Well, it's safe to say 2025 is off to an interesting start. I'll say. And if you're trying to sort through what's real and what's relevant, from a Canadian perspective, we're here for you. Your World Tonight is more than just a recap of daily news. Our team goes deeper on the stories that speak to the moment to give you the full picture. I'm Susan Bonner. I'm Tom Harrington. And I'm Stephanie Skanderas. Together, we bring you the day's news, context, and analysis, all in about 25 minutes.
Your World Tonight from CBC News. Find and follow us wherever you get your podcasts. This is a CBC Podcast. Hi, I'm Bob McDonald. Welcome to Quirks and Quarks and our annual holiday science book show. Just in time for your holiday reading or gift giving, we've got interviews and reviews of some of the season's most satisfying science reads.
like the story of archaeological treasures emerging from the planets melting ice. And so archaeologists are sort of in a race against time because there are probably a dozen ice patch archaeologists in the world, and there are hundreds of thousands of ice patches that have the potential to have this human record entombed within them. And a physicist considers just what alien life might actually look like.
Could we actually understand life more broadly that we would be able to recognize life as it emerges on other planets, even if it looks very different than here? Plus, the pluses and minuses of human suggestibility and science writer Dan Falk with some of his favorite books of 2024. All this today on the Quirks and Quarks Holiday Book Show.
In the year 1991, a group of hikers stumbled upon a corpse in the mountains on the border between Italy and Austria. That was strange, but even more unusual was that this was the body, in a state of near-perfect preservation, of a man who had died 5,000 years ago. It was a glacier mummy that had been locked up in an ice sheet, frozen in time, and was soon dubbed Otsi, the Iceman.
But it turns out, Uzi was just the beginning. As our climate warms, the Earth's ice is melting. And in the decades since Uzi's discovery, thousands of artifacts have been popping up around the world after being released from glaciers and ice sheets. This has all led to the development of a new field of scientific study called ice patch archaeology.
In a new book, ecologist Lisa Barill travels the world to understand what our melting ice is revealing about our past and what it also says about our future. Lisa Barill is a science communicator based out of Yellowstone National Park and the author of The Age of Melt, What Glaciers, Ice Mummies, and Ancient Artifacts Teach Us About Climate, Culture, and a Future Without Ice. Hello and welcome to Quirks and Quarks. Thank you for having me.
What made you want to look at the connection between humans and ice through time like this? You know, I am a wildlife biologist by training, and I've always been interested in the non-human critters that... live on earth and hiking around the mountains where I live in the Northern Rockies. But I'm also really interested in the human relationship to the environment. And so years ago, started about 10 years ago, I read a short article by a local archaeologist who had found
a piece of an ancient hunting weapon called an atlatl which is also known as a throwing spear it predates the bow and arrow and it was found in the mountains near where i live and it turned out to be 10 300 years old and i was just amazed that something so old could be preserved for so long in the mountain so close by to where i i
hike every summer. That's amazing. Well, your book reads like a detective story where you talk about an artifact like that is found and then it's, okay, how did it get there? Who owned it? What went on here? Was that intentional in your book? It was intentional because I wanted to write it as though I was in the process of discovery. Of course, you know how I discovered it. So I did a ton of research and talked with
hundreds of archaeologists and climate scientists. And every piece of the puzzle was just a new and interesting part of the story that I felt like, you know, was kind of a mystery to include. And so, yes, that was very intentional to write it as a detective story. Well, how did ice patch archaeology even come to exist as a field of research? That's such a great question. So ice patch archaeology is the study of these...
artifacts that are melting out of patches of snow and ice that are typically perennial. They exist year round, year in and year out in mountain ranges around the world. And it wasn't until those hikers that you mentioned stumbled upon Utsi, the 5,300 year old mummy in the Utsal Alps of Italy and Austria.
The archaeologists wondered, hey, what else might be melting out of these mountain ranges? What else might be encapsulated or entombed in these ice patches? If it can preserve a mummy for 5,300 years, what else might be in there? And so it kind of was the inspiration for archaeologists to climb mountain ranges around the world and survey some of these ice patches to see what else might be melting out of them.
This is a discipline that has come about entirely because of our warming climate. If the ice isn't melting, archaeologists aren't going to find artifacts. How is climate change affecting this whole process?
Right. These objects make their way into the ice because, well, often a lot of hunters would be attracted to these ice patches for the animals that were attracted to these ice patches, and they would use them as hunting areas. And so a lot of the artifacts that are found in these ice patches have to do with hunting. And so these artifacts become embedded in the ice. And as time goes by and more ice accumulates on these ice patches,
are sort of preserved in time. But as our climate has started to warm, these ice patches are melting back and these objects that have made their way into the ice are now spilling out onto the ground. Now, you also mentioned in the book that there's a time factor involved in this, that as these artifacts are exposed, they're also exposed to the elements and they may not last very long.
