Speaker 1: What on Earth is a wardy comb jelly? And why
Speaker 1: does it sound like it's probably very smelly?
Speaker 2: If the Sun were replaced with a white hole, would
Speaker 2: it be very bright or dark as coal?
Speaker 1: How do willes navigate the seas? Magnetics gravity or mysteries
Speaker 1: of chemistry?
Speaker 2: Whatever question keeps you up at night, Daniel and Kelly's
Speaker 2: answer will make it all right.
Speaker 1: Welcome to another Listener's Questions episode on Daniel and Kelly's
Speaker 1: Extraordinary Universe.
Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I've never
Speaker 2: been tempted to eat a warty comb jelly.
Speaker 1: Hello. I am Kelly Weener Smith. I also have never
Speaker 1: been tempted to eat a warty comb jelly, But I
Speaker 1: feel like the existence of the name wharty comb jelly
Speaker 1: reveals that biologists have a much more fun time of
Speaker 1: naming things than physicists do. What is your favorite species name?
Speaker 2: Daniel wait, I can't get over warty comb jelly, and
Speaker 2: I'm not gonna let it slide that you're somehow congratulating
Speaker 2: yourself for this name. This name is a mess. I'm like,
Speaker 2: is it a wart is it a comb? Is it
Speaker 2: a kind of jelly? Is it a jelly made of warts?
Speaker 2: Can I comb my hair with it? What is going
Speaker 2: on with this name? It sounds like just three random words.
Speaker 2: It sounds like a password recommended by XKCD.
Speaker 1: All right, well, so one, I think you must lack
Speaker 1: imagination because I imagine a jellyfish that is sort of warty
Speaker 1: with some like comy projections. I think they did a
Speaker 1: great job.
Speaker 2: I don't know. I've heard this thing is also described
Speaker 2: as a sea walnut, So I'm not sure anything in
Speaker 2: our vocabulary can really capture the weirdness of this creature.
Speaker 2: Maybe biology has gone beyond naming.
Speaker 1: You know, it has two different life stages, and sea
Speaker 1: walnut describes one of the stages very well, and warty
Speaker 1: comb jelly describes the other very well. So maybe if
Speaker 1: you just knew a little more natural history, you'd follow along.
Speaker 2: So it needs five words in its name, not just three.
Speaker 2: Oh it's oh that fabulous.
Speaker 1: It's pretty fabulous. But I think my favorite species, or
Speaker 1: my favorite common name for a species, is the humped
Speaker 1: trash line weaver. It's a spider that has like sort
Speaker 1: of a humpy shape, but also it puts trash in
Speaker 1: the middle of its web. And I don't remember why
Speaker 1: should have looked that up before the show. But it's
Speaker 1: got a line of trash and it's got a hump,
Speaker 1: and it's a humped trash line. Orb Weaver and I
Speaker 1: love them. They live on my farm in Virginia and
Speaker 1: they are permanent residents.
Speaker 2: Well, there's a well known spider that I think could
Speaker 2: use a better name, And I once heard an episode
Speaker 2: of This American Life where they were speculating about a
Speaker 2: better name for the black widow spider. And my favorite
Speaker 2: suggestion is not family friendly. It has to do with
Speaker 2: the fact that until we had running water, most of
Speaker 2: the bites were on guys using outhouses because of little
Speaker 2: swinging bits that the spiders bit onto.
Speaker 1: Yeah. So I was reading a journal of parasitology and
Speaker 1: there were men who were purposefully letting themselves get bit
Speaker 1: by black widows to try to get a handle on
Speaker 1: how bad the bites are. And the story starts with
Speaker 1: how he was like doing experiments on rodents and ends
Speaker 1: with how many days he was stuck in the hospital
Speaker 1: after he did it to himself. But the doctor treating
Speaker 1: him said, yeah, I've seen someone else with a black
Speaker 1: widow bite, and it was in the same location, but
Speaker 1: alcohol was involved, and so I have since found myself
Speaker 1: wondering if men is like, oh, it's because of the outhouse,
Speaker 1: I just but it was really just other shenanigans.
Speaker 2: Well, there are so many wonderful questions to ask about
Speaker 2: that story and where people get bitten by black widows
Speaker 2: and other things about the universe. And today we're going
Speaker 2: to be celebrating those kinds of questions because we're here
Speaker 2: today not to talk about the things that we wonder
Speaker 2: about the universe, but the things that you wonder about
Speaker 2: the universe. Our podcast is a conversation between us and you,
Speaker 2: and we want to hear from you. We want to
Speaker 2: know what you want explained about this extraordinary universe.
Speaker 1: So let's go ahead and jump into our first question
Speaker 1: about the wardy comb jelly.
Speaker 3: Hi, Kelly, Hi Daniel wanted to see if you could
Speaker 3: discuss the wordy comb jelly things.
Speaker 1: Well. I was excited about this question because honestly, I've
Speaker 1: never heard of the wardy comb jelly, and it turns
Speaker 1: out and has a number of really fascinating features.
Speaker 2: Well, first of all, what do you think inspired this question?
Speaker 2: Is it just the craziness of the name, or is
Speaker 2: it some incredible biological magic that's happening in this critter.
Speaker 1: If I had to guess, I would guess that this
Speaker 1: listener sent us the question because this species has a
Speaker 1: transient anus.
Speaker 2: Another pair of words I never thought would go together.
Speaker 1: Biology is amazing, And.
Speaker 2: I'm hoping that that means exactly what I think it means.
Speaker 1: Yeah. Probably, So let's back up and let's clarify the
Speaker 1: appearance and the diet of this thing. And so we're
Speaker 1: gonna do the inputs and when we get to the outputs,
Speaker 1: we'll talk about the transientanus. So, all right, the warty
Speaker 1: comb jelly you know, if you imagine it, it has
Speaker 1: sort of like a jellyfish shape, okay, but has two
Speaker 1: different stages of its life. When it's small, it's called
Speaker 1: a sidipid. And at this point it looks like it's clear,
Speaker 1: but it has sort of a walnut shape with two long,
Speaker 1: feathery tentacles that come out from the back.
Speaker 2: So why isn't it called a wardycomb jellyfish instead of
Speaker 2: a wardycomb jelly Because when I hear wardcomb jelly, I
Speaker 2: think of a pot of jam.
Speaker 1: Uh. It was probably not named with you in mind.
Speaker 2: And why not is the real question.
Speaker 1: Well, you know, I think jelly so jellyfish might be
Speaker 1: slightly distantly related. There's probably a lot of diversity in
Speaker 1: jelly like things out there. These are some very ancient creatures.
Speaker 1: And also, you know, jellyfish is sort of confusing because
Speaker 1: they're not really fish, and so maybe someone was like,
Speaker 1: let's drop the fish because these aren't.
Speaker 2: Really fish, and also it's pretty good on toast.
Speaker 1: I wouldn't suggest eating these, although I think they're mostly
Speaker 1: water and I don't think they could sting you, so
Speaker 1: maybe it would be fine. Why not? But as they
Speaker 1: transition to adults, they lose those long, feathery tentacles and
Speaker 1: instead they grow these lobes. So I kind of imagine
Speaker 1: like a glass paper weight, but with like ribbons coming
Speaker 1: off of the sides kind of, So it has these lobes,
Speaker 1: and the lobes have these like iridescent spots on them
Speaker 1: that attract little like tiny fish so that they can
Speaker 1: eat them.
