The following is a rough transcript which has not been revised by The Jim Rutt Show or Bruce Damer. Please check with us before using any quotations from this transcript. Thank you.
Jim: Today’s guest is Bruce Damer. He is the chief scientist of the Biota Institute. He’s a research associate in biomolecular engineering at UC Santa Cruz and he’s an astrobiologist working on the science of life’s origins and the future for sustainable paths for humanity. Welcome, Bruce.
Bruce: Thank you, Jim.
Jim: I look forward to this conversation. Today, we’re going to be talking to Bruce about origins of life, also known as abiogenesis. Regular listeners may remember it back in EP40, I talk with Eric Smith on the Physics of Living Systems, including Eric’s work on life’s origins. If this topic interests you, check out good old EP40. There’s lots of good material on the biota.org website. For those who want, what I found to be, I looked at many different documents and sources that Bruce provided for me and that the Google turned up, I found one that was actually the best for my purposes.
It’s a paper titled The Hot Spring Hypothesis for an Origin of Life co-authored with David Deemer. Now, Deemer and Damer’s are annoyingly close in the neuro nets of my brain, but hey, that’s the way it goes sometimes. If people want to read more, they check out that paper. As always, all the links we talk about will be on the episode page at jimruttshow.com. With that, let’s hop into it. Let’s start out with earth, first abiogenic, no life. What was the earth like four billion to three and a half billion years ago?
Bruce: Well, Jim, it was kind of a frightening place. If you walked out of a time portal, say to four 4.0 to 4.1 billion years ago, about the time the guesstimate is that life might have gotten started, that is a few hundred million years after the moon collision event, the moon formation event. Then the oceans then rained out of the atmosphere. All this dense, most of the water coming from the cooling of magma. But after the collision that created the moon, it was all freaking boiling again. It was all magma again. Then the oceans rained out and you had this planet which had immense amounts of volcano and fissures opening up and towering volcanoes in long rows, just blasting just roaring 24/7, big volcanic land masses, a copper or a green colored ocean because it could have been very, very infused with iron and flashes in the sky through a brown haze.
You’d find asteroid impacts coming in, big ones that would all of a sudden reshape the landscape and reshape the atmosphere and dust. If you look through that haze, if you’re standing at your time portal and you’re looking up, you’d see this disc around the sun and it looks like Saturn’s rings, but it’s actually dust from the formation of the solar system. Our neighboring planets just newly born are scooping up that dust so you’d see vans through the dust and the dust is coming in, it’s raining in like snow and flashing and covering the landscape, this red landscape. You’d have no oxygen to breathe and you’d have acid rains, big storm systems and huge tides and the moon much closer, the moon much bigger, maybe even with a little bit of the orange of magma flows on the moon itself. That’s the picture. You would expire quickly without a full, like environment suit with oxygen. It’s a sort of a bad hair day for the earth.
Jim: In fact, the geologist, I think referred to it as the Hadean epoch, as in Hades, right?
Bruce: Right. The fire of Hades. Exactly.
Jim: But then things cool down a bit. Water collected.
Bruce: Yeah. You had this event where the oceans, which were vapor in the atmosphere, suddenly just fell out. They rained out and the whole earth turned into basically a jacuzzi. You’d have the ocean basins filling up lots of hydrothermal activity and vents under those early oceans and lots and lots of hydrothermal activity and vulcanism on these towering volcanic islands and land masses. Think like Iceland today or Kamchatka, places like that. Then on those land masses are bubbling pools that look like nature’s chemistry set. They have different pHs and colors and geyser action is happening because of the rain water, fresh water is raining down and filling chambers that are boiling and bubbling and coming up like a percolator, like Old Faithful and Yellowstone. You have this incredibly dynamic environment on the early earth.
Jim: Presumably if we have higher temperatures, the water circulation rate must have been much higher than it is currently. It’s got to be raining a bunch.
Bruce: It would be raining a bunch and there would be enormous braided river systems going down. There’s no plants, there are no roots to hold the land. There are no microbes anywhere. It’s a dynamic place that is not yet alive. It’s not a biosphere yet. These are conditions we’re calling urable, for the German word early, or origin and urable as being a sister term to habitable. Where a habitable world can host life as we know it as water on the surface, et cetera, sources of energy. Urable is a place that life can get started on and an urable world has different conditions than a habitable world.
Jim: That was a new concept to me. As soon as I heard you say it on a video, I said, “Damn, that’s right.” Right? There’s nothing that says that a world that could support life, let’s say if inoculated with it, is also a world that could bring life into being. That distinction’s actually quite powerful.
Bruce: It’s quite powerful. We watched for years as our colleagues, especially in Mars exploration, because I was part of the Mars 2020 perseverance landing site selection process. It was on a team making the arguments that sort of whittled down to three sites and then they chose Jezero crater. But we kept saying, “Well, life on Mars, there’s a difference between Mars’ conditions where life would start there.” Because it had oceans, it had hydrological cycle, it had rainfall, had volcanoes similar to earth, but it lost the atmosphere, it lost the surface water. Highly irradiated environment, highly sterilizing surface. Mars is no longer urable and it may have been just transiently urable four billion years ago, but it still may be habitable. There may be microbes that got their start in the wet rocks down. We’ve got to drill to find them.
Jim: That’s very interesting and we’ll come back to this towards the end when we start talking about Exobiology extra solar Fermi paradox. Because everybody who listens knows, it’s one of my very favorite topics. We have an earth that’s now cool enough that some kinds of chemical reactions are going to be relatively stable water everywhere, but no life at all. What does a theory that explains the origin of life have to explain?How we get from chemistry to biology? Just very roughly, not that’s going to go through the steps, but what are the big things that need to be explained?
Bruce: The big things, and this is sort of the question of the age and the hour, is where do you get your source of organic building blocks? Because life is made out of lipids and nuclear bases and sugars and amino acids and things like that. Where do they come from? The next one is how do you get them together? How do you get them so they’re close enough to interact? Then the third one, which is the most powerful new idea and origins of life, how do you get them to start to evolve toward a system of natural selection before there’s natural selection, before there are genes to select. That’s what Dave and I call combinatorial selection. How can you get the engine going? As you know that any engine, any system that can pump away from equilibrium is a cycling system. Where do you find cycling systems on a planet, on an urable world like Mars or the earth that can pump a system away from equilibrium?
Jim: I loved your hypothesized general metaphorical answer, which was, as you say, combinatorics. As it turns out, my home academic discipline is evolutionary computing. What you were essentially describing is evolutionary computation as a metaphor for the origins of life. I’m not putting words in your mouth, so tell me if I’m putting too many words in your mouth, you and your collaborator to decide to come up with an approach where the original bootstrap, the smallest component that leads to life, could be discovered by random combination and very rough and ready selection at a very early stage with no sort of magic guidance. No magic needs occur. At least that’s the hypothesis. Is that fair enough?
Bruce: That is fair enough. In fact, I’m an A-Life geek like you and was tracking artificial life in the late ’80s just as Chris Langton was sort of dreaming up his symbions on his apple too. Before SFI got founded, and I went to visit SFI in 1994 in the summer early fall of ’94 when they just moved into that building on the hilltop. I was just completely fascinated and obsessed with the use of computers to try to solve this mystery of life’s beginnings. Did my PhD work actually in Stochastic hill climbing, characterizing little volumes of artificial chemistry all running through a selection process to see if I could get bonds to form. What was the nature of the cosmic wiggle that would take a collection of what we’re in initially, diffused atoms that gradually became bonded to climb to further complexity through maxima.
This is Stuart Kauffman language in a correlated landscape, climbing up, finding the ridges to the next maximum and keeping climbing because that’s actually what you have to be able to do. The universe does that in a very slow poke process by forming stars and fusing things together. Clouds then form and the universe is a very low rate of productivity in terms of creating complexity. It gets to hard rock geology where life is starting, but it’s a long period. The question I had, the universal question I had is how on earth do you kickstart this in a bunch of molecules in a primordial soup environment? How do you get that going? Then how do you get information into the picture?
Jim: As you know, this is a field that people have been talking about for quite a while, right? There are various hypotheses that have come and gone. One that seems to have disappeared, I think it was popular 30 years ago or 25 years ago, was the idea of clay substrates as somehow being a physical catalyst. I haven’t heard about that one much in a while. But two, the big ones that are left. This, I think a lot of our conversation’s going to be about comparing and contrasting these and what your position on this. One that we’ve heard a lot about, I guess it’s probably still the leading theory, I don’t know.
Is the ocean vents theory that deep in the ocean there are ocean vents, rich in sulfuric compounds and other highly energetic compounds which could serve as an energy source for the formation of life and physical substrate perspective. It’s thought that the pomus cells could be places that serve the purposes of membranes even though they’re not actually biological membranes until you could get other kinds of membranes going, et cetera. Then the second goes all the way back to Darwin, and this is the warm little pool hypothesis. That’s the hypothesis that you and your collaborator are basically supporting.
Bruce: In fact, Darwin’s words on this, it’s a letter he wrote to his friend TJ Hooker in 1871, and he talks about, “Oh and what if in some warm little pond there with all sorts of ammonias and phosphoric salts and electricity, et cetera, that…” Here’s the money shot for all this. “That a protein compound should form ready to undergo more complex changes.” What Darwin was talking about with this breathtaking intuition is you need a warm little pond. Warm because you get more chemical activation energy, little because you have to concentrate chemicals together to get them to react. He got that right, he even got some of the components right, the phosphoric salts, et cetera, et cetera. An energy source, and then he talks about the formation of a protein, which is a polymer ready to go undergo more complex changes through cycles. He’s actually talking, what he is talking about is actually a hot spring that can cycle components in form a peptide or a protein, a simple protein out of amino acids, and then somehow let it undergo complex changes.
