Speaker 1: Welcome to stuct to Blow Your Mind production of My
Speaker 1: Heart Radio. Hey are you welcome to Stuff to Blow
Speaker 1: Your Mind? My name is Robert Lamb and I'm Joe McCormick.
Speaker 1: And today we're gonna be talking about something that that
Speaker 1: I've been thinking about doing an episode on for a while,
Speaker 1: ever since I read an article a while back that
Speaker 1: really interested me. And that is the surprising and kind
Speaker 1: of counterintuitive link that has been proposed by many geologists
Speaker 1: now between life as we know it on Earth and
Speaker 1: the fires of mountain doom, specifically the most violent and
Speaker 1: scary of geologic processes like volcanic eruptions on the movement
Speaker 1: of tectonic plates. Yeah, this is a great topic to
Speaker 1: get into. We kind of had a I guess a
Speaker 1: preamble to this's a couple episodes ago when we were
Speaker 1: talking about eggs and we talked about the volcano birds
Speaker 1: and the idea of a volcano being a seeming, you know,
Speaker 1: almost paradoxically to be something that can nourish life as
Speaker 1: opposed to something that's just a purely destructive force. Oh.
Speaker 1: I didn't think about that comparison at all, but yeah,
Speaker 1: the way that the volcanic sand baby sits the egg
Speaker 1: for the for the megapode, so that it can just
Speaker 1: run off and do its own thing, raised by a
Speaker 1: volcano um. But so I thought a great place to
Speaker 1: start here might be with a brief reading from the Voluspa.
Speaker 1: It is a famous old Norse epic poem from the
Speaker 1: collection that is known as the Poetic Edda. Now this
Speaker 1: is a this an anonymous work. The author is unknown,
Speaker 1: But the Voluspa tells the story of the Norse gods
Speaker 1: culminating in their destruction in the fiery doom of Ragnarok.
Speaker 1: And I'm just going to read a couple of quatrains here.
Speaker 1: In anger smites the warder of the Earth forth from
Speaker 1: their homes. Must all men flee nine paces fair Air's
Speaker 1: the son of Jorgan, and slain by the serpent Fearless,
Speaker 1: he sinks, The sun turns black, Earth sinks in the sea,
Speaker 1: the hot stars down from heaven our world fierce grows
Speaker 1: the steam and the life feeding flame, until fire leaps
Speaker 1: high about Heaven itself. And one fun thing about this poem,
Speaker 1: it's a bit of Tolkien trivia. Robert, tell me if
Speaker 1: you've heard this before. But the name of the wizard
Speaker 1: Gandalf that first appeared in in Tolkien's The Hobbit, and
Speaker 1: then of course is like the best character and Lord
Speaker 1: of the Rings. The name of Gandalf comes from the Voluspa.
Speaker 1: Tolkien actually borrowed the name from a section known as
Speaker 1: the Tally of the Dwarves from this epic poem. Originally,
Speaker 1: he was going to apply it to the character in
Speaker 1: The Hobbit who became thorn oaken Shield, the leader of
Speaker 1: the Dwarf party, but then he decided later on that
Speaker 1: it made more sense to apply the name of Gandalf
Speaker 1: to the wizard, I think because Gandalf means something like
Speaker 1: magic staff elf, and I think he made the right choice,
Speaker 1: like Gandalf that makes more sense for the wizard than
Speaker 1: for Thorin. But a cool thing that happens in this poem,
Speaker 1: it's sort of part of the Ragnarok myth, is that
Speaker 1: there is a rebirth that follows this fiery doom. You know,
Speaker 1: after the fire leaps high to heaven and the Kingdom
Speaker 1: of the Gods is destroyed, Earth is not just left
Speaker 1: in cinders. Instead, there is a renewal from the fire,
Speaker 1: and the author rights, now do I see the Earth
Speaker 1: a new rise, all green from the waves again, the
Speaker 1: cataracts fall, and the eagle flies and fish he catches
Speaker 1: beneath the cliffs. So there's this great link between fiery
Speaker 1: cataclysm and rebirth and renewal of life in Norse mythology,
Speaker 1: and and of course there you know, these are symbolic elements.
Speaker 1: I'm not suggesting that they had some kind of scientific
Speaker 1: insight with this. It's it's just something you know that
Speaker 1: I think is taken as a metaphor largely about human
Speaker 1: life itself, but coincidentally it ends up kind of ringing
Speaker 1: true with things we're finding out about geology and nature. Well,
Speaker 1: it's something you've see in a lot of different mythological cycles, right,
Speaker 1: I mean you see it in in in in Hindu mythology,
Speaker 1: you see it in uh various um American mythologies. Uh
Speaker 1: you know, thinking about Mezso and South America in particular,
Speaker 1: is this idea that things will rise, things will fall, Uh,
Speaker 1: that there will be cataclysm, that whole world will be destroyed,
Speaker 1: but new worlds will rise out of them and have
Speaker 1: risen out of them before. Yeah, I was thinking about
Speaker 1: themes of fiery eruption and the greening of the Earth
Speaker 1: together or sort of a creator destroyer duality. One that
Speaker 1: came to my mind that that I thought you might
Speaker 1: know something about, because I know I've heard you talk
Speaker 1: about Hawaiian mythology before. Was the pale myth Yeah. Yeah,
Speaker 1: the Hawaiian goddess Pale is an interesting example a deity
Speaker 1: of fire and volcanism. I was reading a book titled
Speaker 1: Pale Volcano Goddess of Hawaii by H. R. Low Nemo,
Speaker 1: and he points out that when Polynesian voyagers first arrived
Speaker 1: in Hawaii, they would have brought their gods with them. Now,
Speaker 1: now we don't know where in the Hawaiian islands. This
Speaker 1: would have specifically been which of the islands they would
Speaker 1: have landed on, and where and even when remains a
Speaker 1: topic of debate. I've seen dates ranging from three hundred
Speaker 1: seed to a thousand sea, and of course contact with
Speaker 1: the Europeans didn't occur until seventeen seventy eight. But the
Speaker 1: newcomers would have arrived on sailing technology in keeping with
Speaker 1: that of the larger Polynesian expansion, as well as related
Speaker 1: cultural inventions such as gods and goddesses, all of which
Speaker 1: would then evolve into distinctly Hawaiian models afterwards. Now, as
Speaker 1: we discussed in the show before, the Polynesians were some
Speaker 1: of the last true explorers of the inhuman regions of
Speaker 1: the Earth, and their saga, which is full of fascinating history,
Speaker 1: is is it's not unlike what we might expect of
Speaker 1: a space faring civilization with time and space sufficient enough
Speaker 1: to see the splintering and continued evolution of societies from
Speaker 1: region to region as they spread out across these far
Speaker 1: flung habitable spaces. Now, Nemo points out that the first
Speaker 1: Hawaiians brought with them kane kind of lowa uh Ku loan,
Speaker 1: no gods known throughout the South Pacific. But they also
Speaker 1: brought with them what was apparently a minor fire deity
Speaker 1: named Pelee. And they didn't bring any volcano deities with them,
Speaker 1: but but she was this fire deity that seemed to
Speaker 1: pre exist, and she likely remained insignificant for a while there,
Speaker 1: at first, just another minor deity like she was previously.
Speaker 1: But then eventually uh though the Hawaiian islands shook and
Speaker 1: the volcanic mountains, of which six are active today belch
Speaker 1: forth fire, magma, and ash, and this is what Nemo writes, quote,
Speaker 1: this minor deity was apparently transferred to the volcanoes and
Speaker 1: became the goddess Pele, who was destined to hold a
Speaker 1: powerful position in the Hawaiian antheon. The great volcanoes became
Speaker 1: her home, their power, her strength, their beauty and destruction,
Speaker 1: her manifestation, and their unpredictability, her temperament. Now, Paley would
Speaker 1: not be the only god or goddess from a pantheon
Speaker 1: in the world that's associated with with specific volcanic activity.