Yeah, that's right. So one of the most interesting things about ice patch archaeology is that most of the objects contained within the ice are organic. And so in typical archaeology, most archaeologists are finding things made out of stone or bone, things that don't decay over time or that really hold up very well over many thousands of years.
What's unique about ice patch archaeology is that many of the objects that are found in these ice patches are organic and they belong to once living things like bird feathers, leather shoes and grass capes and arrows made of wood. And so these objects are really ephemeral. They decay over time if they're left exposed to the...
air and sunlight and wind, especially in harsh mountain environments. And so the ice and snow has kept them in a suspended state of animation for hundreds and sometimes thousands of years. But once they are exposed to the elements, they decay very quickly. And so archaeologists are sort of in a race against time.
because there are probably a dozen ice patch archaeologists in the world, and there are hundreds of thousands of ice patches that have the potential to have this human record entombed within them. And if they don't go out every year to see what new objects have melted out, we're going to lose anything else that's contained within the ice. Well, take me through some of the artifacts that archaeologists have been finding, including this throwing spear that was near your house. What was that all about?
Yeah, such an interesting artifact. So this archaeologist, his name is Craig Lee, and he was just looking at these ice patches in the Absaroka Mountains.
And he wasn't even really trying to find an artifact. He was actually just milling about. And he happened upon this one particular ice patch. And there was a Doritos bag. And there were other objects that, you know, people had left behind really recently. And he looked over and he saw that there was this stick sticking straight out of the snow. And he thought it looked a bit unusual.
that this is something significant, an ancient hunting weapon, the lateral foreshaft. And it even had these markings on it that he thinks indicate ownership of the person who used this object to hunt with 10,000 years ago. And so that was just...
It's amazing to me that he could see so much in this one piece of wood that many of us might overlook and think, oh, it's just a stick. And I guess we can assume that 10,000 years ago, they were not eating Doritos. That's right. They were not eating Doritos 10,000 years ago. But the thing about an artifact like this is that this is a tool that someone used. I mean, it's a window into their lifestyle.
It is. Yeah. And what I find fascinating about this is that a lot of the animals that were hunted at ice patches came to these ice patches to cool off from hot summer weather. And remember that these.
are ice patches that are perennial, so they exist throughout the year. And hunters would go into the mountains during the summer months when the snowpack was at its lowest extent. They would find these patches of ice because animals were really attracted to them. They used them to escape biting insects. They used them to cool off during the hot summer months. And they probably even grazed around the edges as these ice patches melted and created a halo of green grass. And so hunters...
knew this, they used it to their advantage, and they would sneak up on these animals at these ice patches and hunt them with these ancient tools, which obviously were not ancient to them. They were the latest technology. Well, how are these artifacts, these well-preserved artifacts, filling in the story of human history? Yeah, you know...
Before archaeologists really began going into the mountains and looking at the edges of ice patches for artifacts, they didn't really see mountains as places of human habitation. Of course, that they knew people had been going into mountains for many thousands of years for hunting and plant gathering, but they really thought that it was more of a...
once in a while type of thing that people were actually living there, that they weren't really having this deep connection with the mountains themselves.
And ice patch archaeology turned that on its head where, you know, mountain environments are very harsh and there's not a lot of soil development. So in traditional archaeology, when you're digging in the dirt and surveying an area, looking for the layers of artifacts over time, you don't really get that in the mountains because there's not a lot of soil development. So archaeologists really didn't have a lot to go on. There just weren't a lot of objects melting out of the mountains, which led them.
to think that people weren't inhabiting these places. Ice patches, though, are preserving a lot of that record, that human record that otherwise was not preserved anywhere else in these mountain ranges. We think of traditional archaeology as digging up towns and where people lived and worked, but here you're talking about where they hunted, when they were not in the towns.
That's right. Yes. And these were maybe spike camps well away from villages. There's hunting blinds, stone hunting blinds built up in a lot of these areas near ice patches to facilitate the hunting that they were doing in these mountains. And yeah, most archaeology is at low elevations because that's where most of us live even today. But we're also...
We love to explore the mountains and not just for recreation, but also, you know, for sustenance over time. Now, you went to visit the site where Utsi the Iceman was found high up in the Alps to research this book. What was it like to be there?
It was amazing. So I hiked up from the Italian side and there is a trail that you take right up into a cabin. And I thought it was going to be a relatively easy jaunt up the mountain. I live in mountains. I hike mountains all the time. I do a lot of backpacking. But this was about a 5000 foot elevation gain in about four. And so it was really steep and very exhausting. And the next day I hiked over to the site where Utsi had died.
Being in that spot and looking out across these vast mountain ranges, snow covered peaks and glaciers spilling down the mountains, I was looking at a very similar landscape to the one that he would have looked at 5,300 years ago. There were no buildings. There were no signs of human development whatsoever. And I was just awestruck by how little really has changed in these mountains, but also how much has changed too in respect to.
the amount of snow that is no longer there. Did you feel like you could travel back in time and see the day that he died and that sequence of events? Yeah, I really tried to imagine myself what it was like to...
be Utsi traveling through these mountains. And I don't want to spoil it, but he was running for his life in these mountains and fleeing from someone who was chasing him. And so just having that experience, you know, I can't relate to that, thank God. But it was just really a special experience to try to picture myself in his shoes. What drew you to Utsi's story?