If he’d written perhaps another sentence, he would’ve talked some sort of natural selection acting on those proteins collectively could make them more complex. Darwin was at the very cusp of describing the hot spring hypothesis in 1871. Yet our field kind of went down a bunch of rabbit holes, some very productive areas, but a bunch of rabbit holes for over a hundred years, 120 years or so. We started looking at Darwin’s intuition. Dave Deemer, one of the breakthroughs that got us back to hot little pools was Dave Deemer took a meteorite, a meteorite that’s called the Murchison meteorite, very famous, fell on Australia in 1969. He got a chunk of it when he was at the University in Canberra. What they did was they ground up the meteor into a powder, put it into an acidic buffer, and instantly membranes formed, little compartments formed.
It was a breathtaking paper published in the ’80s, in like 1985-86, that membranes the boundary compartments for what could become the proto cells that become the living cells actually came from space. Then other teams determined that amino acids were also on the Murchison meteorite, up to 70 amino acids. Then they found nuclear bases and then they found actual sort of water on the Ryugu, the Hayabusa 2 samples that came back. That was last week was announced that they found organics and a drop of water in there. It looks like more and more, the solution to where did the organics come from. The problem number one, largely coming from the sky, not as a form of panspermia with living organisms, but the building blocks to make living organisms raining down in abundance in that period because the Murchison meteorite is actually about the age of the earth. It is the real deal. It is the actual material that was available that was coming down out of that disc through that smoggy sky. That was a huge clue for everyone as to the sources of organics.
Jim: Of course, there’ve been other arguments that there are routes to synthesize, chemically synthesize the lipids for the membranes and the amino acids, et cetera. It’s not yet definitive that the meteorites were the key, but it’s at least suggestive. Is that fair enough?
Bruce: It’s very suggestive, but I make it a practice to talk to everyone on either side of the aisle, if you will. In political terms, I spend a lot of time talking to Mike Russell because I really admire Mike and his work predicting alkaline hydrothermal vents and all of his beautiful ideation around gradients. He and I have known each other for years and we’ve recently been in a big correspondence because we went out to Fly Geyser to do our experiments actually in real hot springs with the BBC recording that’s going to be out in a few months, I think it’s a documentary. Mike went there too, and he sent me a picture of him in a cowboy hat at Fly Geyser in Nevada. I said to him, “Look, we need your help as a geochemist to understand this is a highly salacious environment. Here are our slides.
I sent him our early results actually, and he said, I disagree with you on where life can start, but I agree with you that you’re getting very interesting results and that you can form these proto cellular compartments and you can also polymerize those proteins, those peptides because we’re actually able to take the building blocks of DNA, RNA peptides, amino acids, and through wet-dry cycling. This is the key, this is the engine we talked about. We need an engine to dry things away from thermodynamic equilibrium. Dave Deemer also discovered and or proposed and then experimentally discovered that if you dry a solution down, you of course concentrate the water leaves and you get a concentrated medium and chemistry’s more likely. If you dry it down with the presence of lipid membranes, it forms these little sandwiches, little balls, little compartments and layers and between the layers, if you have nucleotides, say the building blocks of RNA, they line up, they pre polymerize, they stack together, and then when the water leaves, it pulls them forward to form a bond what’s called an Esther bond.
That’s called a condensation reaction because water leaves. You can also form peptides, strings of amino acids and DNA can be self-assembled using dry down sequencing. Dave was the only person doing this in the ’90s and 2000s and now it’s ubiquitous. If there isn’t a week that goes by without a paper about a team using wet-dry cycling now to pull together the components of a prebiotic system. It has become like the defacto way of getting things to move forward. This is a little unfortunate for our colleagues working on ocean vents because there’s no way to do a condensation reaction deep in the oceans. In a recent visit a few years ago just before COVID, I went to University College of London and met with Nick Lane who’s a wonderful researcher, a fantastic author and science popularizer. We spent an afternoon there and I did a presentation to his whole group on the hot spring hypothesis because they’re working on the deep ocean vent hypothesis.
One of the things that Nick revealed to me is that he didn’t see a way to make polymers how to get condensation reactions to work in a submerged environment. One of the students actually at that time asked me, “Why is it important to have polymers in the origin of life?” I kind of realized at that point that perhaps, and I sort of confirmed this later, talking with colleagues of Mike Russell, that the objection to the hot spring or this surface sub aerial origin is they don’t like the idea of this dirty material coming in on asteroids and dust particles and somehow they need a pure source. They’ve got a gradient and they’re trying to figure out how to use it. Can they get CO2 to basically in almost an industrial process, make form acid and make the building blocks that lead you to amino acids, et cetera, et cetera, but in these events they’re just like industrial chemical processes.
I realize that they’re working at the very base level of how do we make carbon into organic molecules deep in the ocean on a continuous basis and they flow into little chambers and et cetera, et cetera. But in the entire 30 year history, they’ve never been able to demonstrate it. One of the colleagues, there was a very critical article in nature that was published in December 2020 where you could sort of see the paradigm shift happening. You can look this up, it’s called the water paradox.
Jim: I was going to bring that one up as my next question. You’re doing it, what is the water paradox or the water problem as some people call it?
Bruce: This term water problem was coined by the chemist Steve Benner in Florida, who’s an amazing mind in our field. He said, “Look, the water paradox or water problem is the fact that life exists in water now, but if you just put your prebiotic chemical suit together with water, it will hydrolyze and break everything down.” So if you form a polymer like a little peptide and you leave it or hanging around in water, guess what our fathers told us was the universal solvent. Water will break anything down. The irony is that why don’t you dissolve in the shower? How does life stand up against the degradative forces of water? What does it using enzymes? Using ATP, using energy.
Bonds between the links of DNA form because there’s an enzyme of polymerase that is kicking water out of the way, forming the bonds. You are dehydrating constantly in between the bonds of your polymers, which are you. There’s little dehydration events happening in order for those condensation reactions to happen and for bodies to be built and maintained and repaired. But the irony of the chicken and egg issue is that you don’t have enzymes at the original life. Those are big complicated machines. You have to find a way to do it without enzymes and the chicken egg is solved by wet-dry cycling.
Jim: Of course there are other approaches. In fact this argument is somewhat orthogonal between the ocean vent and the warm pool, though I think it provides a little weight on both sides. This is the question about both catalysis and whether it was metabolism first or information first or whether they co-evolved. I think that’s a really interesting question because sort of your cartoon version of little factories, that’s sort of the metabolism first but somehow we stumbled into the reverse Krebs cycle, which does turn out at least based on the work of Smith, Morowitz and Copley to be sufficient to synthesize everything we need, right? At least that’s their claim. That perhaps metallic catalysis was enough to bootstrap it initially until they eventually developed weak chemical catalysts. Then RNA co-evolved with that system, which has the very interesting attribute of being a semi week catalyst and a carrier of information at the same time, which is kind of interesting and curious. What’s your take and your collaborators take on this question of was it metabolism first? Was it vesicles first? Was it RNA first? Or was it all co-evolved?
Bruce: Our approach was literally to go to nature. What Charles Darwin did in I think it’s 1835, is he as a young man, he boarded the beagle and did it around the world trip. That tested his sort of theoretical notions about the origin of species. When he got to the Galapagos, he got to this amazing place where you could actually see the plasticity of species. You could see finches with different beak shapes, and he could work out that their beak shapes changed because the trees would kind of go extinct or there would be more nut bearing trees or there would be sources of more insect, fruit food supplies. He’d have longer pointier beaks. Only at the Galapagos, that nature taught him and showed him that species are mutable. When he got back to Britain, 20 some years later, out came the origin of species.
What Dave and I have done is saying we have a wonderful set of theoretical ideas of conjecture. There’s a lot of conjecture in origin of life. We have to go to natural analogs on the earth that would have been present four billion years ago, these volcanic settings especially. We have to study them and then we have to try the chemistry actually in them and that nature will teach us. Having done that, come back and come up with a new hypothesis that’s very grounded. One of the places we went in our voyage of the beagle was Northwestern Australia with Martin Van Kranendonk and the Australian Center for Astrobiology. We took this crazy bus from stromatolites, which are these soft rock towers with squishy tops at Shark Bay. They’re living fossils, they’re what used to surround all the continents for billions of years.
These stromatolites are living microbial mats that keep growing up when they’re covered over of a sand grains or sediments, and they’re the most ubiquitous fossil on the earth for evidence for life. Martin and his crew took us up to the Pilborough, to the North Pole dome where we went up to outcrops that had been uncovered after three and a half billion years of being lava entombed. These are the most precious early life locations on earth because you can see the wavy textures of stromatolites in these outcrops.
You can see stream beds, you can see water drop, raindrop preservation from a single rainstorm three and a half billion years ago in the Pilborough. That is what the earth was like. A few hundred million years after life’s origin, we can see it. At the same time, as Dave and I were proposing or first sort of crafting the hot spring hypothesis, and Martin Van Kranendonk and his graduate student, Tara Djokic, discovered the oldest hot spring known in the solar system up in the Pilborough, geyser rite, a mineral that sort of got these bans of titanium oxide that’s clearly laid down by the splashing of geysers.
In there is clear evidence from microbial communities. It’s one of those times in science where there’s a simultaneous discovery from deep time that validates an approach which is conjecture with experiment. We found the oldest evidence for life that is clear on the planet in a hot spring setting, thriving on the land three and a half billion years ago. We put it all together. We said then, “What is in those hot springs?” All the essential elements, wet-dry cycling access to organics from atmospheric synthesis as well as meteoritic dust and rocks coming in.
