We met with Dr. Robert Hazen to discuss the possibility of life on Mars, the origins of life, and much more. Enjoy!
We live in a universe where you can actually see those stars, we can see those planets, we can measure them, we may potentially be able to visit them.” – Dr. Robert Hazen
Mineralogist and Astrobiologist, Dr. Robert Hazen compares the way the earth has changed slowly in the past to the way humans have accelerated those changes in the last century. He also discusses the possibility and probability of life beyond our planet. Hazen argues that from the perspective of a mineralogist, extraterrestrial life is extremely plausible and may even be found on our closest neighbor—Mars. Hazen also shows the diverse perspectives that are required within this field to answer complex questions about the origin of life. Follow along as Carnegie Institution’s Geophysical Laboratory and George Mason University Mineralogist and Astrobiologist, Robert Hazen talks with Dr. Jed Macosko, academic director of AcademicInfluence.com and professor of physics at Wake Forest University.
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Want to hear more from Dr. Hazen? Check out Karina Macosko’s interview with Dr. Robert Hazen here.
(Editor’s Note: The following transcript has been lightly edited to improve clarity.)
Jed Macosko: Hi, this is Dr. Jed Macosko at Wake Forest University and Academic Influence. Today we have Dr. Bob Hazen, talking to us a little bit about his life as a mineralogist and as a person who thinks about extraterrestrial life and life on our planet.
So, before we get into extraterrestrial life, I want to know, as somebody who’s part of Earth science, do you have a lot at stake when it comes to climate change and the global warming and all of that? Or do you try to let other people deal with that?
Robert Hazen: Oh, Jed, you know, the questions about Earth as a planet of change, that is fundamentally important to me as a scientist. I look at Earth through four-and-a-half billion years, and the thing that strikes me so profoundly is how Earth has gone through these many, many different profound changes, from the earliest time when it was just a volcanic world spewing out hot black lavas on a surface that was completely devoid of not only life, but probably water in the early days. And then gradually forming oceans and forming continents, and going through stages where... Again, a completely lifeless surface, but maybe initially black, then gray, then blue, and then maybe a red surface when you start getting photosynthetic oxygen being produced and rusting the surface, I mean, all these different changes. So the period when we had life on land, when we think of what is an Earth-like planet is really the only last few percent of that history.
…humans are changing the near surface chemistry of Earth more rapidly and more profoundly than has ever occurred at any moment in that four-and-a-half billion year history that we can imagine.” – Dr. Robert Hazen
And change happens rapidly, it happens over and it happens over again. And it will continue to happen. There’s no question the Earth is going to change. The thing that worries me, and I do... I am very concerned about this, is that humans are changing the near surface chemistry of Earth more rapidly and more profoundly than has ever occurred at any moment in that four-and-a-half billion year history that we can imagine. We can visualize all sorts of scenarios from giant impacts to huge mega volcanoes to solar flares, to all sorts of things, and nothing in those changes can approach the kind and the magnitude of change that we’re doing in the last century.
So yes, I’m very concerned. And I feel that what I can contribute to this as a scientist is sort of a baseline. How did things change at other points in Earth’s history, what caused those changes, what’s the interaction between life and rocks? And if we truly understand that, if we say, here’s how Earth works, here’s how life and rocks co-evolve, then we see... And we super-impose on that what humans are doing, and it becomes much more dramatic. It’s just a tiny piece of a very big challenge to the scientific and the social fabric of our world, but that’s what I feel I can do.
Jed: That is wonderful. We’re glad you’re doing it. You’re bringing that mineralogist perspective. And in terms of life on other planets, you have said that you really wouldn’t even be studying the origin of life if you didn’t think that it’s happened on many different planets around the universe. Now, other people disagree with that and they say that you’re forgetting the anthropic principle, which is that, yeah, usually when you see only one thing occurring, you should suspect that your data is wrong or that there’s something that you’re not understanding, ’cause it should occur many times, things don’t just happen once, usually, you know? In fact, we just interviewed Dame Bell Burnell, who is the discoverer of pulsars, Jocelyn, and she had to find at least two pulsars before her advisor would allow her to publish it, because he knew that people wouldn’t believe it unless they found two.
So she went on to discover many of them, but isn’t that sort of the case with the Earth is that sort of our feelings that nobody should believe that there’s life on Earth unless there’s life on other planets as well? And yet there’s that anthropic principle that says, Well, if you take off your blindfold after being on a firing line with a whole bunch of other people and you’re the only one standing, well, good for you, but that’s just because everybody else can’t take their blindfold off, they’ve already been shot. I don’t know if you’ve heard this analogy, but...
Jed: We are the only world that could observe the rest of the universe, so maybe we are the only one. So, what do you think about all that?
Robert: So, when you look at the natural world, I think there’s sort of three cases, there’s three possibilities. One is zero. Something is impossible, it simply doesn’t happen. Well, in terms of life, we know that’s not true, because we have one example of a living world, so there is one. And then there are some things in our understanding of the cosmos that are unique, the origin and the Big Bang, that’s a singularity. It’s a one-off thing. Now, some people postulate that there’s a multiverse, that big bangs are happening all the time, but we have no way of measuring or seeing or knowing or have any connection to that. So as far as we’re concerned in our universe, the Big Bang happened once, it’s a singularity. So zero, one, or many.
