
- forces into our theory of physics. So that's good because that means we've got something to go away
- and look for. We can go and look for those new particles and forces. The problem that we then
- immediately run into is that we've been doing that for a long time, and we haven't seen anything.
- Okay, physicists have been doing really, really good, really precise measurements for a long
- time of lots of lots of different things, and they haven't seen any of these new particles or
- forces that could be the dark energy in our universe. This is an image, for example, of
- planets and comets in the solar system. We've been measuring their motion very, very precisely
- for a long time. Absolutely, beautifully well explained with our theory of gravity,
- with general relativity. No room there for a dark energy force. Okay, so why isn't it then, the case
- that we just say we throw out those theories, go back to the drawing board, we need to do better.
- So we need to take a little diversion here and talk to you about particles and forces, and how
- forces are transmitted by particles. So the forces that we know are transmitted by particles, they're
- little particles zipping backwards and forwards, sending information, telling us about the world
- around us and how we should respond to that. If your force is transmitted by a light particle,
- that force can operate over a very long distance. If that force is transmitted by a heavy particle,
- that force only acts over a very short distance. So if you want to hide a new force in your theory
- of physics, one way to do that is to make your particle that's transmitting the force really
- heavy. Then it only transmits a force over a very, very short distance scale. Maybe that's
- too tiny for any of the experiments we've done so far, maybe that explains why we haven't seen it.
- The problem with that, is that if it's only acting on a really, really short distance scale, it
- can't explain what's going on, on the very largest scales in the universe. So that's still not enough
- to solve the problem. So what we realised is that it's possible for the mass of these force carrying
- particles to change. So what can happen is that the mass of the particle is really light in the
- diffuse near vacuum of empty space, but that it becomes… So it's very light in empty space, and so
- you can transmit the force over a longer distance scales, but it becomes very heavy in a dense
- environment. So somewhere like inside a planet, inside a star, the force becomes very heavy,
- the particle transmitting the force becomes very heavy, the force becomes very short range, and
- that's why we haven't seen it so far. So these get called chameleon particles, chameleon forces for
- the maybe obvious reason that they are particles that can change their behaviour depending on their
- environment to try to camouflage themselves from our detection. Once we realised that,
- so this is one example of what you can do, but once we realised that, you can suddenly start…
- Once you've got a theory that explains why you haven't seen it so far, you can start to ask
- the question, okay, well all of these different experiments didn't work, but can we come up with
- something that would be sensitive to these new particles, something that we could use to try and
- detect. Get around the fact that they're trying to camouflage themselves and see if we could see
- them in an experiment. Because these particles are now interacting with ordinary matter, we can use
- all of the tools in our toolkit of physics to look for them and to try and figure out what they are.
- So one of those key tools for determining whether there are new particles in our theory of physics
- is the Large Hadron Collider, you smash particles together at very, very high speeds, you see what
- comes out, and you see if there's any room there for new physics. So this is an old image, this
- is an old particle detector, but the principle of modern detectors is the same, you're looking
- after that first collision for the traces of your particles that are produced in the collision. Then
- you want to look at those really, really carefully and see, are those particles really moving in the
- way that I would have expected, is there any room there that they're slightly deviating from what we
- thought we would have seen? When they interact with each other, again does that happen in the
- way that we expect, or is there room for those particles when they interact? Maybe there's
- just a little something missing, mismatch of energies, maybe our dark energy particle is
- being produced and is just invisible in our detector. At this point I want to be really,
- really clear that the work that I'm talking about here was not done by myself. I've been really,
- really lucky to have lots of really wonderful, really incredibly talented collaborators,
- to work on all of the projects that I'm going to talk to you about. I'm really, really pleased that
- some of them are here this evening as well. So you can look for your dark energy particles in a in a
- high energy collider. What we also realised, was that if our particle, if our dark energy particles
- can change their mass, inside a planet, inside a star, that's fine, they've got enough room,
- they can change their mass, they're really, really tiny, and they're hiding from our experiments.