What drew me to his story is that he was a real person. We can think about him as a mummy, as this well-preserved corpse with all of this history and these unique objects that he was found with. But really what it comes down to is that this was a human being with the same thoughts, the same kinds of emotions, the same kinds of needs and wants as any of us living today.
you know, this lifestyle that we can only imagine from many thousands of years ago. And yet there's a lot of commonality between who he was and who we are today. Well, as our climate changes and more and more glaciers are melting away, what are we losing? Yeah, you know, we are losing a cultural record of our past, one that we only just realized existed only about 30 years ago.
And so we've only had this really short window where we've been able to see what our relationship is to not only these mountain environments, but to the ice and snow itself and to the animals that are attracted to this ice and snow. And if there is no more ice, there will be no more ice patch archaeology. And that is the direction that we are headed.
Currently, we are currently headed to a world without ice. And I just want readers to really think about what that means. You know, there's one aspect where we are going to lose a lot of our water sources because mountains are the water towers of the world. So there's going to be a lot of changes in terms of where we are able to get our water from. But also there's a lot of other cultural aspects that we associate with ice, like there will be no more sledding.
down hills in the winter. There will be no more ice skating and hot chocolate afterwards and building of snowmen. And I think those things, although they're not obviously as important as our water source, they are important to our humanity and to our relationship to the world. So what are you hoping people will take away from this book? What's your message?
Yeah, you know, what I'm hoping people take away is to gain a greater appreciation for how connected humanity is to the world around us, especially when it comes to climate. It affects so much of our history. It's affecting our present with more frequent and severe hurricanes as we've seen this season. And it will absolutely affect our future. Ms. Burrill, thank you so much for your time. Thank you for having me.
Lisa Barill is an ecologist and science communicator based out of Yellowstone National Park. She's also the author of The Age of Melt, What Glaciers, Ice Mummies, and Ancient Artifacts Teach Us About Climate, Culture, and a Future Without Ice. Well, it's become a holiday tradition for us to consult our friend Dan Falk for his suggestions for some great science reads. Dan is a Toronto-based science writer and host of The Book Lab Science Book Podcast.
Here's his first review today. There's no question that animals communicate. Whales can sing and monkeys use alarm calls, but only humans have full-blown symbolic language. So how did we get here? In The Language Puzzle, archaeologist Stephen Mithin draws on the latest research from linguistics, anthropology, psychology, and genetics, guiding the reader through more than a million years of hominin evolution.
Mithin looks at our closest primate cousins, the chimpanzees. Chimps can vocalize, but they don't use words like we do. And chimps don't appear to be able to think about what other chimps are thinking, a skill that human children develop by around age four. Given this limitation, chimps can't cooperate with one another the way humans do. And consider an even closer cousin than Neanderthals.
We shared parts of Europe and Asia with these hominins, and even interbred with them for tens of thousands of years. Yet, as Mithin points out, the Neanderthals never developed symbolic art and used the same kind of stone tools for millennia. Lack of linguistic ability may have been the main obstacle. Mithin suggests that, while Neanderthals could discuss the things they saw in front of them, they may have lacked the capacity for abstract thought.
There are lots of popular books on human origins, but The Language Puzzle, with its laser-like focus on the role of language in human evolution, offers a fresh perspective on the human story. Dan will be back later in the program with more science book recommendations. From the Los Angeles Times, this is Boiling Point. I'm Sammy Roth. I've been reporting on energy and climate change in California and across the American West for a decade.
I'll be asking scientists, politicians, activists, and journalists the same questions. What are the challenges we face to building a better world? And what are the solutions we need to embrace even when it's hard? Boiling Point will be available everywhere you listen to podcasts starting January 16. Okay, I'd like you to close your eyes. Sit quietly.
And just listen to my voice. Your body is feeling heavy. Let yourself sink into your chair. You're feeling relaxed, calm, peaceful. You may be feeling sleepy. Just let your breath flow in and out. Now, if what the movies show is correct, I should now be able to make you quack like a duck or flap your arms like a chicken. Well...
I couldn't. But maybe you'd think neuroscientist Dr. Amir Raz could. Dr. Raz studies and occasionally practices hypnosis. It's part of his study of psychological suggestibility, a subject he first became interested in as an amateur magician and stage performer long before his academic career.
Well, now he's written a new book about his work called The Suggestible Brain, The Science and Magic of How We Make Up Our Minds. Dr. Raz taught and practiced for many years at McGill University and is the founding director of the Brain Institute at Chapman University in Orange, California. Dr. Raz, welcome to Quirks and Quarks. Thank you very much for having me. It's great to be here. Now, you've written an entire book about it, so this may not be the simplest question to answer briefly, but...