If something happened once, okay, that’s a singularity. If it happened more than once, it’s going to be everywhere, because the [0:06:14.6] ____ richness of the cosmos is just beyond our imagining, so that’s basically the ground in which I’ve staked my career, that the origin of life is something that happens relatively easily on an Earth-like planet, Earth-like planets are huge, so the number of places there are to do chemical experiments are vast beyond imagining, and you try those chemical experiments over spans of hundreds of millions of years.
…and if you have countless billions of Earth-like planets, everyone's warm and wet sundae that has the same kinds of minerals and chemical richness, then under that scenario, life is everywhere.” – Dr. Robert Hazen
I did a quick back-of-the-envelope calculation just on typical chemical experiments or chemical reactions that might have occurred on surfaces and on an Earth-like planet given a few hundred million years, 10 to the 54th experiments, which is more than even a very active and capable graduate student can do, 10 to 54. So the fact is, you may have an extremely improbable reaction, it only occurs once in every 10 to the 50th times, but with this back-of-the-envelope calculation, you’d say that that still means there’s 10,000 origins of life on Earth, and if you have countless billions of Earth-like planets, everyone’s warm and wet sundae that has the same kinds of minerals and chemical richness, then under that scenario, life is everywhere.
Jed: Yeah, well, I think that the people who think life only happened once do then tap into the multiverse and say that universes are being put into existence all the time with their own big bangs or whatnot, and therefore we are in the universe that just happened to have a life-producing event, and we are the person on the firing squad line that didn’t get shot, everybody else did, we take off our blindfold and we see that we’re still standing, so they obviously have a different philosophical view that you. I’m not saying they’re right, I don’t...
Robert: Oh, but, Jed, there’s a difference, there’s a difference, because we live in a universe where we can actually see those stars, we can see those planets, we can measure them, we may potentially be able to visit them, we can build big telescopes and analyze their atmospheres, perhaps see surface features. We are going to be able to make measurements and observations, this is not some idle speculation about whether or not there’s multiverses which are made, that means... I wonder if...
Jed: I agree. I think you and I agree about multi-universes.
Robert: In this case we are going to be able to... We’re going to be able to make observations, we may find a different life form on Mars. We have a new rover there now, Perseverance is now on Mars, it’s going to be collecting samples, those samples are going to be flown back to Earth by 2030. We may find, who knows, it’s possible that there’s a microbial ecosystem on Mars that differs from that on Earth, in which case that would be a profound discovery, perhaps the most profound, because if Earth and Mars both have an origin of life that are different, wow. Then life is everywhere, it’s as inevitable as basalt or granite, as oceans of water, it’s just something that happens because of the nature of the cosmos and chemistry.
Jed: And since you’re in this field, I know you’ve seen the numbers that people throw around, Eugene Koonin and people like that, that invoke the multi-universe for the origin of life. I don’t know if you saw his paper from maybe 15 years ago, but you know, I agree. Invoking the multi-universe seems like a bad idea. I think you and I agree on that, but they’re throwing around numbers that are way above 10 to the 54th, even though that seems so huge, they’re throwing around 10 to the 150th. So that, even if you take all of the planets and all the wet worlds and even the dry worlds, it just doesn’t even come close to that 10 to the 50th, 150th number.
Robert: It’s more than all the electrons in the cosmos.
Jed: Exactly, it’s more than... Yeah, so basically, it really comes down to a question of probability and of how much we think we know about what life has to be like, carbon-based and water-based and all this stuff. So what would you say to somebody, maybe like Eugene who says, You know, it’s just so rare that we need to invoke the multi-universe, what would you say about the rareness of that? Is it 10 to the 150th? Is it more, or is it closer to 10 to the 54th?
Robert: We really don’t have any empirical data on which to go, other than the fact that life arose on Earth and it’s very robust, it’s one of many emergent phenomena we see in the cosmos, and we see emergent phenomena over and over and over and over again. It’s just a pattern, it’s this idea of complexification as many interacting objects come together and new phenomena emerge and life just fits that pattern. And to me, I just don’t see why you think it was so rare, what is the observational basis for that? We haven’t observed very many planets or moons at this point, we haven’t, even the most likely neighbor that could be alive, Mars, we haven’t even penetrated its sub-surface in a way that would allow us to determine whether there is life or not.
So it seems to me that people sometimes talk very loudly about philosophical things that cannot be resolved, but in science, what we do is we wait for the observations. My observation would say that the only other way that we can demonstrate life is common in the cosmos is to come up with a laboratory way of synthesizing it that just uses normal chemicals under normal geological conditions. If you can somehow come up with a self-replicating system, then, then life just forms. No one’s done that yet, but there’s been astonishing progress towards really interesting chemical systems that do things like replicate themselves or that can over time mutate and change form or develop all kinds of interesting three-dimensional patterning, not life, not life, but still chemistry doing extremely complicated emergent steps which add levels of complexity.