- If you took a small enough object, if you could make precise measurements on the motion of a
- small enough object, inside that object, there isn't enough room for your dark energy particle
- to change its mass in the way that it needs to, to hide from your experiments. So if you could
- do measurements on small enough particles, you would see that they feel this extra force, whereas
- the larger objects don't. So you would get this quite counterintuitive situation where you drop
- two particles or two objects, and the smaller one would fall faster than the larger one. Now again,
- this is an effect, this is an observation that we have been testing for a long time. Okay,
- at least back to Galileo, we've been saying that large objects and small objects should
- fall in the same way under gravity. So again, why isn't this immediately ruled out? The answer here
- is that maybe we just haven't done precise enough measurements on small enough particles to be able
- to see this effect. Again we were lucky that when we when we started thinking about this,
- that our experimental colleagues had come up with an approach that could do this. So this is
- a photograph of an atom interferometry experiment at Imperial College in the lab of Ed Hinds,
- and what they are able to do inside this vacuum chamber is to drop individual atoms and measure
- really, really precisely how they fall. If you can do that, those atoms, the nuclei of atoms
- are so small that they count as small objects, from the point of view of what we were saying on
- the previous slide. So you should be able to see if they fall faster than you would have expect
- if you were just dropping a tennis ball outside your experiment. Again, this is not just my work,
- but again a wonderful series of collaborators on these projects as well. So then you can put all of
- these things, all of these effects together, and you can also take those questions out to
- the largest scales in the universe and ask these questions about galaxies. Is the distribution of
- matter in a galaxy the one that we would expect, are large objects and small objects in a galaxy,
- is the gas and the dust behaving in the same way that the stars are? When we look at the
- distribution of galaxies in our universe, our large galaxies and small galaxies, galaxies and
- dense environments and galaxies in the diffuse vacua, voids of intergalactic space, are they
- all moving in the same way? Is there scope here to try to look for the effects of dark energy?
- So because dark energy is such a big mystery, because it's such a fundamental part of our
- universe that we don't understand, we need to bring together all of these different scales, all
- of these different tools to try and make progress on understanding what it is from the very high
- energies of particle colliders, to the incredible precision that we have with tabletop scale quantum
- experiments, and to the information that we get from the very, very large scales in our universe.
- Bringing all of that together, we have not yet, unfortunately, seen a dark energy force or a dark
- energy particle. But what we have been able to do is to rule out classes of models, to say these
- theories don't match the observations that we see. These ones are still okay. Maybe we're going to
- have to go away and think of ways of testing those as well. So there's still so much that we don't
- know about our universe. Dark energy makes up, as Maria said at the start, a huge component of our
- universe. It's nearly 70% of the energy in our universe today. We don't know what it is. We've
- made progress on figuring out how to find out what it is, and there's going to be over the next
- decade, a huge amount of new data coming from all of those different types of observations. New data
- is coming in that is going to help us in figuring out what dark energy is. So it's an incredibly
- exciting time to be doing this. Yet we still in the UK at the moment have a cohort of students in
- schools who don't get to experience the excitement and the joy of getting to do physics, and getting
- to understand all of the exciting things it could be, and all of the things that they could go on
- to do and understand about the universe around them. We all need to improve that, to make things
- better. We all need opportunities, and community, and support from the people around us to make us
- feel like we belong and to help us in going beyond the status quo. Then just as a final thank you,
- I wanted to say thanks, a huge thanks to Susan Burrows, to Ed Copeland and to Justin Khoury for
- nominating me and supporting me for this award, and to the Royal Society, to STFC and to the
- Leverhulme Trust for their support financially, and enabling all of the work that I've told you
- about this evening. Thank you very much.
- So thank you very much, that was a wonderful lecture, and there's so many things that I'd
- like to ask you, but of course we do want to hear from the audience as well. Also there might be
- some things coming in on Slido. I don't know if there's anything. Oh right away. There's somebody,
- can you bring the microphone? Here it comes. It's this young man here.
- M1: Okay, thank you. I love the idea of the Girlguiding badge, and that looks amazing. I've
- got a young daughter of my own, who's two, but I was a Scout, so I'm going to send her to the
- Scouts. I was wondering if the Girlguiding physics badge is also available to girls in the Scouts?
