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The Templeton Ideas Podcast is a show about the most awe-inspiring ideas in our world and the people who investigate them.


Dr. Robert Hazen is a mineralogist and astrobiologist based at the Carnegie Institution’s Geophysical Laboratory and George Mason University. His research interests focus on life’s origins, mineral evolution, and mineral ecology. Hazen, who also had a 40-year career as a professional trumpeter, has authored more than 400 articles and 25 books on science, history, and music. Robert joins the podcast to discuss the co-evolution of life and minerals, the stories rocks can tell us if we learn to read them properly, and why humans are drawn to the search for life outside of our planet.

Transcripts of our episodes are made available as soon as possible. They are not fully edited for grammar or spelling.

Tom: Bob, welcome to the podcast.

Robert: Oh, it’s so great to be with you, Tom.

Tom: I wanna start out by asking you a question that goes way back into your history. Do you recall the moment that you fell in love with rocks?

Robert: Wow, what a great question. I think I was maybe eight years old, nine years old, and I love to go out and collect stuff. Butterflies and bugs and flowers, all kinds of things. But we lived in Cleveland, Ohio, near a fossil locality, and I found my first trilobite, a complete trilobite, little enrolled guy, and I said, well, you can go out into the world and find stuff like this. And I wanted to keep doing that.

Tom: That is fascinating. The sort of contingency of, of where you grew up and what you discovered. Cause I was just thinking about my son who’s six, he finds things every day, but they’re like matchbox cars. They’re not fossils from tens of millions of years ago.

Robert: I love what you said about contingency because when I was about nine or ten years old, we moved from Cleveland, which is in a fossil rich zone to Northern New Jersey, which is a mineral rich zone. And so there were no longer any really easy fossil sites, but I had a science teacher who was so great, gave me mimeograph. They used to be called sheets with localities nearby, so within an hour drive, there were some of the most famous mineral localities in the world. And my dad and my mom were great. They supported me, and I built a rock collection.

Tom: Wow. Yeah, doubly lucky. I’ve read that you, in addition to being a scientist who loves rocks and has branched out in many areas, you also play the trumpet professionally. I wonder if you can tell me a bit of background on your love of music and how that came into being as well.

Robert: Music was part of my life since I was very, very young, because my father was a concert level pianist, although also an electrical engineer. And every night he’d practice for two or three hours and I’d hear Bach and Chopin and Liszt and Brahms and incredible music. And it just became part of my vocabulary.

Well, I had an older brother and a sister, both of whom played piano, and so I sort of shied away from competing with them. And there wasn’t enough practice time on the instrument we had, so I, I took up, when I was five years old, violin and played that for a while, and then when I was nine years old, started trumpet and never looked back.

It just was a natural instrument for me and I had great teachers and I had an opportunity when I went to MIT as an undergraduate studying geology, I also was at the New England Conservatory, studying trumpet. It was a tough call, which one I was gonna be — a professional trumpet player or a professional scientist.

Tom: You’ve continued to do both, right? You really didn’t have to have an either or sort of situation, at least not in terms of your entire identity. Right?

Robert: So I retired from professional trumpet playing about five years ago, and I’ve also in the same time played cello, as an amateur, who really loves it. My wife’s a violist and we play string quartets.

Tom: Do you see some connections between your love of music and love of science, or do you see them just as dual passions?

Robert: Well, they’re certainly dual passions and they’ve been extremely complimentary in my life. What I find amusing is many people say, oh, you’re a musician, you must be so creative, and I say, no, a symphonic trumpet player, the last thing you want to do is be creative. You have to play the right note at the right time, at the right volume when the conductor tells you to, and you better not mess up too much.

Whereas science, you go into the laboratory and every day it's like jazz, it's like making up something new.

No one’s telling you what to do. And the process of scientific discovery is such an intensely creative, exciting journey that that’s been the creative part of my life. And in a funny sense, playing music has been, A kind of discipline, you know, practice and play it right. And also a chance to work with incredible people who are experts and see an emergent property, a symphony orchestra where it isn’t just a trumpet or a clarinet or a violin, it’s 80 or a hundred people working together to create something that no one individual could ever do. And I think that has actually transformed my thinking about the evolution of emergent systems.