Speaker 1: But I would imagine that that a volcano god takes
Speaker 1: on a very special significance when you are an island culture,
Speaker 1: So when you're like geographically bound very close amidst a
Speaker 1: vast ocean to that that ground forming and life giving volcano. Yeah.
Speaker 1: Something to think about here is that we we see
Speaker 1: other gods, particularly um gods in the Greek and Roman
Speaker 1: cycle that are associated with with fire and also associated
Speaker 1: with volcanoes, but also associated with the forge, the forging
Speaker 1: of things. Um. We also see this in Lord of
Speaker 1: the Rings with with sarin Is. This is essentially a
Speaker 1: he Festus type character, right, But as we discussed previously
Speaker 1: on the show, in one of our armor episodes. Um,
Speaker 1: you certainly don't see metal work uh, occurring on the
Speaker 1: Hawaiian islands. I mean, you don't see see iron. Therefore,
Speaker 1: the taking in the manipulation, they were using wood and
Speaker 1: fiber and shark tooth based technology and doing and using
Speaker 1: so excellently. But I wonder how much of it too
Speaker 1: has to do with the fact that that Pale would
Speaker 1: have been removed from that there would have been no
Speaker 1: human forge to overshadow the natural cycles of fire in
Speaker 1: the earth, you know. And on top of that, here
Speaker 1: is the volcano itself, Here are the volcanoes and these
Speaker 1: volcanic islands, where where it's it's activity, it's it's it's
Speaker 1: geologic life is so obvious. Now. Nemo spends much of
Speaker 1: this book discussing the ways that Paley is viewed, and
Speaker 1: certainly drives home that that she's not a monolith. Traditions
Speaker 1: and ideas regarding Pale range from religious belief and cultural
Speaker 1: identity to the abstract, the environmental, and even uh. There
Speaker 1: are these, um numerous examples of supernatural sightings in which
Speaker 1: one claims to have seen or believes to have seen
Speaker 1: a beautiful woman standing in the fire. But there certainly
Speaker 1: is this recurring theme of one who creates with volcanic
Speaker 1: fire and may also take back via the same power
Speaker 1: um of a quote traditional spiritual respect for the life
Speaker 1: forms her creation supports. For instance, in the book, Nemo
Speaker 1: does bring up a specific example, uh talking with someone
Speaker 1: who lost uh some property due to a volcanic eruption,
Speaker 1: and they asked him, well, what, how did this change
Speaker 1: the way you think about Pelee? And they say, well,
Speaker 1: I do, it doesn't. Pelee gave this to me. She
Speaker 1: created the land and I was just using it, and
Speaker 1: now she has taken it back. Yeah. The Lord giveth
Speaker 1: and the Lord taketh away. Yeah. Now the lord that
Speaker 1: people are usually talking about when they when they say
Speaker 1: that is the is the the god of of of
Speaker 1: Judeo Christian tradition, right, Uh, which brings up this question. Joe,
Speaker 1: you're more of an Old Testament kind of guy than
Speaker 1: I am. But so have you ever run across this
Speaker 1: argument that yahweh uh in Hebraic tradition may have started
Speaker 1: off as a volcano god. Yeah, I was reading a
Speaker 1: bit about this. Um. This seems like one of those
Speaker 1: things that you it's kind of an interesting idea. You
Speaker 1: can't totally rule it out, but it seems highly speculative
Speaker 1: and based on kind of scanty evidence, So so I
Speaker 1: would say it's one of those things that is possible,
Speaker 1: but probably not. I think it's mainly based on ideas
Speaker 1: about geography, like the idea that you know that Sinai
Speaker 1: Mount Sinai would have had some kind of volcanic element
Speaker 1: in the past, and then referring to specific passages in
Speaker 1: the Bible which described the Lord in terms that people say, well,
Speaker 1: maybe this could be describing a volcanic eruption or something,
Speaker 1: and it's one of those things that you can often
Speaker 1: do with these geomethology. This actually, I guess would technically
Speaker 1: geomethology a geomethology inference, and so I'd say for this one,
Speaker 1: you know, it's not impossible, but it's kind of a reach. Yeah,
Speaker 1: I don't think i'd I'd run across it myself, but
Speaker 1: I saw mention of it, and one of the sources
Speaker 1: that was often there were often was often cited here
Speaker 1: was a book by Jack Miles title of God Biography,
Speaker 1: which is a popular work that seems to discuss this.
Speaker 1: So I looked it up and it's in reference to
Speaker 1: Exodus forty eight. Uh, he writes, quote, nothing in nature
Speaker 1: looks like a cloud by day and a fire by night,
Speaker 1: except a volcano. The depth of the Lord God's compelling
Speaker 1: but contradictory power is well evoked by the extraordinary image
Speaker 1: of a volcano brought into a tent. Now speaking of
Speaker 1: volcanoes and gods and getting back to to Tolkien. Uh. Now,
Speaker 1: I've expressed in the show before that I love a
Speaker 1: good journal paper that that digs into some Tolkien that
Speaker 1: tries to find the science of Middle Earth. We've talked
Speaker 1: about that previously with the Hobbit, you know, the how
Speaker 1: many meals does the Hobbit need a day? And Willy'll
Speaker 1: be able to march across the Earth? Uh. Also we
Speaker 1: got into the metallurgy of the One Ring. So I
Speaker 1: was like, well, somebody, somebody has to have considered Mount
Speaker 1: doom and um and you know, the geology of Middle Earth.
Speaker 1: And sure enough I found a paper titled the Geology
Speaker 1: of Middle Earth by William Anthony Swinton Sergeant, published in
Speaker 1: the journal myth Lore in NI. Now, I know myth
Speaker 1: Lore doesn't have a resounding ring of geologic authority to it,
Speaker 1: but I looked up a Sergeant who lived five through
Speaker 1: two thousand two, and he was a professor of geology
Speaker 1: at the University of Saskatchewan. And he also apparently wrote
Speaker 1: a series of fantasy novels himself, The Perilous Quest for
Speaker 1: lion S. I looked it up. I have not read it,
Speaker 1: but I've noticed you can get at least the first
Speaker 1: two books in the trilogy on kindle and paperbacks. Amazing. Okay,
Speaker 1: so he's the perfect person to right this, a fantasy
Speaker 1: novelist and and clear geek who was also a professor
Speaker 1: of geology. Yeah. Yeah, and uh he wasn't the first though,
Speaker 1: so he when when he dives into this, he ends
Speaker 1: up citing an earlier paper by Robert C. Reynolds titled
Speaker 1: the geo Morphology of Middle Earth, which is published in
Speaker 1: The Swansea Geographer in nineteen seventy four. So basically, what
Speaker 1: Reynolds had done is he'd applied the concept of plate
Speaker 1: tectonics to the entire geography of Middle Earth, recognizing four
Speaker 1: different plates, the Erador played in the west, the Rovanian
Speaker 1: played in the north, and the Harad and more door
Speaker 1: plates in the south. And Sergeant then used this as
Speaker 1: his starting point kind of his bedrock, but updated it
Speaker 1: to reflect changes in plate tectonic theory between nineteen seventy
Speaker 1: four in nine. Oh. Yeah, that's interesting because I would
Speaker 1: say at the time the Hobbit was written, plate tectonics
Speaker 1: was not yet an accepted scientific theory. Yeah. Yeah, it's
Speaker 1: easy to to overlook that, especially for those of us
Speaker 1: who who have grown up in the wake of that
Speaker 1: and you know, just encountered in our science books at
Speaker 1: a very early age. Yeah. It's one of those things
Speaker 1: that just feels like people must have known this for
Speaker 1: hundreds of years. But yeah, the widespread acceptance of plate
Speaker 1: tectonics is fairly recent. Here's a quote from from that
Speaker 1: paper by Sergeant quote. Mount Doom is indeed one of
Speaker 1: four isolated volcanoes, each representing a hotspot at some distance
Speaker 1: from a plate margin, and all of them associated with
Speaker 1: evil doing dhal gouldar in Mirkwood or Thonk in Eisenard,
Speaker 1: and Arab or the Lonely Mountain. So he contended that
Speaker 1: Eisenard was a volcanic crater with central Orthanic itself carved
Speaker 1: via technology and magic from a column of solidified lava
Speaker 1: thrust up from the vent in its last eruption. The
Speaker 1: Lonely Mountain, which is ever shrouded in gray and silent clouds,
Speaker 1: is another, and he argues that Smog's chamber is just
Speaker 1: a reshaped lava tube. But Mount Doom the underlines is
Speaker 1: the only volcano that seems to be truly active in
Speaker 1: the time of the Elbow and Frodo, and the only
Speaker 1: recorded seismic events in the books occur first when Gandalf
Speaker 1: cast down the ball Rog and then when Gallum falls
Speaker 1: into the fires of Mountain Doom with the one ring.