- Clare Burrage: Yes, Scouts are very welcome to do it too! I should have said, and I forgot,
- that on the Girlguiding side that the badge is available for everybody all the way through from
- Rainbows aged four, to Rangers aged 18, and so the same would be true for Scouts as well. All of
- the information, everything you would ever need is on the website, you just have to Google 'I'm
- a Physicist' and it will all come up and then yes, do it and write and say, 'I would like a
- badge please.' Yes, as long as they're happy to wear one that says Girlguiding, that's fine!
- F1: There's one at the back. While we're waiting, I'd like to ask you something.
- The physics teacher was obviously a major thing, and that was lovely that you pointed
- that out. As you've also pointed out, it's very rare to get good science teachers generally,
- and perhaps particularly physics teachers. I know it's impossible for you to think, but do you think
- that you might have gone on anyway? You said you had to do physics A-level! I try and imagine what
- it's like for people where the school really isn't that good, and they do have to wait to
- get to university before getting good teaching.
- people who there just aren't enough people in their school for it to make sense for the
- school to run an A-level physics. I really don't know. It really wasn't on my radar at
- all until I realised that if I wanted to do maths at university, I was going to do, I needed to do
- physics as well. So I think if that hadn't been the case, I think it's really, really unlikely
- that I would have that I would have done it.
- to make it so amazing?!
- Things worked, it's a good start!
- Clare Burrage: The lessons were more interesting, she could talk about physics, like as a person,
- rather than somebody reading from the textbook, reading off a script. I think that's so important
- that you get the sense that this is something that people that you can see actually know about and
- can do, rather than those other people somewhere else, write the textbooks, do the research,
- and then it only dribbles down to you.
- physics A-level in your year?
- was quite average, it was average in most ways apart from size, in that it was enormous. So about
- 2000 students in my school, and I think there were maybe ten of us doing A-level physics.
- F1: How many were girls?
- again, we were really lucky, and this was just an anomaly, but there were four of us.
- F1: Okay, but it's still very…
- physics is a good ratio, but it's still, there!
- at my school, but it's not really got… So sorry,
- there was a gentleman at the back.
- experiment in which atoms were observed to fall, I think in gravity. Could you share
- the results of that experiment as well?
- experiment are that we didn't see anything new. That if you drop atoms, they fall under gravity,
- and that explains everything we see. That you can measure to an incredibly precise precision,
- which I've forgotten off the top of my head. Yes, down to the point that we have been able… So that
- we were looking for one particular, or the main target of that experiment was one particular type
- of dark energy model. With that one experiment, it went from being, there being loads of parameter
- space, really allowed no problems with this model, to being almost excluded as a result
- of that experiment.
- F1: Okay, we're going to have another. A dark matter and energy question! This is from Ben.
- Do you think we have to understand dark matter and energy simultaneously? Given
- that one expands the universe, and the other holds the universe back? Also, what potential
- applications do you think dark matter and energy might have on people's daily lives?
- Clare Burrage: Okay.
- Clare Burrage: Excellent question! So okay, so to take the first part of that one first,
- and maybe just to make sure everyone's on the same page. Dark matter, so I have been talking about
- dark energy this evening, dark matter is another thing that we don't understand about our universe,
- and that is additional matter, which again it's dark, it's not giving off light, and it clusters
- around the galaxies that we see. So it's providing extra mass in the universe, but otherwise it kind
- of behaves like the particles that we're used to. Whether those are connected problems or separate
- problems is a very good question, and like so many questions in cosmology, the exciting thing is that
- the answer is we don't know! So it may well be the case that those things are connected. But actually
- in a lot of the models that we have, they are different things. It's not easy to come up with
- a model that looks natural, that explains both of those problems at the same time. Then the second
- part of the question was is this useful?!
- application that would have an effect on people's daily lives. It's quite specific, actually!
- Clare Burrage: Yes, so I think that really depends on what the answer ends up being. Okay, I'm going
- to give one example of a dark matter particle called the axion, which if it exists, mixes with
- light. One of the ways of looking for axions is an experiment called light shining through walls,
- so you can use a large magnet, you shine your light on the wall, the magnet converts your
- light into axions, converts those actions back into light. So in principle, if you wanted to,
- and they do turn out to exist, maybe you could use those for information transfer,
- something like that, depends what it is.