Speaker 2: This sounds really cute.
Speaker 1: No, it is really cute. You should look up a photos.
Speaker 1: It's cute and it has beautiful iridescent colors. I can
Speaker 1: imagine having it as a pet, and I've seen it
Speaker 1: at some aquarium.
Speaker 2: Because again the name wardicomb jelly doesn't conjure up cute
Speaker 2: images in my mind. But your description was beautiful.
Speaker 1: Well thank you. I mean, biologists have a sense of humor,
Speaker 1: and that's that's what you need to know. And so
Speaker 1: when they're young, they use those feathery tentacles to capture
Speaker 1: very tiny creatures living in the water column. As they
Speaker 1: get older and they get into the low bait stage
Speaker 1: where they have those lobes, I agree, this is not
Speaker 1: a very pretty name for the stage when they have
Speaker 1: those like ribbons coming off the side. Then they're eating
Speaker 1: things like eggs and tiny fish and crustaceans, so they
Speaker 1: start eating bigger things, so they have a transition.
Speaker 2: So does this mean they're up near the surface where
Speaker 2: they can eat those things or do they go much deeper.
Speaker 1: They're swimming around the surface and they can move throughout
Speaker 1: the water column, so you can find them at different depths.
Speaker 1: They also will eat each other. So like for the
Speaker 1: Daniel and Kelly checklist, we've hit cannibalism. So this species
Speaker 1: has a lot of things that you and I love.
Speaker 1: So next we're ar at least that I love. So
Speaker 1: next we're going to talk about poop. That's point two
Speaker 1: for dKu.
Speaker 2: I hope we get to aliens eventually.
Speaker 1: I was gonna say aliens are white chocolate. That's where
Speaker 1: we got to get this kind of station two.
Speaker 2: So tell us about how these things spend their time
Speaker 2: on the body.
Speaker 1: Okay, So as they eat and they accumulate waste, their
Speaker 1: gut expands, and as it expands and kind of balloons out.
Speaker 1: At some point it touches the outside of the body.
Speaker 1: And as it touches the outside of the body, it
Speaker 1: fuses and an anus is formed. So like the gut
Speaker 1: and the outside of the body are only like one
Speaker 1: cell thick, and so they fuse form a hole through
Speaker 1: which waste is expelled, and this happens like every ten
Speaker 1: minutes to every hour, depending on how big they are.
Speaker 1: And then once the waste has been expelled, the gut
Speaker 1: starts shrinking and it pulls away from the outside of
Speaker 1: the body, and that hole is completely covered up. It
Speaker 1: goes away, it totally fuses, and the anis disappears. What
Speaker 1: I know, and it's thought that this is an intermediate
Speaker 1: stage between the permanent anuses so many of us know
Speaker 1: and love, and this early stage of the anus, and
Speaker 1: maybe we should put a warning at the beginning of
Speaker 1: the show. But you could talk about butts with kids, right, yeah, And.
Speaker 2: We could just pretend that permanent Anus is the name
Speaker 2: of a punk band we both enjoy.
Speaker 1: That's right, That's right, yeah, from the nineties.
Speaker 2: I love their second album, Oh my God, so good?
Speaker 2: Are you saying that this is a transition stage sort
Speaker 2: of evolutionarily like that there are some critters that didn't
Speaker 2: have an anus, and then there were critters with a
Speaker 2: temporary anis, and then their critters with a permanent anis.
Speaker 1: So I'm imagining the PhD student who will one day
Speaker 1: have the job of working on the phylogenetic tree studying
Speaker 1: the evolution of anuses. But I did find a paper
Speaker 1: that was hypothesizing that this is a step in the
Speaker 1: evolution of the anus that early on, when you've got
Speaker 1: very primitive species, they have this transient anis that kind
Speaker 1: of comes and goes. But as you move down the
Speaker 1: evolutionary tree, we sort of settle on a better method,
Speaker 1: because why recreate the wheel every ten minutes if you
Speaker 1: don't have to do that? So anyway, yes, this could
Speaker 1: have been a step in the evolutionary path that brought
Speaker 1: us to where we.
Speaker 2: Are today, and does that allow us to extrapolate into
Speaker 2: the future, like go from non to temporary to permanent.
Speaker 2: What's beyond that double triple extra permanent. I can't even imagine.
Speaker 1: I don't know, man, we might need like AI and
Speaker 1: artificial tech to give us, you know, additional new ones.
Speaker 1: I know sometimes you have to move them around following
Speaker 1: surgeries and stuff, but I can't imagine that we're going
Speaker 1: to end up with too many more of them. I
Speaker 1: feel like we've maybe hit the fitness peak on anus
Speaker 1: and we're good where we are.
Speaker 2: So I just heard a talk by Brian Mallow, the
Speaker 2: science comedian who actually lives near you, and he was
Speaker 2: telling me that there's a critter that lives on our
Speaker 2: face that doesn't have an anus. It's called a face mite,
Speaker 2: and it like walks around your face chomping on stuff,
Speaker 2: doesn't have an anus, and events you just explodes all
Speaker 2: over your face. And I was like, wow, that's so
Speaker 2: many gross details.
Speaker 1: It is one of gross details in one story. I
Speaker 1: do feel like there's life stages of insects and stuff
Speaker 1: where they don't have an anus. They just kind of accumulated,
Speaker 1: and then when they move to the next stage or
Speaker 1: when they transition to a different body plan and they
Speaker 1: leave the feces behind. I gotta say, it's convenient to
Speaker 1: be able to, you know, remove your waste as you
Speaker 1: need without yeah, without too much trouble.
Speaker 2: Well, what are the disadvantages of this.
Speaker 1: Of needing to recreate an anus every ten minutes? I
Speaker 1: didn't imagine i'd get asked that today. But here we are, Yeah,
Speaker 1: I but here we are. I don't know. I mean,
Speaker 1: I have not seen reports on, for example, how often
Speaker 1: it fails. Needing to create a new sphincter over and
Speaker 1: over and over again. Seems less efficient than just having
Speaker 1: one that works when you need it, And so I
Speaker 1: imagine the downside is that it's a fail point if
Speaker 1: it needs to be created so regularly, and it's better
Speaker 1: to just I can't say I've thought too hard about this, all.
Speaker 2: Right, Well, then I'm going to connect us to the
Speaker 2: last dot and ask you an alien anus question, which is,
Speaker 2: if we're landing on an alien planet, do you expect
Speaker 2: that aliens are going to have a permanent anus or
Speaker 2: where they have a transient one? What do you think
Speaker 2: are there permanent anuses all over the universe, is my question, Kelly.
Speaker 1: I would say, uh it, you know, it depends. You
Speaker 1: can never know for sure, but if I had to guess,
Speaker 1: I would put my money on Yes. It seems like
Speaker 1: a very convenient feature. And uh, you know, they maybe
Speaker 1: they would have. I'm gonna say, yes, what do you think, Daniel,
Speaker 1: I agree with you.
Speaker 2: I think the universe is probably filled with butts?