We think we have everything we need and we have a smoking gun sitting there in that hot spring, geyser rite. All of that piled up and became, that’s where Scientific American covered it on their cover story in 2017, the audience can look up. What we’re suggesting here is that there are great and well-informed conjectures about scenarios for life’s origins, say at alkaline hydrothermal vents or the use of clay surfaces that can do a little bit of polymerization. But the only way a hypothesis is to gain traction and move beyond conjecture is the accumulating weight of evidence and the weight of evidence around a sub aerial small…
… the weight of evidence around a subaerial small pool, Darwin [inaudible 00:29:06] little pond scenario for life’s origins has been accumulating rapidly and solidly for the last 20 years to the point where the nature… The news story in December 2020 came out, the water paradox. And it was a shouting match in the science media. There have been several of those. There have been these shouting matches, which are characteristic of paradigm shifts that Thomas Kuhn defined back in the sixties. My favorite paradigm shift in science, which I was obsessed with when I was a 12-year-old, was the coming in of the tectonic plates, the whole model that Wegener proposed. If you went to American Geophysical Union in the mid sixties, you’d find all these people screaming at each other around, “Well, no, mountain change are made by up thrust process that’s connected to blocks,” or “Vulcanism is sourced in this way,” or “No, South America and Africa do not fit together like a jigsaw puzzle. It’s a complete accident. You’re misreading the data.”
All this was happening. And I think it was Carl Sagan or somebody who described that when theories in science are put forward, or hypotheses, there’s a shouting match. And you’re shut out. And then, there’s a begrudging acceptance of things. And then, data starts coming in. And the data, the key data for the tectonic plate proposal was they ran a ship. They sailed a ship across what they thought of there might be a ridge. They’ve sailed across the Atlantic. And they had a magnetometer on it. And the magnetometer basically mapped out, like a butterfly, that bands of sea floor that were being emitted by spreading from that mid-Atlantic ridge. And they were fixing on where the magnetic north pole was when the lava came out. And it was a complete pattern. It was a mirror pattern.
And they realized their C4 is spreading. Europe and America are moving apart. Plate tectonics and continental drift are real. And then, that was that accumulation of evidence that piled up to shift all of geology to a more simple model that was testable, where you could then start seeing all the patterns fitting together, like a jigsaw puzzle. And that’s, I believe, where we’re at with Origin of Life when we move back to sub aerial landscapes, to pools on land. Because we have access to so much more combinatorial complexity on a landscape. And most importantly of all, we can go out to the environments and do the chemistry, and get results. And our colleagues at Cambridge are using UV light to get to nucleotides from nuclear bases, for example. And if you scour the literature today, you’ll find hundreds of experiments presuming a land-based pool that are just accumulating more and more evidence.
Jim: Yeah. Very interesting about the paradigm shifts. Interestingly, I was also fairly obsessed with tectonic plates when I was in fifth grade, and actually built a couple of clay-based models showing how Africa and South America fit together, and all that. Of course, at that time, the tectonic plate theory had become the dominant theory, but there was still some laggers out there. Max Plank, famously, said, “Science advances one funeral at a time.”
Jim: Hopefully, it’s not quite that dire, but sometimes it is. So let’s dig in a little further here, to the warm little pool hypothesis. What did these warm little pools look like 3.5, 3.7, 3.8 billion years ago? What were their constituents?
Bruce: Well, we know this pretty precisely. Because the teams in Australia, not only did they find the surface hot spring pool, the guys are right, but then, they took a drilling rig out there couple of years ago. And they made drill cores, all the way down deep into this Archean rock. And they went into hot spring [inaudible 00:33:21]. So these facies that are clearly hot springs. So they could bring the cores up to the surface. And then, they could chemically analyze them so they were not exposed to weathering. So these cores showed all of the components proposed by people, like Steve Benner, that are necessary for that warm little pool to carry a prebiotic chemical reactions. This general set were found. So the way that that little pool in the Archean and the pilgra would’ve looked is very close to what you would see in hot spring pools today. So if you went out to Yellowstone, or perhaps Hawaii, or especially Iceland… Iceland is actually the place where the word “Geyser…”
Which is an Icelandic word. There’s a place called “Geysir” with a geyser that’s going off repeatedly like clockwork. That’s from Iceland. So if you look at Iceland today, and you’d see pools of different colors, different pHs, meaning some acidic and some are alkaline, pools that are more turbid, pools that are connected to other pools by little channels, pools that have completely dried down. And you can see all this stuff in the bottom of them. And what I’d like to propose in Stuart Kaufman terminology is… Consider this. If you had a geologist and a biologist who had booked a day on a time travel machine, and they decided to dial it to 4.1 billion years. And they packed all their gear. They put on their environment suit with their oxygen. And they had their kit. And they went through the time portal. And they walked out onto the crunchy lava-streaming landscape of a Haitian island. They might see, in the distance, this steam coming up. And the steam is from a hydrothermal field, driven, and let’s say, on the flanks of a volcano.
And they walk up to it. And they see different colors. And even though there’s no life there, there’s something going on at the edge of the pool. And it’s this sludge, this slurry, this slick of materials. And the geologist bends down. And he takes out his rock hammer. And he scrapes it and says, “Well, I can’t break it with my rock hammer. So it’s not geology. And I’m not that interested.” And the biologist scoops up a bit of this material. And she puts it under a microscope. And she sees layers of lipid and stuff, clearly organic stuff. Even a little bit of sooty materials, all kinds of stuff. And she says, “This isn’t alive, but it’s not rock. It’s not geology. It’s something else.” And so what they do in the story is, they decide to dial the knob 150 million years forward and go back.
So then, they go back. And they drop themselves onto another land mass. And they’re still steaming pools everywhere. But when they walk up to them, what she notices right away is that slick is still there. And she realized some of it’s coming from being blown in as dust from the landscape of stuff that’s falling on the earth, or seeing synthesize in the clouds of stuff coming out of the volcano. And it’s all collected, but now, it’s different. It’s black. It has a distinct color that it didn’t before. And she’ll scoop that up and look at it under a microscope, and see that there are polycyclic hydrocarbons in there. And we all know that these [inaudible 00:37:00] polycyclics are the most common organic compound in the universe. You can see them. James Webb will be seeing them in clouds around… In star formation. And they can act as a pigment.
And the teams at Asa Ames, an art group, has actually taken these polycyclic and meteoritic quinones, put them into lipids, shone ultraviolet light onto it. And that light is captured by those polycyclic. And it’s coupled into a pH change. And it can be coupled into energy captured directly from sunlight, even before life starts. So it’s a plausible means by which… Not just the energy of wet-dry cycling. Not just the energy of the heat of the pool, or of redox couples that are coming in from the hydrothermal chemistry. But the actual capture of sunlight itself is plausible to kickstart that sludge so that the biologist looks at that and realizes, this is now energized. The pH is lower. It’s around pH two. And she takes out her handy nanopore sequencer, which David Deamer helped to invent through his discovery of nanopore sequencing in the eighties and nineties.
And she sequences the sludge and finds short, basically, DNA-like ligaments, or RNA-like ligaments, as you mentioned earlier, that are acting both as a catalyst and a template. And realizes that through cycling, through the capture of energy, through the cycling process in the pool of wet and dry, through trillions of protocells that form with quadrillions of polymers, the system has selected itself to attach to a pigment to, also, start metabolism is then amplifying these little RNA widgets, which is then making some little simple proteins. And a prebiotic, pre-living, but on the way to life, system has now emerged. And those sludges are now everywhere. They’re on the boundaries of all the pools that they find. They have replicated across a landscape. So there’s now a combinatorial landscape with quintillions of RNA strands trying out different combinations driven by energy, driven by source organics and cycling in varied environments where they’re sharing material back and forth.
And that’s the picture of the one-pot solution for the Origin of Life where it isn’t metabolism first, and then a replicator. It’s simultaneously. And it’s simultaneous for all the players, for the amino acid players and the nucleotide species. And it’s in one pot. And it’s also encapsulated. So there isn’t a membrane first. Ultimately, membranes have to come first because you have to get the chemicals concentrated in small spaces, but it’s combinatorial selection driving this whole thing in this combinatorial landscape. And that’s where computer geek heads like me come in where… I said to the chemist that I met back in 2008, 2009 when I came into the field, “Hey, isn’t the Origin of Life more of a computer science, at least as much as a computer science, OS Buddha problem, than it is individual chemical reactions.” So what I’ve just gone in this long description is a vision which is testable at every stage, where it’s situated on an actual landscape in conditions we are pretty sure were happening. And we can build laboratory simulation chambers to do this.
And we can also go out and do it in places like Rotorua and New Zealand, which we’ve been doing as well. We can take all that conjecture, all those great ideas from Eric Smith and other people, Jeremy England. And we can take them into a box. And we can say, “They’re wonderful. Let’s see if they actually pass a test to become a hypothesis, to become evidence in this setting where we can get so much else working chemically. Let’s try some of those more way-out ideas and see if they’re valid for the question of where life can start.”
Jim: And that, of course, is what science is. You can conjecture all you want. Until you get some facts, you’re just conjecturing. Now, one question for you in this model, the vesicle material, one of the advantage of metabolism, first, is that it provides a plausible mechanism to manufacture lipids and quantity. Is there enough precursors for lipids in the environment to be a plausible source of vesicles?
Bruce: The answer is, quite probably. Because carboxylic acids, which would be available in abundance on meteoritic infall and in interplanetary dust particles coming in, in the early solar system would provide you, basically, fatty acid, lipid membranes in abundance. And there are also… As you pointed out, there are actually synthesis pathways for simple amplifies, simple lipids in the hot spring setting that’s been demonstrated to. There’s actually another piece of work going on, which is called “The biogenic atmosphere.” This is an amazing piece of work. Ben Pierce and colleagues at Johns Hopkins, and many others are working on this. If you whack a planet early on, you change its atmosphere for hundreds of thousands of millions of years. And it changes substantially. So models for an actual observed synthesis pathways in the atmosphere of Titan, which is hydrocarbon-dense, basically, quantum models to show what kinds of things are being made constantly in that atmosphere.