- somebody, oh okay.
- question was that for decades, scientists have been chasing, after the theory of everything to
- unify all the fundamental forces. Now where does dark energy and dark matter fall into
- it? Does it fall under a string theoretic framework or extra dimensional framework?
- Clare Burrage: Yes, so if you are trying to find a theory of everything, obviously you hope that
- it explains your dark energy and dark matter as well, otherwise it's not a theory of everything.
- The problem, or the advantage of string theories is that it gives you lots of different things. we
- don't have one theory of everything now. So within that whole spectrum of theories, you
- absolutely can find candidates for dark matter, explanations for dark energy. What that doesn't
- really tell you is which one of those things is actually the realisation of our universe.
- So in some sense doesn't, at the moment, help so much in guiding us in figuring out which one of
- those options actually is the right answer.
- if that's okay, and then go back to the audience. So what would you recommend to young women or
- anyone else from an underrepresented background who is considering a career in physics?
- Clare Burrage: Do it, okay!
- Clare Burrage: A career, yes.
- and you've got a good degree and you want to start a career. What advice would you give?
- Clare Burrage: Find the people you like working with. Find the people who are going to be excited
- by the things that you're excited by. Find the people who are going to support you, who
- are going to tell you when you get it wrong. But to do that in a nice way, in a constructive way,
- that moves things on. Yes, find the people who are going to be there for you, because there are going
- to be times when you feel uncomfortable. There are going to be times when you feel like an outsider.
- There's going to be times sometimes maybe where you're the only female voice in the room, or,
- yes, you obviously stand out in some other way. So knowing that you have those people and that
- network of support is really, really important.
- so let's say somebody has their physical degree, they come from an underrepresented background,
- and I assume it has to be quite a good physics degree. Then they're looking for a PhD position.
- So how did you find your PhD position?
- F1: Well have to tell the truth.
- undergraduate, so I was very lucky that we already had that relationship. If you don't have that,
- you can still talk to the people that you know during your degree, and ask them,
- 'These are the things I'm interested in, do you know good people who are offering PhDs in
- this subject?' That's often a good way, not just of finding out who's doing exciting things, but
- who's going to be a nice person to work with.
- uses that word a lot, but you have to ask somebody to help you actually don't you?
- Clare Burrage: Yes.
- and what to apply for. How did you get your funding for your PhD, for instance?
- Clare Burrage: So we're lucky, lucky in this discipline that STFC do offer funded places. So
- I had to obviously be good enough to get one!
- weren't just given it!
- funded students available, yes.
- background, but you do need to do well, I think, if you're going to pursue a career, so that. I'm
- sorry, it's just that these are rather personal, about people's careers, which I think is important
- for this prize, specifically that you've got. So what advice would you give to a first year student
- who started to study physics at university, but is finding the content is getting very hard?
- Clare Burrage: Ask for help? The worst thing you can do in that situation is hide,
- and just go to your room and think that by getting… Well, it is important also to go and
- get your head down and work on the things that you're doing. There is a huge amount of support
- for students in university today. For the students who are struggling, we can recommend resources,
- textbooks, other ways of… Sometimes you just need to hear something explained in a different way
- and it will click for you, and you've only got one lecturer giving it to you once. So we can try to,
- we always try to help with that. We don't want people to struggle when they don't have to.
- F1: That's fantastic. Thank you. So sorry, ack to the audience, so this gentleman here?
- M4: Hello, that was very interesting, and I see you've succeeded very well. I'm recalling my own
- experience at school, had a wonderful physics teacher in Manchester called Mr Copley, and I
- was always fascinated by the experiments, which were good, they all seemed to work. One of which
- was the methylated spirits one, where evaporation causes cooling and the glass stuck to the plate.
- I always wanted to try and embark on a career in physics or A-levels. I was discouraged by my lack
- of ability in maths, so I became a chartered surveyor in the end! Nevertheless, that's the
- background, but in my later years I've always had a fascination with physics of, you know,
- Carl Sagan's books and things like that, I've always enjoyed his theories and his experiments.