Speaker 1: Good. Yeah, all right, Well, I'm guessing that's what the
Speaker 1: listener wanted us to talk about. But this species is
Speaker 1: well known for two other things. One, it lives on
Speaker 1: the east coast of the US, and it's been introduced
Speaker 1: in Europe into like the Caspi and c the Black
Speaker 1: Sea and the Baltic Sea, and it's caused a lot
Speaker 1: of problems there. Part of why it causes a lot
Speaker 1: of problems is because when it is in the water,
Speaker 1: it's consuming a lot of crustaceans and eggs and tiny fish,
Speaker 1: and so it's been a problem for the native fish
Speaker 1: because it's eating the baby stages of the native fish,
Speaker 1: and it's eating the food that those baby stages of
Speaker 1: the native fish eat, so it's competing.
Speaker 2: That's not so nice.
Speaker 1: Not so nice, so people have been trying to get
Speaker 1: rid of them. But the other thing that they're well
Speaker 1: known for is a result that was just published last year,
Speaker 1: twenty twenty four. It is one of the few species
Speaker 1: we know of that is able to turn back the
Speaker 1: clock and transition back to an earlier life stage. So
Speaker 1: let me give you some details. So we talked about
Speaker 1: how it has that sidipid stage where it's a walnut
Speaker 1: with feathery tentacles, and then it has a low bait
Speaker 1: stage where it's a paperweight with some ribbons. And if
Speaker 1: you've got it in the low bait stage and you
Speaker 1: starve it or give it a lob back to me
Speaker 1: where you remove one of the lobes, which is not
Speaker 1: very nice to no. No, Essentially, if you stress it out,
Speaker 1: it's able to essentially go back in time and it
Speaker 1: absorbs the rest of its lobes and it goes back
Speaker 1: to the sidippid stage, So it goes from having those ribbons,
Speaker 1: it absorbs those ribbons, it goes back to looking like
Speaker 1: a walnut with feathery appendages. So it can like go
Speaker 1: back in time and reverse its development, which not a
Speaker 1: lot of species can do. We don't know that that
Speaker 1: like extends its life span. But if they go back
Speaker 1: in time and then they grow back, they can grow
Speaker 1: back that other lobe. So it would be like if
Speaker 1: you lost an arm and you can be like, no,
Speaker 1: not cool, you like absorb a bunch of body parts,
Speaker 1: go back to just being like a ball of cells,
Speaker 1: and then you sort of go through the development again
Speaker 1: and now you've got both arms or something like that.
Speaker 2: Well, maybe there's a great advantage to having transient bits
Speaker 2: is that you can generate bits at will, and so
Speaker 2: if you lose one boom, you can grow an arm
Speaker 2: or like, hey, I could use a second head today,
Speaker 2: let me grow another one.
Speaker 1: Yeah, I don't know that they grow like twice as
Speaker 1: many of the ribbons and they usually come back with
Speaker 1: the same number of ribbons. But another thought for the
Speaker 1: benefit of this reverse development is that if you're going
Speaker 1: around and you're trying to eat babyfish and there's like
Speaker 1: just no baby fish, it's not the right time of
Speaker 1: year and you're starting to starve. When you go back
Speaker 1: to that tentacle phase, you can now access a lot
Speaker 1: of the much smaller food stuff, and so it could
Speaker 1: be a way to like open up the kinds of
Speaker 1: foods that you're able to eat at a time when
Speaker 1: the foods that you are really well shaped to eat
Speaker 1: are no longer available. So they've got this interesting reverse
Speaker 1: development that we don't understand very well.
Speaker 2: Fascinating.
Speaker 1: Well that is all I have to say on the
Speaker 1: wardy comb jelly.
Speaker 2: And wait, this is the last question, which we teased
Speaker 2: in the intro. Oh do you think the wardy comb
Speaker 2: jelly is very smelly?
Speaker 1: Oh? No, no, it's mostly water. I'm guessing it. I
Speaker 1: don't think it smells bad, but I agree it's got
Speaker 1: a kind of stinky name.
Speaker 2: What do you think I think probably if you put
Speaker 2: it on toast and left it, it would smell pretty bad,
Speaker 2: as basically everything from the sea does.
Speaker 1: I mean, I think just about any organism, if you
Speaker 1: let it die and you left it on your toast
Speaker 1: for a while, you're going to regret that decision.
Speaker 2: Well, that's just fermentation. And sometimes fermentation is delicious, you know,
Speaker 2: you get marmite or whatever, or cheese, and sometimes it's not.
Speaker 1: Yeah. Well, you know our conversation went from transient anisis
Speaker 1: to cheese. And let's see what the listener has to say.
Speaker 3: Hi Kelly, Hi Daniel, Thanks for talking about the wordy
Speaker 3: comb jelly. Maybe one day we'll all be able to
Speaker 3: regrow our parts inside or out, or even flip them around. Thanks.
Speaker 2: All right, we're back from talking about the transient holes
Speaker 2: in wordy comb jellies to talking about a very different
Speaker 2: kind of hypothetical cosmic hole.
Speaker 4: I'm Sammy, I'm ten, and I want to know what
Speaker 4: would happen if this sun was aplace with a white hole?
Speaker 2: All right? I love this question, and I that young
Speaker 2: people are thinking about the universe and asking questions. And
Speaker 2: thanks to all the parents out there who listen to
Speaker 2: the pod with their kids.
Speaker 1: So, Daniel, what are white holes? And do they come
Speaker 1: and go depending on how recently youth consumed a meal?
Speaker 2: You know, when we started this episode, I was like, well,
Speaker 2: there are no connections between these topics. Now I'm seeing
Speaker 2: them more and more. Yes, maybe aliens with transient anuses
Speaker 2: are going to use cosmic white holes to come and
Speaker 2: visit us and tell us about it and learn all
Speaker 2: about our permanent ones.
Speaker 1: We can hope, but hopefully they don't eat us. I
Speaker 1: guess that wouldn't be cannibalism. So I'm not really connecting
Speaker 1: the dots there, But anyway.
Speaker 2: Yes, So Sam is asking a great question. Basically, he's
Speaker 2: wondering what does a white hole look like? And could
Speaker 2: his serve as an alternate sun, etc. So let's talk
Speaker 2: about what a white hole is. Number one. A white
Speaker 2: hole is a hypothetical thing. We don't know that white
Speaker 2: holes exist in the universe, and we're not even really
Speaker 2: clear on what a white hole is, you know, like
Speaker 2: a black hole, we have a very crisp concept for
Speaker 2: what it is. It's a prediction of general relativity. We
Speaker 2: talk about it, we understand about it, we can calculate
Speaker 2: about everybody agrees what a black hole is a white hole,
Speaker 2: and we'll get into what it is exactly. Is the
Speaker 2: sort of a fuzzy set of concepts that are closely related.
Speaker 2: And so if you read about white holes and you
Speaker 2: listen to this episode and you might think, on, that's
Speaker 2: not what I heard, and then you go read another
Speaker 2: article and you're like, that's not what I understood to
Speaker 2: be a white hole. That's because there is nothing that
Speaker 2: it is to be a white hole. It's like a
Speaker 2: set of ideas that people are still sort of developing
Speaker 2: that all go by the same name, which can be.