And if you have a planet like Earth, which has hundreds of millions of years and an awful lot of surface area to work with, it strikes me that we really don’t know enough yet to have to resort to multiverses or galaxies far, far away. I think our galaxy is probably very sufficient to produce multiple living worlds.
Jed: Well said. Well, I do remember Norman Pace, who was at Berkeley when I was there, saying that in order to get the first self-replicating system, you can’t just have a reaction, you have to have upwards of a thousand working genes, in other words, a thousand working molecular machines, to get that going, and to me, that just seemed to preclude the origin of life, but he believed in a naturalistic origin of life, and he said he had faith that some day we would figure it all out. That’s exactly what he told me.
Robert: Okay. Norman Pace is a really smart guy and far be it from me to disagree with what he said, but he is a molecular biologist, and one of the things you find is people who are in molecular biology think that all life is based on DNA and RNA, and it has to have this complex protein mechanism to interpret and translate and have ribosomes and all this sort of thing. So yes, he’s absolutely right, if you’re talking about a modern kind of cell, you need thousands of reactions and it’s just inconceivable, but I imagine much, much simpler metabolic forms, for example, you have an energy-rich surface of a mineral and molecules form on it, and then they start using the energy of the surface in a way to just make copies and spread out across the surface.
It’s not a cell, it’s just a flat set of molecules that replicate. Then you hit a different kind of mineral and say, Oh, I need to get a different strategy now if I’m going to survive. And selection helps you find that strategy and then you start making more and more of these self-replicating chemical systems, and then some place long down the road from there, Norman Pace comes along, and he can think about genetic material and proteins and all that, because that just happens to be one of the mechanisms that makes the whole thing more efficient. But you have to start someplace, and I believe you can start much, much, much, much simpler than those thousands of reactions. I think it can be just a very simple set of surface chemistry that happens to be self-replicating because you’re templating yourself.
And life is still doing that today, evolution is still going along, we still have viruses that challenge us and then we challenge the viruses, we do things like invent vaccines, that's part of biological evolution, that just keeps getting more and more and more…” – Dr. Robert Hazen
And natural selection is amazing. Basically, you select for things that work and you reject things that don’t, and if you have a system that can mutate rapidly and try lots of different possibilities, once in a while you hit on something, this works a lot better, I’m going to keep it, and then it works a lot better, and then it works a lot better, and then you have the organic molecules that participate in that efficient self-replicating, they win, and they keep winning and they keep figuring out ways to make process. And life is still doing that today, evolution is still going along, we still have viruses that challenge us and then we challenge the viruses, we do things like invent vaccines, that’s part of biological evolution, that just keeps getting more and more and more...
I mean, if you said, Well, I can’t imagine another worlds living because how in the world are they going to invent vaccines, you know] But vaccines only came after millions, hundreds of millions of years, billions of years before that of other evolution in this arms race that is the living world.
Jed: Well, this is fascinating. And do you welcome it when new people join in, in the fun of trying to figure out origin of life? We just interviewed a guy who used to work with Rick Smalley, the winner of the Nobel Prize down at Rice University, his name is Jim Tour, and he’s just sort of burst into this origin of life field coming from nano technology and thousands of papers and patents, and now he’s in the thick of it, so I don’t know. Do you like it when somebody new comes in, or does it shakes things up?
…we started asking questions in new ways, and now some of the things that we started asking and addressing 25 years ago are mainstream in the field, they're just sort of accepted ideas, and other people are going to come along and they're going to have new ideas and new insights, and so that's just fundamentally… it's critical.” – Dr. Robert Hazen
Robert: Oh, Jed, I love it. I think that’s what keeps it dynamic, especially early career people who come with totally fresh ideas and they ask those naive questions. Well, I think that’s what I was. Look, I wasn’t born an origin of life researcher, and in fact, I was well into my 40s when I first started even asking questions as a mineralogist, totally naive questions. You know, what’s this mineralogist doing talking about... We’re talking about the origin of life here, and he’s talking about rocks. What does that... But we started asking questions in new ways, and now some of the things that we started asking and addressing 25 years ago are mainstream in the field, they’re just sort of accepted ideas, and other people are going to come along and they’re going to have new ideas and new insights, and so that’s just fundamentally… it’s critical.
You need people who are open-minded and listen and discuss and learn, and that way the field moves forward.” – Dr. Robert Hazen
It’s so important to the field to bring in new ideas and new... It’s still true, nobody gets a PhD in origin of life, they get a PhD in something else, and then they come to the field and bring their own insights and hopefully they read widely, they listen to other people, they keep an open mind. The worst thing that can happen, and I’ve seen it happen any number of times, is people fall in love with their own theory and just basically decide that’s gotta be true. It began with Stanley Miller , and it sets the field back in profound ways. You need people who are open-minded and listen and discuss and learn, and that way the field moves forward.
Jed: Very good, thank you so much, Dr. Hazen. The next time we can talk about what Stanley Miller got wrong in his epic experiments. But that’s enough for today, and thank you so much for joining us.
Robert: Oh, I really enjoyed it, Jed, thanks so much, this has been great.
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