From a psychologist's point of view, what is suggestibility? Suggestibility, even if we are not trying to philosophize about it too much, intuitively is a form of communication that brings about a belief or thought without explicit imposition or command, even without awareness sometimes, making it impossible for the person to oppose or feel the need to do so.
Well, tell me how suggestibility led you from being a teenage magician to being a neuroscientist. I very quickly came upon fellow magicians, very young fellow magicians who were doing hypnosis shows. And I was struck by the fact that they really, it was very obvious to me, as it was obvious to them, that they knew very little about hypnosis, if anything, actually.
They usually would buy some kind of a booklet, a 12-page booklet from the brick-and-mortar magic shop that we had in the neighborhood, and they would learn some patter by heart. And then they would take center stage, and with their charisma, with their stage persona, they would just hypnotize people. And I was shocked by the fact that you can do that without having any formal hypnosis training or even psychology degree. So how did you take it from there?
I started asking questions and I started asking questions about what is the process like and what is happening, including what is happening at the physiological level. People were doing some dramatic things. The behaviors were quite stunning. And I started looking more into the scientific literature. And sure enough, I was already getting on my way to study psychology and human behavior and neuroscience.
You write a lot about the connection between suggestibility and hypnotizability. What's that connection? So hypnosis is really interesting, and that was my gateway into this world. But hypnotic suggestion and the whole reason or the whole notion of hypnotic susceptibility is not necessarily what we think about as our everyday suggestibility.
hypnotically suggestible. It refers to a very specific kind of suggestibility that we have. And some people are very good with it, some people not so good. But there are many other flavors of suggestibility that people have. And one person might be more suggestible on Thursday, less suggestible on Monday. It's something that also changes dynamically with time and also with age.
Well, in some minds, it might feel like suggestibility is a bad thing, like it's a weakness in my character. I'm not like that. I'm not going to let you have power over me. That's right. I think that our natural tendency is to think of ourselves as autonomous agents, and we would like to think that everything that we do is because of us and our decision-making is completely independent of the world, and we're doing things that are very much our will, and we have free will.
the sensation that we have. But we can demonstrate that, especially for people who are extremely suggestible, you can sometimes create situations and contexts where you give people a suggestion and they will do things that later they will attribute to themselves. So they sort of have a post hoc ascription. They sort of think, they look back at it and they explain to themselves why they did it, not for the reason, not because you told them to do so or you...
suggested something to them but because they felt that this was the right thing to do on their own well let's move beyond the magician's performance to medicine one of the big themes in your book is the real power of suggestibility for mental health and medicine take me through some examples of that
Yeah, so in medicine and particularly in mental health, which is a very large part of what we are experiencing today, you know, in the post-corona world and also with the world that is very much tied to technology with screens and with fake news and all kinds of things that are going on in that domain, we have a lot of mental health issues that are...
probably more pointed than they were before. And it turns out that some of the, you know, I would say backbone drugs that we're using in psychiatry, for example, if it's antidepressants and other drugs are sometimes less.
potent, less effective than we initially thought about them or what we actually expected them to do based on promises that were represented to us by the medical community or by the pharmaceutical community. And we are beginning to see that there's a lot of expectation effects and a lot of expectancy responses in humans who are responding to all kinds of situations such as depression, anxiety, and so on. Well, give me an example of how suggestibility could be used to treat anxiety.
So first of all, I want to just make very clear that I'm not proposing or suggesting that people should drop their medications. That would be very unprofessional and dangerous. What I'm suggesting is that the power of suggestion can be extremely powerful and sometimes as powerful as some of the medications that we sometimes take and the doctors sometimes prescribe for us. In the case of depression, there's a lot of research showing...
that when we look at clinical significance, we see that really for some drugs that are often used, there is no real difference clinically between using the drug or using something that would be a placebo, something that does not have the active ingredients. When we recognize something like that, it doesn't mean that the drug doesn't work. It just means that it works as effectively clinically as.
a placebo, a non-drug. When we recognize something like that, we know that there's a lot of room for things like hope and therapy and things that we call non-specific parameters to help the patient. Now, you point out in your book that this goes beyond what we think is mental issues. It extends to things like eyesight or vaccine side effects.
When we are talking about expectation effects, we need to understand that sometimes what we are experiencing, if it's side effects from vaccinations, if it's even headaches or even skin rashes and things like that. could be sometimes a result of psychological states or how we in neuroscience like to call it, in cognitive neuroscience, brain states. The same is true for our ability to even shape our sensation and perception. So yes, you can actually interfere or enhance.
sometimes reduce and diminish your ability to perceive certain things. It could be eyesight. It could also be taste. I can, for example, by telling you a good story and creating the right context, change your perception of taste. Well, this leads naturally to a rich thicket of ethical complexities here. For one thing, there's the double-edged sword of your health or mental state being, it's all in your mind. Tell me about that.