Speaker 1: Confusing, sort of like our study of the anus, you've
Speaker 1: got multiple stages. We're not really sure how to define it,
Speaker 1: but all right, go.
Speaker 2: On, yeah, yeah, So most commonly, a white hole is
Speaker 2: thought as something like the opposite of a black hole.
Speaker 2: So a black hole is a region in space, an
Speaker 2: event horizon, which nothing can escape. Right. Remember that gravity
Speaker 2: is the bending of space time in the presence of
Speaker 2: mass and energy. So the Earth and bends the space
Speaker 2: around it, which affects the way things move around it.
Speaker 2: And if you have enough mass and enough energy, you
Speaker 2: bend space so much that you change its shape so
Speaker 2: that nothing can escape. It's not that black holes have
Speaker 2: intense gravity to pull on things, even light. It's just
Speaker 2: that the shape of space is such that nothing can escape.
Speaker 2: Space only points in one direction past the event horizon,
Speaker 2: towards the center. So no matter how fast you go
Speaker 2: or how you wiggle or struggle, you're always going towards
Speaker 2: the center. That's the black hole, a region of space
Speaker 2: where nothing can escape because of the shape of space itself.
Speaker 1: Okay, so if I were to just guess a white hole,
Speaker 1: so you'd imagine it would be exactly the opposite. So
Speaker 1: is it is everything running to escape from a white hole.
Speaker 1: Nothing can you get pushed away from it if you
Speaker 1: get too close.
Speaker 2: A white hole is a region of space that nothing
Speaker 2: can enter, so things can escape it, but nothing can
Speaker 2: enter it. And the opposite of a black hole. A
Speaker 2: black hole things can enter but nothing can escape. A
Speaker 2: white hole is a place where nothing can enter, but
Speaker 2: things can escape.
Speaker 1: How is that made?
Speaker 2: Yeah, and that's a different question, right, Like what is it?
Speaker 2: And could it exist? It's a different question from how
Speaker 2: do you make it? That's an important subtlety, right, Like,
Speaker 2: for example, a wormhole, which we'll talk about in a minute,
Speaker 2: is something which can exist in general relativity, and a
Speaker 2: white hole can exist in general relativity. But that doesn't
Speaker 2: mean that there are any or that we know how
Speaker 2: to go from a universe without one to a universe
Speaker 2: with one. It's like the difference between saying, oh, I
Speaker 2: know how to eat a soufle. I know soufles exist,
Speaker 2: and I know how to make a soupfle from ingredients.
Speaker 1: Right, it's hard to make a soufle, yes, exactly.
Speaker 2: The recipe is a challenge. So those are actually two
Speaker 2: different questions, Right, is it possible for them to exist
Speaker 2: in the universe? And is there a series of actions
Speaker 2: you can take to create one.
Speaker 1: Two different questions are we going to answer either.
Speaker 2: H we have no idea about the second one. We
Speaker 2: are going to talk about the first one, right oka, like,
Speaker 2: can general relativity accommodate this? What does it even mean?
Speaker 2: What are we talking about here? And so the first
Speaker 2: concept of a white hole, and I think the most
Speaker 2: generally discussed one, is a sort of mathematical extension of
Speaker 2: space time. Roger Penrose is famous for thinking about black
Speaker 2: holes and the structure of space time, and he came
Speaker 2: up with a cute little diagram to draw the whole
Speaker 2: universe and like a little square where infinities are like
Speaker 2: squeezed down into the corners, so you can draw things nicely.
Speaker 2: And they're called Penrose diagrams. You can google them and
Speaker 2: see them. They're a little hard to wrap your mind around,
Speaker 2: and we're not going to try to explain them today.
Speaker 2: But these diagrams do inspire the concept of white holes,
Speaker 2: because if you look at the diagram, the whole universe
Speaker 2: is like a diamond and black holes are on one side,
Speaker 2: and you can ask, hmm, what could be on the
Speaker 2: other side, And so it's just sort of like, hey,
Speaker 2: let's ask questions about this diagram and is it possible
Speaker 2: there's something there we hadn't considered the way you might
Speaker 2: be like, oh, there are positive numbers, could there be
Speaker 2: negative numbers? There are particles, could there be antiparticles. It's
Speaker 2: just like this search for symmetry in the universe and wondering,
Speaker 2: and then people realized, well, there's really nothing preventing that.
Speaker 2: Like in print, Well you could have a region of
Speaker 2: space that nothing could enter, but things could escape from.
Speaker 2: And the way to think about it in terms of
Speaker 2: these Penrose diagrams is just some region of space where
Speaker 2: you can get messages from but you could never reach.
Speaker 2: And that seems really weird. I have two sort of
Speaker 2: ways to think about it for you. Number one is
Speaker 2: to just reverse the black hole. Like if you think
Speaker 2: about black holes not as a big blob of stuff
Speaker 2: pulling in on you really really hard with its gravity,
Speaker 2: but literally a rearrangement of space so that space only
Speaker 2: points in so that no matter what you do, you
Speaker 2: are moving towards the center. Remember that black holes and
Speaker 2: gravity are all about the shape of space itself, not
Speaker 2: forces on stuff within space. Now just reverse that. Imagine
Speaker 2: a points in space where space points outwards, and the
Speaker 2: only way you can go is out. There is no in, right,
Speaker 2: there's only motion outwards. So if you accept that black
Speaker 2: holes are space pointed in, then white holes are just
Speaker 2: space pointed out.
Speaker 1: So for white holes, nothing can get in, but stuff
Speaker 1: can come out. Where is the stuff that comes out
Speaker 1: coming from?
Speaker 2: Great questions?
Speaker 1: Did the gut gets filled into the white hole?
Speaker 2: And great question? And in general general relativity has no
Speaker 2: answer to that, right, It doesn't predict anything that could
Speaker 2: come out it nothing comes out, could be that green
Speaker 2: eggs and ham comes out, right, General relativity is no
Speaker 2: idea what could come out. In general. However, there are
Speaker 2: some theories that connect white holes and black holes via
Speaker 2: a wormhole. And say, for example, if you have a
Speaker 2: black hole where things go in, and then you have
Speaker 2: like basically a tube that connects it to a white hole,
Speaker 2: things come out the white hole after they've gone in
Speaker 2: the black hole. And so in that sense, a black
Speaker 2: hole and a white hole are two ends of a
Speaker 2: one directional wormhole transit, and so things come out the
Speaker 2: white hole that fell in the black hole. But you
Speaker 2: can't go the other.
Speaker 1: Direction, right, So I'm tempted to ask how many anuses.
Speaker 1: That means the universe has for Sammy, well.
Speaker 2: That would be one, right, because you can think about
Speaker 2: your digestive system as a tube. There's an in in
Speaker 2: and out and usually one direction always.
Speaker 1: But there's more than one black hole in the universe, right,
Speaker 1: So there's more than one anis that's true.
Speaker 2: And we don't think that all black holes are connected
Speaker 2: to white holes, right. Some of them just eat stuff.
Speaker 2: There's no anus there at all. It just gets bigger
Speaker 2: and bigger and maybe eventually explodes like a face mite
Speaker 2: on your face.
Speaker 1: I don't know, mmm, love these connections.
Speaker 2: Yeah, So that's sort of the concept of white holes.
