Her career has been spent studying the darkest recesses, those pockets of space that until now have just been dismissed as mysterious or enigmatic matter. But Randall is not afraid of getting up close with it. Her work revolves around comprehending the true nature of ‘stuff’ and what actually makes up the world around us.
It’s her research on dark matter that most intrigues her. Accounting for around 25% of the universe, as yet there is no conclusive evidence of what this stuff actually is, or indeed its purpose here.
In this uncharted territory, Randall’s theories are so advanced that it almost seems as if she is waiting for the technology to catch up. Her most recent book Dark Matter and the Dinosaurs sent shockwaves throughout the scientific community, postulating that dark matter caused a ‘butterfly effect’ of sorts, accounting for the extinction of dinosaurs. This tangential creativity along with the fundamental questions she poses on our existence have awarded her genius status and an inclusion on TIME Magazine’s 100 most influential people list. We can’t wait to see where her mind takes us next.
Would you say that being imaginative is one of the key factors of approaching such work?
Not always, I think there are many different types of scientists. There are some who are more formal and mathematical, who just like to work things out and then there are some who are more numerical and like to simulate things. I do think that you want to be someone with different ideas. For me it is much more valuable and fun to contribute something I feel like other people wouldn’t necessarily do. I do think it’s important to have, not necessarily an interdisciplinary approach, but within a discipline there are many different aspects and I think being aware of a lot of them is very helpful. I think what is not recognised as much is that the imaginative stuff is not just coming out of thin air, it’s coming out of a very strong grounding in many different aspects of the science. A lot of the so-called imaginative things come from me knocking my head against the wall while trying to work through what the potential solutions are to various problems. You have to be willing to go beyond what everyone has thought about before to some extent, but I also think its incredibly important that you have the groundwork done before.
When would you say that you are at your most creative in your work?
That’s so random. Maybe when I’m unhappy? I’m not really sure, I’m joking. But some things that are described as the most creative didn’t seem like that at the time. The warped extra dimension came about because we recognised what the theory had given us, we were paying attention, we understood what the problems were and that this could be a solution to various things, and just by working it out. But it wasn’t like I got up and said ‘Let’s be creative today’. I mean we were working hard and very intensely don’t get me wrong. I think we were trying very hard when we had done the project before that which was to do with something called supersymmetry. We were trying very hard to find a solution to the problem, but by working it out the answer just came out by really understanding the physics.
Obviously your work is based on established science but you are also constantly exploring the unknown.
Well I think the thing that is more daunting is a concern about when we will be able to test some of these ideas because it is getting harder and harder to do that. With not knowing things, I’m actually more shocked by how much we do know and understand about cosmology and particle physics. Don’t forget, a lot of this was found in say the last 100 years so it’s quite amazing how much progress we’ve made. I guess I’m just a little bit more humble, I don’t think its automatic that humans are able to just figure everything out. What is daunting sometimes though is thinking how are we going to figure it out? A lot of what drives my research now is trying to think of things that we have a chance of measuring even if we didn’t think we did.
So let’s go to one of the theories that has gained you widespread notoriety in your book Dark Matter and the Dinosaurs. You postulated that 66 million years ago there was a cataclysmic event, the possibility that a comet influenced by dark matter wiped out most of the dinosaurs. We don’t conclusively know that right?
We absolutely don’t conclusively know that and I never pretend that we do. For the purposes of the book I use it as a way to try connecting basic elements of matter to what we see here on Earth. That’s a very speculative example but I talk about a lot more realistic examples and for me it helps draw the science, it gives us a target of what we think this so called dark matter does because we can discuss what it’s density and thickness would be, and it just gives us a general target of what we can and can’t test.
Has there been any other compelling evidence that has come out since you wrote the book to support that hypothesis?
The evidence is slow. My students actually re-did the analysis, being more careful, taking into account the gas in the galaxy, and actually found a result even better than the one we found. A lot of the time when you go and reanalyse these things it looks worse, so that I found encouraging. It doesn’t prove anything but it is encouraging. We are still waiting for data from what is called the Gaia satellite, which is measuring a billion stars on the Milky Way to learn more.
"You have to be willing to go beyond what everyone has thought about before to some extent."
Lisa Randall on pushing the limits of science
Is there a lot of evidence to support the theory that dark matter affects us in our daily lives?
It depends what you mean by ‘affects us’. It was essential to the development of our galaxy and the lifetime of the universe, and without dark matter we wouldn’t be here having this discussion. In terms of what it does today, I mean it’s a bit of a circular reason but given the speed of stars and the potential for keeping stars in our solar system of course one could rightfully argue that without dark matter stars would not be going at the speed that they are going at. So in our daily lives it’s not playing a big role but it does have a big role in establishing the system by which we got here.
