Speaker 1: There's a new comment approaching from deep space. Could we
Speaker 1: get sick if it's dust gets in our face?
Speaker 2: The jewel wasp parasitoid feels around its host brain. How
Speaker 2: did evolution come up with this? It's totally insane.
Speaker 1: Scientific theory, model, hypothesis or law. Do these words really
Speaker 1: mean anything or naw?
Speaker 2: Whatever? Questions keep you up at night. Daniel and Kelly's
Speaker 2: answers will make it right.
Speaker 1: Welcome to another Listener Questions episode on Daniel and Kelly's
Speaker 1: Extraordinary Universe.
Speaker 2: We've done twenty two of these.
Speaker 3: Hello.
Speaker 2: I'm Kelly Wiersmith. I study parasites and space, and all
Speaker 2: of these questions today have a bit of biology in them,
Speaker 2: so I'm pretty excited about it.
Speaker 1: Hi. I'm Daniel. I'm a particle physicist, and I'll admit
Speaker 1: there's a bit of biology in everything we do.
Speaker 2: Oh yeah, but there's not physics in everything we do,
Speaker 2: so that's good news.
Speaker 1: Yes, yeah, no, of course there physics is everything.
Speaker 3: Yeah.
Speaker 2: I guess I should have gone with chemistry, and then
Speaker 2: we could have bonded even though we knew we were
Speaker 2: wrong exactly.
Speaker 1: Yeah, then we could confirm each other's biases.
Speaker 2: Yep, yep, anyway, I blew it, I'm sor right moving on.
Speaker 1: But today we're not here to talk about my biases
Speaker 1: or about your biases. We're here to answer questions from you,
Speaker 1: from people out there wondering how the universe works, trying
Speaker 1: to make sense of it and scratching their heads a
Speaker 1: little bit, And.
Speaker 2: We try to help you scratch your heads for a
Speaker 2: slightly shorter amount of time. And so if you have
Speaker 2: a question that is keeping you up at night, send
Speaker 2: it to us at questions at Danielankelly dot org. It
Speaker 2: might take a few months for the answers to come
Speaker 2: back to you and go online, but we answer every
Speaker 2: question at least by email, and some of them even
Speaker 2: make it.
Speaker 1: On the show because we believe in the value of
Speaker 1: human curiosity. I'm interested in particles, Kelly's interested in parasitoids.
Speaker 1: But everybody's curious about something. And my favorite thing about
Speaker 1: science is that we're all curious about different things, which
Speaker 1: is why we get to learn about so many different
Speaker 1: amazing things in the universe, even chemistry, and.
Speaker 2: All of the questions that we get I feel like
Speaker 2: are super fascinating and make me think about things in
Speaker 2: different ways. So feel free to help expand our minds
Speaker 2: by getting us to think about a new question.
Speaker 1: That's right, and because this podcast is not just about
Speaker 1: what we're curious about, it's about what everybody's curious about.
Speaker 1: So join the conversation. Send us your questions to Questions
Speaker 1: at Daniel and Kelly dot org.
Speaker 2: And our first question today comes from Tim, who lives
Speaker 2: in the greatest of these United States, which is of
Speaker 2: course Virginia.
Speaker 1: What did we say about confirming our biases today?
Speaker 2: That it's great, That's probably what we said.
Speaker 1: All right, let's hear from Tim, who, unfortunately it lives
Speaker 1: in Virginia.
Speaker 3: Oh, Daniel and Kelly, it's Tim from Virginia.
Speaker 4: I was watching YouTube and watching videos about our newest
Speaker 4: interstellar visitor, Atlas and Omama and.
Speaker 3: What was the other one called?
Speaker 4: Not Benue the other one? So anyway, this is Atlas,
Speaker 4: is the third interstellar visitor that we've had in our
Speaker 4: solar system. And they were talking about how it doesn't
Speaker 4: pose a threat to Earth. But I was wondering, if
Speaker 4: it leaves a debris field and its wake, what are
Speaker 4: the chances that it has some sort of unknown virus
Speaker 4: or bacteria or like maybe even like their version of
Speaker 4: tartar grades which can survive in space that they just
Speaker 4: deposit in our Solar system. That could possibly if a
Speaker 4: planet goes through its trail, could get scooped up by
Speaker 4: a planet and cause problems. Thought it might be a
Speaker 4: fun question for both of you to answer. Thanks for
Speaker 4: what you do.
Speaker 2: Bie, Oh, this is a fun question. So not that
Speaker 2: long ago you and I talked about umumout no ooh muama.
Speaker 2: Recently you and I talked about o muamua and Avi
Speaker 2: lobes hypothesis that it was an interstellar visitor and if
Speaker 2: anybody wants more information they can go pull that up.
Speaker 1: Hypothesis is being very generous to Avi.
Speaker 2: Yes, yeah, idea while smoking banana peels might be uh.
Speaker 1: Better sensationless nonsense cooked up to sell his book.
Speaker 2: Oh yeah yeah, we are not pulling any punches today.
Speaker 2: And so Daniel remind us what do we know about
Speaker 2: these interstellar visitors?
Speaker 1: So most of the comments we see come from inside
Speaker 1: our Solar system. They either come from the Kuiper Belt,
Speaker 1: which is a big chunk of rocky, icy stuff out
Speaker 1: there deep in the Solar System, or long period comets
Speaker 1: come even further out from like the Ort Cloud, a
Speaker 1: hypothetical never yet observed bunch of icy rocky blobs way
Speaker 1: way way out past Pluto. And so most of the commets,
Speaker 1: Haley's comment, and the other stuff that we see come
Speaker 1: from inside our solar system. But you know, our solar
Speaker 1: system is not alone in the galaxy, and every once
Speaker 1: in a while an icy rocky chunk from another solar
Speaker 1: system will drift over and enter our backyard. And until
Speaker 1: this year, we'd only ever seen two of those. Omiamua
Speaker 1: famous because it was the first and sort of surprised everybody.
Speaker 1: We saw it pretty quickly after we turned down a
Speaker 1: telescope capable of finding these things, which is always awesome
Speaker 1: because we didn't know how often we would see these.
Speaker 1: And when you see one immediately you're like, oh, wow,
Speaker 1: maybe these aren't so rare.
Speaker 2: Yeah, And I gotta say, one of my favorite facts
Speaker 2: that I've learned while working with you is that the
Speaker 2: ort cloud is a maybe it's a thing that we
Speaker 2: think exists but haven't actually confirmed, and that I think
Speaker 2: was something that you discussed in response to a listener's question.
Speaker 2: And so anyway, love what I'm learning. Keep going.
Speaker 1: So twenty seventeen, we saw O mum it was pretty weird.
Speaker 1: It was like a bare object that was either long
Speaker 1: and thin or very flat, and it was rotating weirdly,
Speaker 1: and so the reflections were strange. Lots of speculation about it.
Speaker 1: In the end, it looks like it was mostly the
Speaker 1: nucleus of a comet that had already lost all of
Speaker 1: its stuff and outgassed a little bit on the way
Speaker 1: out of the Solar System, giving it a little bit
Speaker 1: of acceleration. Then in twenty nineteen we saw the second one, Borisov.
Speaker 1: This is a bigger object, more like a standard comet,
Speaker 1: had a coma. It was outgassing. Still very cool to
Speaker 1: see these things from deep in space. And you know,
Speaker 1: this is awesome because, as you say, a lot of
Speaker 1: our knowledge about the rest of the galaxy is hypothetical.
Speaker 1: It comes either from just observation or from speculation and
Speaker 1: from models. So to see something come and visit us,
Speaker 1: we get to study in much more detail and learn
Speaker 1: a lot about the rest of the galaxy. And so
Speaker 1: in twenty twenty five we're very excited to see the
Speaker 1: third one, which is called Atlas.