Speaker 2: Another way to think about white holes that's maybe easier
Speaker 2: to grapple with is try to imagine a region of
Speaker 2: the universe where you can get messages from, but you
Speaker 2: could never send messages too, And that seems contradictory, like
Speaker 2: how could you do that? But actually that exists in
Speaker 2: our universe already. It's our cosmic horizon. Like there are
Speaker 2: galaxies out there that sent us photons, but they are
Speaker 2: now past our cosmic horizon because of the expansion of
Speaker 2: the universe. If we shout a photon at them, it
Speaker 2: would never reach them. So there's a whole region of
Speaker 2: the universe where photons have escaped. They've come from there,
Speaker 2: but they can't go to there. So I'm not saying
Speaker 2: that everything outside the observable universe is a white hole,
Speaker 2: but it's just sort of a way for you to
Speaker 2: get a handle on what are we talking about.
Speaker 1: Okay, so I've absorbed a lot of information and the
Speaker 1: you know, my brain is a box and it's overflown
Speaker 1: and some has started to fall out. So I think
Speaker 1: you've already said this, but just to confirm, white holes
Speaker 1: are not anything that's really supported by physics theory. It's
Speaker 1: more of a thought experiment that arose out of a
Speaker 1: way that we decided to portray the way the universe
Speaker 1: could look. But that could have just been a result
Speaker 1: of our artistic way of trying to explain things.
Speaker 2: It could be, yes, it could also be that we're
Speaker 2: exploring the true nature of the universe and discovering it
Speaker 2: in our minds before we discover it in the universe,
Speaker 2: the same way we did with black holes. People thought
Speaker 2: exactly the same thing about black holes before we found them.
Speaker 2: They were like, well, that's cute, but it's just a
Speaker 2: mathematical oddity. I'm sure that doesn't actually exist out there
Speaker 2: in the universe. That would be bonkers, And then of
Speaker 2: course we found them. And so sometimes mathematically exploring the
Speaker 2: corners of our minds can reveal the true nature of
Speaker 2: the universe, which is amazing and philosophically deep and incredible
Speaker 2: and really kind of a as close as you get
Speaker 2: to a spiritual moment, I think in cosmology.
Speaker 1: Yeah, yeah, I'll give you that. That's incredible.
Speaker 2: So everything you said is true, But I think the
Speaker 2: implication that therefore is probably not really out there, I
Speaker 2: think is a question mark.
Speaker 1: All right, So can you remind me what was Sammy's
Speaker 1: question in particular?
Speaker 2: So Samy was like, if you replace the sun with
Speaker 2: a white hole, what would it look like? Oh, and
Speaker 2: before we get to that, we had to consider one
Speaker 2: more idea about white holes, because white holes, again a
Speaker 2: broad topic. So we've talked about white holes is sort
Speaker 2: of like inverse black holes region of space time that
Speaker 2: you can escape and not enter, or maybe the back
Speaker 2: end of a wormhole. But there's one more version, which
Speaker 2: is the quantum version of a white hole.
Speaker 1: What's that?
Speaker 2: And this suggests that there are no black holes actually
Speaker 2: that the things we see out there in the universe
Speaker 2: that look like black holes are actually just slowly collapsing
Speaker 2: stars because in regions of very high mass, time slows down.
Speaker 2: Talked about time dilation many times, and so perhaps what's
Speaker 2: happening is stars are collapsing, but time has slowed down
Speaker 2: so much that it looks like a black hole. It's
Speaker 2: just a very very slowly collapsing star. And there are
Speaker 2: folks out there like Carlo Ravelli who thinks that it's
Speaker 2: not actually going to collapse all the way to a singularity.
Speaker 2: Quantum mechanics will somehow prevent that from happening, push it
Speaker 2: back and invert it, and eventually a black hole sort
Speaker 2: of bounce back and turn into something which emits all
Speaker 2: of its mass.
Speaker 1: Wow.
Speaker 2: So this is Carlo Ravelli's concept of a white hole.
Speaker 1: Ah okay, all right, very cool. And so we've talked
Speaker 1: about three different ways to get white holes, or three
Speaker 1: different ways of thinking about it. Does each one of
Speaker 1: them give a different answer to Sammy's question?
Speaker 2: Yeah, absolutely it does. So you know, if white holes
Speaker 2: are just some region of space that you can't escape,
Speaker 2: and you replace the Sun with a white hole, then
Speaker 2: like maybe nothing would come out right, there's no prediction
Speaker 2: for anything to come out. It just depends on what
Speaker 2: happened to be in that regional space in the deep
Speaker 2: deep past before it formed, right, and so probably nothing.
Speaker 2: If the white hole that we put in the center
Speaker 2: of our solar system is the back end of a wormhole,
Speaker 2: then what comes out depends on what's going in that
Speaker 2: black hole. If there are aliens out there and they're
Speaker 2: treating that black hole as like a cosmic dumpster. They're
Speaker 2: like making really dangerous elements in their crazy experiments and
Speaker 2: they're dumping it in a black hole for their safety,
Speaker 2: then you know we're going to be the cosmic dumping
Speaker 2: yard of some alien physicists, which could be amazing, like wow,
Speaker 2: you could see some cool stuff come out of that
Speaker 2: white hole though, or it could be really bright, you know,
Speaker 2: like what if that black hole eats a star or
Speaker 2: something like an enormous amount of radiation could come out
Speaker 2: of it. Or it could be just like weird alien leftovers.
Speaker 2: Who knows, I.
Speaker 1: Would eat weird alien leftovers, give it a shot.
Speaker 2: If I had to choose between weird alien leftovers and
Speaker 2: wardycomb jelly on toe, I'm not sure what I would choose.
Speaker 1: Yeah, it'd be a tough decision. So what about Carlo
Speaker 1: Ravelli's vision of a white hole.
Speaker 2: Yeah, so if white holes are actually slowly collapsing black
Speaker 2: holes that then reverse, then you're gonna get something with
Speaker 2: an enormous amount of radition. It's going to be very,
Speaker 2: very bright. And one of the inspirations for white hole
Speaker 2: research is that there are things in the universe that
Speaker 2: are very bright that we don't understand, things like gamma
Speaker 2: ray bursts, these very short lived, incredibly bright waves of
Speaker 2: gamma rays, very high energy photons. Nothing in the universe
Speaker 2: we know about can make them, and yet we see
Speaker 2: them and people wonder like, oh, maybe those are white holes.
Speaker 2: People also talk about, you know, the Big Bang maybe
Speaker 2: being the result of a white hole in the early universe,
Speaker 2: because people like thinking about cyclical universes, like the whole
Speaker 2: universe turns into a singularity and then bounces back into
Speaker 2: a big white hole. Anyway, Sammy, the answer is, we
Speaker 2: don't know if white holes are real, and if they are,
Speaker 2: it depends on which flavor of white hole you get.
Speaker 1: Do you think that Sammy wanted to know what would
Speaker 1: happen to Earth if the Sun was replaced by a
Speaker 1: white hole, or what would it be like if the
Speaker 1: Sun was replaced by a white hole? I think in
Speaker 1: all of these situations, Earth is toast.