It’s like smog over Los Angeles. There’s whole kinds of things are being made. If you are in a smoggy city, you can smell, basically, the hydrocarbons that are made on a daily basis through photochemistry. So if the earth was whacked, it would basically create a factory for organics. This is some of the predictions that would’ve been raining down in pure form, relatively, not encased in a rock. And so that’s yet another source for the organics that we had to get whacked at just the right rates. And that could include organics to give you your lipid boundaries. But the key thing here that convinced a lot of our colleagues, Arman Kunjani and others, that the ocean was implausible as a place for life to start. As he pointed out, we did some work in Yellowstone where we introduced these simple lipids, these fatty acid membranes that are very leaky and very fryable, into hot spring waters that we took directly out of Yellowstone pools, both acidic and alkaline.
And they formed… And you could even see it. I’ve got a picture of these vials that… I’ve shaked them up and they go milky because there are micelles and compartments that form instantly from these simple meteoritic lipids. And then, we took those same lipids, we took some sea water from Santa Cruz harbor, and we put it into the same mixtures. And it basically collapses the [inaudible 00:44:41]. And the ocean water collapse the whole system. So you get these little crystallized little clumps everywhere. And that’s one of the big arguments that you would need specially designed biological lipid boundaries to have a stable protocell in a marine setting or in a highly salty setting. And so that’s another argument where life had to evolve the ability to existed in the ocean at all. And that’s an extremophile environment for early life.
Jim: Well, I did read that in… I don’t know if it was in your paper or one of the other papers when I was researching around. And one of the things that reminded me of is, we do know that the salinity of the ocean was much lower in those days. In fact, that’s hypothesized that it’s similar to the ionic content of the cellular medium, probably not by coincidence. Now, does the concept that a highly ionic solution of the current salinity would destroy naive lipid vesicles without energy pumps? Is that also true at the level of salinity that we would predict at, say, 3.7 billion years ago was much lower?
Bruce: I’ve read other articles, this is not my area of expertise, that argued that the salinity was similar in those years. And then in fact, the oceans also had a high amount of dissolved iron. So you had even more species to deal with that would affect membrane stability, and also the ability for prebiotic chemistry to happen. And in no laboratory in the world that I know of are attempts being made to use those… Other than distill water to do your experiments. And if you actually propose to use something like seawater, a lot of the chemists would say, that would just complicate matters and things might not work. So they wouldn’t use that. Now, of course, our colleagues at JPL are doing these wonderful simulated chimneys called “Chemical gardens,” sometimes, inside the laboratory. They’re doing these pressure vessels and making these artificial smokers. And so they are attempting to get some carbon fixation, some, say, amino acid to form. But yet, there’s very little evidence for it.
But on the other hand, there’s a very attractive chemical gradient. But one thing that Dave Deamer pointed out… There was an article published about five years ago where the author simply drew a membranous boundary that was supposedly formed with the mineral. You mentioned pumice earlier. So like a little compartment of pumice. And then, they placed, basically, an ATP synthase inside that mineral compartment and said, “Here it is, ATP synthase would form here, and would start the process of making ATP in the chimney environment of a hydrothermal vent.” And it was so nonsensical that there was a dispute that went into the New York Times about this. And Dave wrote a piece for Nature Communications that were invited to write a critique. And Dave pointed out to the colleagues that not only… Where does this ATP synthase appear? It’s a very evolved enzyme. How can you just simply place it there and saying, it just appeared magically?
And the second thing is that the width of the mineral membranes is a thousand times that of a lipid. So it’s a thousand times. So it’s very much like saying, “The Niagara Falls has an energy potential because it falls over a meter,” or something. You get this great drop off on Niagara Falls, but if you extended that to a mile, you’d have a rapids system that does the same drop. And the potential energy is not there. You have to have a membrane that is thin in order to capture energy. And this is one of the things that Dave is also critical about. The more recent work… He was a colleague of Hans Morowitz. And Hans Morowitz was really focused on cell boundaries and cell membranes as the place where energy can be captured across membranes, chemiosmosis, Peter Mitchell’s work, very early on. But recently, there’s just… When we read Eric’s misproposals, he doesn’t even mention membranes in the book, the last book he did with Morowitz, which is absurd. Because only in the [inaudible 00:49:21] of a boundary membrane are you going to be able to capture a gradient.
So in the hydrothermal vents scenario, if they cannot have stable lipid, there’s no source for lipids in the hydrothermal vent for one thing. And they can’t form a boundary, a little protocell, a little compartment in a marine… In a salty environment. So there’s no way to ever get chemicals together. There’s no way to undergo the most important step in my book, being a geek head, which is combinatorial selection. Trillions of protocells, each with different contents, being pressed through selection barriers so that we can see what… In the days of Santa Fe Institute, the great search for the origins of emergence itself, of complexity itself through cycling steps, through artificial life program, genetic programming. That’s the juice where… Once we start seeing that happen in molecules inside the particular compartments, we’ll really be on the track. And that’s really the next frontier for Origin of Life work.
Jim: As you pointed out, JPL is still working on the black smoker hypothesis. Don’t they have an assumption that physical containment within a porous rock substrate could provide a semipermeable membrane-like function and the approximate scale would be necessary?
Bruce: That has never been shown. And so that was the criticism in the New York Times of that particular nature article, it’s called… By Weiss and Martin, Bill Martin. And it’s basically observed what they were showing in the article, that a rock pore, a rock compartment is so thick, it’s not semipermeable. And not only that, it’s not replicable. You can’t make rock pore environments and subject them to selection that you would need in order to kickstart a form of evolution, combinatorial selection. Even if you had clumps of organics within those rock pores, it’s not small enough and not concentrated enough. And you’re in a flow reactor, a flow through system. All that is just, basically, dissipating to the bulk of the ocean and being lost. And there’s no way to form a polymer from a building block. So you can’t do information. And you can’t do a catalysis and expression. You can’t get functions out of polymers because you can’t get to polymers. As Nick Lane had told me a few years ago, “We can’t get to polymers in this system.” The question being, “Well, why do you need polymers at the origin of life?” No polymers, no life.
Jim: That’s pretty clear. If you can disprove polymerization, then you can disprove that is the route for origin of life. Now you mentioned something, it’s one of my favorite topics actually, which is semipermeable membranes. One of the key parts of the evolution of [inaudible 00:52:23] life had to have been the evolution of the semi permeability of the membranes, the math there. And again, I’ve actually used some of these approaches in evolutionary computation, thinking about membranes and protocols, and things of this sort. What passes the membrane in both directions turns out to, actually, be very interesting and important. Could you talk about that a little bit?
Bruce: Yeah. In a period of a morning, you can take egg yolks and render them down, and make fossil lipid… Make a little pile of powder of fossil lipids, or you can buy a lipid compound. You can buy fatty acids. And as soon as you put them on a slide… Get yourself a real cheap microscope, maybe based on your phone. You can place this little powder, maybe a milligram of material, on a slide and put some water, put a drop of water. And you’ll watch a whole universe unfold. Compartments, little cork screw shapes, as the water comes in, as the energy changes, as the lipid forms the boundaries and adjusts. And actually, inside those layers, there is the lipid membranes that are butting off material. There’s all kinds of transport happening. The bilayer is actually composed of jostling heads and tails, amphiphilic molecules.
One side is positively charged. The other side is negatively charged. And the tails are wiggling together. And they’re flipping. The tails are doing this dance. And the molecules themselves are flipping. And every time they flip, there’s a transient pore that’s opened up. And water can shoot through. And small molecules can shoot through. Now, it turns out… And this is an amazing fact of that. It’s not just one water molecule. The transient pore opens up due to wiggling, and a line of water molecule starts squirting through. And it turns out that if you’re doing this amazing trick of having a protonated solution on the outside and a receiver… A donor for an electron and a receiver for an electron on the inside, the hydrogen, for instance, if it’s a hydrogen, it’ll attach to the water on the squirting, marching line of water molecules. And it will basically jump along like, what’s called, a water wire. And it will pop off the other side.
So we get an electric wire along that group of water molecules that’s marching through that membrane. So way more is going on than just stuff wiggling through. And in some sense, that water wire is the precursor. It’s the great ancestor of all pores that follow. Because it’s built in to the very physics, the biophysics of that membrane and what is going on with energy getting across it. And that’s an incredible clue as to origin of life, that it’s… Actually, everything that we see, Jim, in our solutions for… Life basically takes over stuff that’s happening naturally through self-assembly. The butting off of protocells, layering, polymerization, and even these water wires where energy is transacted all exist in the warm little pool environment that’s cycling. And life simply evolves polymers, enzymes to take over those jobs. So in the pre-life system, the sludge at the edge of the pool, stuff is happening in there that looks like biology and acts like biology.
It’s just… It’s happening because of physics. The physics of amphiphiles, the physics of membranes are the key. They’re the organizing matrix for everything that comes. So in a way, of course, you need organics. You need polymers. And you need metabolism. You need energy sources. But none of it’s going to happen without that sludge, without those layers of amphiphilic… Lipid layers, bilayers that are just giving you a place to do it. And we call that “Sludge of progenitor,” the very substrate in which life can emerge. So that’s a new term we’re also currently writing a book chapter on.
Jim: Yeah. So people hated the idea of humans coming from monkeys. What did they go think about humans coming from sludge?
Bruce: It’s an Ig Nobel sludge and maybe it will win the Ig Nobel Prize one year.
Jim: Hopefully it wins the actual noble prize some year. So let’s now dig in to the mechanisms of your small pools. Cause you are focusing on a specific subclass of small warm pools, which are ones that cycle with respect to their hydration that go from fully liquid to gel-like, to dry. So why don’t you run us through this subclass of small warm pool that you believe is central to the pump that allows this work to happen.
Bruce: So this is… You could call this, given that we’re here in Northern California, “The Jacuzzi origin of life.” So if you sit in your Jacuzzi, and you really shouldn’t shampoo your hair there, and take a bath, but even if you don’t do that, your skin cells and your organisms is letting loose all kinds of stuff in your Jacuzzi. And if you dry down your Jacuzzi to clean it out, you’ll notice this band of white around the outside.
Jim: Yeah. The famous bathtub ring, right?