Speaker 2: Well, and you must have been very excited because you
Speaker 2: are really into aliens, and oh, Muhamoua was sent by aliens.
Speaker 2: It was an interstellar ship, right, That's what I heard.
Speaker 1: You know, there's a lot of really interesting stuff about
Speaker 1: oh muha And it's totally reasonable to ask, like, does
Speaker 1: this look like a natural object or is it weird?
Speaker 1: And could it be artificial? That's totally legitimate, and we
Speaker 1: should be excited and open minded about what we could
Speaker 1: see and all the people out there excited to have
Speaker 1: aliens come visit. I'm definitely near the top of the list,
Speaker 1: But we also should be skeptical about it. And those
Speaker 1: claims require a lot of evidence. And there's a lot
Speaker 1: of push by the chair of the Harvard Physics Department
Speaker 1: to call this thing aliens, and he wrote a whole
Speaker 1: book about it, and we did a whole episode about it,
Speaker 1: and there's lots of videos describing in detail how this
Speaker 1: was not an effort sort of primed by scientific integrity unfortunately.
Speaker 1: So we're very sure that oh Muamua is a comet
Speaker 1: and it's and it's interesting and sort of planetary physics
Speaker 1: sort of ways, but it's not an alien object.
Speaker 2: Okay, got it. Thanks for clearing that up for me. Yeah,
Speaker 2: And so tell me more about the twenty twenty five
Speaker 2: Interstellar Visitor.
Speaker 1: Yeah, so this is pretty fresh and new, and it's
Speaker 1: still approaching us right It hasn't reached the closest point
Speaker 1: to the Sun that it's going to reach.
Speaker 3: It.
Speaker 1: It's coming into the Solar system still, which is exciting.
Speaker 1: When we found Omuumu was already on its way out
Speaker 1: and moving really fast. So every day it got more
Speaker 1: distant and smaller and harder to image. But this is
Speaker 1: coming closer, and so we're getting better and better and
Speaker 1: crisper and crisper photographs of it. So the first images
Speaker 1: we had got of it, you can look these things
Speaker 1: up online. These come from the two meter twin telescope.
Speaker 1: These are ground based telescopes, and they show it like
Speaker 1: a big, fuzzy blob. And from those pictures we couldn't
Speaker 1: really tell what it was or how big it was.
Speaker 1: We could tell it's something around twenty five to forty
Speaker 1: kilometers across, but we didn't know how much of that
Speaker 1: was like the actual thing, and how much of it
Speaker 1: was like a dusty coma or gas being boiled off
Speaker 1: of the surface by the Sun. So those were our
Speaker 1: first measurements about it, and we knew where it was
Speaker 1: and how fast it was going, so we could tell
Speaker 1: it was coming from outside the Solar system, but we
Speaker 1: didn't yet know what it was.
Speaker 2: Is a coma just the like dust and stuff that
Speaker 2: trails behind a comet.
Speaker 1: Yeah, exactly, And most of that comes from the sun, right,
Speaker 1: Solar radiation, the particles, the photons, the electrons, the protons
Speaker 1: that come from the Sun will impact the comet and
Speaker 1: boil some of that stuff off, and we'll dig into
Speaker 1: that in a minute. But that's where the comet's tail
Speaker 1: comes from. And the tail should grow as it gets
Speaker 1: closer and closer to the Sun. And so right now
Speaker 1: still pretty far from the Sun and the coma sort
Speaker 1: of small, but we expect that as it gets closer
Speaker 1: and closer and it heats up and the Sun fries
Speaker 1: it more, it's going to get it longer and longer tail. Yeah.
Speaker 2: Can we tell the difference between the junk that's getting
Speaker 2: kicked off because of the Sun and the center of it.
Speaker 2: Is it clear enough to differentiate?
Speaker 1: We can, in fact, And so we have also space
Speaker 1: based imaging. So we have Hubble, we have sphere X,
Speaker 1: which is a deep infrared telescope, and we have James
Speaker 1: Webb's based telescope. But before those space telescopes were able
Speaker 1: to take a picture of it, there's a lot of
Speaker 1: discussion about what is this thing. It turns out it's
Speaker 1: coming in sort of close to the plane of the ecliptic,
Speaker 1: which is the planet that all the planets are on.
Speaker 1: And so our friend Abvi Lobe made a big deal
Speaker 1: about this, and he suggested that this was evidence that
Speaker 1: it was an alien visitor sent intentionally to visit our
Speaker 1: solar system.
Speaker 2: So he's still on the same kick.
Speaker 1: He is still on the same kick, okay. And he
Speaker 1: saw the fuzz around the object, and he misinterpreted that
Speaker 1: to be like motion smears, like if you're taking a
Speaker 1: slow picture of a fast moving object, it will smear,
Speaker 1: because he didn't understand that astronomers already know about that
Speaker 1: effect and build it into their telescopes with tracking to
Speaker 1: avoid motion smearing. So he was arguing that it wasn't
Speaker 1: a comet, that it was a bare object, maybe metallic,
Speaker 1: and the fuzz was from motion smearing. Astronomers told him
Speaker 1: how he was wrong, he mostly ignored them. Again, it's
Speaker 1: not a discussion that's inspired by scientific integrity. He's just
Speaker 1: trying to sell his books. And then we've got space
Speaker 1: based telescopes to take a clear picture of it, and
Speaker 1: you can see in those pictures a very bright core
Speaker 1: and a fuzzier coma, so you can tell the difference
Speaker 1: from the coma and from the core, and then SPHEREx
Speaker 1: can do some really cool stuff where they see the
Speaker 1: spectrum of light that comes off of it. So the
Speaker 1: core of it is like two to four kilometers and
Speaker 1: the rest of it is a fuzzy coma. And what's
Speaker 1: really fascinating is that that fuzzy coma is mostly carbon dioxide.
Speaker 1: So these things that are from deep space, they have
Speaker 1: rocky cores, but there's a lot of ice on them,
Speaker 1: and there's carbon monoxide ice, carbon dioxide ice, and then
Speaker 1: water ice, and these things evaporate at different temperatures. Carbon
Speaker 1: monoxide evaporates at a pretty low temperature like forty kelvin.
Speaker 1: Doesn't take a lot of solar rays to fry off
Speaker 1: all the carbon monoxide. Carbon dioxide at about one hundred kelvin,
Speaker 1: and water at hundreds of kelvin. But we don't see
Speaker 1: any carbon monoxide in the coma. So this thing is
Speaker 1: probably a combination of CO two carbon dioxide and water,
Speaker 1: and since it's still far out on the Solar System,
Speaker 1: it's mostly outgassing the CO two which sublimates on the surface.
Speaker 1: And when it gets closer, we'll probably see some water,
Speaker 1: some water ice turn into steam.
Speaker 2: Is there rock in there too, and that's just not
Speaker 2: getting kicked out into the coma.
Speaker 1: Yeah, exactly. Probably there's also rock out there. And you know,
Speaker 1: Avi responds to this and saying he thinks actually the
Speaker 1: thing glows on its own and it's not just reflecting light,
Speaker 1: which astronomers pointed out was just him misreading a plot
Speaker 1: in a paper, maybe intentionally, maybe not, who knows. Anyway,
Speaker 1: you should mostly ignore all of his nonsense and pay
Speaker 1: attention to the astronomers who actually know what they're talking about.
Speaker 1: So it's a fascinating object. We're going to learn something
Speaker 1: about deep space, and you know what things are made
Speaker 1: out of. This thing is probably a chunk of ice
Speaker 1: and rock from somebody else's ort cloud, right, some other
Speaker 1: star has ort clouds, and we snagged a piece of
Speaker 1: it because they lost it. It's going to be really interesting.