Speaker 2: Earth is not in a great shape in any of
Speaker 2: these situations. Yeah, and in many cases the white hole
Speaker 2: has mass also, so you could continue to orbit it
Speaker 2: while you're getting fried with alien cosmic junk.
Speaker 1: Thumbs down. All right, what do you think, Sammy?
Speaker 4: I prefer if the sun was not a plate to
Speaker 4: a white home, although that that end of a wom
Speaker 4: hole idea does sound pretty cool.
Speaker 1: All right. Our last question comes from Rhonda and is
Speaker 1: about humpback whales.
Speaker 5: Hey, Daniel and Kelly, it's Ronda and I live in
Speaker 5: North Alabama. I was recently scrolling through the Internet and
Speaker 5: saw a whale of a tail about how whales migrate.
Speaker 5: They were saying that whales migrate because the bacteria in
Speaker 5: the bumps in their back aligned with magnetic north. I
Speaker 5: was just wondering if you might be able to clarify
Speaker 5: that a little bit. Let me know if it's true.
Speaker 5: Huge fan of the show, Love you guys, and thank
Speaker 5: you so much for feeding my curiosity.
Speaker 1: Well, this is a great question, Ronda. I was super
Speaker 1: excited to have the opportunity to dig into navigation for
Speaker 1: humpback whales. A little bit of background, There are humpback
Speaker 1: whales at both of the poles. They tend to feed
Speaker 1: in polar regions, and for example, Antarctica has loads of
Speaker 1: this crustacean called krill that they eat, and you find
Speaker 1: it in really high densities there. So they go to
Speaker 1: the polar regions to feed, and then when it comes
Speaker 1: time to have babies, they head up to the tropics
Speaker 1: where the is warmer and shallower. We think maybe those
Speaker 1: are better baby nursery conditions, so they head up there
Speaker 1: to breed, and then when the babies are old enough,
Speaker 1: they head back down to the cold areas where their
Speaker 1: food is found in high abundances.
Speaker 2: So this is similar to how birds migrate, but it's
Speaker 2: just much more massive in underwater.
Speaker 1: Yes exactly, and I mean incredibly long distances. Imagine going
Speaker 1: from you know, Antarctica to the tropics, like that's a
Speaker 1: huge distance, and they often make very straight line paths,
Speaker 1: and so it's been for a long time a question
Speaker 1: how do they remember, you know, when they're very young,
Speaker 1: when they make this journey for the first time, how
Speaker 1: do they remember where they've gone, and how they go
Speaker 1: back to the same place, and how do they go
Speaker 1: there without Like, you know, I get lost when I
Speaker 1: go to the grocery store sometimes, like how do they
Speaker 1: not get lost?
Speaker 2: And it's a super fascinating question. I heard that these
Speaker 2: whales move in a straight line relative to the earth
Speaker 2: rather than relative to the water, right, which requires some
Speaker 2: kind of navigation because you know, no matter what the
Speaker 2: currents are, they find a way to follow the path,
Speaker 2: which suggests that maybe they know where they are on
Speaker 2: the earth, which is amazing.
Speaker 1: It's crazy. But let me just take a step back
Speaker 1: to talk about why it's so hard to answer this
Speaker 1: question in humpback whales. So if you were asking this
Speaker 1: question in pigeons, for example, you could take a pigeon
Speaker 1: from one place and if you thought that maybe they
Speaker 1: were paying attention to some queue in the northern hemisphere,
Speaker 1: you could transport them to the southern hemisphere and then
Speaker 1: see how they change their behavior. If they thought they
Speaker 1: were paying attention to magnetic fields, you could, like I
Speaker 1: don't know, stick a giant magnet on their back that
Speaker 1: confused them and then look to see do they get lost?
Speaker 1: If you thought they were looking for visual cues. You
Speaker 1: could you know, put them in a giant arena and
Speaker 1: move the cues around and see how that messed things up.
Speaker 1: And then you could do other things, like you know,
Speaker 1: could put blindfolds on them and if you think that
Speaker 1: they're just you know, responding to magnetic fields or something.
Speaker 1: But with humpback whales, they're endangered, or at least they're threatened.
Speaker 1: I can't remember what their status is right now. But
Speaker 1: you can't do any of those things to them. Yeah,
Speaker 1: you can't move them to the other hemis. You can't
Speaker 1: poke their eyes out. You shouldn't poke their eyes out.
Speaker 1: You can't do the kinds of manipulative experiments that you'd
Speaker 1: need to really try to nail this stuff down. So
Speaker 1: the best that we can do at the moment, as
Speaker 1: we can look at old records for where humpback whales
Speaker 1: were killed in the era where whaling was popular, and
Speaker 1: now that we have technology for tracking animals, you can
Speaker 1: put trackers on them and you can follow their movements
Speaker 1: over time and then you can collect data on how
Speaker 1: their movements are correlated to things that you think might
Speaker 1: be important for navigation.
Speaker 2: So we basically have to wait for natural experiments like
Speaker 2: if the magnetic poles flip, or if the currents change,
Speaker 2: or if the visual conditions change, we can look to
Speaker 2: see how it affects the whales, but we can't induce
Speaker 2: those changes ourselves.
Speaker 1: Right, And unfortunately humans are doing some of those experiments now.
Speaker 1: So one of the things we think they queue into
Speaker 1: is water temperatures or following certain currents or certain salinities.
Speaker 1: And as global climate change is happening, that's impacting water
Speaker 1: temperatures and that's impacting where currents go. And I guess
Speaker 1: the good news is that for humpback whales these changes
Speaker 1: are relevant to their smaller movements, so it's relevant to
Speaker 1: where their food sources are. As their food sources, for example,
Speaker 1: maybe track certain water temperatures. But even as all of
Speaker 1: this stuff is changing, they are still taking pretty straight
Speaker 1: line paths up to their breeding ground, which suggests that
Speaker 1: that's not the main cue that they're using. So even
Speaker 1: as this changes, they're still getting to where they need
Speaker 1: to go. So one of the leading hypotheses is that
Speaker 1: the Earth's magnetic fields are being used by these giant
Speaker 1: whales to try to figure out where they're going to go.
Speaker 1: And Daniel I should tell you that while I was
Speaker 1: writing this outline, I just assumed that you would be
Speaker 1: able to explain these to us, and I didn't give
Speaker 1: you the heads up or research it ahead of time.
Speaker 1: Was I right?
Speaker 2: You actually were right. I'm really fascinated by this. Okay,
Speaker 2: and the folks in my department here at UC Irvine
Speaker 2: biophysicists who study this question of how birds migrate, for example,
Speaker 2: which is a very similar question and one of the
Speaker 2: leading hypotheses has to do with quantum mechanics. Actually, there's
Speaker 2: like a protein inside bird's eyeballs which has two different states,
Speaker 2: and it flips back and forth between these two states,
Speaker 2: and the rate at which it flips depends on the
Speaker 2: magnetic field. So this is a thing which actually does happen.
Speaker 2: And so in principle, is a mechanism by which an
Speaker 2: animal could sense a magnetic field Because like we don't
Speaker 2: think humpback whales or Canadian geese are like building little
Speaker 2: compasses and strapping them to their bodies, as cute as
Speaker 2: that would be, they need some sort of biological mechanism.
Speaker 2: What we don't know is if that's really the mechanism.