- Regarding the current work you're doing, the issue of dark energy and dark matter obviously
- is a good connection. What about background cosmic radiation? Is that connected do you
- think to the energy that we're talking about?
- cosmic radiation on an enormous range of different energy scales, from ultra-high energy gamma
- rays all the way down to microwave radiation, which is possibly what you're thinking about.
- Certainly what that very, very low energy microwave radiation that we can see across
- the whole sky. That is an incredibly good test of our theories of physics. We get the light
- from the very, very early times, from the moment when those first atoms had formed and it travels
- all the way through the universe from then, to us, and so it's telling us both about what
- was happening at those early times, but also about what has happened in the universe since
- then. So it's an incredibly good tool in our toolbox of figuring out what our cosmology is,
- what the history of our universe is, yes.
- here.
- So thank you for that phenomenal lecture, as I would definitely expect from this.
- So you said you only took A-level physics because it was basically a necessity to do a mathematics
- degree. Sure enough you studied mathematics, but was there a point or a period when you gradually
- came to the realisation that actually, I'm more a physics person than a maths person. Or was it the
- influence of Anne, or was it something else?
- process. I think, again I was lucky, we were lucky, that our maths degree was very,
- very broad and that it went all the way from very, very pure abstract mathematics all the way through
- to very applied things, and I found that I much, much preferred the more applied side of things
- that maths actually at the end of the day was more useful, more interesting to me as a tool
- for understanding things. So that's really the way into physics then that it's a language for
- describing the world or the universe around us. That then turns out to be interesting and useful
- for physics. So that was the, yes.
- the front here, yes.
- grammar school and we had a science six and an art six. It was equal numbers in each. I then went to
- teach at an all-boys independent school, again equally split. But then when the girls started
- to join the school, it then became polarised. A lot of the boys dropped out of the art subjects,
- and it seems to me that the problem is that different subjects are associated. That's where
- the problem is, so you've got to have a lot of confidence then to go for the subject that
- doesn't seem to be associated with your sex.
- really common story that if you're in an all-girls high school, that these issues
- around studying physics, are at least much less than they are in mixed schools. Actually to quote
- another Institute of Physics report, they did a really, really interesting project looking
- at tackling stereotypes in schools and found that it's not just enough to tackle stereotypes around
- one subject that you want more girls to study physics. That actually you have to take the
- whole curriculum approach and also tackle those stereotypes about why boys are not choosing other
- subjects as well. That's the only way that you can actually properly fix these problems.
- F1: Okay, interesting. So to go on from that, there's a question here. If you could change one
- policy to improve access to physics, what would you do?! That's actually really hard question!
- Clare Burrage: Can I have two?!
- Clare Burrage: I think it would be possible to make the A-level curriculum more interesting. I
- think there is a challenge, even when it's well taught, I think it's perhaps not as
- engaging as the other STEM subjects. Yes, I think there's a huge challenge around physics teacher
- recruitment. That if I'm setting the policy and I don't have to worry about anything else,
- that that is where I would put my money.
- curriculum too, to make it… Any more, there's loads of questions, I want to
- try and be fair, there's somebody here!
- Did I hear right? Did you say that dark energy makes up about 70 per cent of the
- universe? How do you get to that figure? How do you determine that number?
- Clare Burrage: Right, so that is an estimate of if you took everything in the universe today,
- turned all of the matter into energy, shook it all up, so it's evenly distributed, and then split up
- that energy into the different components. What you get is that all of the ordinary matter that
- we're made of makes five per cent of that total, that the dark matter that we've spoken about makes
- 25 per cent, roughly 25 per cent of that total, and the dark energy makes the 70 per cent. How we
- actually get to those numbers is through a large number of different cosmological observations.