Speaker 1: It's not going to come close to the Earth. So
Speaker 1: if you're worried about this thing because it's a bit
Speaker 1: chunk of ice and rockets about the same size as
Speaker 1: the one that ended the dinosaurs. But it's not gonna
Speaker 1: hit the Earth. In fact, when it makes its closest
Speaker 1: approach to the Sun, we're gonna be on the other
Speaker 1: side of the Sun.
Speaker 2: That's reassuring. I like that, although I'm sure we'll see
Speaker 2: it less well, and that's a bummer, but trade offs.
Speaker 1: All right. So that's the setup. Tim has a really
Speaker 1: fun question. He's wondering, like, what if this thing really
Speaker 1: does come from aliens? What if it's like loaded with
Speaker 1: their viruses or alien tartar grades and those things boil
Speaker 1: off and they sort of make a path through the
Speaker 1: Solar system and some of them come to Earth. Are
Speaker 1: we in danger?
Speaker 2: What do you think?
Speaker 1: Awesome question. Yeah, well, we're not gonna pass through any
Speaker 1: sort of dense part of its tail, Like we're gonna
Speaker 1: be on the other side of the Sun when it turns around,
Speaker 1: and it's gonna exit the Solar system. So it's not
Speaker 1: like it's gonna leave a long wake that we're gonna
Speaker 1: fly right through. But you know, it is leaving particles
Speaker 1: and bits of itself in our solar system, and so
Speaker 1: who knows if this thing actually is from aliens and
Speaker 1: like seeded with all sorts of weird microbes, maybe they
Speaker 1: designed this thing to like explode when it comes close
Speaker 1: to the Sun and spray all of its stuff everywhere
Speaker 1: through the Solar system, in which case some of them
Speaker 1: will come to Earth and could potentially, you know, come
Speaker 1: through the atmosphere and land on the surface and infect
Speaker 1: people's brains and convince them to live in Virginia rather
Speaker 1: than California. I mean, we're talking deep tragedies here.
Speaker 2: Oh give me a break, man, That's where.
Speaker 1: He was going, right. They might even convince them to
Speaker 1: study chemistry. I mean, those aliens, who they're up to
Speaker 1: no good.
Speaker 2: I mean that would be a nefarious plot, absolutely so,
Speaker 2: But do you think so? Okay, So, when we were
Speaker 2: doing our tartar grade episode, which we did a little
Speaker 2: while back, we showed that, yes, tartar grades are like
Speaker 2: resistant to tons of things, but when you expose them
Speaker 2: to the radiation in space, they do kick the dust. Yeah,
Speaker 2: they can't survive that indefinitely, and I would have to
Speaker 2: imagine there's not a lot that could survive in interstellar voyage.
Speaker 2: But I guess we can't rule it out.
Speaker 1: What do you think it depends? I mean, you could
Speaker 1: survive an interstellar voyage if you're the core of one
Speaker 1: of these objects, right, if you're shielded by a lot
Speaker 1: of ice and rock, then yeah, you could survive the radiation.
Speaker 1: You know, whether you could survive being frozen that long
Speaker 1: and your metabolism could restart, you know, I think that's
Speaker 1: a biological question. But I think we've seen that in
Speaker 1: lots of critters here on Earth. So I think it's
Speaker 1: plausible for things to be frozen at the core and
Speaker 1: survive the interstellar trip and even the solar wind. But then,
Speaker 1: you know, once it disperses in our solar system, you know,
Speaker 1: then it's vulnerable again. And I think that's the most
Speaker 1: dangerous point.
Speaker 2: Yeah, when it gets kicked out of the coma or
Speaker 2: kicked into the coma.
Speaker 1: Yeah, and less of course they come out in you know,
Speaker 1: tiny little microscopic alien ships, and so they have their
Speaker 1: own shielding. I mean, if we're going to speculate here, like, let's.
Speaker 2: Go all in, right, let's go lob style.
Speaker 1: Let's pretend we're the chair of the Harvard Physics.
Speaker 2: Department, that would be pretty solid.
Speaker 1: Exactly, So Tim, this is a really exciting event. It's
Speaker 1: super fascinating. There's no evidence that it's aliens, like the
Speaker 1: astronomers want to believe that it's aliens, but so far,
Speaker 1: there's nothing that points in that direction. But of course
Speaker 1: you don't know. And it could be that it comes
Speaker 1: deeper into the Solar system and we learn new stuff,
Speaker 1: in which case we're all very happy to believe that
Speaker 1: it's aliens if the data points that way. And in
Speaker 1: that scenario, it's not going to directly leave a wake
Speaker 1: for us to fly through, but it could disburse stuff
Speaker 1: which eventually will come to Earth. I mean, there's a
Speaker 1: lot of cosmic dust that falls to Earth every day,
Speaker 1: so he could contribute to that. We could all be
Speaker 1: breathing in bits of an alien package one day.
Speaker 2: Could we have all already breathed in o mua mua bits?
Speaker 1: Oh yeah?
Speaker 2: Absolutely nice exciting. We are connected through space and time.
Speaker 2: All right, let's see what Tim thinks of our answer.
Speaker 2: Is he going to sleep well tonight or not? Let's
Speaker 2: find out.
Speaker 3: Hey, Daniel and Kelly, thank you for answering all of
Speaker 3: my questions.
Speaker 4: I can rest assured now knowing that Earth won't go
Speaker 4: through an alien comments tail and gain a whole bunch
Speaker 4: of microbes.
Speaker 3: That will convert us to alien life forms. Keep up
Speaker 3: with the good work.
Speaker 1: Thank you. All right, we are back when we're answering
Speaker 1: questions from listeners, questions we get every email and also
Speaker 1: questions on our discord. If you love thinking about the
Speaker 1: universe and hearing us chat about it, you might want
Speaker 1: to chat with us. We are very active on our discord.
Speaker 1: If you want to join, it's for everybody who's curious
Speaker 1: about the universe. Go to our website www dot danieland
Speaker 1: Kelly dot org. Well you'll find the link to join
Speaker 1: the discord. So many fun, nice people talking about the
Speaker 1: universe and asking questions. Kelly tell us about this question.
Speaker 2: Well, at first, I'd like to just note that we
Speaker 2: also have the best moderators, so you know, another good
Speaker 2: reason to come join us. All right, So Marco from
Speaker 2: Discord had this question about parasite manipulation of host behavior.
Speaker 1: And Marco is not just another Kelly sock puppet account.
Speaker 2: I mean, you'll never know, You'll never know.
Speaker 5: Hi, Daniel and Kelly, I have a question about the
Speaker 5: jewel wasp discussed in Ed Young's book An Immense World
Speaker 5: Horrified as an understatement, as is the sentence. I had
Speaker 5: a nightmare about this. In the book, Young describes how
Speaker 5: the jewel wasp feels around for the cockroach brain with
Speaker 5: its stinger, and I keep wondering about the evolutionary mechanisms
Speaker 5: at play here. The wasp doesn't know what a brain is, obviously,
Speaker 5: but how on earth could it have evolved the precision
Speaker 5: to accomplish this. I'm well to side This strongly implies
Speaker 5: that the wasp has not only absurd command of its
Speaker 5: own body, but the body of the cockroach as well.
Speaker 5: There's a ton of evolutionary time to miss the sweet
Speaker 5: spots and the cockroaches back and head and not be successful.
Speaker 5: There's a neat series I've been watching on octopuses, and
Speaker 5: it discusses how these intelligent creed learn everything on their
Speaker 5: own without parental support. Wasps aren't teaching their young where
Speaker 5: to sting, So how does this amazing ability emerge from
Speaker 5: this tiny little wasp brain? Just realized I've been listening
Speaker 5: to the podcast long enough to realize the answer is,
Speaker 5: we don't know. Thanks for everything, love the show. Can't
Speaker 5: wait to hear the answer, all right.