Speaker 1: Uh So, Ultimately, he's as for a world in which
Speaker 1: all the major events are revolving around activities at a
Speaker 1: single active volcano, Middle Earth is is rather seismically calm,
Speaker 1: while still being quote geologically like our own world. Well,
Speaker 1: I gotta say, I do not know what natural processes
Speaker 1: could create that perfect rectangle of mountains around more door.
Speaker 1: That seems impossible to me. I always looked at that
Speaker 1: map and said, ah, that's just that doesn't look like
Speaker 1: real Earth. You've gotta make the outline a little more jagged.
Speaker 1: I understand, surrounded by mountains, but come on, look at
Speaker 1: those corners. Uh. This is one of the things I
Speaker 1: really liked about about our Scott Baker's work where he
Speaker 1: his fantasy work takes place in this world of the
Speaker 1: Three Seas that is very much Middle or Earth that's
Speaker 1: been you know, transformed via these various philosophical ideas and
Speaker 1: a lot of you know, the Crusades interjected in there
Speaker 1: and some other influences. But there is a more door
Speaker 1: like location in the books with a central fortress and
Speaker 1: then mountains surrounding it. But in in his books, this
Speaker 1: is essentially an impact crater created by this thing from
Speaker 1: space or beyond that has come to the Earth, and
Speaker 1: that is the central uh fortress in the middle of
Speaker 1: this uh, this this vast crater, and so the mountains
Speaker 1: encircling it are those that were cast up by that
Speaker 1: impact A plus very plausible. I like it. So anyway,
Speaker 1: there's there's some just additional token to just really kick
Speaker 1: things off here. But um, again, I would say that
Speaker 1: that saron and certainly is getting more connected to those
Speaker 1: those gods such as have Hestas, uh Adronus and Volcanos. Uh.
Speaker 1: They are all smiths in the human sense, all creators
Speaker 1: through technology rather than through the nature. That seems to
Speaker 1: be their key metaphor here. The volcano. Well to bring
Speaker 1: it back into the real world and look at this
Speaker 1: duality of you know, the same entity that might be
Speaker 1: both responsible for the creating sustaining of life, but then
Speaker 1: also fiery destruction and and explosive calamity. I want to
Speaker 1: start by asking a question that we talked about on
Speaker 1: the show a good bit, and that question is, when
Speaker 1: you're looking at other planets, you stare out of the
Speaker 1: night sky and and you're trying to find examples of
Speaker 1: other planets that might be able to sustain life, what
Speaker 1: are the conditions you would check for. I think the
Speaker 1: most obvious is liquid water, right absolutely. I mean water
Speaker 1: is the thing that, uh, more than just about anything
Speaker 1: else we just can't remove from the equation and get
Speaker 1: to life as we know it. Yeah, and that's one
Speaker 1: of the things we talked about when we discussed Brian
Speaker 1: Green's book The Until the End of Time. He has
Speaker 1: this great section where he connects the chemical properties of
Speaker 1: water to its role in the evolution of life. You know,
Speaker 1: the great power of water as this polar molecule and
Speaker 1: as a solvent, as a sort of three dimensional canvas
Speaker 1: for the drafting of the structure of cells, allowing for
Speaker 1: energy to be processed and harnessed for replication. Uh. And
Speaker 1: of course all of these virtues depend on water being
Speaker 1: in its liquid state. Water and it's frozen or vapor
Speaker 1: state is not really useful for the evolution of life.
Speaker 1: But in addition to just looking for the direct presence
Speaker 1: of liquid water, there are other conditions you might be
Speaker 1: able to look for that could, at least in theory,
Speaker 1: make a planet more hospitable to the origin, evolution and
Speaker 1: maintenance of life, at least in theory, And you might
Speaker 1: not expect it, but volcanic eruptions and the plate tectonics
Speaker 1: that volcanic eruptions might signal are another one of those conditions.
Speaker 1: So maybe we should take a break and then talk
Speaker 1: about that when we get back. Than alright, we're back.
Speaker 1: So the idea we're discussing here is the idea that
Speaker 1: that the that just as pale is not merely at
Speaker 1: a stroyer, but is also a creator volcanoes and the
Speaker 1: underlying plate tectonics that they represent might also be key
Speaker 1: to life. Yeah, and so I want to talk about
Speaker 1: an article that I was reading by a researcher named
Speaker 1: Craig O'Neill. So O'Neill is a director of the mcquarie
Speaker 1: Planetary Research Center, and he's an associate professor of geodynamics
Speaker 1: at mcquarie University, and he's done some direct research on
Speaker 1: on simulating the evolution of heating models, and you know,
Speaker 1: he thermodynamics within planets or geodynamics, And so he starts
Speaker 1: off by talking about how that you know, there are
Speaker 1: two things that make Earth unique in the Solar System.
Speaker 1: You might think, because of the conversation we were just
Speaker 1: having a minute ago, that one of them is liquid water,
Speaker 1: but actually no, there are other objects in the Solar
Speaker 1: System that have liquid water. Sometimes people bring up the
Speaker 1: example of Mars. I think that's still an open question.
Speaker 1: Of course, Mars doesn't have lakes or rivers. There's some
Speaker 1: indication that it may have transient liquid water here and
Speaker 1: there on occasion, such as in these features called recurring
Speaker 1: slope lineer though, I think I was reading a report
Speaker 1: that there is spectral analysis that has disputed the interpretation
Speaker 1: of these sort of dark spots that appear on slopes
Speaker 1: as as actual water. I guess we don't know for
Speaker 1: sure what they are, but um, there are other examples
Speaker 1: that are more straightforward, like it is totally scientific consensus
Speaker 1: at this point that Jupiter's moon Europa has liquid water
Speaker 1: under its icy surface. It's got the shell of ice
Speaker 1: on the outside. Underneath that, it's got some motions. They're
Speaker 1: sloshing around, they're having a good time. Who knows what's
Speaker 1: happening there. But there is also possibly subsurface water on
Speaker 1: Ganymede and on Enceladus. So the two features that O'Neill
Speaker 1: singles out that actually make Earth unique within the Solar
Speaker 1: System are that Earth has plate tectonics and that Earth
Speaker 1: has life. And the question that he's raising is whether
Speaker 1: these two unique features are actually causally related. If it's
Speaker 1: not a coincidence that Earth's crust breaks apart into plates
Speaker 1: that shift around and move over its surface, that float
Speaker 1: on top of the mantle, uh, that sort of spread
Speaker 1: apart in in some places and then subduct and move
Speaker 1: down and get sucked back into the mantle and other places.