Yeah, I mean, I think that this idea of it's all in your mind used to be historically something that would be a way to dismiss what people are saying. So, you know, if we said, oh, this is all in your mind, it basically was a euphemism for saying you're making it up or it didn't exist or it doesn't exist or whatever you're feeling is not real. That's the euphemism, at least historically.
What we are saying, particularly with our ability today to do things like imaging of the living human brain and with our understanding of certain psychiatric conditions much better than we did 50 years ago or 100 years ago.
Today, it's all in your mind is not the same euphemism. Today, it's all in your mind is true because we live in our minds. We really do. We live in our minds and we sort of think things to ourselves. And sometimes what we say is not exactly what we think and what we feel is not exactly what we say. And this creates a very interesting and complex interaction.
Most people today, if I told them that I could put some kind of a small screen on their forehead that they couldn't see, but other people could see when they look at them, and this screen would display what they're really thinking, that would change their thinking. It would force them to change their thinking because they wouldn't want to be transparent. They wouldn't want other people to see what's going on in their...
inner brain, in their inner mind. And that's really interesting because we're getting with all kinds of brain imaging technologies and all kinds of electroencephalography, fancy technology that we have in the neuro labs, we're getting to a point where we're beginning to, we're on the cusp of beginning to identify some processes, cognitive processes, and we can sometimes tell things are happening even before they actually happen. So we're getting sort of edging closer, itching into the field.
of sort of mind reading technologically. We're still far away, but it's all in the mind. Well, then there's the ethics of misleading people with treatments like various versions of placebos where you give them a pill but don't tell them that it's a non-drug. Tell me about some of that. Yeah, the ethics of deception is very, very tenuous. We have to be very, very careful in order to come up with procedures that are on the one hand ethical and on the other hand judicious.
We used to think, for example, that giving people placebos automatically meant that we have to deceive them. We had to tell them this is actually a very strong drug and it's coming from Switzerland or something like that, and they would have to pay a lot of money for it. Only then would the placebo work. But we have discovered, again, through experimentation and through all kinds of interesting, I would say, paradigms, that even giving people open-label placebos, in other words, you give them a placebo and you say, this is a placebo.
But we think it's going to help you. And here's why. People get better. People can get better when they report suffering from lower back pain, from migraines, and so on. There's a long list of things. Even when you give people...
placebos and you tell them openly that it's a placebo, it can work. This shows us that deception perhaps is not necessary always, but there's something about taking a pill. There's something about playing with the expectation. There's something about enhancing the, I would say, non-specific parameters that we can play with in order to guide, tailor, I would say, even mold the response that we can get from patients.
On a certain level, what you're saying about our suggestibility is kind of depressing. I mean, we like to hope that we're rational, you know, we make reality-based decisions about things like health or politics. But you're arguing that suggestibility makes us vulnerable to truthiness, a new term we have about persuasive-sounding arguments. Yeah, well, you know...
I guess what I'm trying to say here is not so much that it's just about truthiness, although that's definitely something worth thinking about. But I'm trying to say that everyone really is highly susceptible to some form of suggestion.
This is not something that we're trained to think about, and it's not something that we usually acknowledge. But even without realizing it, suggestions can shape our perceptions, our behaviors, even our physiological experiences in very profound ways. Subtle cues, expectations, beliefs can dramatically influence our decisions, our physical sensations, our emotional states, whether in everyday life or in clinical settings. And I think that that's something that people are...
beginning to understand more and more definitely in the scientific realm, in the medical realm, but also patients and lay people are beginning to understand that expectations are very powerful. So what's some concrete advice you have to maybe defend ourselves against problematic suggestibility or maybe even take advantage of it?
I mean, when it comes to defending ourselves, it depends on the particular context. Suggestibility is not a sign of weakness. It's a complex and deeply rooted aspect of the human mind, and we can leverage it to our advantage, not just for mental health and performance sports, but to self-regulation and resilience training. Even critical thinkers are suggestible. Even intelligent people are suggestible. There is no panacea. The only way...
to deal with suggestibility when it comes to false information is digital literacy and following the rules of critical thinking. Just one last thing. Do you still do magic? I do. I do magic, you know, in social situations. And there's always the question when I go to a scientific conference if I'm the best magician among the scientists or the best scientist among the magicians, and I'm not sure that I can know how to answer that.
Dr. Raz, thank you so much for the book and thanks for your time. My pleasure. Thanks for the questions and thanks for the interview. Dr. Amir Raz is a neuroscientist and the author of The Suggestible Brain, The Science and Magic of How We Make Up Our Minds. I'm Bob McDonald and you're listening to the Quirks and Quarks Holiday Book Show. Now here's another review from science writer and bibliophile Dan Falk.
A western lowland gorilla named Charles was one of the most beloved animals at the Toronto Zoo. When Charles died earlier this year, people mourned for him. But what did his fellow gorillas think? They must have noticed his absence, but did they understand that he was gone for good, that he could never come back to life?