Speaker 2: So, first of all, I love that Marco clearly has
Speaker 2: been paying attention and suspects that there's a high probability
Speaker 2: the answer is going to be I don't know.
Speaker 1: Good job, Mark, welcome to the forefront of science.
Speaker 2: Everyone great, that's right, And so yes, the answer at
Speaker 2: the very end for a lot of these questions is
Speaker 2: going to be we don't know. But let's talk about
Speaker 2: some of the things that we do know first, because
Speaker 2: I love this system and I'm going to use it
Speaker 2: as an excuse to tell you all about it.
Speaker 1: Yes, so tell us about the jewel wasp and what
Speaker 1: it does to poor cockroaches. Are we going to feel
Speaker 1: sympathy for cockroaches at the end of this?
Speaker 2: Oh maybe? And then I got to talk about the
Speaker 2: parasitoids that manipulate web building behavior in spiders and actually
Speaker 2: makes you feel sympathy for spiders. That's another day. I
Speaker 2: love those systems. Their videos are just like nuts.
Speaker 1: Anyway, all right, today we're pro cockroach. Tell us why?
Speaker 2: Okay, well I'm gonna I'm actually gonna end up on
Speaker 2: team Jewel Wasp. But anyway, so right, So jewel wasps.
Speaker 2: They're beautiful, they're kind of iridescent. They need to lay
Speaker 2: their eggs somewhere and provide their babies with a meal.
Speaker 2: And so essentially what they're going to do is paralyze
Speaker 2: a cockroach, hide it in a really great spot, lay
Speaker 2: an egg on it. That egg is gonna hatch, eat
Speaker 2: the cockroach from the inside, and then leave its carcass
Speaker 2: when it's done. That's the big overview.
Speaker 1: And the cockroach is alive while these things are growing
Speaker 1: inside of it.
Speaker 2: The egg is attached to the outside of its body.
Speaker 2: But then the baby does eat its way in. Oh yes, yeah,
Speaker 2: it's it's pretty gruesome.
Speaker 1: And why does the cockroach have to be alive? Is
Speaker 1: that so that it stays fresh and tasty the way
Speaker 1: you like put like living lobsters into pots.
Speaker 2: Yeah yeah, I don't feel comfortable about that. Don't do
Speaker 2: it myself. But anyway, so this would be like you
Speaker 2: wouldn't want to leave the puid spinach for your baby
Speaker 2: out on the counter for like a week. You know,
Speaker 2: you want your cockroach and your spinach to be fresh,
Speaker 2: all right, So here's here's how the process goes down.
Speaker 2: So the jewel wasp and the cockroach get in a
Speaker 2: tussle because the cockroach knows that the jewel wasp is
Speaker 2: bad news. So the first thing that the jewel wasp does,
Speaker 2: if it gets lucky enough and can get the angle right,
Speaker 2: is it stings the cockroach in the thorax so like
Speaker 2: the chest kind of region, and this will paralyze the
Speaker 2: cockroach's front legs for up to five minutes. And so
Speaker 2: this makes it so the cockroach can't fight back quite
Speaker 2: as well, and the jewel wasp will deliver its second sting.
Speaker 2: The second sting is in the head, so it goes
Speaker 2: through the neck kind of moves through the tissues until
Speaker 2: it finds the brain. It's got this like ovipositor that
Speaker 2: delivers the sting, so it's almost like a needle at
Speaker 2: the end, and so it puts this needle up into
Speaker 2: the brain and it delivers another sting. And this sting.
Speaker 2: I know it's nasty, this sting, but I love it.
Speaker 2: This sting does a couple of different things.
Speaker 1: It's nasty and just the way Kelly loves.
Speaker 2: Yeah, Well, nature's horrible but fascinating. And so now the
Speaker 2: cockroach starts grooming itself furiously, and I think we're not
Speaker 2: totally sure why that is happening. Maybe it's because they
Speaker 2: want the meal to be like super fresh, no, like
Speaker 2: bacteria infecting your meal, And so the cockroach cleans itself
Speaker 2: up a lot. And then another interesting thing is that
Speaker 2: the cockroach technically is capable of moving, but its desire
Speaker 2: to initiate its own movement pretty much goes away. So
Speaker 2: it can move, but it doesn't it's desire.
Speaker 1: We're talking about what it's like to be a cockroach,
Speaker 1: Like we're in the mind of the cockroach thinking about
Speaker 1: what it wants.
Speaker 2: So all right, I'm being a bit anthropomorphic about it.
Speaker 2: I don't know what the cockroach is thinking. But whereas
Speaker 2: usually cockroaches in an area where they know that there's
Speaker 2: like something dangerous, ye would initiate movement and would get
Speaker 2: out of there, this cockroach just kind of stands around.
Speaker 2: But it's still capable of moving because the parasitoid will
Speaker 2: like find a good nesting spot and then come back
Speaker 2: and grab the cockroaches antenna and lead it to a
Speaker 2: nesting spot, and the cockroach will follow.
Speaker 1: It's like, yes, it's like driving it. Yeah, so this
Speaker 1: way that way.
Speaker 2: Yeah. The way it's usually talked about is like it's
Speaker 2: like walking a dog on a leash or something like that.
Speaker 2: It just follows and so then it gets moved into
Speaker 2: this little like nook where everything can be hidden so
Speaker 2: that nothing will eat the cockroach and also eat the baby,
Speaker 2: because the cockroach can't fight back really anymore, and it
Speaker 2: will the mom will put the cockroach in the nest,
Speaker 2: lay the egg somewhere on the cockroach, I think, like
Speaker 2: near its leg, and then seal up this little nest
Speaker 2: site with you know, leaves and rocks and stuff like that.
Speaker 2: And then the rest of the process takes about eight days.
Speaker 2: The egg hatches, eats the inside of the cockroach, pupates inside,
Speaker 2: so it goes through a couple developmental stages in the
Speaker 2: body of the cockroach.
Speaker 1: So it's basically laid the egg along with some food.
Speaker 1: It's sort of like a chicken egg is the embryo
Speaker 1: with the food, but the chicken provides it instead of
Speaker 1: stealing it from a cockroach.
Speaker 2: All right, Yeah, that's exactly right. And a lot of
Speaker 2: parasitoids do this. There are parasitoids, you know. Just the
Speaker 2: other day I saw a parasitoid dragging a giant spider.
Speaker 2: It had paralyzed, and it was dragging it to its
Speaker 2: nest so that it could then lay eggs on it
Speaker 2: and keep its meal fresh. And so what's special about
Speaker 2: this system, not from the perspective of the cockroach, of course,
Speaker 2: but is that a lot of parasitoids will paralyze food
Speaker 2: and then lay their eggs in or on it as
Speaker 2: a meal for when they hatch. But you've got this
Speaker 2: extra layer where the parasitoid is also able to like
Speaker 2: direct the cockroach to go to a particular location, rather
Speaker 2: than needing to like physically drag it there, which a
Speaker 2: bunch of others have to do. Wow, amazing, yes, amazing.
Speaker 1: So the cockroach like participates in its own demise.
Speaker 2: It does it does?
Speaker 1: It's complicit.
Speaker 2: That's gross complicit. I don't know that. That's that word
Speaker 2: has too much human baggage. It unwillingly, unwittingly does, does
Speaker 2: the wasps bidding? Okay, So Marco was interesting in the
Speaker 2: fact that when that second sting happens, and the sting
Speaker 2: is happening in the brain, the wasp that is stinging
Speaker 2: the brain, it's mom isn't there to teach it how
Speaker 2: to do that. So how does it just know where
Speaker 2: to sting in a brain? And at the end of
Speaker 2: the day, the answer is going to be we don't
Speaker 2: really know, but I'm going to give you a little
Speaker 2: bit more detail about what is actually happening when it
Speaker 2: stings the brain. So we talked about how it puts
Speaker 2: its little like hypodermic needle esque but into the neck
Speaker 2: of the wasp and it starts going up to the brain.