Speaker 1: Does that process contribute to the creation and sustaining of life. Yeah,
Speaker 1: this is an interesting idea because it basically comes down
Speaker 1: to the question of of whether a geologically active planet
Speaker 1: is necessary for life, like if there's something there's something
Speaker 1: in this Uh, this continued geological life that makes biological
Speaker 1: life more possible, right, And I guess there are ways
Speaker 1: that a planet could be geologically active but not have
Speaker 1: plate tectonics. Like I'm going to get to this in
Speaker 1: more detail and a bit, but there are models of
Speaker 1: planets where there are not plates on the surface, where
Speaker 1: the surface is basically just one single spherical hard crust
Speaker 1: sitting on top of the mantle, but it can still
Speaker 1: have volcanic eruptions that could in some ways regulate the
Speaker 1: heating of the planet and control its atmosphere in a
Speaker 1: way that that could sustain life according to some researchers.
Speaker 1: But but we'll get in more detail about that in
Speaker 1: a minute. So we know that one of the prerequisites
Speaker 1: for the evolution and survival of life as we know
Speaker 1: it is liquid water. But why is it that Earth
Speaker 1: has maintained the conditions necessary for liquid water basically the
Speaker 1: entire time it's existed. Ever since we've had liquid water,
Speaker 1: there has been the ability for water to stay liquid.
Speaker 1: It's been long enough to allow life to continue evolving
Speaker 1: the entire time Earth has existed. So how is it
Speaker 1: possible that Earth has been able to maintain these habitable
Speaker 1: conditions in an almost adaptive and almost kind of accommodating
Speaker 1: kind of way, right like, especially since the external conditions
Speaker 1: have changed, like the Sun has grown thirty percent brighter
Speaker 1: over the same period of time, so the heat inputs
Speaker 1: on Earth have gotten much greater, and yet still the
Speaker 1: the atmospheric climate of Earth has stayed relatively stable. And
Speaker 1: O'Neill offers the answer that what's going on here to
Speaker 1: keep Earth relatively stable is it's is the profile of
Speaker 1: its geological activity. Primarily it's plate tectonics. So first of all,
Speaker 1: you've got the idea that when you have plate tectonics,
Speaker 1: you tend to create volcanoes at the edges of tectonic plates,
Speaker 1: and when volcanoes erupt, they release stuff from the earth.
Speaker 1: Stuff from the mantle comes up and is released up
Speaker 1: into the atmosphere. Probably the most important things that get
Speaker 1: released here are carbon dioxide and water vapor. Now this
Speaker 1: this is a great point that we sometimes lose track
Speaker 1: off perhaps when we think about volcanic eruptions and they're
Speaker 1: more destructive aspects. The idea that uh that you could
Speaker 1: have and you do have examples of terrific volcanic eruption
Speaker 1: um blocking out the sun, essentially forming a kind of
Speaker 1: nuclear winter type effect. Uh, sometimes on on the scale
Speaker 1: of an entire planet, right, I mean, so that that
Speaker 1: could be the case if particles get ejected up into
Speaker 1: the atmosphere, that that shield the Earth from the Sun's rays,
Speaker 1: and that can create a cooling effect. But over the
Speaker 1: long term, what they're what they're releasing is greenhouse gases,
Speaker 1: which which even though there may be particles that block
Speaker 1: out sunlight and cool the Earth at a shorter term,
Speaker 1: on a longer term, they are the volcanoes are polluting
Speaker 1: the atmosphere with c O two and with water vapor
Speaker 1: that trap heat down in the atmosphere. So that works
Speaker 1: to help keep the atmosphere warm. But then there are
Speaker 1: processes of plate tectonics that work in the opposite direction
Speaker 1: to uh, the natural process of plate tectonics. It not
Speaker 1: only releases these materials into the atmosphere, it also cycles
Speaker 1: the deep back into the belly of the Earth. Now
Speaker 1: the question would be, well, why is that important? Well, obviously,
Speaker 1: if you just keep pouring more and more greenhouse gases
Speaker 1: like c O two into the atmosphere, the Earth could
Speaker 1: end up like Venus, you know, it could end up
Speaker 1: with so much trapped heat that the surface boils and
Speaker 1: there's no liquid water and thus no life. So how
Speaker 1: does Earth deal with the extra carbon dioxide that gets
Speaker 1: released from volcanoes. Well. As the tectonic plates of Earth
Speaker 1: slide around on the surface, there are sites where those
Speaker 1: plates get sucked back under the crust and into the mantle.
Speaker 1: The Mariana Trench is one example of a location where
Speaker 1: the plates are gobbled up by the Earth. And as
Speaker 1: these plates get sucked in, they take substances with them.
Speaker 1: They take water, they take a carbonate or carbonic acid,
Speaker 1: which is the mineral form of carbon dioxide. So the
Speaker 1: process is essentially taking c O two back out of
Speaker 1: the atmosphere and sucking it down deep into the air Earth.
Speaker 1: By the way, speaking of of Venus, um should should
Speaker 1: drive home that the Venus is apparently lacking in plate tectonics.
Speaker 1: Oh yes, and but for a long time, scientist didn't
Speaker 1: think there would be any kind of volcanic activity. But
Speaker 1: according to a Reuter's report that came out just this month,
Speaker 1: scientists have identified thirty seven volcanic structures on Venus that
Speaker 1: appear to be recently active. Well I didn't know that,
Speaker 1: but that is an interesting indicator, and we can talk
Speaker 1: about more examples throughout the Solar System as we go on.
Speaker 1: That is totally possible to have volcanoes without having plate tectonics.
Speaker 1: Though if you look at a map of volcanoes on
Speaker 1: Earth's surface, some volcanoes just appear at random, you know,
Speaker 1: they might be in the middle of a plate, just
Speaker 1: some mantle hot spot somewhere. But most of the Earth's
Speaker 1: volcanoes they line up right along those lines at the
Speaker 1: boundaries of plates. So, for example, the western coast of
Speaker 1: the America's the whole ring of fire, you know, around
Speaker 1: the edge of the Pacific Ocean plate is where a
Speaker 1: ton of the Earth's volcanoes are. But there's another interesting
Speaker 1: feature of plate tectonics that that helps remove carbon dioxide
Speaker 1: from the atmosphere, and that is mountains. I had never
Speaker 1: thought about this before, but I read about this in
Speaker 1: a couple of articles in O'Neill's and another one I'm
Speaker 1: going to mention in just a minute. So the process
Speaker 1: goes like this. As plates move around on the surface
Speaker 1: of the Earth, they're floating over the mantel, they smash
Speaker 1: into each other and they bunch up where they get smashed,
Speaker 1: so as they smash into each other over the millennia,
Speaker 1: they raise up the bedrock at their impact points, and
Speaker 1: one one plate pushes the other up, and as the
Speaker 1: rock is raised up, it forms mountain peaks of exposed
Speaker 1: mineral bedrock. And O'Neill points out that mountains are one
Speaker 1: of Earth's major CEO two sinks. It's a place where
Speaker 1: CEO two from the atmosphere can be moved and stored
Speaker 1: in a stable form. Of course, another example that we
Speaker 1: could think about would be trees and plants. Remember that
Speaker 1: the flesh of a plant is made out of carbon
Speaker 1: compounds that are built out of c O two that
Speaker 1: gets sucked out of the atmosphere and fused into carbohydrates
Speaker 1: using the energy from the sun. This is what photosynthesis is.