Bruce: The famous bathtub ring. And if you scraped that and looked at it, it would be very, very complex because…
Took that and looked at it would be very, very complex because a lot of it’s made out of lipid. It’s made out of broken down bits of cells and all kinds of things. There’d be all kinds of stuff in there. So think of it like if you took a zillion bubble baths and the bubbles in the bubble baths with the little experimental proto cells and within them wasn’t just air or water, volumes of water, but it was little bits of DNA and RNA, each of which have to do a job. They either do no job at all and their bubble could pop. But if there are just a few polymers within those proto cells, when they’re floating around in the jacuzzi, it stabilizes them. So you get like a bubble bath, you get lots of bubbles on the surface that don’t pop. Now these are bubbles underwater, but they’re stable because they have the polymers in them.
If they didn’t have the polymers in them, they’d fall apart because they’re just made out of fatty acids and they’re very friable. So as the jacuzzi drains down or dries down, the surviving bubbles form that sludge on the bottom. And another magical moment happens because now they’re all jostled together and when things are jostled together, they’re even more stable. And not only that, but a truly wondrous thing can begin, the network effect. Because if there’s a chemical reaction happening in one little proto cell bubble, it might make a product that diffuses across that sludge into another little proto cell, which triggers another reaction, which triggers a third and a fourth. And you get the spontaneous and arising of the first network in the universe because physics doesn’t do networks very well. But this is a point to point nodal based network emergence in the sludge, in the gel phase when everything is jostled together.
Jim: That’s key. Let’s draw that line. There’s the wet phase when it literally is a pool, and then there’s the gel phase where there’s still enough moisture to allow some motility of the chemical species, but not fully dilute either. That’s very important.
Bruce: And there’s another powerful thing that’s happening when the pool’s drying down, it’s getting more concentrated. So the sludge forms, it’s sticking up above the water a little bit. And then the pool water’s drying down, highly concentrated full of organics and other solutes, and those are pushed in to the gel. And so where you could get metabolism, where you could get Stuart Kaufman’s auto catalytic sets is that moment. And this is what we covered in his book, A World Beyond Physics, because the auto catalytic sets have everything they need to get going. When you’re in the gel, when you’re in the sludge, there’s more exposure to sunlight because the pool’s dried down, concentrated material are squirting in across these membranes, little nodes are being set up, concentrations are rising like crazy. Catalysis is happening, sunlight captured, pool redux couples are captured. And so you get this rich metabolism thing very much like after the rains first come in the spring in the desert.
Well, when they come they make those moist soils and that’s when you get the maximum metabolic activity on the land. And then as the sludge continues to dry down, all of these little proto cells fuse, bing, bing, bing, bing, bing into layers. And the layers are the transport highways for polymers to move around and mix together. Because sometimes the polymers have their feet stuck into the membrane and you get this massive network, Conway’s game of life thing happening for geek like us from the eighties. You get this new regime of the layered, mostly dryer regime where there’s still mobility, but there are layers by their thousands. And there’s this city of polymers moving around stuff colliding, colliding probabilistically to find new combinations of polymer to polymer or polymer to energy or polymer to simple things. And then lo and behold, whether it be a single drop from dew or a flush from a geyser, that pool fills up again.
And everything that’s happened in the moist in the dry phase is now butted off. And we can wash this under microscopes into little vesicles that contain new random sets of things for testing for stability. And then back to metabolism and back to synthesis of polymers and then back to test you out in the world like a seed or a spore back to the moist environment, get together and get your metabolic things going. And then back to the dry phase, synthesize your polymers. And this goes and goes and goes and ends up being the pattern we see on the landscape of a field of grass that is growing like crazy in the spring because of the moist soils. It’s creating its compartments for DNA and RNA called seeds in the summer and the fall. And then the big rains come in, blow everything around, move the seeds around and the spores and everything in the environment ready for another cycle.
So the very pattern of nature all the way through the microbial community, the plant world, the fungal world seems to be this incredible thermodynamic engine of wet dry cycling. The whole planet seems to be patterned on that. And this is when I was in the Australian desert at a place called Gallery Hill. I saw a shoe leather like substance on the ground on the desert. And Martin Van Kranendonk came up and said, That’s a microbial map that’s called a desert map. And if you pour water on it right now, it’ll come alive within 30 seconds, trillions of organisms. So I took my water bottle out and I poured it on a rock. It was flowing down to where all this desert mat was and it suddenly became spongy. And basically now it was alive because it had been dry, dry, dry for months and months, but everything’s in stasis.
And then I had that flash of insight at that moment, which was, oh my gosh, the origin of life came as a communal unit, not individual cells. It was a communal unit of proto cells in collaboration 4 billion years earlier than this mat that I’m seeing at my feet. And then Martin drove us all the way up to the pel rock where we actually saw the evidence of it. And that desert mat in the desert of Australia was very adapted to mostly dry and only getting wet during cyclones. But its ancestor existed 4 billion years earlier and the evidence was in the rocks three, three and a half billion years, just a days drive north of where we were.
Jim: A few things he mentioned Stuart Kaufman, again, I think I’ll point out to the audience. I did an interview with Stewart in EP 18, relatively early in my podcasting career on his book A World Beyond Physics. So that’s a quite interesting episode people might want to check out next. As we both know, a key ingredient to any kind of evolutionary ratchet is a selection process, which of course in full on Darwinian evolution where we have actual relatively high fidelity replication, fitness equals rate of successful replication. What have you guys hypothesized is the nature of the selection process that allowed a ratchet to move towards greater and greater complexity. And where did that occur? Did that occur at the gel phase, at the dry phase, or at the rehydration phase? We’re in this drying and wedding pool, the selection ratchet occur. And what does that ratchet look like?
Bruce: That’s a superb question because it’s at the edge of the science. And so literally we’re inviting our colleagues who are now doing wet dry cycling to now look toward the ratchet to look toward things that they can do in their solutions, in their systems of wet dry cycling to start molecular evolution or at least combinatorial selection. Because the prediction we have is that step number one, the first selection barrier is that you have to overcome is stability. We call it the S polymer for stable because what if your little proto cells that butted off just all fall apart? You end up with sludge all the time, no new polymers. So if the polymers stabilize the compartment they’re in, they are S polymers, they don’t even have to have a particular sequence. They can just be any polymer that just helps stabilize the compartment it’s in. So that’s selected for, that’s already been achieved both in the laboratory and in field work.
The next polymer that we think is going help with that is pore forming. We were talking about pores earlier. Well it turns out that pores are also stabilizing and that they let dangerous stuff, things with high osmotic pressure out of a proto cell so they would have two jobs to help create stable membranes and also to let things in to start metabolism. So we think the P polymer, the pore forming polymer will be next because it doesn’t have to be specific. It only has to jam its foot in the membrane and create the transient pore. And it turns out that groups led, led by Christian Meyers in Germany have done that. They’ve actually evolved the first P polymers in their system. And it also turns out that leading researchers like Jack Szostak back in Wayne 1993, they evolved a ligation performing ribosome through random selection of 300 mers of RNA sequences going through a tube, which the selection criteria were basically glass beads, which would cause the RNA sequences to stick to the beads.
And over several weeks you can read this wonderful paper, they amplified out of random sequences was formed a ribosome capable of ligation activity just through chemical evolution. So there’s an entire field now of chemical evolution, a lot of being done by Gerald Joyce at Scripps Institute. Beautiful work that has shown that in the laboratory we can start with random sequence of RNA or other compounds and we can, based on the design of selective criteria, we can pull out unique design and unique solutions that emerge from the random sequence that no one could predict. And so the pot spring hypothesis brings all that together and says we have a glass tube called lipid. We have compartments that we can put things in and do molecular evolution inside the lipid environment. And we predict that beyond the P polymer would come, the M polymer, the first metabolic polymer that is capturing energy, perhaps solar, perhaps chemical that’s doing a little out of cataly cycle.
This amplifying material that makes the whole community more robust. The protanote, which is the collection of emerging proto cells becomes more robust. And then after that, perhaps the first catalyst would emerge that really kicks up all of those auto catalytic cycles. It makes it more efficient. But along the way you have to have the I polymer to get the C polymer, the catalyst, you need the I polymer, the information storing polymer. And this is the work that we’re going to start undertaking next year. Early work has suggest that if you have a short strand of DNA and you introduce hot water, those strands separate they melt. And that’s in industry in medical sciences called PCR polymerase chain reaction. That’s how genes are sequenced using a PCR device.
But what if in a warm little pond you had a double strand of a DNA like material that when the hot water hits it melts comes apart, it can then express through Watson-Crick base pairing another polymer that will then pop off and perhaps the strand can then close. And you have a way to express a quasi gene or a proto gene without having complicated enzymes. This is the work we’re doing starting January with a wonderful new student coming from Lithuania through the Biota Institute. We’re going to try to make this work.
Jim: That last one’s really interesting. I’m just sort of thinking here live. So this might be a stupid question, but could thermal change in near real time be part of this, right? Cause one of the things, you go to a place like Yellowstone, it gets hot, it cools off, then it gets hotter again and cools off. Could that real time near real time temperature change, break the DNA and then if the temperature range just right, let it recombine, right? So you get the separation recombination without all the very complicated and expensive machinery that advanced life has.
Bruce: You’ve nailed it on the head and hit that proverbial nail again Jim. Jack Szostak’s group at Harvard has proposed something like Yellowstone Lake as a place because you end up with a very cold surface. Because on the early earth we had a fainter young sun. So it may have not been as hot as we think. There may have been frozen environments. So they’re proposing that polymers that are making the transit from the hot spring vent in the lake, getting up into that cool environment would have chemically different changes. And then they would melt, they would strand separate. And then this would be a place for amplification and temp lighting.
We would add that into the hot spring environment because we need the wet dry cycling to actually make those polymers in the first place. So literally it’s all coming together into a picture that we have in the sub aerial landscapes in pools, whether they have some cool environments, dry environments, hot infusions, and simple dew forming events, diurnal dew forming steam that is creating, sheens on rocks. That’s enough of a wet dry cycle to do a lot so that these environments are so rich.