- So one of them is the observations of the cosmic microwave background radiation. So this microwave
- light from the very early universe that tells us, as we said, it gives us really
- good information about the early universe and how things have evolved. We also have observations,
- from much more recent cosmological history, observations of supernova in distant galaxies,
- that when they explode, so a supernova is exploding star, and there are certain types
- of supernova that always go off with the same brightness. So if you see some that you look out
- at the sky, some are brighter, some are dimmer, you know that the brighter ones are closer to
- you and the dimmer ones are further away. So you can use that to construct a model of what
- has been happening in the recent cosmological history, because you have a way of turning the
- 2D information that you see on the slide into 3D information. Also we can we can learn also
- by looking at the light from galaxies, how they are moving, whether they're moving towards us
- or away from us. A whole load more observations of how matter is distributed, how galaxies are
- distributed in the universe. You put all of that together into your model of what you think gravity
- is doing, and what particles you think exist in the universe, and you run that forward. You see,
- if I put these things in at the beginning, do I get a universe that matches the one that we see,
- and the ones that match are the ones that give us 70 per cent dark energy today.
- M6: Thank you.
- Very good, let's have somebody at the back, on the right, at the back.
- M7: Love the talk. Looking forward, what do you think would be the most beneficial
- piece of technology or testing facility that we could realistically get in the next 30,
- 50 years to probe the problem of dark energy? Would it just be a larger
- particle collider or something more novel?
- lots of different things, approach. I think that we don't know, we don't even really have a good
- enough theory of dark energy at the moment to say, this is pretty much probably the right answer, we
- just need to go and look for this. There are too many possibilities at the moment. I think we need
- to spread our bets a little bit, and maybe that means doing a number of smaller experiments rather
- than putting all your eggs in one basket.
- F3: Thank you for the lecture and for sharing your story. You gave us your origin into physics,
- but I'm curious about your origin into dark energy. Why did you pick
- this field and what motivates you about it?
- back to my PhD, and my PhD supervisor, because I didn't start doing this,
- for the handful of experts in the room, the start of my PhD was on supergravity models of inflation,
- which is completely the opposite end of the end of the universe. The very, very early times,
- and, yes, getting towards this string theory, fundamental theories of everything, that the
- question was about before. So I knew I wanted to do cosmology, because when you do cosmology,
- you get to do everything, you get to do gravity, you get to do particle physics,
- you get to do large scale stuff, you get to do small scale stuff. so that I
- knew that that was what I wanted to do. The original project that I started on, for me,
- turned out to be way too far away from anything that was actually ever going to be measured,
- or at least measured in a reasonable amount of time. I was so lucky that Anne works on so many
- different things, and that she had other projects going on, and she was like, 'Well, why don't we
- try this?' That's where things started.
- position to ask you something else! Which is that I'm a biologist, it's not important what I do,
- but biology doesn't tend to work in quite such big teams. It probably will more in the future.
- There's still the possibility as an individual to have your own idea, and to design an experiment,
- and test it, still just about possible. Chances are you probably need to collaborate with a few
- other people, but I'm very struck that your area is huge teams and this is just
- completely a professional question. I'm sorry for those people who are not scientists here,
- but how do how do you manage everybody's egos and everybody?! Everybody thinking that their
- idea is right, and that their interpretation is right, and I'm just… It always sounds as if it's
- all one big happy family, but is it really?!
- within those large collaborations. Probably for partly the reason you suggested! Actually
- the atom interferometry, the experiment that was done at Imperial, that was a team of three
- experimentalists and three theorists. So it is still possible in physics to make progress. Yes,
- there are huge challenges and I don't think that we know all of the answers to, yes, how
- to work in a ginormous team like that, how to make sure that everybody has opportunities to develop
- their career. You can do things internally, and if the collaboration is big enough, then that's a big
- enough community that you can progress your career within that. Even if people from the outside
- don't know who you are, maybe people within the collaboration know who you are. Yes, it's hard.
- F1: So you do need to be a very good communicator, not just to the outside world,
- but to each other.
- F1: So that the old fashioned idea of a weird scientist who can't speak to
- anybody and so on. That's over really, isn't it? In fact, communication is incredibly
- important, isn't it?
- F1: I'm sure that there was another question there.