Speaker 2: And there have been some experiments trying to figure out
Speaker 2: what happens inside the cockroach's brain. So one thing they
Speaker 2: did was they injected carbon fourteen radio labeled amino acids
Speaker 2: into the stinger and then they look to see where
Speaker 2: it ended up in the cockroach. And it does end
Speaker 2: up in this area called the subsophageal ganglion, so it's
Speaker 2: like kind of the bottom part of a cockroach's brain.
Speaker 1: So injecting carbon fourteen labeled amino acids this is just
Speaker 1: a way of tracing like where something go. Like add
Speaker 1: like a little dye to so you can see where
Speaker 1: something goes. But in this case, it's not a visual die.
Speaker 1: It's like you're measuring the radioactive decays or how does
Speaker 1: that work?
Speaker 2: Yeap, that's exactly right.
Speaker 1: Fascinating, Well, yeah, yeah.
Speaker 2: Pretty cool experiment, Okay, And then they did some other
Speaker 2: experiments to try to figure out what it is that
Speaker 2: the wasp is queuing in on, to figure out where
Speaker 2: it's supposed to deposit what we we call this the
Speaker 2: stuff that gets deposited during the sting venom, which is
Speaker 2: awesome anyway. So they've done things like humanly euthanize a
Speaker 2: cockroach and then remove its brain and then give it
Speaker 2: back to the wasp. And when you do that, the
Speaker 2: wasp spends a bunch of time like searching and not
Speaker 2: delivering its venom. It's like, what something is missing in here,
Speaker 2: and so it's like it's definitely.
Speaker 1: It's looking for the brain.
Speaker 2: It's looking for the brain, and it gets kind of
Speaker 2: confused when it's not there. And so then the scientist
Speaker 2: looked a little bit closer at the ovipositor and they
Speaker 2: found sensors on there, and some of the sensors are
Speaker 2: mechanical receptors, so they like can touch things, and some
Speaker 2: are chemical receptors. And so first they wanted to dive
Speaker 2: into what happens with the mechanical receptors, and so they
Speaker 2: took all the mechanical receptors off of the wasp, and
Speaker 2: the wasp just kind of like searched around for a
Speaker 2: really long time. It was super confused because it couldn't
Speaker 2: feel anything. Then they humanely euthanized the cockroaches and they
Speaker 2: put a very soft substance that wasn't very brain like
Speaker 2: into the head of the cockroach, and the wasp also
Speaker 2: searched around for a really long time and was like,
Speaker 2: what is going on? But then they put a hard substance,
Speaker 2: harder substance that's more like the brain, and the wasp
Speaker 2: responded more quickly. So it doesn't have to be a brain,
Speaker 2: but it's got to feel right.
Speaker 1: So they're testing what the wasp wants to sting, and
Speaker 1: they're like, how about a squishy brain having an actual brain?
Speaker 1: How about some of it feels like a brain. They're
Speaker 1: like exploring the space of what the wasp is willing
Speaker 1: to engage with. That's fascinating.
Speaker 2: Yeah, yeah, And if you like kind of mix up
Speaker 2: the brain and kind of change its consistency, like mixing
Speaker 2: it up with like scissors or something, they also are
Speaker 2: confused and are like, what the heck is going on here?
Speaker 2: So it looks like the mechanical stuff really matters, And
Speaker 2: so that suggests to me that there's some genetic coating
Speaker 2: that gets passed from generation to generation, doesn't need to
Speaker 2: be learned where they know, like it goes in the neck,
Speaker 2: and then you look for something that feels a certain way.
Speaker 2: And I don't think we've looked close enough in this
Speaker 2: system to understand exactly how that happens. But we have
Speaker 2: looked at other behaviors that are you know, what we
Speaker 2: would say is innate. They just happen without learning.
Speaker 1: So it's so important that it touches the brain that
Speaker 1: the system has evolved requirements to ensure that it only
Speaker 1: happens when there's like an actual brain there to be
Speaker 1: delivered on, not just like randomly spraying this stuff in
Speaker 1: the head of the cockroach.
Speaker 2: Yah. So presumably the chemical cocktail that gets delivered into
Speaker 2: the brain is expensive to make in some way, like
Speaker 2: requires a lot of energy or certain nutrients or something.
Speaker 2: So you don't want to go stinging things and wasting it.
Speaker 2: And so if this cockroach seems like it's totally off
Speaker 2: for some reason, then you abandon it.
Speaker 1: Well, go go find the cockroads through the bigger taste
Speaker 1: of your brain.
Speaker 2: That's right, Well, there are other parasitoids that can test
Speaker 2: and see, like, are there already parasitoid wasps living inside
Speaker 2: of this insect because I don't want my babies to
Speaker 2: have to compete with babies that had a head start.
Speaker 2: And so there's all sorts of like crazy stuff that
Speaker 2: happens when the wasp is like evaluating its host for quality.
Speaker 1: All right, So this is really fascinating and very complex behavior.
Speaker 1: And I feel like Marco's question is essentially, how does
Speaker 1: the wasp evolve this kind of behavior? The mom is
Speaker 1: not there to teach it, which means it must be
Speaker 1: somehow innate, which suggests that it's like in the code
Speaker 1: of the DNA, which means it comes from evolution, not
Speaker 1: from like the wasp culture. How is such a complex
Speaker 1: process ever evolved? It feels impossible to imagine that you
Speaker 1: develop such an intricate system because it needs many parts
Speaker 1: to work all at once.
Speaker 2: Well, maybe your imagination is limited, Daniel, No, I'm just kidding. Yes,
Speaker 2: it is very complicated. So one of the ways that
Speaker 2: we look at the evolution of complex behaviors is that
Speaker 2: we'll look at things that closely related species are doing,
Speaker 2: and sometimes you can see the steps that build in
Speaker 2: a more complicated behavior. So, for example, this system has
Speaker 2: two stings, and one of them is a little bit
Speaker 2: more complicated, but a lot of other parasitoids, as we've
Speaker 2: already talked about, do one sting to paralyze their prey.
Speaker 2: So you can see that as like a beneficial early step.
Speaker 2: We have not in this system been able to work
Speaker 2: out the order in which all of these complicated things
Speaker 2: evolved and sort of built up.
Speaker 1: So let me just make it explicit. You're suggesting that
Speaker 1: it's a complex series of behaviors, but there probably are
Speaker 1: simpler versions of it that are also beneficial. You don't
Speaker 1: need all the complex pieces in order to gain some benefit,
Speaker 1: and that would allow you to tell the evolutionary story.
Speaker 2: Is that the argument that yep, that's exactly right, and
Speaker 2: every intermediate step needs to be beneficial in order for
Speaker 2: it to keep passing through the population, unless you've got
Speaker 2: drift going on. But anyway, okay, so these are there
Speaker 2: are beneficial steps, and you know, you can imagine something
Speaker 2: like initially the jewel wasps only stung the cockroach once
Speaker 2: and paralyzed it, and then you had to drag it.
Speaker 2: But then there was one wasp that had some mutation
Speaker 2: that made it extra stabby, and it stabbed once in
Speaker 2: the thorax and once in the brain, and that did
Speaker 2: something that made the cockroach a little bit easier to handle,
Speaker 2: which meant the mom could lay more eggs and could
Speaker 2: do this more times. And maybe that got passed on genetically,
Speaker 2: and you can imagine generation after generation that's just honed
Speaker 2: and more and more beneficial.
Speaker 1: And maybe my imagination is limited, but does the phrase
Speaker 1: extra stabby appear in the biological literature anywhere?
Speaker 2: No, that that's just because I'm super creative. You know,
Speaker 2: that was my creativity. I'm just kidding, You're very creative.