These are the kinds of questions that philosopher Susanna Monso tackles in her book, Playing Possum, How Animals Understand Death, a fascinating book that invites the reader to think about death from the point of view of the creatures we share the planet with. Monso shows us that there's no one conception of death that all animals share. Instead, death seems to spark a tremendous variety of reactions across the animal world.
Ants, for example, will remove a dead ant from their nest, but they appear to be merely responding to chemicals emitted by the corpse. The removal happens on autopilot, so to speak. In contrast, chimpanzees have been observed lingering near the body of a dead chimp, inspecting it with great interest, especially those that had been close to the deceased animal. Other chimps would react aggressively, giving alarm calls or even attacking the chimps' remains.
Monceau suspects there may be some aspects of understanding death that are uniquely human, and yet we're far from being the only creatures that have some awareness of life's fragility. The concept of death, Monceau argues, is likely to be more widespread in the animal kingdom than we usually imagine. Playing Possum is one of those rare non-fiction books that had me wondering, why didn't anyone write this book before now? Dan will be back with one more review at the end of the show.
Have you ever contemplated what it means to be alive? I mean, I think we'd know it if we saw it. I'm alive. So are you. So is the tree outside my window, the shrubs below it, and the bacteria in the soil below that. But would we recognize life if we saw it elsewhere in our universe?
If that place has different chemistry than we do on Earth, life could look very different than it does on our planet. Arizona State University theoretical physicist, astrobiologist, and author Dr. Sarah Walker argues that if we ever want to answer the big question of, are we alone in this universe, we need a fundamental rethink of how life came to be right here on Earth.
In her new book, Life as No One Knows It, The Physics of Life's Emergence, Dr. Walker introduces a new theory that may help us better identify potential alien life off our planet and get a better idea of how it took root on our planet. Hello and welcome to Quirks and Quarks. Thank you so much for having me. I'm delighted to be here. First of all, what do you think is wrong with the way we've been searching for life elsewhere in our solar system and in the universe?
I think it's very anthropocentric. So it's very focused on life as we understand it on Earth. And if we're thinking about life, what we've been doing so far is going to other planets and expecting to find the same exact evolved structures as we find on Earth. And these are things that are highly evolved.
molecules, for example, like DNA. You know, DNA is a very, very complex structure. It might be a molecule, but nonetheless, it's incredibly complex and probably the result of a lot of progressive stages of evolution. And it might be very unlikely that such a structure would emerge on another planet. But the challenge is, could we actually understand life more broadly than the particular
things that we observe as being manifestations of quote-unquote life on Earth, that we would be able to recognize life as it emerges on other planets, even if it looks very different than here. So anticipating what aliens could be like is actually quite hard. Well, what we hear from spacecraft that go to other planets or moons, they say, oh, we found a molecule like methane that can only be made by life. There could be life there. What's your problem with that?
So I personally would not assign much stock to a simple molecule like methane being a biosignature because molecules that are fairly simple can be produced abiotically. So a lot of these things that we hear reported in the news, like a sign of life, oxygen detected potentially in an exoplanet, that hasn't happened yet, but other gases, and methane, you know, on Mars.
they're not strong enough evidence to really say that life is there because we can't rule out the possibility of what are called false positives or these non-biological scenarios that could produce the same signal. I talked to one scientist looking for life in the universe. He said there are the pro-lifers and then there are the chemists. Actually, that's a fair assessment. I can see where they were coming from.
Well, in your book, you propose an idea called assembly theory that you say can help us get to the bottom of these questions. So tell me about this theory. Yeah, so the theory was actually originally developed by my colleague Lee Cronin at the University of Glasgow. And he runs a very large experimental lab. But he also thinks very deeply about the problems of original life and how we can detect life because he's trying to build experiments to...
solve the origin of life. And so the theory that we've been working on together has evolved to be one about the nature of how complexity gets built up over time in what we call life. So fundamentally, I think about life as how information structures matter across space and time. There are some things that exist on this planet that simply can't exist anywhere else in the universe. Things like you and I that require 4 billion years of evolution.
to construct something like us. We're very improbable objects outside of such a process, but our planet seems to be able to produce humans pretty readily because all of that evolutionary infrastructure exists now in the modern biosphere to produce things like us. And so what we try to do with assembly theory is formalize this kind of intuition that many of us have about the nature of complexity and how it's related to the phenomena of life in a way that we can go into the chemistry lab
without knowing anything about the molecules, how complex they are, and whether this is indicative that they must be the product of evolution and some kind of information processing system. When you say complexity, what do you mean by that? So there are a lot of different ways that people think about complexity, but I mean it in a very precise sense that there are some objects that simply could not exist unless there was...
sort of set of constraints to make that structure. So DNA is a good example that I already brought up. So DNA is the genetic material inside living cells. All of us have genomes that, you know, have been evolving, you know, for billions of years and encode information, you know, like that specifies our development and that we're human and not a chimpanzee. And so...