Tom: Let’s pivot back from music to science. If you could tell me a little bit about what makes origins so captivating?

Robert:, So origins are important because we want to know where we came from. We want to understand if there’s some sort of drive in the universe that leads to beings like us who can be thinking about our origins. That’s pretty astonishing for me. There’s another dimension, though. I’m a mineralogist. I think about minerals and what I’ve realized over the last 15 or 20 years is that if we want to understand the past, that the only thing you can hold in your hand that is millions or in some cases billions of years old, are minerals — rocks, and minerals. The fossils are only preserved because they’re preserved as minerals. Every mineral is a time capsule. It’s waiting to be opened, and this is a kind of new revelation for my field. Mineralogy for many, many decades has been principally a physics and chemistry problem. In fact, a mineral species is defined as a unique combination of chemistry and structure.

So there’s 5,900 mineral species each with a unique combination. Well, that doesn’t talk about age, that doesn’t talk about process, and it doesn’t talk about origins. And so I’ve been recasting the field of mineralogy into something called mineral evolution. A very strange concept to people who think of evolution as only being associated with biological objects. But when we say no, no, I mean minerals have changed through time, and in fact there’s a co-evolution of life and rocks.

Tom:  I read in one of your books that you said that there’s atoms in each of our bodies that were formed at the time of the Big Bang 13.7 billion years ago. How is that even possible that we have like atoms in ourselves that date to not just the beginnings of our solar system before, but the beginnings of the universe?

Robert: I found this an extraordinary thing. Most people, when they talk about the Big Bang and the few minutes after that, they talk about how the first atoms appeared, and that’s mostly hydrogen and  helium, which makes up most of the stars we see in the sky. That earliest, earliest few minutes of the cosmos, there were intense interactions and a few atoms of carbon, a few atoms of oxygen and silicon and other heavy atoms were formed, and those are part of our bodies. So about one in every trillion carbon atoms, it’s calculated, came from the Big Bang itself, and you’ve got trillions upon trillions of carbon atoms in your body. So that means you’ve got a whole bunch of Big Bang atoms and we’re sitting here breathing and eating food that has carbon in it, and some of that carbon is from the Big Bang. It’s just amazing to think about how ancient and how ongoing these processes have been.

Tom: Yeah, it gives a very different impression of the sort of connectedness of the universe versus the sort of solitary sense that none of it has anything to do with us. So focusing on mineralogy again, you’ve been collecting since, I think you said since you were eight. Do you have a favorite mineral?

Robert: I’m torn by that question cause I have two. One of my favorite minerals is extremely common and which means that you could, when I was young, I could buy nice specimens and not spend a fortune. And that’s the mineral pyrite, iron sulfide, sometimes known as fool’s gold. And the reason it’s become a favorite of mine now is because pyrite through our studies, has been shown to form in more different ways over a longer period of earth history that any other mineral, it forms at high temperature and at low temperature. It forms in water- rich environments, but also in sulfur-rich environments. It forms abiotically, but also life can make Pyrite. So that’s a really versatile, fascinating study. And this also ties into our feeling that there needs to be a new classification system of minerals. One that not only recognizes that pyrite, which according to the International Mineralogical Association, is pure FeS2 in the pyrite structure idealized, but we recognize that every pyrite is different. They contain incredible amounts of information, trace and minor elements, and solid and fluid and occlusions, and the sizes and shapes and the grain sizes. All these things are attributes of pyrite that tell us how they form. So I say if we go to Mars and we find pyrite, that’d be cool. But my question is what kind of pyrite? Pyrite is so information-rich, and that’s why I love pyrite. But I’ll tell you my other. Co-favorite mineral, which is a very personal thing, is the mineral Hazenite, which was named after me about 10, 15 years ago, because it only forms in one place in the world. In Mono Lake, California, it forms only in the dry season. Every time it rains, all the Hazenite night in the world disappears, and it is microbial poop. And actually microbes secrete in the dry summer months because the phosphorus level gets so high. They can’t stand it. They have to get rid of the phosphorus, so they pump out these little crystals, which is the mineral Hazenite. My good friend Sean Solomon, who’s the director of Lamont-Doherty at Columbia University, he says, “Hazenite happens.” Just think about it.