Speaker 2: But yeah, so we don't know exactly the path that
Speaker 2: this took, but you can imagine how it would have
Speaker 2: built up, and then you know, it's possible somebody could
Speaker 2: test this by looking at closely related wasp species and
Speaker 2: maybe if you understood more mechanistically about how this was
Speaker 2: all happening, you could understand how one step could happen
Speaker 2: after another. But for this system, I would say, we
Speaker 2: don't have a really good evolutionary answer.
Speaker 1: I think that all makes sense that complex behaviors of
Speaker 1: all from simpler behaviors that are also beneficial, and it
Speaker 1: sometimes takes a while to figure out what path you
Speaker 1: can take from simpler to more complex. I think the
Speaker 1: thing that blows my mind is that these complex behaviors
Speaker 1: feel kind of fragile, like everything has to work for
Speaker 1: this to happen, and it feels like there's so many
Speaker 1: ways for it to go wrong. It's incredible that it
Speaker 1: relies on such a complex system. And then it mostly works.
Speaker 1: And then I look at you know, like humans, I've
Speaker 1: raised a child. It's complicated. It feels like there's so
Speaker 1: many ways it can go wrong. And then I walk around,
Speaker 1: I'm like, wow, all of these humans, they were raised
Speaker 1: by people. It seems to mostly work. It's incredible. Yeah,
Speaker 1: you know, biology seems so fragile, but it is pretty robust.
Speaker 2: Yeah, I mean, it is incredible. But you know, there's
Speaker 2: plenty of times when jewel wasps go after cockroaches and nature,
Speaker 2: and the cockroach wins and the jewel wasp doesn't get
Speaker 2: to sting.
Speaker 1: Or heay cockroache, hey cockroache.
Speaker 2: Or you know, the jewel wasp dies for one reason
Speaker 2: or another or just doesn't. Like, there's plenty of times
Speaker 2: in nature where these things do fail, and those individuals
Speaker 2: usually just get wiped out of the population, And just
Speaker 2: so it doesn't sound like I'm saying, well, whenever we're
Speaker 2: talking about complex behaviors, we always just imagine a picture.
Speaker 2: There are systems where step by step we've sort of
Speaker 2: figured this stuff out. And I'm working on finding a
Speaker 2: behavioral geneticist to come on the show to talk to
Speaker 2: us about those answers. So stay tuned.
Speaker 1: All right, Well, I think that's a pretty good answer
Speaker 1: for Marco. Let's inject that into his head and see
Speaker 1: how his brain responds.
Speaker 2: Did we lead you to the answer, Marco? I promise
Speaker 2: we won't lay any eggs on you.
Speaker 6: After hearing your answer, I admit I'm no less terrified
Speaker 6: of jewel wasps. I can only hope I don't have
Speaker 6: another fever dream frantically trying to keep one from stinging
Speaker 6: the back of my head by jumping into water. I
Speaker 6: can't find forever in awe of evolution, coming down to
Speaker 6: random events and mind boggling numbers until some advantage emerges
Speaker 6: and gets successfully encoded. I keep going back to a
Speaker 6: couple of points you made. One is that without passing
Speaker 6: down knowledge genetic coding instructions and organisms behavior, the LOSPs
Speaker 6: are compelled to behave as they do the.
Speaker 5: Evolution handles the rest.
Speaker 7: As with most of the podcast episodes, we end up
Speaker 7: with more questions like how did Kelly end up on
Speaker 7: Team Jewel Wasp. I can't side with that freak show.
Speaker 7: I fully support Wally's cute sidekick, not the Jewel Wasps.
Speaker 7: That feels like siding with monstrous killers, or the seventeen
Speaker 7: percent of people that prefer white chocolate not tolerate it
Speaker 7: but like it better. It truly is an extraordinary universe.
Speaker 3: Thanks Daniel and Kelly.
Speaker 2: Next up, we have a question from southern Scotland. And
Speaker 2: I am so excited because I got to go to
Speaker 2: Scotland for the first time last month. I was in Edinburgh,
Speaker 2: which is probably not where Ben is from. But Ben,
Speaker 2: your country is beautiful. I loved it, and vegetarian haggis
Speaker 2: a plus.
Speaker 1: And I'm going to Scotland next week for a wedding
Speaker 1: in Inverness.
Speaker 2: Yeah, and you're gonna wear kilts.
Speaker 1: I'm gonna wear a kilt exactly all right. But today
Speaker 1: the question is not about Daniel's wardrobe at Scottish weddings.
Speaker 1: It's about what these terms in science mean. So let's
Speaker 1: hear Ben's question.
Speaker 8: Hello, Daniel and Kelly. It's Ben here from Cukubree in
Speaker 8: southern Scotland. I'd really like to know what you think
Speaker 8: is the difference, if any, between a theory, a law,
Speaker 8: a hypothesis and a model. I'm especially curious about Darwin's
Speaker 8: theory of the origin of species. Is this a typical
Speaker 8: scientific theory? Does it of predictive power? Can it be
Speaker 8: refuted by experiment? I feel I really need the combined
Speaker 8: advice of a particle physicist and the powascientologist to help
Speaker 8: to settle these questions. I really enjoy your podcast.
Speaker 2: Oh this is a really great question.
Speaker 1: This is a really fun question. I'm really glad that
Speaker 1: Ben asked it, because it's one of these questions where
Speaker 1: if you ask philosophers or if you ask scientists, you'll
Speaker 1: get a different answer. And if you ask different philosophers
Speaker 1: and different scientists, you'll get lots of different answers. It's
Speaker 1: something a lot of people are not very precise about.
Speaker 2: Frankly, yeah, I think when I was an undergrad, I
Speaker 2: remember in my biology class there were definitions of all
Speaker 2: of these terms, and then I was very confused later
Speaker 2: on when they were used in ways that were not
Speaker 2: at all consistent with what was in that textbook. And anyway,
Speaker 2: now I know we're all sloppy.
Speaker 1: Well, you know, scientists are practitioners who are not experts
Speaker 1: in the philosophy of science. We go out there and
Speaker 1: we do science, and we say theory, we say law,
Speaker 1: we say model. We haven't all taken philosophy classes or like.
Speaker 1: The distinctions between these things are argued by nerds who
Speaker 1: are super excited about it. You know, we're excited about
Speaker 1: the biology or the chemistry or the physics or that
Speaker 1: kind of stuff. And so when you hear scientists talk
Speaker 1: about it, they're not often being very precise because they're
Speaker 1: not experts in the definitions of these terms. Philosophers of
Speaker 1: science are the folks who really narrow down on this.
Speaker 1: But again, also philosophers of science disagree reasonably with each
Speaker 1: other about how to describe this stuff. So I'll break
Speaker 1: it down for you in a way that makes sense
Speaker 1: to me, but definitely other people will have different definitions
Speaker 1: of this. This is not definitive in any sense, and.
Speaker 2: If I could just mention that, I also think another
Speaker 2: thing that makes it complicated isn't just that most of
Speaker 2: us don't actually know what these terms mean. It's that
Speaker 2: even if we did, when you understand something, it's not
Speaker 2: usually like there's a clear yeah switch that gets flipped
Speaker 2: where you're like, oh, now we've entered law lands. Before
Speaker 2: we were in hypothesis land. It's like you need to
Speaker 2: slowly accumulate and it's not always clear when it's time
Speaker 2: to like update to a new term. And so anyway,
Speaker 2: that probably complicates things too.
Speaker 1: Yeah, yeah, So let's start with laws. I think of
Speaker 1: a law as something the universe actually does. There's some
Speaker 1: truth out there, and one of the basic assumptions in
Speaker 1: science is that the universe follows laws and we don't
Speaker 1: know them, but we can do experiments and think about
Speaker 1: it and all this sorts of stuff to try to
Speaker 1: figure them out. So we think the universe follows some
Speaker 1: sort of concise, simple fundamental rules, and those are the
Speaker 1: laws of the universe, all right, still with me?