The environment that’s at the boundary between the atmosphere, the mineral geosphere and the hydrosphere, that boundary is where the maximum chemical complexity and power energetic, basically thermodynamic ratchet is possible at that boundary. And even today, if you look at life at the water’s edge, the edge of a marshland, it is just rocking it right there. That is the place where water meets soil or mineral and air is the place where you have the maximum complexity in life.
Jim: And a lot of solar throughout there too as well. The marshes are the richest producing areas with Chesapeake Bay or near where I grew up famous. It’s the great protein factory.
Bruce: In fact, when I was visiting Freeman Dyson at the Institute for Advanced Study, we would have lunch together every once in a while. And he said, I grew up in Bournemouth at the edges of the oceans. And as a child, and this is in the 1920s, he would walk and look at all a rich life in those little pools and watch how they dried down and chemically changed. And it made him wonder about the origin of life back in the twenties as Freeman Dyson, the physicist.
Jim: Interesting. Now I really, really like this I polymer this. Of all the things I’ve learned about your approach, this is the one that I go, aha. Cause if this actually works, it answers or at least provides a road to answering one of the great difficult questions in evolutionary biology, which is, as I mentioned, my core field is evolutionary computing. And as you know, I’ve been fooled with a life and similar things, there’s a well known problem in evolutionary computing, which is known as the error catastrophe if the replication between rounds, shall we call it, of evolution, if the error rates too high, there’s a rather crisp limit to how much evolution can happen. And when you get the error rate low enough, the ability for evolution to ratchet massively increases. This has always been one of my questions about the RNA world. You know, RNA world is not at all good at precise replication, very high error rates.
And yet we know in advanced life there’s very elaborate machinery to detect and even correct errors in DNA. So how does the very high error rate RNA world ratchet itself high enough through the error catastrophe to create the higher fidelity air corrected DNA world that all life, every bit of life, no exceptions, exhibits today on earth. And in fact, one of the best conversations I ever had in my life’s four hour discussion with Stuart Kauffman about exactly this question. And we both said, that’s a good question. We couldn’t come up with any answers. Maybe this is part of the answer.
Bruce: Well, I can give you, if we again situate ourselves in the cycling pool, what we gain from that to overcome Manfred Eigen’s error catastrophe, I think they called it at one point, Eigen and his collaborator. And also Freeman points it out on his book on origin of life, is if you look at individual replicators in isolation, they’re undergoing a serial replication. Of course this is all their models show the summation over errors and then the whole system crashes. But if you have a cycling system and a population, a population of replicators, some of which are pretty high error rate, of course they will crash out. But however they are added to by other replicators and the replicators interact with each other. And in the beginning we have to ask ourselves, what is the job of a replicator? The job of a replicator in the beginning is to make stuff that’s just good enough.
And this was, came out of a conversation I had with Freeman, just good enough to do a job in its own context. So we can’t use modern biology really as a guide to proto biology because we have to do certain jobs. And one of them is to keep our proto cells together. So let’s look at the first job stability. The proto cell doesn’t wobble apart in solution. We just need any polymer. We could just have dimers two chain polymers that would keep the proto cell from wobbling apart. So the replication thing is just give me any polymer. It can be a periodic crystal with any structure, any symbol order. So a replicating process in that case is just wet dry cycling in the self assembly and addition elongation of polymers. So that’s the job the replicator has to do is step one is not too tough of a job, but it does the trick.
Now what if we get a pore, the first proto pore? Well, it might have to have a foot that can stick into the membrane, but that foot could be composed of any number of say nine sequences of monomers. But they had to be there to give you basically the polarity for that foot to stick in there. So the replicator job there isn’t so tough either. So it can have a higher error rate to make that little inefficient pore just good enough to do its job. So in the proto biological world, in the pro genian where life is emerging, this epoch of life’s emergence, we don’t have to have high fidelity replicators to get the system going. And because we have trillions of experiments going, hammering away at that selective barrier hammering away and the whole system’s already stacked up, it’s already stable, it already has pores and it already has a primitive form of metabolic energy capture it just cranking away so that progonote, that material is already able to grow.
It’s already able to capture energy material and grow. So it’s truly exhibiting the properties of life. But in no way is efficient replication needed to get it to that phase. It’s not at this level and from this level more efficient replicators can then start to emerge when you get that first beautiful auto catalytic set closure and you get more precision. But you can see, Jim, how it would stack up. It’s doing just a good enough job, just a good enough job. Now it’s getting more fine tuned now it’s getting more fine tuned. And because you have a community that’s trying to get across the selective barriers, you have what Stewart Kauffman calls an exploration of phase space done on a massive scale in a single microgram of lipid and several quadrillion polymers that you could do in a system you can hold in your hand, commonatorially going through literally you could do it on your kitchen stove top, you are holding in your little frying pan.
And we’ve done this in frying pans on stove tops because it’s just like any other laboratory equipment. We did this before we went to New Zealand. You are creating a combinatorial system that is so powerful that is capable of functional discovery, explorations of phase space, and potentially this pre evolution. But the replicator only has to do a job that’s suited to that stage, that phase, and that will create the substrate or the platform for the next more efficient replicator to come. And having a population, having cycling, having lots of tries will get you over that Eigen error threshold.
Jim: I’d like to see the math on that. We’ll talk soon about the Fermi paradox and a typical 12 year old nerd, I was sure there had to be hundreds of thousands of intelligent species in the galaxy. I mean just read [inaudible 01:20:46] right? But as I got older and started learning about things like the air catastrophe, I am now at the point of agnosticism. It’s just possible that climbing mountain probable to get to the high fidelity, really high fidelity, three or four errors per billion, which is really remarkable in advanced life may have been so implausible. It only happened once in the history of the universe or at least the galaxy. And we just don’t know. That’s the thing that’s interesting. But we’re going to have the possibility of finding some evidence to repudiate that hypothesis. Before we go to Fermi Paradox and astrobiology, let’s do a short dive into the actual experiments that are being done to affirm or disaffirm the warm pool hypothesis. Because as you point out, these things can be done without too much expensive apparatus. Who’s doing what? Just a quick survey and what are they finding out?
Bruce: Oh gosh, there’s so many teams now. For example, up at McMaster University in Canada, the Origins Institute built a custom half million dollar chamber called the Planet Simulator. And it looks like a glorified pizza oven, but it has a dome on top. They can introduce any atmosphere they want. They can put in UV radiation, they can put in moisture, and they can do wet dry cycling in the simulation of an atmosphere of a world, of an herbal world, let’s say. And they can also do x-ray de fraction onto mineral surfaces where they’ve dried down. And with that x-ray de fraction, they can determine that there are structured polymers there. Well, oligonucleotide, for example, through x-ray confirmation, right in the situation of the simulation itself. Brilliant work, breathtaking work. And if we zoom over to Seattle to University of Washington, Roy Black’s group is doing another aspect of that.
They’re saying if peptides, little strings of amino acids are attached to membranes, what happens? Well, they stabilize vesicles against flocculation against basically falling apart. But what they’re now proposing is that membranes that had lots and lots of polymers attached to them create a co localization. So instead of stuff floating around in solution and trying to get together, now they’re on highways of membranes, they’re colliding in a two dimensional medium and they’re going to get together a lot more easily. So the whole co localization story behind what we’re calling a progenitor is being really powerfully worked on at University of Washington and then down at Georgia Tech, the Center for Chemical Evolution and Nick Hud’s group, amazing work on wet dry cycling, creating what are called depside peptides, perhaps an early form of peptides. They’re looking for also informational molecules. They’re also using wet dry cycling. And then all across the world, there are teams going to Ladakh in India, going to Rotorua in New Zealand to do hot spring based work out there in the real wilds of the work.
And then of course at University of Cambridge using UV light. This is Matt Powder and John Sutherland using UV light to get from nuclear bases, which were available for meteorite sources to nucleotides that then can form polymers at University of Cambridge. And it goes on and on. There’s group after group in Oslo, there’s a group doing, studying how lipids form these re complex compartments, and they’re discovering that tethers form between a lipid mass in the gel phase, in the sludge. There are tethers that cause material to go back and forth on almost a physical network space. And that’s the group at University of Oslo.
Jim: Well, it sounds like there’s a lot of good work. Maybe somebody will stumble into the proto cell level, at least at some point. Do you see that in the near horizon or is that still years and years out?
Bruce: Well, a lot of the work coming out of the Szostak lab at Harvard, and researchers like Irene Chen, who’s now at UCLA, they’re doing proto cell work. So they’re actually making artificial proto cells putting enzymes into them, having them basically compete with other proto cells for membranous material. In fact, Irene’s work 10 years ago as a student, as a PhD student, was to show that you can have proto cells take amphiphile, take lipids away from other proto cells if they have a polymer inside, and it doesn’t really matter what polymer it is. So artificial proto cells, synthetic biology approaches to designing proto cells and then watching them, watching catalytic reactions happen inside a simple proto cell, not in a derivative of a living cell. So Jack’s group is sort of took the lead on that years ago.
Jim: Very cool. This is what I love to see in science where theory and experiment are working together. Experiment without theory is wandering into wilderness theory without experiment is blue sky hypothesizing?
Bruce: We call it hand waving. It’s fun to do.
Jim: Exactly right. It’s fun to do. One of the things, the Santa Fe Institute, we have to work hard with our theorists to make sure they stay in touch with experiment and data. And I’d say they’re pretty good at it. So that’s a good thing. So thank you very much for this tour of the cutting edge warm pond, revitalized theory. It’s been wonderful. I learned some new things here, particularly about the I evolution. I’m going to dig into that. You have to send me a paper or two on that one. I mean, that was a eyeopener for me. Let’s move on now and talk just briefly. We’re probably already over our time, but That’s right. Time’s cheap. I’m retired. What the hell? Right. And about the Fermi paradox and the astrobiological implications of your hypothesis.