Tom: That’s very humbling, Bob. I’m glad you take it in stride.

BOB: Yeah, it is. It’s the only mineral that is only known to form by microbial action. So that’s, that is a distinction. As a bio mineral, it’s pretty special.

Tom: How did your colleague actually discover it?

Robert: Mineral neurologists know that if you wanna find a new mineral, one way to do it is to go to extreme environments where the chemistry is unusual. And the other environmental, it could be pressure, temperature, it could be the pH of the water. It could be the fact that they’re unusual microbes. It could be any one of a number of things. And so my colleague, Heshan Young and Henry Sun. Heshan, was a postdoc of mine and they, they went to Mono Lake thinking that they might find some interesting biominerals. They certainly found a whole number of minerals cause there’s all sorts of things that get deposited along the banks of Mono Lake, but this was a brand new thing. And when you find something new as a mineralogist, you have to describe it, you have to give its crystal structure, its chemical composition, some of its properties, and you apply to the International Mineralogical Association, you’d submit that information along with a proposed name and they very kindly suggested Hazenite in honor of me, because I’ve been working on the whole idea of the co-evolution of minerals and life, and it just seemed like the perfect choice for them, and I’m extremely gratified because there’s 5,900 minerals. There’s a lot of mineral names out there, but still to have something like that named after you. And, and having it relevant to my research was quite special.

Tom: That’s a pretty cool story. Yeah. You’ve done a lot of investigating as an inhabitant of our planet that we live on. Tell me a little bit about, living on this third rock from the sun, what do you learn from studying about the earth that might be able to apply to studying other planets and moons out there in the cosmos that might or might not harbor life? Like what’s the sort of transferable knowledge that you and your colleagues gain?

Robert: What we’ve understood is that time is a very important dimension in understanding complex worlds. That in fact, our universe, somehow has a direction in time when it comes to certain physical occurrences. Now, one of those directions in time is caught up in what’s known as the second law of thermodynamics. It’s the only one of the sort of classic laws of nature that has a direction, and it says that if you have a hot cup of coffee sitting on a table, it’s not gonna spontaneously get hotter. In fact, it will get cooler, heat spreads out from the hot cup of coffee to the cooler surroundings. And that’s a direction. All the other laws of nature work either way, frontwards or backwards. And what my colleagues and I have been thinking about is, wow, that’s, that’s fascinating. But is that really the whole story of time? Is that the only thing we see in the universe that happens if things tend to deteriorate? This is called law of increasing entropy, but I’m looking out a window right now and I’m seeing trees. I’m seeing flowers. I see birds and squirrels. I see clouds in the sky, and I also see buildings and power lines. I see automobiles. I, mean, those don’t seem to be chaos. Those don’t seem to be things that, that are increasing in entropy. There’s something else going on here, and studies of minerals have really enhanced this idea, Tom. The, the idea that we started out with a planet that had extremely simple minerals, typically minerals only composed of two or three elements, only about 20 different kinds of minerals. And yet we look on Earth today and we’re over 5,900 minerals and counting. Something has changed through time, something’s gotten more complex, something’s gotten more patterned, something’s gotten, if you don’t mind me saying it more interesting. That’s something the universe does and it’s not the second law of thermodynamics, and so we think it’s something else.

Tom: After the break, I talk with Bob about human curiosity, how minerals in life co-evolve, and how rocks can tell us stories if we learn how to read them.

Abby: You’re listening to the Templeton Ideas podcast from the John Templeton Foundation. If you’re enjoying this episode, check out templeton.org/news for more awe-inspiring perspectives from scholars, journalists, and colleagues.

Abby: You can sign up there to get our newsletter in your inbox or follow us wherever you are on social media. Now, let’s get back to our conversation.

Tom: So far as I know, humans are the only species that are looking for life outside of our own planet. What do you think that says about us as humans, that we are so curious and have this longing to, to find life elsewhere?