Speaker 3: Yeap?
Speaker 1: Cool? Now we don't know who those things are, but
Speaker 1: we can have theories about it, so we went it
Speaker 1: from law to theory. Theories are like our explanations for
Speaker 1: how the universe works. So general relativity, for example, is
Speaker 1: a theory about how matter bends space and how space
Speaker 1: tells matter to move. Quantum mechanics is a theory that
Speaker 1: tells us that space is filled with oscillating fields. These
Speaker 1: are theories. They're like our explanatory frameworks to describe the
Speaker 1: things that we see in the universe, and we hope
Speaker 1: that those theories line up with the truth the laws
Speaker 1: that are actually out there in the universe. And so theories,
Speaker 1: it's kind of a fuzzy term, right, Theories are sort
Speaker 1: of like our ideas. They include a bunch of evidence
Speaker 1: and they come together to give like some sort of
Speaker 1: coherent explanation for how something is working in the universe.
Speaker 1: A theory is not just like a random guess, not
Speaker 1: just like, hmm, maybe it's this, right, like a fan
Speaker 1: theory to explain the ending of some movie you just saw. Right,
Speaker 1: It's something that's really based in evidence and has been
Speaker 1: tested and it's sort of part of our explanation of
Speaker 1: the universe.
Speaker 2: Yeah, lots of different labs have looked at it. It's
Speaker 2: been looked at from lots of different angles. Predictions have
Speaker 2: been tested.
Speaker 1: Yeah, agreed, Yeah, so the whole like, you know, gravity's
Speaker 1: just a theory, man, doesn't mean that like we don't
Speaker 1: know anything about gravity, or it's just like one of
Speaker 1: ten options to explain why we stick to the surface
Speaker 1: of the Earth. Right, A theory can be something that's
Speaker 1: very well developed and understood.
Speaker 2: I don't know, was vity really the best pick. There
Speaker 2: seems like there's a lot we don't know about gravity.
Speaker 1: There is a lot we don't know about gravity. That's
Speaker 1: the other thing about a theory is that they're never complete, right,
Speaker 1: They're evolving, their changing. You know, gravity is a wonderful,
Speaker 1: amazing theory, but there's definitely a lot we don't know about,
Speaker 1: you know, what's going on at the center of black
Speaker 1: holes or the early universe, or fundamentally how gravity works
Speaker 1: for particles.
Speaker 3: Right.
Speaker 1: Definitely, it's a not complete explanation of the universe. It's
Speaker 1: an explanation of part of the universe. And we don't
Speaker 1: have a unified theory. We'd love to have one, because
Speaker 1: we think there is one set of laws, but we
Speaker 1: have sort of piecemeal theories that we think are approximating
Speaker 1: those laws.
Speaker 2: Excellent. I'm glad we have a scientist slash philosopher on
Speaker 2: the show.
Speaker 1: So there are laws out there. We try to build
Speaker 1: theories about how the universe works and follow those laws.
Speaker 1: What's a model in that sense, and model is a
Speaker 1: very overloaded term in physics, we use model to mean
Speaker 1: sort of a simplified version of a theory, because theories
Speaker 1: are complicated. If you wanted to calculate the orbit of
Speaker 1: the Earth around the Sun, you couldn't use general relativity.
Speaker 1: Nobody knows how to do that calculation. General relativity really
Speaker 1: really nasty. The only times we've ever been able to
Speaker 1: solve problems with general relativity are in simplified settings, like
Speaker 1: an empty universe, a universe with just a black hole
Speaker 1: in it, a universe filled with uniform dust. None of
Speaker 1: those correspond to our reality. Our reality is too complicated
Speaker 1: to solve with the full theory, and so we build
Speaker 1: a model. We can simplify the universe. We can say, like,
Speaker 1: let's assume the universe is empty except for the Earth
Speaker 1: and the Sun. Now, let's do the calculation, and we
Speaker 1: hope that the calculation is still relevant to the real universe. Right,
Speaker 1: we find a simpler version something we actually can crank
Speaker 1: on and hope that the answer is still irrelevant. Or
Speaker 1: we can simplify the calculations. We can say, well, let's
Speaker 1: use an approximate version of the theory. You know, Einstein's
Speaker 1: equations for general relativity. If things are far apart and
Speaker 1: masses are not too high and they're slow moving, they
Speaker 1: reduce to Newton's theory. And so you can use Newton's
Speaker 1: theory for most stuff. You want to calculate whether your
Speaker 1: cannon ball is going to fly over the castle walls,
Speaker 1: you don't need to use general relativity. You're going to
Speaker 1: get basically the right answer using a simpler model, right,
Speaker 1: a model of general relativity, which is just Newton's equations.
Speaker 1: And so, you know, spherical cows are a fun joke
Speaker 1: because that's the kind of thing physicists do. We're like, well,
Speaker 1: let's replace a complex situation with a simpler situation where
Speaker 1: the answer is basically the same. And so a model
Speaker 1: is a simplification. Either you've simplified the universe or you've
Speaker 1: simplified the theory so that you can get some answers out.
Speaker 2: Yeah, and models are great. They help you decide if
Speaker 2: you know your simplification.
Speaker 1: Yeap.
Speaker 2: When you do a simplification, you're making assumptions that some
Speaker 2: things don't matter that much. And so then when your
Speaker 2: model gives you an answer and you test it, you
Speaker 2: can see, oh, was I right? That the thing doesn't
Speaker 2: matter that much? And you know, ideally it's an iterative process.
Speaker 2: The model gives you a prediction you can test, You
Speaker 2: actually go out and you test it, and then you
Speaker 2: update your model as needed.
Speaker 1: That's right, and it's import to understand that every calculation
Speaker 1: anybody has ever done uses models, uses simplifications. All of
Speaker 1: physics uses approximations. If you want to calculate how the
Speaker 1: Earth goes around the Sun, in principle, you need to
Speaker 1: include the gravitational tug from every single object out there
Speaker 1: in the universe which is pulling on the Earth. Most
Speaker 1: of those are negligible, and some rock out there in Andromeda.
Speaker 1: It's really not going to change the path of the
Speaker 1: Earth in a way we can measure, but in principle
Speaker 1: it does, so we always do approximations. It's impossible to
Speaker 1: ever do full calculations in any of our theories for
Speaker 1: any situations. So all of science is approximate to some degree,
Speaker 1: and that's where a lot of science happens is figuring
Speaker 1: out how to be clever about it. What approximations can
Speaker 1: I make so the answer is still useful and irrelevant right,
Speaker 1: and I can get this done in a PhD length
Speaker 1: of time and not be here for ten thousand years.
Speaker 2: That can often be a very painstaking part of the process. Though,
Speaker 2: What are my parameter estimates that are reasonable and useful
Speaker 2: and that can be a lot of work.
Speaker 1: That's right. And so that's what a model is. And
Speaker 1: let me say that model is used very differently in
Speaker 1: different fields. Like I talk to computer scientists and machine
Speaker 1: learning people. For them, a model is like a trained network.
Speaker 1: They talk about neural networks as my model or their
Speaker 1: boosted decision tree is a model. They use model I
Speaker 1: means something they very different than physicists do. And I
Speaker 1: know biologists talk about like model systems. They're studying the brain.
Speaker 1: They're doing it in mice, or they're doing it in rats,
Speaker 1: or they're doing it in flies. To them, that's the
Speaker 1: meaning of model, like which model system are you using?
Speaker 2: But when someone says to you, you know, what do
Speaker 2: you do? When you say, oh, I do modeling, they
Speaker 2: know that that means that you are using equations to
Speaker 2: try to capture the dynamics of a system and are
Speaker 2: making predictions that way. So I think we use the
Speaker 2: word model in a couple different ways, one of which
Speaker 2: is model systems.