- F4: Thank you. I particularly like your enthusiasm. I think, if I'd had you as a physics
- teacher, I might… Well, no, actually, I did find it very, very interesting, it just was in a school
- where it was a subject that didn't matter, so I was alone in liking it in school and I was
- no good at maths. I've got always interested in cosmology and I've got a question, it's probably
- going to show you why I never did any physics, and I'm probably very stupid. You mentioned the
- fact that the constant speed of acceleration might not be constant. How does that work with E = mc2
- if the constant is not constant, does that interfere, or am I completely stupid here?
- Clare Burrage: So the first thing I should say is that this is the new results that are… Maybe this
- is not constant, it is still tentative, and that's exciting because there's new stuff to
- come over the next few years, but I don't want to put too much weight on that because we're
- not 100 per cent sure that that is definitely happening. Firstly in cosmology,
- your ideas of energy, what energy is and how it's conserved. You have to rethink them a little bit,
- because energy is only conserved if your background is not changing with time. So
- if your universe is expanding, yes, things are a little bit more complicated, and you have to
- think things through a little bit differently.
- more, I think. So Samuel says, unlike the UK, there are many girls around the world
- who still don't seem to have access to STEM subjects at all. What could we, as physicists,
- do to make physics available to everyone?
- F1: A hard one though, isn't it? Yes.
- in the sense that if you do have access to it, there is a lot of resources out there. and there
- are brilliant initiatives, taking physics, taking STEM subjects into countries all over the world,
- where they don't necessarily have the resources, or the teachers,
- or the training to do that normally, but it's nowhere near the scale that it needs to be to.
- F1: No, no, I have to say I was very impressed by the Girlguiding badge. You have taken that,
- well not you personally, but that has been taken. So last question is,
- what difference would it have made to you as a young person to have been able to participate in
- the Girlguiding badge? That's a nice question!
- I think like I said the story I wanted to tell was that for me physics was quite boring,
- and not very exciting. So I think doing it and just getting to do it and getting to play with it,
- and doing short things, small little things that you see something happen and it's like,
- oh I didn't know that. I think seeing physics be fun, at an early age,
- would have made a massive difference.
- question, but one, it's burning, right!
- F1: No, it's fine, no, it's good.
- F1: Oh wow.
- back now! So I guess I just wanted to ask, do you feel pressure being a role model to younger women,
- since you are, is it pressure for you?
- Clare Burrage: Oh wow, well that's really kind of you, first of all. Oh, I haven't thought
- about that, so I’m not sure. I think I do feel on some level that it's important to be visible,
- and that it's important to talk to everybody, and to try to be nice. To go and talk to all
- of the… Or at least as many of I can, of the young people coming up, younger people
- coming up in our discipline. I think, I can't think too much about myself as a role model,
- otherwise my head is going to… It just feels, yes, I struggle sometimes to feel that I am doing
- enough to be a role model. Yes, there are very few women in our field, and I know that I hugely
- benefited from the role models that I had to look up to, and so I'm going to try and do my best.
- F1: Well you've done a fantastic job. So this is time now for me to move onto the main part
- of the evening really. Which is to speak on behalf of everyone here, and everyone online,
- that this was a wonderful talk, and also a wonderful Q&A, and to thank you very
- much for giving that, and for joining us on this special evening, to congratulate you
- of course for this award. So first let's have a huge applause please.
Join us for the Royal Society Rosalind Franklin Prize Lecture by Professor Clare Burrage.
The types of matter that form people, planets and stars make up only 5% of the content of our Universe. The remaining 95%, composed of dark matter and dark energy, remains one of the greatest unsolved mysteries in physics. While dark matter forms halos around galaxies, dark energy drives the accelerating expansion of the universe, yet neither has been directly detected.
Professor Clare Burrage will demonstrate how her research bridges disciplines from particle physics to quantum measurements, from astrophysical observations to laboratory experiments, to probe the dark Universe. Professor Clare Burrage’s work not only advances cosmology through her influential contributions, but also reshapes who is seen as a physicist. Professor Burrage will also speak about her Rosalind Franklin Award project which aims to engage girls of all ages with the joy and excitement of physics, and to inspire the next generation of physicists.
About the Royal Society
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