Joanna McDonald
Welcome to Longitude Sound Bytes, where we bring innovative insights from around the world directly to you.

Hi, I am Joanna McDonald, a recent graduate from Rice University. I will be your host today.

In our new series, we are presenting highlights from short conversations with professionals about what constitutes as beautiful in their line of work. The examples and experiences they share are not only inspiring, but also informative about the interesting projects they work on. So, join us in exploring reflections on beauty spanning from science and engineering to other fields.

In this episode, our guest is Peter Denton, an astrophysicist at the Brookhaven National Labs in New York.

He specializes in particle theory, which means he thinks about ideas about how the universe works, how it might work, how it doesn’t work. He also thinks about dark matter and black holes, but the biggest part of his research is on the elusive ghost like particles called neutrinos.

We had a chance to hear Peter speak on our podcast episode 124 earlier this year. Now he returns to share his thoughts on what he finds beautiful in the world of physics and how he sees creativity in scientific research leading to innovation. Let’s get started.

Peter Denton
I’ve been thinking about, the definition of what beauty is to me in the kind of work that I do. What I like and what I find to be beautiful is when the data and science and nature itself surprises us. Because we have these human ideas, we have these human intuitions we’ve developed over years and decades and even centuries about how the universe seems to fit together. And these provide guiding principles, which are very useful and very helpful. But nature doesn’t often care about these things. The way the world works, however, it works. And our intuition is often incorrect. And I find that when we see something that contradicts that in a very stark way, I find that to be surprising, and we learn something, obviously about the physics itself in question, but about our overall intuition and to me, I think that’s very exciting, and I think that’s a big part of why I like science. I think one can call that beauty.

So, one example that’s related to neutrino physics, that I think is very poignant, is in 1998, so not super long ago, though a little bit before my time. An experiment in Japan discovered that neutrinos have mass. This was surprising to say the least. In fact, I think shocking would be appropriate here.

Neutrinos are fundamental particles. There’re only about 20 different fundamental particles, and neutrinos are three of them. The main thing neutrinos do is that they don’t do very much. They don’t bump into things a lot, they just kind of flow right through stuff. We discovered them a little less than 100 years ago, and measuring their properties ever since that, it seemed that they were massless. And everybody expected them to be massless. People wrote down theories, assuming they’re massless. And this was the default assumption by everybody, forever. And then in 1998, neutrino experimentalist, named Takaaki Kajita, who ended up winning the Nobel Prize for this showed conclusively at very high significance that in fact, neutrinos do have mass and they do this strange thing called oscillations. And people, people were not prepared for this. This is not something that people were anticipating. People weren’t out there saying, oh, you know, the universe would make a lot more sense if only neutrinos had mass. No. People did not see this coming. And you know that surprise, that change, when the whole field has to go back and ask yourself, okay, what are we doing? What is going on? What do we know? And what guiding principles should be used when something comes out of left field that we didn’t expect? I find that to be beautiful. It’s nature telling us that our instincts and our prejudices about how the world should fit together, which are often very helpful in many cases, but sometimes, you know, they lead us to miss things that may be sitting right in front of us.

Joanna
Peter uses the word oscillation, which is not a very common word. Not everybody is familiar with it. So, what is oscillation?

Peter
I glossed over that but that’s a really important part of this whole story. The whole mystery about this thing from 1998 that turned into a massive global effort in the last 25 years, is about internal oscillations. And what was shown in 1998, and what we’ve now seen in many other environments and experiments around the world, is that neutrinos, they evolve in time.

So, if you start with some source of neutrinos, like let’s say, a nuclear reactor or the upper atmosphere, there are neutrinos being produced in all different kinds of environments, and then you measure them. You go down the street, or you go a block later, or you go to another city, and you measure them there. And then what you find is that it’s different. And it’s not just because they’re farther away but they are actually changing. The fact that they are changing over distance tells you that they experience time. The neutrinos know how far they have traveled. And because they know how far they have traveled, combined with Einstein’s theory of special relativity, this tells us that they cannot be massless. Massless particles don’t know how far they travel. They don’t have any internal notion of time. So, like light particles, they’re the same when produced, and when they travel, whether you know, it’s a foot from my laptop to my face, or from the sun, you know, a zillion miles away to the earth, it’s all the same to them. But neutrinos, they can tell. And so, that means they have mass. It’s a very subtle effect but it ends up having pretty big consequences for a lot of things.