Speaker 2: You know, this is like something inside their body that's happening.
Speaker 2: We don't know if it's connected to their sensory organs
Speaker 2: or somehow to their brain to allow them to somehow
Speaker 2: like see or experience these fields, or actually even use
Speaker 2: them in their navigation.
Speaker 1: There's a newer hypothesis that there are bacteria that also
Speaker 1: respond to magnetic fields, and they sort of align themselves
Speaker 1: with magnetic north And the idea here is that you'd
Speaker 1: have these bacteria and then the animals would have some
Speaker 1: way of sensing what the bacteria are doing. And this
Speaker 1: is what the listener was referring to. But actually what
Speaker 1: I had imagined you would explain was why does Earth
Speaker 1: have magnetic fields in the first place.
Speaker 2: Yeah, oh that's awesome. It's a little bit of a mystery.
Speaker 2: I mean, we know that magnetic fields are generated by
Speaker 2: charges in motion, right, Like, give an electron, it just
Speaker 2: generates an electric field. You move the electron, you give
Speaker 2: it a velocity, you get a magnetic field, which is
Speaker 2: already kind of mind bending because it means that like
Speaker 2: whether the electron has a magnetic field around it is
Speaker 2: frame dependent. You know, Like I'm holding an electron, I
Speaker 2: see it as an electric field. You whiz, buy me
Speaker 2: in a car, you see that electron having a magnetic field,
Speaker 2: So we like disagree about whether there's a magnetic field there,
Speaker 2: which is crazy. Yeah, that's a whole fascinating story about
Speaker 2: the development of special relativity. But anyway, charges in motion
Speaker 2: generate magnetic fields. There are no magnetic charges in the
Speaker 2: universe that we know about that could just generate magnetic
Speaker 2: field while sitting there. So most of the magnetic fields
Speaker 2: are generated either by like electrons spinning that quantum version
Speaker 2: of motion can generate a little magnetic field, or you
Speaker 2: have the electron itself is like flowing in a current,
Speaker 2: And so what's flowing underneath our feet when there's lots
Speaker 2: of rock and metal in motion underneath our feet, and
Speaker 2: we think that that motion is probably generating the magnetic field,
Speaker 2: but we don't totally understand it. The magnetic field is
Speaker 2: weird and not reliable. The poles flip and flip it
Speaker 2: in a irregular way, like sometimes every fifty thousand years,
Speaker 2: sometimes once a million years. The poles are always migrating
Speaker 2: a little bit, and sometimes they're like, you know, north
Speaker 2: and south will flip, which is weird. Meanwhile, like in
Speaker 2: the sun, it's super regular every eleven years, the Sun
Speaker 2: flips its magnetic field, and this has to do with
Speaker 2: like currents of plasma going through the Sun. Again not
Speaker 2: totally understood. So roughly we think it's flowing currents within
Speaker 2: the Earth, but there's lots of detailed questions we don't
Speaker 2: know the answers to all right.
Speaker 1: Well, so the idea here is that, either through the
Speaker 1: bacteria that live with the whales or different senses that
Speaker 1: there are organs that they have in their body that
Speaker 1: have not yet been identified, they're able to sense these
Speaker 1: magnetic fields and follow them from one place to another,
Speaker 1: and there's some good evidence that this has happened. For example,
Speaker 1: whales tend to get stranded more often during solar storms,
Speaker 1: and what they think is happening here is that when
Speaker 1: there's a solar storm, it's messing with the whale's ability
Speaker 1: to sense the Earth's magnetic fields. So it's not that
Speaker 1: it's messing with the Earth's magnetic fields, it's just sort
Speaker 1: of giving the wrong information to whatever the whale is
Speaker 1: using to figure out where the magnetic fields are, and
Speaker 1: so whales are more likely to get stranded. Essentially, the
Speaker 1: idea here is that they're not able to read the
Speaker 1: Earth's magnetic lines anymore, and so they end up in
Speaker 1: places where they're not supposed to be.
Speaker 2: So that's really interesting, and it sort of suggests that
Speaker 2: whales are using the magnetic field or that something else
Speaker 2: about these solar storms might be affecting their senses. Do
Speaker 2: we know anything about the history of whale migration as
Speaker 2: the magnetic field shift.
Speaker 1: I did find a paper that tracked humpback whales over
Speaker 1: a fifteen year period, and during that period there were
Speaker 1: pretty significant shifts in the magnetic fields. And even in
Speaker 1: years where there were shifts, the whales were going on
Speaker 1: the same paths and essentially a straight line. So these
Speaker 1: shifts didn't seem to move them off course, which suggests
Speaker 1: that it's not just the electric field. Maybe it's the
Speaker 1: electric field plus some other things that they're using to
Speaker 1: correct themselves. But it does make it look like this
Speaker 1: is not the whole story.
Speaker 2: Could they be using just visual cues, like hey, turn
Speaker 2: left at this canyon and then go around this underwater
Speaker 2: mountain cause they just have like amazing memories.
Speaker 1: They could They could have amazing memories. They also often
Speaker 1: travel with other individuals, so you know, like sometimes when
Speaker 1: I think I'm lost. I'll never ask that because that
Speaker 1: would just make it worse. But like if i'm you know,
Speaker 1: if I'm in the car with a friend, I'll be like,
Speaker 1: you know, oh, do you remember Chase Bank being on
Speaker 1: that side of us last time? Or should it be
Speaker 1: on the other side? Are we going the wrong way?
Speaker 1: And so, you know, whales travel with friends might use
Speaker 1: each other. And additionally, whale calls can be heard over
Speaker 1: very great distances, and so it could be that they can,
Speaker 1: you know, hear that, like Frank is way up ahead,
Speaker 1: and they're just following the noises that Frank makes or
Speaker 1: Fran And so it could be a combination of noticing landmarks,
Speaker 1: you know, sharing information with each other, and then listening
Speaker 1: to the sounds of the seas to get to where
Speaker 1: they're going.
Speaker 2: Is there any chance that they're like popping up to
Speaker 2: the surface and opening their eyeballs and like using the
Speaker 2: stars to navigate.
Speaker 1: There have been some folks who have proposed that they
Speaker 1: think it's more likely that they might be using cues
Speaker 1: from the sun than cues from the stars. We don't
Speaker 1: know that whale vision would allow them to see the
Speaker 1: stars with the level of detail that you would need
Speaker 1: to navigate by it. And so there are folks who
Speaker 1: are interested in that question. But I'd say at the
Speaker 1: moment that's a pretty hotly debated topic in the field,
Speaker 1: and there's not a clear consensus. Although I do absolutely
Speaker 1: love the idea of the humpback whales navigating by the stars.
Speaker 2: That's beautiful, that would be gorgeous. Well what if they're
Speaker 2: just really good good at dead reckoning. You know, what
Speaker 2: if they don't need navigational cues, they're just like, I know,
Speaker 2: I swim in this direction for forty five minutes and
Speaker 2: then I turn, I swim in that direction. It's hard
Speaker 2: to conceive of. I mean, imagine like driving to your
Speaker 2: friend's house, like across country with your eyes closed. Yea, right,
Speaker 2: just like knowing when to turn. That would be crazy.
Speaker 2: But hey, maybe whales are just good at that.