The structure of assembly theory, like what we're trying to do in terms of formalizing complexity is to say that to get to something like a molecule like DNA actually requires a lot of constraints in the possible kinds of things that could have been built that aren't DNA. Like in chemistry, it's actually quite...
hard to think about how many possible molecules there are because we've got, you know, like over a hundred elements and they can combine in all kinds of ways. And every time that you put a bond onto a molecule, you're moving into like a space of possible configurations that grows larger and larger. So sometimes I like to use Lego as an analogy. So instead of thinking about DNA, we could think about like a Lego Hogwarts castle.
And if you imagine smashing the molecule or smashing Lego Hogwarts into the building blocks. So for DNA, it would just be the atoms. And for Lego Hogwarts, it would be the Lego building blocks. And then you want to figure out how many steps would it possibly take for me to make that structure again if I could follow the shortest possible route. And we have a few physical principles that we put into this. One is you can only use parts that you've made in the past. So there has to be a memory in the system. And so if you're taking two legs.
blocks together, you can reuse the part you've made, but you can't use something that you haven't made to try to make Lego Hogwarts. And so that minimum set of steps where you reuse parts to get to the final object is what we qualify as the complexity. So I think about it as a minimum causal depth or like sort of a minimum amount of time to produce the object.
Oh, I see. So you're saying something like DNA, which is incredibly complex, can't appear just by itself. It took a series of steps to get to DNA.
Yeah, so if we go back to the experiment where we smashed DNA and we smashed Lego Hogwarts all the way down in their building blocks, and now we don't have any kind of evolved structure like us that knows what Lego Hogwarts is or knows what DNA is, and we just start like shaking a tray full of these molecules or shaking a tray full of Lego, you know, we don't have any expectation that those objects are going to spontaneously form. If you just did naive statistical estimates, it would be probably billions of lifetimes of the universe before you would expect.
to get Lego Hogwarts spontaneously forming out of that. So what we actually observe in nature is the successive refinement and evolution of structures building on past structures. And that's really what we're trying to formalize. But the minimal route is important for reasons of measurement and objectivity of the way that we're talking about this approach. So how many steps have you found an object has to have in order to make it classified as life?
Yeah, this is a great question. So one of the reasons I am really excited about this approach to complexity is because we can test it in the laboratory. And so this is what Lee and his lab were doing when I started working with them is they were trying to develop an idea of going in the lab and measuring whether a molecule was necessarily the product of an evolutionary process and was necessarily indicative that life existed in that system. And so what they did is they're able to take this idea.
idea of measuring the minimum number of steps and map it to a standard measuring equipment in the chemistry lab. And so this particular set of experiments that they first did this with, they were using something called a mass spec. And they used the mass spectrometer to...
analyzed a bunch of non-living and living samples. And what they found is living things were the only ones that had produced molecules above 15 steps. So it seems to be that 15 is the boundary in the aqueous covalent chemistry of Earth that might be indicative of this kind of threshold where there's a minimum complexity above which we only expect to see living things produce those structures. And that's sort of the key conjecture of the theory is that
The universe, in the absence of life, has a upper bound on the complexity it can generate. But in the presence of life, there isn't an upper bound. And the complexity can keep increasing. Okay. So if something took less than 15 steps to put together, it's chemistry. And if it's more than 15 steps, it could be made by life. That's correct. And this is one of the ways that we avoid false positives. So if you're above the threshold value, then...
You can be very confident that the signal that you're looking at is produced by life. So could we develop then a kind of life meter to detect life, even if we don't know what that life will look like, that we could put on a robot spacecraft to say, well, how many steps did it take to make that?
Yes, this is exactly the goal. It's a formal approach backed by a pretty rigorous theory that we think is quite explanatory that maps to a measurement system that you can do in the lab and can be extended to mission science. And you would be able to go and measure a sample and say, you know, this one is almost alive but not, but this one is definitely, you know, past the signature that we would expect is above the threshold for life detection.
in a real sense, developing this idea of a life meter into a formalized approach that is scientifically tractable. You mentioned how selection plays a part in increasing complexity in the molecules that can exist. How does that selection occur before life and evolution as we know it begins?