Robert: So I wonder if it’s a longing to find life elsewhere that’s driving us, or just an intense curiosity about the nature of the cosmos itself, whether or not there are other living forms or not.

Certainly, it's, it's almost inconceivable to imagine that we're alone in the universe when there are billions upon billions of galaxies with trillions upon trillions of stars and that many planets or more because it seems like every star we look at has planets.

So it, it’s hard to imagine there not being another set of planets that are earth-like or, or maybe even more conducive than our planets to life. And I think we wanna find that out and understanding our place. Is the universe, in a sense, a lawful place where life is just one inevitable consequence as inevitable as stars and planets and minerals as inevitable as the periodic table. And I think that’s a very profound question. And people in philosophy and theology and science all want to have serve an answer to that question. That’s why we explore.

Tom: Talk a little bit more about natural selection. Cause I think that’s a concept that, and sometimes I feel like is exclusive to biology or some sort of monopoly on natural selection. Yeah. Yeah. Can you gimme some instances of natural selection that are taking place outside of life?

Robert: What we would argue is that Darwin’s natural selection is a very important, beautiful example of a much more general universal principle. Primarily what Darwin is saying is that the successful characteristics of the parents are passed on to offspring, and so you get gradual transitions to evermore adapted organisms. And that’s very different from mineral evolution. It’s very different from atmospheric evolution or isotope evolution because you don’t have common descent in those cases. But you do have other properties where you’re mixing up atoms or protons and neutrons or molecules in ways that try lots of different combinations, and some combinations turn out to be more stable. They turn out to persist. And then you can build on that saying, oh, now I’ve made mineral A. Now I can alter mineral A to make mineral B. And now once I have mineral B oh, now I can alter mineral B to make mineral C. And you have a progression. You get larger and larger. And so early in Earth’s history, there were only about 20 different minerals at the beginning. And then through the earliest solar process, there are about a hundred minerals. And then you alter those minerals. There are about 300 minerals, and then earliest Earth had maybe 500 minerals, and then new processes came along and a thousand and then 3000. And then when life came along, completely changing the near surface environment and thousands more minerals came into being that never could have come in being before.

So that’s an evolution. That’s an evolving process. And in fact, towards the end stages of this, the minerals are co-evolving. With biology and I don’t see how you can separate the two of them because the biology is evolving, because the minerals are changing just as the minerals are evolving cause the biology is changing.

And so it becomes a much grander picture of evolution being baked into the fabric of the cosmos, right from the Big Bang on. And biological evolution is, yes, it’s an incredibly important part of this. It may be though, that you want to expand this to society, to the evolution of languages, to the evolution of culture, to the evolution of science itself can be thought of as a continuing process of, of many different possible configurations.

You, you have processes of thinking up all these different new ideas and then you have a selection process. Maybe our idea will be selected and people will say, yeah, we think this is a possible way that the universe works, maybe it won’t be selected, it’ll be rejected, and that’s the way any evolving system works.

I’m pretty passionate about this, I have to say.

Tom: Yeah. Well, when I learned about the Newtonian universe, when I picture it in my mind’s eye, it feels pretty dark, pretty empty. We are, as humans are this tiny little speck out there in this black dark space. Fast forward a little bit. I learned about Einstein’s universe.All of a sudden, that black sort of empty cold space starts to feel more exciting to me. It’s got shape, it warps, it moves. Time is wrapped up into it. But still, even in the Einstein’s universe, I still feel kind of alien because there’s nothing about life that’s kind of in that, at least not in that picture of how I understand Einstein’s universe.

But as I reflect on the idea of a universe as it’s self evolving. It feels more like I’m a part of it and that life isn’t incidental, but it’s just another stage of evolution of the universe. It feels more personal to me. Does that resonate with you at all?

Robert: Tom, this has been a profoundly moving part of my scientific career. Yes, it does resonate, and I’ll tell you, Tom, that something has long troubled me or confused me — we have these laws of nature. The one temporal law, the one law that seems to have a direction and time is the one that says, increasing chaos, increasing entropy, the heat, death of the universe. And yet I look out the window and I don’t see that.