Biological implications of your hypothesis. One thought I had when I was reading your papers was, “Even as soon as our ability to take a look at Mars carefully and Europa or Enceladus, that’s how you pronounce it, might provide us a pointer to who’s right on this one.” Right? If turns out there was life, we find life signatures or existing life under the surface of Mars, that’s at least the finger pointing in your direction. Mars was wet and then it dried out. Sounds pretty similar. On the other hand, if we find life or life signatures on Europa or a world where no light could have penetrated the ice, it all had to happen, its chemistry in the dark, then that would be a pointer in favor of the other theory, the deep ocean vent theory. Does that make sense to you?
Bruce: Yes. And in fact in our article published this summer called Urability basically worlds in which life can start. We identified 28 factors that we think have to be present for the chemistry to get going. This is a little independent on whether they’ll find life signatures. So for example, Enceladus, which is a small moon of Saturn, it’s under a 20 to 30 kilometer ice shell and you have very cold ocean. But we know some of the contents of the ocean because of geysers coming up through cracks of the ice on the South Pole and the Cassini mission flew through them. Just an amazing achievement that we were able to get some of the chemical composition of those geysers and their emissions planned there and to Europa and of course the Dragonfly mission to Titan, that’s a very different environment.
And so it’s like the most dramatic Hollywood thriller in that you have these two competing hypotheses. They’re very exciting and billions of dollars of space missions hang in the balance and the results hang in the balance. What we would suggest is keep an open mind, because if we find evidence for life under the ice at Europa, it may have been that it was inoculated with bacteria that might have started on Mars or Earth. We just don’t know until we get a full organism. What we believe and what we propose is those worlds are not Urable, but they’re certainly habitable, but they may be sterile. So there’s three words for you.
Jim: I love that new model, Urable. That’s a really good concept. That word has added to my hierarchical complexity of how I see the universe.
Bruce: You’re the first podcaster to utter it because it’s only two months old. It’s a newborn word.
Jim: Well, I love it. That’s a great opportunity. Thanks for being the first guest on a podcast to talk about the concept. And so Mars not Urable today, but the hypothesis was in the past, right? For some reason to believe it had a much thicker atmosphere and we know it had surface water, whether it had a standing ocean or not. I think it’s still open question, but it may have been Urable in the past. In fact, we all know the hypothesis is maybe Earth’s life evolved first on Mars, then traveled to earth on meteorites. And if we could find any existing biosignatures enough to look at the DNA or the metabolisms, we might be able to tell. There’s two different answers. One, same life, two different planets, which is very interesting in itself and one of the great scientific discoveries of all time, but even more interesting would be two different lives completely chemically incompatible with each other. And we just don’t know. We will find out fairly soon if there’s any life at all. Of course the third answer might be the most likely which is nope, never was life, isn’t life.
Bruce: And here is something to think about which was another incredible, needle in the haystack, moment. So as in the late 2000, think 2007 or ‘8, the Spirit rover was crunching along in the surface of Mars, one of its wheels got jammed, probably a stone stuck in it and it became a trowel. And toward the end of the mission it was driving along through an area called Columbia Hills near an outcrop called Home Plate. And I remember the announcement of this, it was so exciting and it dragged through the saw and it turned up what looked like white powder, which wasn’t snow, it was opaline silica. It was the silica, the centers that formed around hot springs. And by accident they discovered a 3.7 billion year old preserved Yellowstone on Mars. And so in its remaining life, the Spirit rover imaged the area and found what looked like very close to the digitate silica, little finger-like rocks that you would find near hot springs in New Zealand or in El Tatio, Chile where these digitate rocks are infused with microbiota.
And the microbiota literally as they form by water wicking away and silica being left, becoming a mineral, the microbiota are in there shaping how those things turn out. And so we literally have a picture of a hot spring on Mars, which if it was on earth, would preserve life very well, be a strong biosignature. We need to go back to that location. Those are the rocks we need to actually do biodetection because those are the rocks that if we were walking out in the Pilbara or we were walking near a hot spring, we would pick those rocks up, thin slice them and look for microbial chemical traces. And so that’s the exciting news. We already found a hot spring on Mars that could have biopreservation from right about the right era as Mars was drying out.
Jim: Wow, I did not know that. That is big news. I mean hopefully we’ll get our shit together and get back to that spot and take a look. That’s kind of nice that we actually are able to zero in on a very plausible spot to take a first look rather than have to look around a big planet. And of course, even Venus could have had life earlier, it may have had a Urable period early on. And again, some people say, “Hey, there’s a warning. What happens when you pump too much CO2 into your atmosphere?” Right? Because CO2 levels are lower, Venus, it would be hotter than the Earth, it wouldn’t be the hellish place that it is today.
It’s got what, a 25, 30% CO2, maybe more than that in its atmosphere. So anyway, let’s move on to a last question. I pondered this and I couldn’t come up with anything useful. You as much deeper thinker on the question may be able to. As you well know, the new space telescope and other soon to come space instruments are going to be able to start doing spectrographic analysis on the atmospheres of exoplanets around other stars. And there’s many hypotheses about what might constitute biosignatures. Do you have any thoughts on whether these kinds of remote sensing will one, tell us anything about whether life exists and two, whether they’ll provide anything useful to distinguish between the two hypotheses?
Bruce: Well, in terms of the biosignatures of the atmosphere, that’s, of course, methane is a major biosignature. And yet methane sources that are widths of methane that have been detected in Mars’ atmosphere may have geological sources, geochemical sources. So again, that’s out of my department. But when we meet with our colleagues who are working on exoplanets, who are working on the Kepler data, who will be working with James Webb and who are also doing an amazing job of modeling virtual worlds. They’re creating these hypothetical planets. We develop the Urability framework for them, basically saying those worlds of course may be habitable in the TRAPPIST-1 system, for example, those wonderful lineup of planets.
Jim: Around the little red star, right?
Bruce: The little red star with very low energy output. And what we can do now, and this is what some of our students are working on and as we meet our exoplanet colleagues and say for the first time, we can give you a framework with these 28 factors that if it was applicable to your modeled world around TRAPPIST-1, would give it a score, an Urability score. Can it start life? Of course if life arrived there from elsewhere, that’s another question, can it be sustained? Possibly. But the Urability of those worlds can now be scored with, we have a box now to put a framework around it and this goes back to Frank Drake and the Drake equation.
Jim: Famous Drake equation.
Bruce: The famous, in a sense, this interview is in the memory of Frank Drake because he passed away, he passed from this earth a few weeks ago. But if you look at the Drake equation, there’s the FL, the factor which is the number of worlds that can start life. And so that’s one of the important factors. The next one along is the one that where complex life emerges, multicellularity. And then the next one along is where intelligence, so technological civilizations can emerge, et cetera. But what we’re starting to propose to our colleagues is that the assumption that microbiota bacteria, something like a bacterium, emerges easily in these environments is not a necessarily strongly supported assumption. And that bacteria may be hard, they may be as hard as getting to Nick Lane as he describes the transition to eukaryotic life. That was a hard transition. That took several billion years to get to the point where eukaryotes, big cells that had organelles.
Jim: And we still don’t know how it happened. That’s still a gigantic mystery. And again, it’s another one of these pruners on the Drake equation that may mean that we’re unique.
Bruce: And that the transition, if we’re talking about the -progenian epoch, which is not geological, but a chemical biological epoch from the self assembling little protocells in these water environments all the way to the first microbial map where the sludge turns into more of a living sludge and is able to colonize, that transition, if you break it down into the parts, it’s a vast chasm of happenstance of the exploring a phase space of happy accidents, of an incredible amount of tries and retries, extinctions, failures and restarts over and over and over again. It’s not a given that you’re going to get to a protocell which becomes a living cell able to divide itself and push its genetic material into other cells that are then viable. That’s basically the transition from the progenian into the Precambrian. That would be the transition. So here’s an example of how hard this is and how fun it is to do thought experiments in this space, in this chasm, going across this chasm.
What would possess a protocell to evolve the tools or somehow combine the previous tools to do a division? That’s the D Polymer for dividing, duplication, dividing, the D Polymer which is really a complex set of polymers to do that job. And you have to find selective barriers that make that come into being. Because in a nonteleological approach, which we’re taking here, there isn’t a goal or a design objective, There isn’t a blueprinting. Now we have to learn how to divide. It just happens. And so one can say what are the selective pressures in the late progenian? Just as things could learn to divide on their own inside their communal complex. And it turns out one of them, it came to me a few years ago, was trash. If you couldn’t get rid of the trash that accumulates in your house, in your bathroom, in your kitchen and whatnot, your house would become unlivable.
But what do we have as a technique to do that? We have garbage bags and sewer systems and we put it out on the curb. And so it keeps our environment of our home livable. Well, in the progenian period with protocells, there’s no active pores to cycle stuff out. That’s a high tech thing but there is trash collection and it’s the pinching off of what are called exosomes or little liposomes that with a simple protein you can pinch off. And this is a very common thing in living cells today, liposome compartments, exosomes are just everywhere, full of cargos of various things, some of it trash. So you could imagine that a selective barrier that those things are pushed up against is the accumulation of byproducts and trash and stuff that if they could get rid of it would mean that they were more robust, therefore it would be selected and amplified.
And at the late progenian, perhaps this budding off of trash compartments got tied together with the division of the whole compartment at the very moment when the genetic material was present on either end of the wobbling vesicle. And so you could see that great moment where the wobbling vesicle wobbles apart under timed control just as the contents were duplicated. And now you have the transition to the linear descent of genes rather than it’s complete horizontal sharing in the wet/dry cycling. And now all the proteins and DNA and RNA are being made in solution, they don’t require drying down because enzymes have emerged and you have the transition from the protocell community to the living microbial community. And it happens bit by bit. So a lot of cell divisions fail, doesn’t matter because they’re inside a communal complex. So a cell division can be tried and fail and won’t kill the whole organism because it’s sitting in its communal sludge.