I think, to bring this idea of oscillations back to beauty. I think one of many strange things about the fact that neutrinos oscillate is that it doesn’t happen on these human scales. When I say a kilometer, that really is what it is approximately, the measured number for neutrinos produced in a typical source, like a nuclear reactor, this is something where you just have uranium or whatever, just some heavy elements, they’re just producing neutrinos with some properties. And the thing they’re doing happen to kilometer later. And I think what they’re doing is a fundamentally quantum mechanical phenomenon.

Now when we think of quantum mechanics, we think rightly of very small things. Like computer chips in our computers and our phones and, and everywhere. They work because of quantum mechanics. And the chips have to be small, but they also can be. So, it’s a benefit, but it’s also just that’s the way it has to be. And atoms and chemistry, and these things are, of course, also all governed by quantum mechanics. And there’s a scale to quantum mechanics. Quantum mechanics says that the effect is only relevant if you’re at some scale. And that’s some tiny number. And if you’re at large things like humans, or tennis balls, or walls, or windows or trees or whatever, then these quantum effects, they average out and they go away. That’s the standard rule of how you separate quantum things, where you have to use a more complicated theory, from classical things where you know, our intuition about balls going up and down, and friction and all this stuff is pretty good. But there’s exceptions to this, and there’s things that break this. And neutrinos is one example of that.

It’s the same small parameters that says that, you know, chemistry is doing its quantum mechanical things on the size of an atom, which is a billion times smaller than human size objects. But the neutrinos do their things on scales of kilometers, or even the size of the Earth. And it’s because there’s a smallest skill for quantum mechanics, but neutrinos, remember, I said, they’re very people thought they’re massless. It turns out, they do have a mass. But we don’t actually know what it is. But we do know that it’s very small in any relative units. And it turns out that, you know, a small number divided by a small number takes you to something that is kind of big-ish. And so, that’s why you have something that would seem like it should be absolutely tiny. You should only see effects related to this kind of stuff in the size of an atom that actually happens between here and like, a block or two over there. And I think that’s so cool to be able to see quantum mechanical phenomena in distances that like you would drive or go for an afternoon walk. Of course, you can’t see the neutrinos with your eyeballs, you have to build a detector to measure them and so on. That’s how real life works but it happens on human macroscopic scales, just due to some sort of cancellation.

Joanna
Where are all the neutrino detection experiments happening? Peter had mentioned a goldmine in South Dakota for the DUNE project he works on. DUNE is Deep Underground Neutrino Experiment, detecting neutrinos generated on earth. But there are also neutrinos that originate from the sun and the starts, which are detected elsewhere.

Peter
There’s many neutrino experiments around the world with different goals and different priorities. There’s one at the South Pole called Ice Cube. And this was envisioned by a physicist I know pretty well named Francis Halzen, who was a close colleague of my late PhD advisor, Tom Wyler. And something like 40 years ago, Francis Halzen, wrote a paper that said that if you instrument a cubic kilometer, or like a mile by a mile by a mile of water, and he’s thinking of ocean water at the time, you can detect these astrophysical neutrinos from explosive sources out there in space. And it took decades, it took incredibly hard work, both in terms of designing and construction and obviously getting the funds in place for this to happen. But he and a team of three or 400 scientists from around the world have constructed this. They decided to do it the South Pole for various reasons, and it has worked out very well for them.

So, the South Pole is inhospitable. It’s not a pleasant place. I’ve never been, but I have colleagues who have been there. It’s cold. It’s remote. It’s desolate. It is sunny for six months, and then it is nighttime for six months. At nighttime there’s no flights in or out. The people there are locked in. But they’ve got doctors and chefs. Hopefully everything goes well for them every winter over there.