Are you constantly competing with people that theorise about what dark matter actually is?
I mean there are many different competing proposals and I think it’s just important to outline any possibility that can be trusted. Not all of them will be right but we have no idea, it’s a very hard thing to test – after all, it’s matter that hardly interacts with us.
Can you talk a little bit about how that specific theory in Dark Matter and the Dinosaurs came together?
Well it’s actually a really cool story because it’s just kind of the way science happens. There was data from a satellite tracking protons coming from the centre of the galaxy. We realised that if a fraction of the dark matter carried its own charge it would be much thicker than we conventionally think dark matter is, in which case signals could be a lot stronger potentially. That was kind of our starting point, we realised that we could have this dense dark matter based on new interactions within the dark matter sector.
What happened then was kind of fun because I was invited to give a lecture at Arizona State by Paul Davies. I was talking about this research and how our idea has been that the dark matter that interacts could potentially collapse into a disk shape, like the disk around the Milky Way. Paul Davies heard that and said ‘Oh, so you could explain the extinction of the dinosaurs.’
I had never thought about this question before, of what triggered this enormous object of 10-15 kilometres big to hit the Earth 66 million years ago and wipe all the dinosaurs out and is on the planet to this day. There were various proposals to try and explain that, none of which really worked. One of them involved how our solar system, when it orbits around the Milky Way every 250 million years or so, it bobs up and down through the Milky Way plane, like horses on a carousel. And the idea was that as it goes through the mid plane of the Milky Way, where all the stars and the gaps are, maybe something triggered a comet from the outskirts of the solar system, what is known as the Oort Cloud. The problem was that if it was just the ordinary matter that we know about, it didn’t happen frequently enough to match the data and it didn’t happen quickly enough to get this kind of peak that you see every 30 or 35 million years or so. So we realised that our disk could solve the problem.
"I had never thought about this question before, of what triggered this enormous object of 10-15 kilometres big to hit the Earth 66 million years ago and wipe all the dinosaurs."
Lisa Randall on the last great extinction
With relation to dark matter for instance, are you a fan of calling things ‘enigmatic’ or ‘mysterious’ or does that push us away from trying to understand what it actually is?
Well there are certainly ideas out there waiting to be discovered, both theoretically and observationally. But a lot of times we just won’t know until we make the observation – we really want to see something that tells us the nature of dark matter for example, and we can guess many possibilities but we really want to see something that will match the data to that. So is there something that will make all of this tie in together? Obviously that’s always the dream. With regards to calling these things ‘enigmatic’ or ‘mysterious’, I think you’re right, we are just alienating people from the actual science.
Would you say that there is a renaissance in scientific inquiry and technological progress in the last decades and going forward?
I wouldn’t say it’s a renaissance; I think there have been some steady advances. As technology develops, science develops along with it and I think people miss that a lot, like the electronics revolution in turn relating to the development of quantum mechanics.
A lot of detailed measurements are getting harder to do, they involve bigger efforts and more expensive things, so as a society we have to realise this is what we need to progress. So in some sense, yes we have made a lot of advances and we have a lot of interesting things but I do have concerns watching how things are today about how much we are going to move forward. At least those are the questions I ask.
If you had to hedge your bets on the next big scientific discovery what do you think it would be?
I mean it doesn’t really matter what I say but I would say that one of the reasons why I think about dark matter is because I think that we have a better chance of learning something new about that than the other parts of particle physics that I learn about. So in that sense I think it’s a promising direction.
You also undertake a lot of other artistic pursuits for which you’ve won numerous awards. How does that tie in with the work you do?
I worked on A Projective Opera that premiered at the Pompidou Centre in Paris and went on to several other places, and it was the composer Hector Parra who contacted me about that. People contact me about a lot of things but this project sounded particularly intriguing. He is a very talented young composer and I just spent a long time writing these passages and painstakingly thinking about the logic of how we got where we are today, why we answer the questions we do and the reasons behind the science. So it was just really fun to think about going in a completely different direction and introducing people to the ideas of what’s around. And as a physicist to be told that your work is going to premiere at the Pompidou Centre; I mean how exciting is that?
What is your next project that you have turned your attention to?
We are spending a lot of time thinking about whether or not dark matter can have its own charge, because I think it’s a very interesting possibility to see if that would be testable in the astronomical measurements. The idea is that just like dark matter doesn’t interact with our charge, maybe dark matter has its own charge with which we don’t interact and that of course would be super exciting because it would mean that dark matter is a much richer sector than we thought.
Photo Credit For Feature Shot: Phil Knott (Camerapress)