Yeah, so I mean, this is the key question. I think for a long time, you know, a lot of people think that evolution is really unique to life or selection is really unique to life. And part of the conjecture of assembly theory is that the mechanism of selection actually has to operate before the thing that we observe is life. And in chemistry, it's pretty obvious that...
there are a lot of mechanisms of selection. Like you have molecular recognition, catalysts can speed up some reactions over others. And so really what we're looking for in the original life is if you do sort of unconstrained prebiotic chemistry experiments or you look at samples from meteorites. So the Miller-Urey experiment is a very famous original life experiment. It basically is famous for making amino acids. But if you let it run too long, it produces an undifferentiated tar, which is kind of like a black goo of all kinds of organic compounds.
you can't distinguish all of them. And this is also what we see in meteorites. They have a lot of organic molecules. They can produce amino acids, but because there's not any selective constraints on which molecules are produced and the space of possible molecules is so large, it's exponentially large. If you think of all possible structures you could make out of, you know, the same building blocks as Lego Hogwarts, you know, you can't even actually iterate over all possible configurations of those Legos.
think if you have a whole bunch of atoms in a meteoritic sample and they're just totally unconstrained to make whatever structure, you're just going to get a combinatorial mess. What we see in the emergence of life is that we don't get a combinatorial mess of all possible simple chemical structures. We see...
directed processes that template and scaffold to make more complex molecules along specific lineages or reaction pathways that build into higher complexity. And so that's really the transition that we're looking for, even before we would identify life, is to look for selectivity that leads to constraints in these combinatorial chemistries. And we know of a lot of them from the prebiotic chemistry literature, like if you add a mineral, it will exclude some classes of reactions and favor others.
So there seems to have been a succession of selective steps that became increasingly refined in the transition from geochemistry into biochemistry. How much of a paradigm shift is your assembly theory from the way we've been approaching these questions about the origin of life? I think it's a pretty radical departure for a number of reasons. One of them is that traditional approaches to the origin of life have been very definitionally.
So this idea of metabolism versus genetics comes from people that think life is about self-organizing chemical cycles or life is about replication and heredity. So you pick your definition of life. It informs your hypotheses about what chemical system you're going to go in the lab and engineer and say is prebiotic and then, you know, make claims about original life processes.
Assembly theory and the approach we're taking is much more agnostic to the kinds of chemistry that might have been implicated in the original life and is also much more rigorous in...
formalizing a boundary between non-life and life by saying that there's a threshold in complexity where we could definitively say it's life. And so the other thing I think assembly theory allows us to do is to start talking about the formal sets of selective constraints to build particular chemistry, which allows us to remove ourselves from the experiments and ask questions about how chemistry can do this on a planetary environment.
without us imposing our ideas of what life is ahead of time or how it should evolve. And I'm hoping this opens the possibility of discovering other kinds of chemical life that we can't even anticipate yet.
Have you had discussions with the people at NASA who are designing robots to go, say, to the moon of Jupiter, Europa, which is believed to have an ocean under its icy crust and maybe life down there, or Enceladus, a moon of Saturn, that may be the same way, about how they can use your assembly theory to incorporate it into their robots? Yeah, absolutely. Actually, I'm most excited about doing original life experiments in the lab and particularly just understanding what life is.
It's also really exciting to think about the possibilities for mission science. And both Lee and I have been in conversations with people developing NASA missions about how we would possibly detect molecular assembly on other planetary bodies. And there are some technical challenges there with the kind of instrumentation they've been using and the resolution of the instruments for measuring molecular properties. But it's definitely within sight that it might be possible.
Dr. Walker, thank you for the book and thank you so much for your time. Yeah, thank you for having me. It was really a delightful and fun conversation. Dr. Sarah Walker is a professor of theoretical physics and astrobiology at Arizona State University and the deputy director of the Beyond Center for Fundamental Concepts in Science. Her new book is Life as No One Knows It, The Physics of Life's Emergence.
And here's one last review from science writer and host of the Book Lab podcast, Dan Falk. There's no question that modern science has an impressive track record, going back some 400 years. But some scholars believe that the traditional scientific approach has left something out. That's the argument laid out in a book called The Blind Spot, Why Science Cannot Ignore Human Experience. It's by Adam Frank, Marcelo Gleiser, and Evan Thompson.
The book takes issue with how science has traditionally been done, dividing up nature into bite-sized chunks that can be studied in isolation, with a clear division between the observer and the thing being observed. They believe that this method, in spite of its successes, has failed to account for, as they put it, mind, meaning, and consciousness. To give one example,
The authors argue that in spite of everything that Newton and Einstein discovered about the nature of time, we still struggle to explain the passage of time. Our best theories, they believe, have left us with a mathematical abstraction that fails to account for how it actually feels to be a living being caught up in time's flow. I won't say I agree with everything in the blind spot, but it's well-argued and provocative and leaves the reader with a lot to think about.
So those are some of my picks for science books that you might want to check out this winter. For Quirks and Quarks, I'm Dan Falk. And that's it for our holiday book show. If you'd like to get in touch with us, our email is quirks at cbc.ca or just go to the contact link on our webpage at cbc.ca slash quirks, where you can read my latest blog or listen to our audio archives.
You can also follow our podcast, get us on SiriusXM, or download the CBC Listen app. It's free from the App Store or Google Play. Quirks and Quirks is produced by Rosie Fernandez, Amanda Buckowitz, and Sonia Biting. Our senior producer is Jim Levins. I'm Bob McDonald. Thanks for listening. For more CBC podcasts, go to cbc.ca slash podcasts.