So, Antarctica is a continent. There’s land underneath it. But there are two and a half kilometers of ice, which is just insanely tall amount of ice stacked on top of it. So, they drilled holes to the bottom. By drilled, I mean, they shot hot water, and the water melts the ice, and then they have holes, that’s just water, then they dump in a bunch of detectors. And these detectors are kind of the sizes of basketballs with a bunch of electronics and sensors and stuff on some chain of cables. And they dug like 86 of these holes, and they dropped them in all the way to the bottom. So, the bottom one kilometer out of that two and a half kilometers or so is instrumented with detectors. And they’ve been running successfully for more than 10 years, measuring neutrinos from outer space in extreme explosive events. So, when stars explode, or when galaxies start spewing out stuff, this will create all kinds of particles including neutrinos. And they’ll make it through to the earth. And Ice Cube is sitting there waiting for them to come. And they have measured them. And people are starting to use this to differentiate and understand what these extreme sources are in the universe, which I think is pretty exciting.

Joanna
Exploration of neutrinos appear to be a form of underground science.

Peter
We build a lot of our things underground. As I mentioned, DUNE is in a goldmine. So, it’s put there looking for very rare neutrino interactions with lots of other stuff. So, you want to shield all that other stuff and there’s no substitute for just rock. And putting rock on top of something is not so doable. But instead, it’s much better just go under the earth. And it’s much better to use a hole that somebody else has dug and digging your own a hole. So typically, it’s gold mines, nickel mines, things like this.

And of course, you know, famously in South Dakota, there is a pretty huge gold find there that you know, really shaped figuratively and literally, the area and dominated the culture and dominated all kinds of things for a century or more. And you know, people extract gold for any number of reasons, but mainly to get rich.

Now, we are converting these into particle detectors for neutrino experiments and also looking for trying to understand the particle nature of dark matter. And the fact is, this is going on around the world. And I think this is really cool. That people, you know, were financially motivated to dig really deep holes looking for precious metals. And at some point, it runs out either there’s, there’s no more gold, or the amount of gold is so little compared to the price of gold and whatever, and the mines eventually start to shut down. And physicists are usually like waiting, knocking on the door, like, please, please let us in. Once you guys are done, we want to take over the mine and move in and do this.

This recently happened in Australia within a pretty deep mine they had there. There’s a deep mine in China that’s being used for this, and several across the U.S. and Canada and elsewhere.

So, we put these detectors down there. In the mine in South Dakota, where they’re building DUNE right now. There have been experiments there since the since the 60s. In some parts of the mine that were unused once they dug out a region, and then they were done looking for gold there. And this is continuing on. I think it’s very cool. I think it’s quite beautiful to connect something that is so in some sense materialistic or capitalistic or about you know, profit driven, and then transitioning the same facility, and really also, many the same people in the town working there who are working to dig for gold are now you know, enlarging the caverns and adjusting the infrastructure needs for a particle physics experiment, which is a very different goals, a very different objective. It’s about just understanding the way the world works. It’s just such a stark contrast in some ways.

It’s a tiny mining town. Less than a 1000 people live there, who are working on the mine now, but also many of them were working on the mine in the days when it was a gold mine. This is their world and they’re now transitioning, in some sense, to physics. Even if they’re doing the same work they’ve always been doing, the goal and the objectives are different. And we think it’s important for the people working on it to understand why we are doing this, why are we digging these big holes in the ground? Why are we installing this sophisticated equipment in this deep underground location? What do we benefit from that? I think that this outreach like this podcast today, but also with going out and finding people. There’s pub talks where, you know, you find people in a bar, and you get a certain kind of audience for that or you go to the school and you get a different audience for that. I think that’s a very important part of science. And I think it’s beautiful. I think it’s a wonderful, it’s a nice way to connect, what the actual objectives are with people doing frankly, a lot of the hardest work.

Joanna
It’s a unique form of repurposing operations that not only expands scientific exploration but also create jobs in rural America. How well are these efforts received by the locals? Well, Peter speaks about the origins of the gold mines when they were first established, compared to the efforts in place today.

Peter
Digging this gold mine was not seen well by the people who lived there, at least the indigenous people. The Lakota, and Nakota and the Dakota tribes primarily. And the idea of scarring the earth, this land there is beautiful. It’s also one of the prettiest places I’ve been in the US. And, you know, it’s, they cut a huge gouge out of basically a mountain there, that’s gone forever. The rocks are strewn about, and the gold is obviously gone.