And that was one of the great insights we had early on is that the community, the niche in which all these things are emerging is a supportive matrix. It’s a surround, it’s the progenitor, which nurtures and basic protects this process of biology. It’s the very first ecosystem. And working with colleagues in Oxford, John Odling-Smee, were writing a book chapter for MIT press which is about that niches came first. That this sludge is the first niche that begets the ability of life to emerge within it. And one other little point that it blew my mind when I first thought of it, I asked the question, “Did life emerge from a simple environment or a complex one?” And this is at the very edge of complexity theory and biology. And there’s a metaphor for you which is if you go into an inventor’s workshop and you see their little machine that they’re trying to make, this like an efficient, like a Dyson vacuum cleaner. The workshop is full of parts, bins and shelving of super huge number of parts-
Jim: And 1200 prototypes that didn’t work.
Bruce: Yeah and a million parts that may never been used in a prototype. And the inventor’s workshop is the model, I believe, for the progenitor workshop that begets life in that in order to get a simple, efficient set of circuits going and a protocell to living cell, you need a huge surround of a larger number of building blocks to get that selection to work. And this is at the very nub where complexity theory meets biology.
Jim: So this is really interesting in that I’m going to again put words in your mouth so spit them out if I’m going too far here. But there had to have been a quite rapid increase in complexity from physics just prior to that complexity being mined to create biology. Is that what you’re trying to say?
Bruce: That is the most beautiful telling of this I’ve ever heard, Jim.
Bruce: There’s a bump. Now consider what is that bump made out of? If you cycle gram quantities of that lipid membrane and put a bunch of Bragg’s Amino Acids from a bottle or nucleotides together and you make a sludge that’s like a cubic centimeter and some of it has polymers and you cycle it a number of times, you have made something more complex potentially than the planet that it sits on. There are more distinct objects there, distinct volumes, motion and commonatorial complexity and that little cube of EX Noble sludge that potentially the land mass that sits on.
Jim: Yeah, that’s really interesting. That’s a really important idea that there was some form of complexity bootstrap and life was along the way, but it wasn’t the beginning. We tend to think of life as being that bootstrap, but your hypothesis is not bad. That it could very well have been that there was a necessary exponential increase in complexity in the chemical, physical domain before you had enough peace parts in the mad scientist workshop to create life.
Bruce: That’s it. And prior to this idea, which we’re putting out in this new chapter called The Progenitor, the substrate in which life can emerge, which will guide hopefully all future experiments. Prior to this, our colleagues have been doing individual down tequilibrium chemical experiments and very simple protocells sort of on their own. And when you asked the colleagues, “Do these things wind down to equilibrium?” And they say, “Of course they do.” We get certain number of products. Is this sufficiently complex? Is it protocell in dilute solution with a few things in it sufficiently complex for life to emerge? And they would say, “Of course it’s not. We’re just trying to show one step or something.” So what we go back to them and say, “We’re all in agreement. We need a substrate that is sufficiently complex. And what about this? And this is realistically plausibly formed by meteoritic organics or organics from other sources.”
And you can make them in five minutes. And in fact, the experiments Dave and I are doing in the lab now, we’re literally doing polymerization in half an hour of a large number of short RNA polymers with the lipid and ligation and elongation going on all at the same time. So the stuff is cheap to do, it’s easy to cycle and then it’s tough to analyze because what you’re looking at in your blob in your hand, went from a simple bunch of building blocks now to something that’s gigantically complex. So how do you pull it? Use HPLC. Can you really see them? Do you use nanopore sequencing? Do you spin them down into a palate and just measure the amount of polymers? That’s what we’re doing. And then we’ll go on to nanopore sequencing, which we can sequence those little polymers. And then what if the polymers start doing jobs? How do we know they’re doing jobs? Well, the only way to know right now is to see that the number of protocells and the mass of the gel phase, that progenitor grows over time.
Jim: Exactly. If there’s a net metabolitic output, right? That’s what you’d be looking for.
Bruce: So now to the fairly paradox, which is I know where you wanted to get.
Jim: This will be our exit question. Now you know more about this than anybody I’ve ever talked to. Because you think about it both in terms of you understand evolutionary computation, the mathematics, the air catastrophe. You understand tremendous amount about various pathways, the origin in life. So what’s your probability that we humans are the only general intelligence in the galaxy at this time?
Bruce: What I would propose is a sort of new Drake equation that looks backwards in time. So you start with the intelligent human technological civilization and you go through the number of fortuitous catastrophes, combinations. The fact that our planet had to maintain liquid water for 4 billion years on its own, which is not a given, we are now finding, all the way through complex organisms, fungi, things like that, back through eukaryotes, back through the microbial community, map community, which is still like the predominant form of life and will be in the universe, all the way through the chasm, the molecular collateral chasm to that first little sludge in the pool and you create a new Drake equation.
And you say what is required as a selective barrier, fortuitous changes in the environment, dumb luck. And you could come up with a reverse Drake equation all the way from life’s origins and all the way even to the planetary milu, the types of worlds, the Urable worlds argument. And from that, this is a Brownlee and Ward’s Rare Earth approach. This is just a brilliant bunch of work. But could we do a new Drake equation? We may be going down back to *steady institute to do another talk on Urability as applies to Frank Drake and the Drake equation. And what I’d like to do is propose the reverse Drake equation because we’ve got more data points on the incredible rarity, quite plausibly of the rise of homo sapiens at the end of the game.
And so we could get some numbers, you could some boundary conditions and least a working framework to take off where Frank were left off or where Sady he is currently working. My prediction is if you add the factor, if you add Urability which gives you a lot more solid thing to argue that. And that also if you add the proposal that bacteria may be hard, microbes may be hard. You now have a more realistic picture. Because if microbes are hard, that produces the inventory of worlds where microbes can start and worlds die out from underneath microbial emergence. Mars probably in. So Martians are always going to be halophilic extremophiles in the rock.
Jim: If they exist at all, right?
Bruce: If they exist at all. So there is no future path. So the majority of life in the universe is halophilic microbes in rocky crust.
Jim: If it exists at all, even it turns out you can cross the hard jump to bacteria. Getting any further may be very difficult.
Bruce: So my prediction is as we open our minds to this reverse Drake equation idea, and then we factor in the sheer number of exoplanets, we can put those two things together like this. We can stack them up and then we have to classify the exoplanet as Urable or not. And we have to factor in what if bacteria emerge fortuitously somewhere and they are able to spread? Well, that gives you a little bit distribution, always gives you a little bit of a leg up.
And then all the other factors for complex life we’re going to emerge out of a decade old process of saying, “My prediction is we are extremely rare. Extremely rare. And that technological civilizations that are sort of out there looking and even asking the questions of their own origin, are vanishingly rare and probably separated by great distance.” And we may be effectively alone, but we might have a lot of microbial cousins around on worlds that no longer carry the capacity to carry them to complex organisms. But it’s an exquisitely beautiful, rare and unlikely occurrence that we exist at all. And that could be a subject for an subsequent podcast. Does that give us a real sense of responsibility?
Jim: I argue this all the time. It’s why I say the firming equation is the second most important question in science. People always say, “Well, it’s the first. You say it’s the second. First is, why is there anything, right?” Or a long wave of being able to answer that one. But yeah, if we are it or effectively it, let’s say at the galaxy level, then the responsibility on us not to fuck up is gigantic. If it turns out there’s a hundred thousand general intelligences in the galaxy and we fuck up ourselves, frankly, oh, well, but if we’re the only one, maybe the only one in the universe, and we have two choices, to become the martian bacteria and irrelevant, or to bring the universe to life. To blow that opportunity is a crime of the largest imaginable magnitude.
Bruce: And like a Hollywood car chase, you might ask toward the end of the movie, “Why us? Why now?” Well, as James Lovelock who also passed away this year, pointed out in his book Rough Ride to the Future, there’s this beautiful chapter saying, “Hey, fellow humans. This thing which I call a Venus Terminator is approaching the earth. The line in the solar system where Venus was just too close to the sun, so it’s atmosphere boiled off and became a hot house hell, that terminator is very close to us. He predicts a hundred million years to have a 3% increase in incident solar radiation when we’re across that, Terminator means that the atmosphere has to have zero CO2 in it to prevent a runway greenhouse. So it isn’t billions of years for complex life in the future, it’s hundreds of millions. It’s a fraction of a percent of the history of life on Earth remains the bump where complex life can exist.
And you can see this, according to Lovelock, by the belt deserts. So the belt deserts around north and south are evidence that *gaya is failing. We’re products of that because we were cast out into East Africa with a riff valley into a desert drying environment, a wet/dry cycle, which forced us to become who we were or are. And so the evidence of those belt deserts is a biosphere that’s losing its ability to support plants on land. So you have glaciation and then you have desertification. Glaciation, it’s a swing in the pendulum. And with climate change, we’re pushing more energy in, but it’s a world that’s dying.
It’s in late middle age or early old age as far as complex life is the case. And so there isn’t anything to follow us. So if there is a life force is there is a dictum or a drive to reproduce and to carry on, it may be getting pretty intense because the whole planet’s about to undergo this decline. So it’s the last time to do the ultimate act as it was with protocells, even though it wasn’t theological, was to carry on and divide. Maybe it’s our job. We are evolved to create new biosphere and spread the jewels of life in more than one place because this world is a womb, but it is also a tomb.
Jim: Yeah, I like to say it, bring the universe to life. That’s actually the purpose of humanity, especially if we’re alone. Well, Bruce, let’s wrap it there. This has been one of the most interesting conversations I’ve had in a damn long time.
Bruce: Thank you, Jim. It’s an absolute pleasure. You are one of the few people on the planet in 4 billion years of evolution with which we can truly geek out on the origins question.
Jim: Yeah, it’s been great. I think the audience will love it.