Speaker 1: Yeah, I mean, this could be an example where my
Speaker 1: personal experience limits my ability to imagine an answer. It
Speaker 1: is hard for me to imagine that. But you know,
Speaker 1: they've got giant brains. Maybe they're putting some of that
Speaker 1: giant mass to like incredible processing abilities to navigate incredible distances.
Speaker 2: All right, So what's the answer then, to the listener's question,
Speaker 2: I would say.
Speaker 1: The answer is, we don't completely know. It probably has
Speaker 1: something to do with landmarks, something to do with sharing information.
Speaker 1: They might be using the magnetic fields to some extent.
Speaker 1: They're paying attention to currents and temperature, but even when
Speaker 1: those change is not throwing them off course. So it's
Speaker 1: probably a what we would call like multimodal signals like it.
Speaker 1: They probably making lots of different kinds of information and
Speaker 1: integrating it. But at the end of the day, we
Speaker 1: can't do the sort of manipulative experiments we'd need to
Speaker 1: lock it in, So we're just gonna have to keep
Speaker 1: waiting to see what sort of experiments nature throws at
Speaker 1: us so that we can collect data as we go.
Speaker 2: Amazing.
Speaker 1: Oh and I forgot. There was one other queue that
Speaker 1: has been getting a lot of attention in the papers
Speaker 1: that I read, and that's gravity as a sort of landmark.
Speaker 1: And so I think the idea here is that there
Speaker 1: are like mountain ridges that are made of dense materials,
Speaker 1: and so they pull on these giant whales a little
Speaker 1: bit more, and so you can use these as sort
Speaker 1: of cues as you move around their environment, because these
Speaker 1: don't change much you know those mountains. If they're there
Speaker 1: one year, they're probably going to be there one hundred
Speaker 1: years from now. And so there's some thought that those
Speaker 1: are cues that are being used. What do you think
Speaker 1: as a I mean, I know, we don't know what
Speaker 1: particle makes gravity, but does this make sense?
Speaker 2: It makes sense sort of from a physics point of view.
Speaker 2: I mean, we all feel gravity, and gravity mostly points down,
Speaker 2: but gravity would points straight down if the Earth was
Speaker 2: a perfect sphere. If you're standing next to like a
Speaker 2: huge blob of stuff, then you're gonna feel it's gravity also,
Speaker 2: and so the net gravity is gonna point like a
Speaker 2: little bit to the side. And so if there are
Speaker 2: like dense deposits of iron under the ocean floor or something,
Speaker 2: and whales are super sensitive to the direction of gravity,
Speaker 2: they have some like internal biological pendulum, then in principle
Speaker 2: they could detect those and I guess in principle you
Speaker 2: could use that to navigate. To me, I'm not sure
Speaker 2: how much of a navigation a help it is because
Speaker 2: it doesn't provide you like longitude latitude information the way
Speaker 2: the stars do, right, It just tells you that you're
Speaker 2: near a landmark. To me, it seems like about as
Speaker 2: useful as eyeballs, not as useful as celestial navigation.
Speaker 1: Well, but if you can't see the stars, then you
Speaker 1: know that doesn't help so much. And we don't know
Speaker 1: that the whales can see the stars. Does it matter
Speaker 1: that they are so like many orders of magnitude bigger
Speaker 1: than we are. Does that make it easier for them
Speaker 1: to detect differences in gravity along the Earth's surface.
Speaker 2: You definitely have a larger force on larger masses, right,
Speaker 2: But of course they also have larger mass, so it
Speaker 2: is the same acceleration which they sense in their stomachs probably,
Speaker 2: so like maybe they're sensing shifts in how their stomachs
Speaker 2: move or something. I mean, And what I mean by
Speaker 2: like as good as eyeballs is that you know, if
Speaker 2: you could see underwater features like oh, there's a mountain underwater,
Speaker 2: or there's this cliff underwater, that seems to me as
Speaker 2: good as this gravitational stuff. It's not like it tells
Speaker 2: you where you are on the planet. It's still local
Speaker 2: information in that way. But yeah, maybe whales are doing that.
Speaker 1: And that would give a whole different meaning to like,
Speaker 1: I've got this gut feeling the mountain is actually pulling
Speaker 1: your gut to the right, and you're like, we should
Speaker 1: go right.
Speaker 2: I mean, you're joking, But your gut is an accelerometer, right.
Speaker 2: That's why on a roller coaster you feel like you're
Speaker 2: leaving your stomach behind or it's in your mouth. There's something.
Speaker 2: It's for exactly that reason. You are measuring a change
Speaker 2: in the local acceleration away from the normal Earth's gravity.
Speaker 2: And so, for example, if you walked by some super
Speaker 2: dense deposit of material, you would feel the same way.
Speaker 2: You would feel a force pulling in a weird direction,
Speaker 2: and yeah, it'd be a gut feeling.
Speaker 1: Well, usually it pass out on roller coasters before I
Speaker 1: get that feeling. So but maybe if I was slowly
Speaker 1: walking along the ocean floor, I'd be able to sense
Speaker 1: it better. But all right, so I think the summary
Speaker 1: point here is that we don't really have it all
Speaker 1: figured out yet. It's probably more than one thing. They're
Speaker 1: probably integrating cues from a variety of different sources, but
Speaker 1: one way or another, they make these amazing migrations.
Speaker 2: Well, you might be wondering, how is Daniel going to
Speaker 2: connect this question of whales back to the aliens and
Speaker 2: their auses.
Speaker 1: I'm dying to now.
Speaker 2: It's a lot easier than you might imagine. Any fan
Speaker 2: of Star Trek knows that in Star Trek four the
Speaker 2: aliens were interested in the humpback whales because it turns
Speaker 2: out they're the smartest critters on Earth, and so maybe
Speaker 2: aliens will come to Earth to talk to not just
Speaker 2: about their navigation, but you know, to get advice about
Speaker 2: whether or not they should promote their transient aeuses to
Speaker 2: permanent ones.
Speaker 1: Oh my gosh, I am so proud of the way
Speaker 1: you tied it all together. It's only missing cannibalism and
Speaker 1: a dig on white chocolate. Bravo.
Speaker 2: You know, we try to end these episodes about inspiring humanity,
Speaker 2: and I'm not sure that accomplished that, but I did
Speaker 2: find some connective tissue.
Speaker 1: I'm impressed. And on that note, let's see if Ron
Speaker 1: does impressed. Wow.
Speaker 5: Thank you so much Daniel and Kelly for digging into
Speaker 5: that question about humpback whales and how they migrate. I
Speaker 5: found it was really fascinating and I've never heard some
Speaker 5: of those theories before. I really can't wait until the
Speaker 5: aliens get here to interpret the answer for us too.
Speaker 5: Thank you again.
Speaker 2: All right, Well, we had a lot of fun talking
Speaker 2: about jelly and white holes and whales and tying it
Speaker 2: all together in surprising ways. And we also had fun
Speaker 2: because we're answering your questions, and we'd like to think
Speaker 2: that we're scratching your curiosity inch because there's so many
Speaker 2: incredible things to be curious about in this universe. So
Speaker 2: please share your curiosity with us and with the other listeners.
Speaker 2: Write to us to questions at Daniel and Kelly dot org.
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