People came in and scoured their land, and we can’t fix that. But there’s been a number of efforts in the physics community when this has been going on to reach out and connect with these people and have a conversation. We’re interested in doing this, how do you feel about this, and it’s this okay? The responses that at least I’ve heard, and I cannot say that this is, you know, representative of everyone, but is things like, it’s it is different when it’s trying to understand nature than it is when it’s trying to make somebody rich. And that is something that they seem to feel as a different thing.

And the other thing is that some of the caverns have to be enlarged for these experiments, so they spent years digging out rock and they actually finished about a year ago, but the rock isn’t being transported somewhere else. It’s not being quarried and sold off or anything like that. It’s actually going to fill in, in some sense part of the, what’s called the open cut the big gouge out of the mountain, so it’s all staying. So, the rock is staying there, and the physics community went to great lengths to ensure that. When we need to build an experiment that is large and interacts with the land and community in a non-trivial way, we have to be cautious about to ensure that the beauty of the results are shared with everybody, and also that we’re not destroying any existing beauty that we do or maybe even don’t appreciate, but that other people do. So, this is something that we think about a fair bit.

Joanna
What is the role of creativity in scientific endeavors?

Peter
I think art and research are really very similar. Obviously, they’re portrayed as being as this whole left brain, right brain narrative, which I think is people take way too seriously. But they’re really very similar. And one thing that is certainly true in art, for my limited understanding is that pushing the envelope. I mean if you paint in the same way as Monet, or as Van Gogh, like, that’s obviously technically a fantastic achievement, but it’s not innovative. Right? You’re never going to be famous for doing something a similar style as someone else.

You know, I don’t know, what’s interesting art. I guess that’s for society to decide, but it’s innovating, it’s doing something that people haven’t done. And of course, it’s reflecting the modern age in terms of not only the culture, and the community and society, and what’s going on in the world, but also the technology and what is available and what can be done. Of course, you know, art now includes television, and movies and animated things that were not available, 20, 30, or 100 years ago. I think that’s great. And that’s wonderful.

But science is very similar, right? Doing things that are the same thing as what people have done in the past, is not really scientific research. That’s like a homework problem. So, if you’re building an experiment, or you’re doing a calculation, that’s already been done, obviously, it’s gonna be a good exercise to see if you know what you’re doing, and if you have the skills to do it, but at the end of the day, science is about doing things that no one has ever done before. And every single thing that is done is things that no one had done before. And the same way that, you know, novel art, if you want to be successful as an artist, you cannot just be out there, tracing over or using the same style as someone before, you have to create something new, something beyond.

It’s the same in physics, you have to create some new idea, and it could be new experimental technique, it could be a new idea for how the universe fits together, or, you know, some combination of the two, that is to say some way to test some new idea. And this is essential to everything is this creativity, this looking at this, and this can come from, you know, new technology, you know, we look to see what kinds of new materials are available for detecting things, and so on. Usually physicists are developing new technologies, even before they hit the commercial market. The top physicists, it’s not necessarily about being able to calculate the best and running the computer the best or doing the biggest, most sophisticated formula or something like that. It’s about having a completely novel idea about saying, let’s do this thing that nobody ever thought of before, but can be really impactful. And that’s what makes a big difference.

So I think in that way, and this notion of the role of creativity, and also, you know, creativity, combined with knowing what everybody else has done, you have to know what’s been done in the past before you can say that what you’re doing is new, and then generating a new idea out of nothing out of talking to people out of listening to what other people have to say reading things. This is exactly the same thing that painters do, the composers do, the novelists do. You have you know what everybody else has done and then do something that’s nothing like that. I think that’s an obvious connection to beauty that it’s about innovation and creating new ideas. And I often think about how this is similar to composing a symphony or improvising a solo or something like that.

Joanna
What’s interesting about what Peter is saying about the role of creativity in scientific or artistic endeavors is that it sounds similar to a piece of advice given to me by a music professor while I was still a music composition major as an undergrad at Rice University. And what he said went something along the lines of this, it’s not fair to put the expectation on yourself to completely reinvent the wheel every time you sit down to write a piece of music. Instead, seek and search out ways to create new variations or innovations or hybrids of materials that you already know exist.

[music]

Longitude

This podcast is produced by a nonprofit program that engages students and graduates in leading interviews, narrating podcast episodes, and preparing library exhibitions. To view the episode transcript, please visit our website Longitude.site

Join us next time for more unique insights on Longitude Sound Bytes.