Robert: And I think for thousands and thousands of years, humans have recognized that there are. What might be considered complimentary aspects of the cosmos or competing forces, if you will, the idea of creation and destruction in a very colloquial way, and, and I know this is getting far away maybe from some people’s scientific thinking, but the second law of thermodynamics has always seemed to me as kind of a law of destruction, a law of chaos, but there also is a tendency in the university to to create things. And so why wouldn’t there be if we see that all around us all the time? If it’s been part of philosophy and theology and in human experience for millennia, why wouldn’t there also be some kind of scientifically valid, rigorous statement of how organized systems come into being? And so what we’re talking about when we talk about, it’s actually called the Law of Increasing Functional Information, but what it is it The Law of Evolution, it’s saying that there are ways that the universe spontaneously creates local pockets of order in a universal state of increasing entropy.

And that’s really profound and you need both sides of this coin. You can’t look out the window and explain what you see without both sides.

Tom: I would have to say that most of us every day will absolutely overlook rocks, minerals, things that we stub our toes on. Maybe we’ll enjoy birds, trees, blue skies, clouds. I feel like rocks are probably one of the most overlooked, underappreciated substances in our daily lives. What would you as mineralogist say or, or perhaps remind us or encourage us to not just overlook them?

Robert: Every rock that you see that you stub your toe on, that just lies in the side of the path, whether it’s a gorgeous, brilliant blue crystal with shiny faces or just a dull gray, non-descript blob. It’s like having a book in your library and it’s sitting there and all you need to do, if you read the language that that book has been written in, if you’re willing to take the time to take the book off its shelf and open it up and start reading, it has a story to tell us, and the story it’s telling us is the entire sweep of the history of our planet, of our solar system, and even going farther back in time, there’s nothing else that provides us with that story.

There is absolutely no way that we can know what Earth was like a billion or 2 billion or 3 billion years ago without looking at those volumes. The testimony of the rocks, and if you're interested in where we came from, if you're interested in the story of perhaps where we're going, you have to look at the rocks.

Tom: I love it, Bob. Now you, from a very early age were captivated by rocks and minerals and fossils, and you’ve dedicated your career to understanding them ever better. Can you tell me a little bit about how you’ve changed in your relationship to these objects and maybe how it’s changed your perception of the world since you were a kid with your just intense curiosity.

Robert: Wow, Tom, when I first, uh, went to the American Museum of Natural History, I probably was 10 years old and I went into the old Morgan Hall of Gem and Minerals, and I saw row after row after row of minerals arranged according to their chemistry. And their structure, and I spent hours looking at those specimens and each label told you the chemical formula like SiO2 CaCO3 and the name and the mineral and its crystal system, and the locality where it came from, and I just studied and poured over those beautiful specimens.

And then imagine how I felt a year ago when I went to the opening of the New American Museum of Natural History Hall of Gem and Minerals, and now those same specimens that I saw when I was a child arranged by what was then known as the Dana System, are now arranged by Mineral Evolution. The same idea I introduced in 2008 and the same specimens that I studied as a child, but now they’re talked about when were they formed, how were they formed, what is the context?

What stories are these minerals telling us? It is a transformation in the way mineralogy is done, and it’s one that I’ve been so fortunate to be a part of and to now see it transcribed and watching children who were my age when I first went to the museum staring slack jawed at those specimens in the new context, learning about earth history and the story of our planet.

TOM: That is a momentous change. Bob, I thank you very much for taking time to talk to me today and I really appreciate our conversation.

Robert: Tom, thanks so much. I really appreciate the chance.

Abby: You’ve been listening to Templeton Ideas from the John Templeton Foundation, where we fund research and tell stories that inspire people with awe and wonder. We’re proud to support leading scientists, philosophers, and theologians from around the world. Learn about the latest discoveries related to black holes, complexity, forgiveness, and free will at templeton.org/news.

If you like what you’ve heard so far. Follow us and leave us a review wherever you get your podcasts. Our program was produced by Jakob Lewis with Great Feeling Studios. Our theme song is by Dan Burns. Our staff includes Thomas Burnett, Abby Ponticello, Benjamin Carlson, David Nassar, Gerald Nelson, Alyssa Settefrati, and Juliette Plummer.