Speaker 1: So as plants build their bodies, they suck c O
Speaker 1: two out of the sky. But mountains also suck CO
Speaker 1: two out of the sky, but in a different way.
Speaker 1: They suck it out through weathering. So as rain pours
Speaker 1: down on the mountains, the c O two dissolved in
Speaker 1: the rain water mixes with the minerals that are exposed
Speaker 1: in the rocks of mountains. This forms new minerals, and
Speaker 1: then eventually those new minerals with the c O two
Speaker 1: locked inside, drained down the sides of the mountains and
Speaker 1: end up in the oceans. So every time you see
Speaker 1: a mountain range, you think that is like, it's like
Speaker 1: a toilet for carbon dioxide. It's just like the Skies toilet.
Speaker 1: It is what that mountain is. Well, I don't know
Speaker 1: if that's the most romantic way to have to think
Speaker 1: of the mountains, but I think it's beautiful toilet of
Speaker 1: the okay, But still the point, the point is valid, yes,
Speaker 1: And then there are other sinks as well. Also. C
Speaker 1: O two gets dissolved directly into the ocean water itself,
Speaker 1: so it's it's coming into the ocean in multiple ways.
Speaker 1: It gets absorbed directly from the atmosphere into the ocean,
Speaker 1: and it drains from the weathering of mountains and rocks
Speaker 1: down to the oceans and ends up in the ocean floor,
Speaker 1: often in the form of limestone. But in both of
Speaker 1: these forms, the carbon dioxide that's locked up in the
Speaker 1: ocean eventually can get subducted, right because at these places
Speaker 1: where the plates meet, it gets sucked back down into
Speaker 1: the mantel. Now, this takes a really long time. The
Speaker 1: processes we're talking about take place over over geologic time,
Speaker 1: not like on human civilization a line. So if you're
Speaker 1: getting your hopes up about the idea that, oh, you know,
Speaker 1: Earth has a natural thermostat, we we don't have to
Speaker 1: worry about climate change, Unfortunately, that's not how this works.
Speaker 1: The natural thermostat that's established by plate tectonics has helped
Speaker 1: keep the Earth within a temperature range where it can
Speaker 1: maintain an atmosphere and liquid water and at least some
Speaker 1: life forms. But this temperature range that it maintains is
Speaker 1: number one, it's huge compared to the range that will
Speaker 1: support stable human civilization as it currently exists. Like human
Speaker 1: civilizations and cities and agriculture and the ecosystems we depend
Speaker 1: on are all much more fragile than the baseline of
Speaker 1: just maintaining an atmosphere, liquid water and some life and
Speaker 1: then of course, the other point is that this process
Speaker 1: takes a really long time. So even even if it
Speaker 1: could help maintain in a much narrower range that we
Speaker 1: depend on, uh, it takes a long It takes you know,
Speaker 1: beyond human civilization levels of time to really reach equilibrium.
Speaker 1: But to just to sum up the process of how
Speaker 1: the thermostat actually works, I'm gonna quote directly from O'Neill.
Speaker 1: He says, quote, if the Earth gets too hot, high
Speaker 1: levels of rainfall and erosion start bringing c O two
Speaker 1: levels down. If the Earth gets too cold and freezes over,
Speaker 1: the erosion mechanism stops, right, so it stops raining on
Speaker 1: the mountains and draining into the ocean. But vulcanism due
Speaker 1: to plate tik tonics continues pumping c O two into
Speaker 1: the atmosphere and the levels build up, eventually melting the
Speaker 1: ice caps. It was this mechanism that allowed Earth to
Speaker 1: recover from a global ice age in the neo Proterozoic
Speaker 1: about six million years ago. Yeah, so again we're talking
Speaker 1: about processes that they are taking place at geologic scale
Speaker 1: and not a human lifetime scale. But then also on
Speaker 1: top of that, even if you were exceptionally long lived,
Speaker 1: do you are essentially immortal? These are not pleasant changes
Speaker 1: to go through, I would imagine, like in either direction,
Speaker 1: and we're dealing with goth catastrophe here. Oh yeah, and
Speaker 1: these changes again, what we're talking about is how the
Speaker 1: Earth's plate tectonic thermostat if if this theory is correct,
Speaker 1: which it seems like it probably is. How the plate
Speaker 1: tectonic thermostat is able to maintain Earth as a habitable planet,
Speaker 1: So like it's still going to have liquid water, it's
Speaker 1: still going to have an atmosphere that's a very low baseline.
Speaker 1: You know that during this time they're going to be
Speaker 1: mass extinctions there. You know, sea levels are going to
Speaker 1: be hugely rising and falling. Huge parts of continents get
Speaker 1: covered in ice, and then the ice retreats. So these
Speaker 1: are this is not like stuff that would be like,
Speaker 1: oh it's cold outside today. These are these are world
Speaker 1: changing variations. They just don't change to the point that
Speaker 1: Earth is no longer habitable like Venus or Mars. Does
Speaker 1: that make sense? Yes, Still, out of catastrophe comes life.
Speaker 1: And speaking of that, we're going to take a quick
Speaker 1: ad break, but we'll be right back. Alright, We're back,
Speaker 1: all right. So we've been talking about theories in geology
Speaker 1: about how volcanoes and plate tectonics might be important for
Speaker 1: making the Earth habitable for life and maintaining its ability
Speaker 1: to host life over time. One of the things we
Speaker 1: were just talking about was the idea of plate tectonics
Speaker 1: is a natural thermostat regulator for temperature on Earth. That
Speaker 1: it that allows the Earth to release and absorb greenhouse
Speaker 1: gases in a cyclical way that basically keeps the Earth
Speaker 1: from turning into Venus or Mars or some other uninhabitable
Speaker 1: hell um. Now, there was another article I was reading
Speaker 1: that was in Quanta by the science writer Rebecca Boyle
Speaker 1: from June seen that mentioned a number of other theories
Speaker 1: that have connected plate tectonics and volcanoes two various life
Speaker 1: related plot processes on Earth and uh and I found
Speaker 1: this all really interesting, so I just wanted to explore
Speaker 1: a few of the things that she gets into in
Speaker 1: this article. One of them is the idea that plate
Speaker 1: tectonics might possibly have been important for the origin of
Speaker 1: life itself. Now, this one is somewhat controversial because we
Speaker 1: don't know for sure when plate tectonics began on Earth.
Speaker 1: We we don't know how early it got started. There
Speaker 1: their various theories about that. But for example, Craig O'Neil,
Speaker 1: the author of the article I was just talking about
Speaker 1: before the Break, has been involved on research that posits
Speaker 1: that before the Earth had plate tectonics, it had a
Speaker 1: period of what was what is called a stagnant lid state,
Speaker 1: where it didn't have plates sliding around. It had this
Speaker 1: sort of single hard shell floating on top of the mantle.
Speaker 1: But Boil's article points to research about how the subduction
Speaker 1: of plates on ocean floors actually creates conditions that are
Speaker 1: that are friendly to various types of extreme deep ocean
Speaker 1: life that we think of as being similar to, or
Speaker 1: possibly the direct analogs of the earliest life on Earth.
Speaker 1: Uh to quote one section boil Rights quote. As the
Speaker 1: Pacific Plate is dragged down into Earth's mantle, it warms
Speaker 1: up and releases water trapped within the rock in a
Speaker 1: process called serpentine ization. The water bubbles out of the
Speaker 1: plate and transforms the physical properties of the upper mantle.