Speaker 1: Yeah, and I think that fits in because, like you're
Speaker 1: using the mouse as a model system to understand Alzheimer's
Speaker 1: because you can't and you shouldn't, do experiments on humans,
Speaker 1: and so use the mouse brain as a stand in
Speaker 1: as an approximation for the human brain. Because know, it's
Speaker 1: not okay to do the things the humans that you
Speaker 1: do to mice, and maybe it's not okay to do
Speaker 1: to mice either, but it's maybe more okay. I think
Speaker 1: it's the argument biologists make.
Speaker 2: Yeah, yes, depends on who you're talking to, but I
Speaker 2: guess I'd prefer it happened on mice.
Speaker 1: Yeah, all right, And so the last term was hypothesis.
Speaker 1: We test our model by generating hypotheses. We're saying, here's
Speaker 1: my model of the universe. I think that this interstellar
Speaker 1: comet is made of ice and co.
Speaker 3: Two.
Speaker 1: Let me generate a hypothesis about what James Webspace telescope
Speaker 1: we'll see when we point it at it, and then
Speaker 1: I can compare that hypothesis to what we actually see.
Speaker 1: So the model predicts something that's our hypothesis, and then
Speaker 1: we compare it to reality in order to learn whether
Speaker 1: the model is correct or not.
Speaker 2: Yep.
Speaker 1: Cool. So we have laws, theories, models, and hypotheses. And
Speaker 1: the last bit of Ben's question was a sort of
Speaker 1: loaded question about Darwin's theory. I hear a lot of
Speaker 1: this discussion online about how evolution is just a theory man,
Speaker 1: and because it all happened in the past, it's not
Speaker 1: really predicting anything. It's just descriptive, and therefore it's unfalsifiable
Speaker 1: and not really scientifically valid. And I wonder if these
Speaker 1: critiques are really done in good faith. You know, these
Speaker 1: are folks attacking evolution, trying to use the language of
Speaker 1: science to undermine it. But I don't think they really
Speaker 1: believe in the scientific process personally. Yeah, agree, So let's
Speaker 1: talk about it. Darwin's theory is definitely a theory. I mean,
Speaker 1: it provides an explanation for how speciation happens. Right, There's
Speaker 1: lots of evidence out there that it's pulled together. It
Speaker 1: definitely qualifies as a theory, and in that sense, it's
Speaker 1: not just like some dude's random guess, right, It's a
Speaker 1: well established explanation for a huge variety of stuff that
Speaker 1: we see out there.
Speaker 2: What do you think, Yes, so for one hundred and
Speaker 2: fifty years, we've been trying to decide if evolution through
Speaker 2: natural selection is supported by the data. And you know,
Speaker 2: there's probably evolutionary biologists in every department that does research
Speaker 2: around the world, and we have found results that make
Speaker 2: us think about evolution through natural selection in a different way.
Speaker 2: But in one hundred and fifty years, none of us
Speaker 2: have come up with a result that's like, oh, definitely,
Speaker 2: we drop this theory. So we've got one hundred and
Speaker 2: fifty years of researching coming up with predictions based on
Speaker 2: this theory that are supported by future work. So yeah,
Speaker 2: I agree with you.
Speaker 1: Yeah, And Ben asks like, is this a predictive theory?
Speaker 1: And I think the answer is absolutely. You know, it
Speaker 1: predicts lots of things about what you should find out
Speaker 1: there in the world. You should find fossils, you should
Speaker 1: find simpler behaviors leading to more complex behaviors. You should
Speaker 1: see real time evolution, you know, when communities respond to
Speaker 1: changing circumstances. You should see a connection between the species
Speaker 1: that we observe and the genetic information that leads to them.
Speaker 1: This is I think a really powerful confirmation of natural
Speaker 1: selection is finding the sort of mechanism the DNA, the
Speaker 1: biochemistry that underlies all of this, and seeing confirmed in
Speaker 1: the history of that evolution in the DNA, I think
Speaker 1: it's super fascinating. You know, we can learn things about
Speaker 1: like when community is diverged by seeing the differences in
Speaker 1: their DNA.
Speaker 2: Yep, yep. And you know, yeah, Darwin is clearly like
Speaker 2: the best scientist of all time. Sorry, Daniel. And so
Speaker 2: if you could be the scientist who finds the data
Speaker 2: that refutes this theory, yeah, you could replace the name Darwin, right,
Speaker 2: And so there's no.
Speaker 1: Mainstream narrative the biology is trying to protect.
Speaker 2: Yeah, that's right, that's right.
Speaker 1: Now every scientist out there wants to overthrow the mainstream
Speaker 1: narrative because that's how you become a famous scientist. And
Speaker 1: also that's what we all want to do. We want
Speaker 1: to learn the truth about the universe. We're driven by
Speaker 1: our curiosity to reveal the truth, not to support some
Speaker 1: sort of dogma. But you raised I think the last,
Speaker 1: maybe the most important point is that the question about
Speaker 1: whether this could be refuted. So can you, Kelly, imagine
Speaker 1: some evidence that hypothetically would undercut this theory of evolution.
Speaker 2: At this point, we have so much evidence. It's kind
Speaker 2: of hard to imagine something we could have missed and
Speaker 2: like one piece of information that would refute everything. So
Speaker 2: I think at this point, if you had a finding
Speaker 2: that like multi cellular life existed before we found unicellular life,
Speaker 2: like it just popped into existence or something, we would
Speaker 2: have to look really hard at, like have we collected
Speaker 2: all the data and all the different places, Like yeah,
Speaker 2: because there's this mountain of evidence and you've got this
Speaker 2: one thing that maybe doesn't fit. But I do think
Speaker 2: that if there were evidence out there, scientists would be
Speaker 2: open to considering it and looking at it and trying
Speaker 2: to understand if that makes us wrong, or if it's
Speaker 2: just a shady corner in the room of evolution that
Speaker 2: we haven't explored yet and we just need to move
Speaker 2: into that into that area instead.
Speaker 1: Yeah, And I think the question is reasonable, Like we
Speaker 1: expect theories to do more than just describe the data
Speaker 1: we've seen. We want them to generalize. If they really
Speaker 1: are coming close to the truth the laws of the
Speaker 1: actual universe, they should be able to predict things we
Speaker 1: haven't seen. And Ben's question is like, well, hasn't this
Speaker 1: all this stuff happened in the past Yeah, a lot
Speaker 1: of the stuff has happened in the past, but we
Speaker 1: haven't seen it yet, and so we can predict, like
Speaker 1: I predict what I'm gonna find when I dig into
Speaker 1: the ground. Yeah, the stuff is already there and the
Speaker 1: events already occurred, but if we haven't seen it yet,
Speaker 1: then it's fair to predict it and to treat that
Speaker 1: as a test of the theory.
Speaker 2: Yep, agreed.
Speaker 1: All right, So Ben, let us know if we answered
Speaker 1: your question about the definition of these terms and their
Speaker 1: application to Darwin's theory of the origin of the species.
Speaker 8: Well, Daniel and Kelly, even though the classification of groups
Speaker 8: of ideas is obviously a complicated topic, I just knew
Speaker 8: that it would come up with some clear insights. Thank
Speaker 8: you very much, and it's good to hear that Darwin's
Speaker 8: amazing theories are currently being used by scientists to help
Speaker 8: both explain and predict many phenomena. I wish you all
Speaker 8: the best for your trip to Inverness, Daniel, and I
Speaker 8: hope the weather matches that in southern California so you
Speaker 8: can stay comfortable wearing that kills.
Speaker 3: All right.
Speaker 2: Well, that was a ton of fun. As always, I
Speaker 2: learned a ton hopefully the listeners learned a ton too.
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Speaker 2: and Kelly dot org. You can join us on our
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