Speaker 1: This transformation allows methane and other compounds to percolate out
Speaker 1: of the mantle through hot springs on the otherwise frigid,
Speaker 1: cold floor. And it's this type of chemical reaction that
Speaker 1: that on the ocean floor could possibly have given rise
Speaker 1: to the earliest chemical metabolism and jump started a chemical
Speaker 1: evolution of what would become cells and life as we
Speaker 1: know it. We don't know for sure, but it seems
Speaker 1: like one of the plausible origin theories for life on Earth.
Speaker 1: In other words, the sort of ancient chemistry labs that
Speaker 1: are are firing off random concoctions that that then end
Speaker 1: up benefiting the emergence of life. Right now, there's another
Speaker 1: thing Boils article mentions that touches on an issue we've
Speaker 1: discussed on the show before, which is the Cambrian explosion. Apparently,
Speaker 1: plate tec tonics have also been implicated as a possible
Speaker 1: cause of the Cambrian explosion. Now, brief refresher on what's
Speaker 1: going on here. Remember we've talked about this fascinating paleontological
Speaker 1: mystery before roughly five hundred and forty million years ago.
Speaker 1: There is a dramatic change in the fossil record before
Speaker 1: roughly forty million years ago, in a period that we
Speaker 1: know is the edi acron. Most of the life we
Speaker 1: have evidence of is very simple. It's soft bodied worm
Speaker 1: like creatures, sort of leaf shaped, multicellular fraunds. A lot
Speaker 1: of soft bodied organisms, many of which are not preserved
Speaker 1: very well. Um and there is not There doesn't seem
Speaker 1: to be a lot of diversity of body forms taking
Speaker 1: shape rapidly, but then over a period of time that
Speaker 1: is geologically really sudden. There's this proliferation of animals with
Speaker 1: lots of different body types that have hard body parts
Speaker 1: that are preserved very well in fossils, so we have
Speaker 1: good records of them. This is when you get the trilobites, Anamala, Carus, Hallucigenia, Opabinia,
Speaker 1: all of your favorite monsters of the ocean primeval. This
Speaker 1: is the Cambrian explosion, And the question is what explains
Speaker 1: this apparently sudden acceleration of evolution and diversification of life
Speaker 1: that happened about five and forty million years ago. Now,
Speaker 1: there are a lot of competing theories. Some I think
Speaker 1: some paleontologists say, well, maybe the rapidity of the Cambrian
Speaker 1: explosion is sort of overstated, maybe there's some bias in
Speaker 1: the fossil record, But I think it's generally agreed that, yeah,
Speaker 1: a lot of new animal forms really do show up
Speaker 1: pretty fast, and so other theories have to do with
Speaker 1: like changes in the composition of the atmosphere. One that
Speaker 1: we've talked about on the show that was pretty interesting
Speaker 1: is that it was a reaction to the evolution of
Speaker 1: hunting and active predation. As a novel thing on planet Earth.
Speaker 1: There had not been hunting before, and suddenly as soon
Speaker 1: as organisms are hunting each other, there's just like this
Speaker 1: rapid race to find new ways that bodies can be
Speaker 1: But Boil's article points to research from that actually links
Speaker 1: the Cambrian explosion to plate tectonic activity. So this is
Speaker 1: a paper by Ross Large at All published in Gondwana
Speaker 1: Research in and what's their theory, Well simplified, it goes
Speaker 1: sort of like this, plate tectonics smash continental plates together.
Speaker 1: So the plates are moving around and they smashed together,
Speaker 1: and at the places where they smashed together, it often
Speaker 1: raises up mountain ranges. And these mountain ranges at the
Speaker 1: borders of plates consists of exposed mineral bedrock that's heaved
Speaker 1: up into the sky. We talked about this a bit earlier,
Speaker 1: and we we needed this a bit too in the
Speaker 1: gold episode where we talked about looking for gold in
Speaker 1: the ocean, and we talked just very briefly about why
Speaker 1: one pans for gold in mountain streams. Yes, Yes, a
Speaker 1: very good point. Yeah. So the rock that gets lifted
Speaker 1: up as it smashes together at the edges of these plates,
Speaker 1: the mountains that get raised up can be hammered by
Speaker 1: the elements that exposes the underlying minerals to you know,
Speaker 1: the wind, but primarily the rain, and the rain drains
Speaker 1: chemical nutrients from the rocks down into the oceans, and
Speaker 1: this causes a proliferation of chemicals like phosphorous, copper, zinc, selenium, cobalt,
Speaker 1: and stuff like that in the seas. These nutrients in
Speaker 1: the ocean then allow high biological productivity, the proliferation of life,
Speaker 1: intense competition, and so it's kind of like the some
Speaker 1: of the most important chemicals of life have been hidden
Speaker 1: by the gods uh in the deep earth and mountains.
Speaker 1: They're the Prometheus figure freeing those and releasing them into
Speaker 1: the ocean where they can become a part of life exactly, yes,
Speaker 1: um and so boil rights quote. Maybe more surprisingly, Large
Speaker 1: and his colleagues also found that these elements were low
Speaker 1: in abundance during more recent periods, and that these periods
Speaker 1: coincided with mass extinctions. These nutrient poor periods happened when
Speaker 1: phosphorus and trace elements were being consumed by the earth
Speaker 1: faster than they could be replenished. Large said, so in
Speaker 1: times where the all of these very biologically useful elements
Speaker 1: like phosphorus and some of the other ones we mentioned
Speaker 1: are getting sucked back down into the mantle. It's subduction
Speaker 1: areas faster than they're getting released from the from mountains
Speaker 1: and and other deep mineral sources. These are bad times
Speaker 1: for life on Earth. Suddenly, it's like life is not
Speaker 1: getting its vitamins. Boil's article also mentioned several other interesting
Speaker 1: theories I'm not going to go deep into detail about.
Speaker 1: One is that plate tectonics could be responsible for atmospheric
Speaker 1: oxygen on Earth. There's basically a two step procedure here. Uh.
Speaker 1: First of all, plate tectonics create continents with rocks that
Speaker 1: don't react with oxygen in the atmosphere as easily as
Speaker 1: the iron rich early rocks of Earth did. And then
Speaker 1: after that, carbon dioxide gets released from rocks into the
Speaker 1: air and the ocean. That feeds the growth of photosynthetic
Speaker 1: organisms like algae, which in turn produced oxygen as a
Speaker 1: waste product, sort of an oxygen two step, which, of
Speaker 1: course at the time was very bad for Earth because
Speaker 1: oxygen is a poison and it will kill you. But
Speaker 1: we evolved in the wake of that poison atmosphere and
Speaker 1: here we are breathing it. And then another interesting idea. Uh.
Speaker 1: That article mentions is the work of Robert Stern, who
Speaker 1: is a geologist at the University of Texas, Dallas, who
Speaker 1: posits that because of plate tectonics, we have more opportunities
Speaker 1: for evolution on Earth than you might expect otherwise because
Speaker 1: the rearranging of continents and seas through plate tectonics drive
Speaker 1: selection effects and the evolution of new species. Uh. Starn says, quote,
Speaker 1: you need isolation and competition for evolution to really get going.
Speaker 1: If there is no real change in the land sea area,
Speaker 1: there's no competitive drive and speciation. That's the plate tectonics pump.
Speaker 1: Once you get life, you can really make it evolve
Speaker 1: fast by breaking up continents and continental shelves and moving
Speaker 1: them to different latitudes and recombining them, which I don't
Speaker 1: know if I had ever thought about it quite like
Speaker 1: that before, but you do kind of see this effect
Speaker 1: throughout history as continents drift around, they smash into each other,
Speaker 1: they separate from each other. You see different life forms
Speaker 1: kind of going their own way. Yeah, coming into contact
Speaker 1: with each other for the first time. Um, you know,
Speaker 1: just changing the the scenarios that are driving evolution. Um. Yeah,
Speaker 1: that's that's fascinating. I've never really thought about it that way,
Speaker 1: but if you you could look at a planet with
Speaker 1: plate technomic tectonics as being like the ideal laboratory for
Speaker 1: um for for the for for evolution to take place
Speaker 1: in uh, it's it's kind of like it has an
Speaker 1: automatic shuffle mode in place. Yeah. I like that plate
Speaker 1: tectonics puts biology on shuffle. That's so good. Otherwise you're
Speaker 1: just gonna listen to that one track over and over again,
Speaker 1: and you're just gonna listen to the first three. You know,
Speaker 1: you need to have it shuffled up every now and
Speaker 1: then so you'll you'll you'll you'll experience the album in
Speaker 1: a new order and suddenly you're gonna find new favorite tracks.
Speaker 1: All right, I want to talk about one last thing
Speaker 1: before we finish up here, which is an article I
Speaker 1: was reading about the use of volcanoes and plate tectonics
Speaker 1: as a proxy for habit ability when searching for exo planets,
Speaker 1: because that makes sense based on everything we've said here.
Speaker 1: You know, in the same way that we would look
Speaker 1: for signs of water on another world as a potential
Speaker 1: as a potential sign that conditions could be right for life,
Speaker 1: then perhaps looking for volcanoes makes sense as well. Yeah,
Speaker 1: so I was reading about this in a in a
Speaker 1: NASA press release that was covering a paper published an
Speaker 1: Astrobiology in TWI by Im Misra at All called transient
Speaker 1: sulfate aerosols is a signature of exoplanet vulcanism. I think
Speaker 1: these researchers were out of the University of Washington, and
Speaker 1: they're publishing a method for detecting volcanic activity on exo
Speaker 1: planets to figure out which ones might be good candidates
Speaker 1: to host life. For all the reasons we've been talking
Speaker 1: about now, this began with students trying to find ways
Speaker 1: to detect plate tectonics on exo planets. Obviously, you can't
Speaker 1: resolve the surface of an exo planet with a telescope
Speaker 1: or look at it long enough to know if it's
Speaker 1: got continents that are moving around. Um. But the lead
Speaker 1: author Misra said in this press release quote, I came
Speaker 1: up with the idea of looking at explosive volcanic eruptions
Speaker 1: as a proxy or stand in for plate tectonics. I've
Speaker 1: done some work modeling aerosols produced by volcanic eruptions for
Speaker 1: other projects, so I started looking into how we might
Speaker 1: detect an eruption and what it would tell us. Now,
Speaker 1: this is specifically focusing on explosive volcanic eruptions that tend
Speaker 1: to happen at the edges of tectonic plates. Again, I
Speaker 1: mentioned this earlier, but if you look at a map
Speaker 1: of tectonic plates, you'll notice that the boundaries match up
Speaker 1: to lines of volcanoes on the surface of the Earth. Now,
Speaker 1: what is it about explosive eruptions in particular? We you know,
Speaker 1: we've all seen footage of volcanic eruptions that are not
Speaker 1: particularly explosive. They're basically kind of gentle lava flows, relatively gentle,
Speaker 1: you know, it's still a planet. And even during more
Speaker 1: you know, middle of the road volcanic eruptions, the gases
Speaker 1: and aerosols that get expelled from the Earth off intend
Speaker 1: to fall back to the surface pretty fast, at least
Speaker 1: fast on a geological scale. But during these really highly
Speaker 1: explosive eruptions, gases and particles shot up from the volcano
Speaker 1: or often shot into the stratosphere where they can linger
Speaker 1: for months or years, and they affect what's called the
Speaker 1: transit transmission spectra of the planet. This is something that
Speaker 1: we can actually detect with telescopes at at a distance
Speaker 1: of you know, as far away as other stars and
Speaker 1: their planets are. So, by looking at the frequency of
Speaker 1: light reflected by an exoplanet as it transits in front
Speaker 1: of its star between us and its star, you might
Speaker 1: be able to detect whether there are transient sulfate aerosols
Speaker 1: from explosive eruptions in the stratosphere, which in turn would
Speaker 1: be a good indicator, though not a guarantee, of plate
Speaker 1: tectonics down on the surface. The authors of the study
Speaker 1: right quote, we propose that the detection of this transient
Speaker 1: signal would strongly suggest an so planet volcanic eruption if
Speaker 1: potential false positives such as dust storms or bowl eyed
Speaker 1: impacts can be ruled out. Furthermore, because scenarios exist in
Speaker 1: which O two can form a biotically in the absence
Speaker 1: of volcanic activity, detection of transient aerosols that can be
Speaker 1: linked with vulcanism along with detection of O two would
Speaker 1: be a more robust biosignature than O two alone. Right.
Speaker 1: So this is another This is linking to another idea
Speaker 1: people have had that if you can look at an
Speaker 1: exoplanet and detect oxygen free oxygen in its atmosphere. That
Speaker 1: might be a sign of life in the atmosphere because
Speaker 1: you know, oxygen is often a byproduct of organisms, like
Speaker 1: photosynthetic organisms on Earth, but you know O two can
Speaker 1: be produced by other things. So they're saying, if you
Speaker 1: find that, and you find signs of volcanoes, this is
Speaker 1: a good sign that this is a living planet. I mean,
Speaker 1: it sounds like a solid argument to me based on
Speaker 1: what we've seen here. And it's and the thing is,
Speaker 1: I mean, it's still vital information about the nature of
Speaker 1: a given world. So it's not like you'd be you know,
Speaker 1: you know, chasing after uh a wild hair here. This
Speaker 1: would be essential information either way, exactly. Now. On the
Speaker 1: other hand, we mentioned that volcanoes are not a sure
Speaker 1: sign of plate tectonics, and this brings me back to
Speaker 1: something I wanted to talk about. That was also from
Speaker 1: Craig O'Neill, because O'Neill was writing about how you know,
Speaker 1: because of the assumed association between plate tectonics and life,
Speaker 1: some astronomers and astrobiologists are interested in looking for exoplanets
Speaker 1: with the potential for aliens and UH and they've tried
Speaker 1: to focus on places where plate tectonics seemed likely to exist,
Speaker 1: and one candidate that O'Neill points out was long thought
Speaker 1: to be these planets called super Earth's their terrestrial rocky
Speaker 1: planets like Earth, like Mars, like Venus, but even bigger
Speaker 1: than Earth. And O'Neill writes that it was once believed
Speaker 1: that the odds of finding plate tectonics on big planets
Speaker 1: like this was higher, but now it seems like that
Speaker 1: might not actually be true because computer simulations have shown
Speaker 1: that you can probably have very large rocky planets without
Speaker 1: plate tectonics and instead with a surface conforming to this
Speaker 1: thing I mentioned earlier called the stagnant lid model, which
Speaker 1: sounds gross. Basically, it's where the interior of the planet
Speaker 1: is hot, it's cooling, it's releasing its heat, and the
Speaker 1: heat is released through volcanic eruptions. But the surface does
Speaker 1: not have moving plates, and so no recycling of water
Speaker 1: and CO two to the interior like we have in
Speaker 1: the subduction on Earth. Uh, no formation of mountains or
Speaker 1: natural mineral sequestration like we have on Earth. It's just
Speaker 1: going to be kind of a big rocky planet with
Speaker 1: a hot interior that has volcanoes, but the volcanoes just
Speaker 1: sort of poke up occasionally out of its solid, spherical,
Speaker 1: rocky shell. And O'Neill and the co authors of his
Speaker 1: of his paper that this article was based on, we're
Speaker 1: addressing the question of how is it exactly that planets
Speaker 1: evolve over time, And they came to the idea that
Speaker 1: planets might start hot and turbulent and then far down
Speaker 1: the road they end up cool and geologically inactive. And
Speaker 1: that quote. We found that the evolutionary track of planet
Speaker 1: takes depends not only on its size, but on how
Speaker 1: it starts. For example, two planets identical in every other
Speaker 1: way but with different starting temperatures may evolve down very
Speaker 1: different evolutionary paths. And so what they argue is that
Speaker 1: plate tectonics like we have on Earth might simply be
Speaker 1: a phase in the evolution of planets, sort of a
Speaker 1: lacuna between two eras of stagnant lids. And it's possible
Speaker 1: Earth was once a stagnant lid planet with a single
Speaker 1: hard shell, and now we have plate tectonics, and may
Speaker 1: maybe one day we will not have plate tectonics anymore.
Speaker 1: So if this is the model that habitable worlds take
Speaker 1: you would you would end up having, assuming they lived
Speaker 1: long enough, some sort of highly evolved life form ruling
Speaker 1: over a stagnant lid Earth. That's that's possible. Though there
Speaker 1: was another report I was reading that that complicates all this,
Speaker 1: because you know, as I was saying, this is still
Speaker 1: not a fully settled question. I was reading a report
Speaker 1: from Penn State News about a couple of Penn State
Speaker 1: researchers geoscientists there named Bradford Foley and Andrew Smile, who
Speaker 1: argued that no, in fact, they're findings show that you
Speaker 1: don't necessarily have to have plate tectonics to sustain life
Speaker 1: on a planet. Given certain conditions, you can just have
Speaker 1: volcanoes basically keeping the planet roughly the right kind of temperature. Now,
Speaker 1: that wouldn't invalidate all the stuff we've said about the
Speaker 1: role that plate tectonics have played in the evolution of
Speaker 1: life on Earth. But it's still basically just an unsettled question.
Speaker 1: It seems to me whether or not plate tectonics are
Speaker 1: really necessary for the existence of life on a planet
Speaker 1: or not. By the way, one cool thing I came across,
Speaker 1: I didn't get super deep into this but it's also
Speaker 1: hypotheses about what happened to Earth's early stagnant lid in
Speaker 1: order to turn Earth into a into a planet with
Speaker 1: with subducting plates, plates moving around, sliding under each other.
Speaker 1: And one theory is that was asteroid bombardment. So Earth up, yeah, exactly.
Speaker 1: Earth may once have had this this solid shell on
Speaker 1: the outside where without moving plates, and then some kind
Speaker 1: of impact or series of impacts broke it all up
Speaker 1: and got things churning around, and ever since then we've
Speaker 1: had a crust in the form of moving plates instead
Speaker 1: of one solid plate. And that that has a very
Speaker 1: kind of divine feel to it, right, like a stagnant
Speaker 1: world that is no longer advancing or creating anything new,
Speaker 1: and so now some force beyond them has to rain
Speaker 1: down destruction so that so that like new possibilities can
Speaker 1: emerge our of this shattered stagnantally. Yeah, And and the
Speaker 1: one last thing I want to mention here is that
Speaker 1: O'Neill points to one of my favorite objects in the
Speaker 1: Solar System as an example of a of an object
Speaker 1: like a planet that can be geologically active and have
Speaker 1: volcanoes without having plate tectonics. And that example, of course
Speaker 1: is Jupiter's moon Io, the yellow hell of Galilee and Sulfur.
Speaker 1: You know, this was one of my favorites, and when
Speaker 1: we did the episode about Jupiter's moons and so iow
Speaker 1: is Jupiter's innermost major moon. It's very geologically active, even
Speaker 1: more so than Earth. It's the most volcanic object in
Speaker 1: the Solar System. And this is a result of tidal
Speaker 1: forces that act on the guts of Io. It's gravitational
Speaker 1: man handling by Jupiter slashes the guts of this moon
Speaker 1: around and UH and its heat mostly escapes to the
Speaker 1: surface through what O'Neill calls heat pipes. These are volcanoes,
Speaker 1: not through the movement of tectonic plates. So to come
Speaker 1: back to our our god analogy here, in this case,
Speaker 1: the god that is Jupiter is UH is too involved
Speaker 1: in the in the in the nature of the planet.
Speaker 1: It's like a um and micro managing oppressor UH as
Speaker 1: opposed to one that just periodically brings about destruction. Yeah, exactly, Jupiter,
Speaker 1: it will never leave you alone. And I think what
Speaker 1: Ion needs to do is to go down into the
Speaker 1: void and get the dim O organ to come up
Speaker 1: and and kill Jupiter like he does in UH. In Oh,
Speaker 1: what's that play Prometheus Unbound? There you go. But anyway,
Speaker 1: so I don't know, I found this really interesting. I
Speaker 1: don't think I had ever looked this deeply into how
Speaker 1: entangled the geology of Earth um and specifically it's it's
Speaker 1: mineral geology, It's rocks are with the with the evolution
Speaker 1: of life on Earth. I think i'd always thought primarily
Speaker 1: about like temperature and liquid water. Yeah, or i'd i'd
Speaker 1: probably focus more on sort of everyday human level things
Speaker 1: like the fact that, okay, that you know the soil
Speaker 1: near volcano is going to be rich and good for
Speaker 1: growing things, or that volcanic activity creates land that can
Speaker 1: eventually be become habitable that sort of thing. But this
Speaker 1: is a much much deeper dive into like the the
Speaker 1: truly geologic um level of the whole equation. Uh So, anyway, Yeah,
Speaker 1: I think that does it for now. But but I
Speaker 1: hope you've enjoyed this journey into the volcano absolutely, And
Speaker 1: of course, as before when we discussed volcanoes on the show,
Speaker 1: we want to hear from you about your experience with volcanoes,
Speaker 1: life near volcanoes, visiting volcanoes, active and dormant, um, how
Speaker 1: does this affect your interpretation of these amazing sites? And
Speaker 1: if you want to check out other episodes of Stuff
Speaker 1: to Blow your Mind, well you can find us wherever
Speaker 1: you find your podcasts and wherever that happens to be.
Speaker 1: Just make sure you rate, review and subscribe if you can.
Speaker 1: These are acts that really helped the show out in
Speaker 1: the long run. Before we wrap up, I've just got
Speaker 1: to say so, I don't forget. We need to get
Speaker 1: some mountains or the toilets of the atmosphere T shirts made. Oh,
Speaker 1: I don't know if that is good. That would be
Speaker 1: a best seller. I don't know why not? Worst T
Speaker 1: shirt ever? Okay, anyway, huge thanks as always to our
Speaker 1: excellent audio producer Seth Nicholas Johnson. If you would like
Speaker 1: to get in touch with us with feedback on this
Speaker 1: episode or any other, just to say hi, or to
Speaker 1: suggest a topic for the future, whatever you want, you
Speaker 1: can email us at contact at stuff to Blow your
Speaker 1: Mind dot com. Stuff to Blow Your Mind's production of
Speaker 1: I Heart Radio. For more podcasts for my Heart Radio
Speaker 1: with the iHeart Radio app, Apple Podcasts, or wherever you're
Speaker 1: listening to your favorite shows, bid think Point fo