Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions #14

Transcript

Listener Questions #14 · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: If everything is quantum fields, how do their ripples make
• 0:11
  Speaker 1: banana peels?
• 0:13
  Speaker 2: What's the mutation rate for the common cold? Does the
• 0:15
  Speaker 2: virus change moving through my household?
• 0:18
  Speaker 1: Is their mass? In pure information? Do I get heavier
• 0:22
  Speaker 1: with more education?
• 0:24
  Speaker 2: Whatever questions keep you up at night, Daniel and Kelly's
• 0:27
  Speaker 2: answers will make it right.
• 0:28
  Speaker 1: Welcome to another Listener Questions episode on Daniel and Kelly's
• 0:33
  Speaker 1: Extraordinary Universe.
• 0:48
  Speaker 2: Hello. I'm Kelly Wienersmith, and I study parasites and space,
• 0:51
  Speaker 2: but not parasites in space.
• 0:53
  Speaker 3: Not yet, at least that's all right.
• 0:55
  Speaker 4: Hi.
• 0:55
  Speaker 3: I'm Daniel.
• 0:55
  Speaker 1: I'm a particle physicist, and I want to figure out
• 0:58
  Speaker 1: the problems of the universe before the aliens come and
• 1:01
  Speaker 1: spoil the story by telling.
• 1:02
  Speaker 2: Us, oh, interesting, you know. The intro sort of makes
• 1:06
  Speaker 2: it sound like maybe this is going to be an
• 1:07
  Speaker 2: episode about Bigfoot or something. We both have gotten a
• 1:10
  Speaker 2: little bit out there with our intros this morning, but
• 1:14
  Speaker 2: we're going to bring it down to Earth, which reminds
• 1:16
  Speaker 2: me of an interesting talk that I gave on Earth. Well,
• 1:19
  Speaker 2: I don't know if it's interesting. It was my talk,
• 1:21
  Speaker 2: the talk that I gave for Western University Space Day
• 1:24
  Speaker 2: recently and I was giving my usual City on Mars
• 1:28
  Speaker 2: talk and up in the balcony was an entire Girl
• 1:32
  Speaker 2: Scout troop boom.
• 1:33
  Speaker 1: Do you think they were looking to plan an expedition
• 1:35
  Speaker 1: to space?
• 1:36
  Speaker 2: I don't know. Girl Scouts can do anything. Many maybe
• 1:38
  Speaker 2: they were. Maybe they're planning on taking over the world,
• 1:40
  Speaker 2: but they want to know how to take over space too.
• 1:42
  Speaker 2: They did bring delicious cookies, so that was great.
• 1:45
  Speaker 3: Do they ask good questions?
• 1:46
  Speaker 2: That's what I was going to say. They asked the
• 1:48
  Speaker 2: greatest questions, so they asked fantastic questions. And I was
• 1:51
  Speaker 2: a little bit nervous because I hadn't planned on there
• 1:53
  Speaker 2: being kids. So I have a whole section about how
• 1:56
  Speaker 2: the process of expanding family size might be indited by
• 2:00
  Speaker 2: the space environment. And the first question that I got
• 2:04
  Speaker 2: was one of the girls from the Scouts raised her
• 2:06
  Speaker 2: hand and said, in your section on reproduction. And I
• 2:10
  Speaker 2: immediately was like, oh God, this is not a good start.
• 2:15
  Speaker 2: I don't want to give the birds and the bees chat.
• 2:17
  Speaker 2: And she said something about the image you used on
• 2:20
  Speaker 2: that slide had two adults in spacesuits holding two babies
• 2:24
  Speaker 2: in spacesuits. Wouldn't it be expensive to make spacesuits.
• 2:27
  Speaker 1: For babies, all right, it's an engineering question.
• 2:29
  Speaker 3: Yeah, And I think I.
• 2:30
  Speaker 2: Said something like I am so relieved that that's what
• 2:33
  Speaker 2: you asked, And then I explained, like, you know, sometimes
• 2:36
  Speaker 2: it's hard using arts to explain concepts, because we didn't
• 2:40
  Speaker 2: actually mean that people will probably be bringing babies in
• 2:42
  Speaker 2: space suits out on the surface because space radiation. You
• 2:45
  Speaker 2: probably wouldn't want to expose your baby to that on
• 2:47
  Speaker 2: the Martian surface.
• 2:48
  Speaker 1: And then you need like constantly new spacesuits as they grow.
• 2:51
  Speaker 1: I know, as a parent of children who once grew
• 2:53
  Speaker 1: very rapidly, that's very frustrating how quickly they outgrow all
• 2:57
  Speaker 1: their stuff.
• 2:57
  Speaker 2: Oh my gosh. Yes, but I mean eventually we will
• 2:59
  Speaker 2: need different shapes and sizes of space suits for the
• 3:01
  Speaker 2: diversity of body types that will be up there. But
• 3:04
  Speaker 2: my question for you is, have you ever worked with
• 3:07
  Speaker 2: an artist or use some art that didn't at all
• 3:11
  Speaker 2: portray what you had intended and you didn't realize it
• 3:13
  Speaker 2: would be taken seriously because you just meant it to
• 3:17
  Speaker 2: be like a cute, funny image about families in space,
• 3:19
  Speaker 2: for example.
• 3:20
  Speaker 1: Well, the stuff that I write about usually is pretty
• 3:22
  Speaker 1: family friendly, but often it's kind of abstract, and I
• 3:27
  Speaker 1: struggle sometimes to describe it accurately with words, and then
• 3:31
  Speaker 1: I wonder, like, hmmm, how is my illustrator friend going
• 3:35
  Speaker 1: to put this into a picture? Like what visual can
• 3:37
  Speaker 1: you use to describe quantum fields and tie this all together?
• 3:41
  Speaker 1: But I've been lucky to work with very talented illustrators
• 3:44
  Speaker 1: who do a great job of making these exceptional visuals,
• 3:48
  Speaker 1: taking the abstract and making a concrete so that the
• 3:50
  Speaker 1: reader can understand the concepts.
• 3:53
  Speaker 2: To be clear, I think my artist collaborator, slash husband
• 3:56
  Speaker 2: does a great job. But I think sometimes you just
• 3:59
  Speaker 2: assume that the audience will get that this is just
• 4:01
  Speaker 2: like a fun artistic image, as like a palette cleanser
• 4:04
  Speaker 2: for the difficult stuff we just told you. But you
• 4:07
  Speaker 2: know it doesn't always go over the way that you intended.
• 4:10
  Speaker 1: Yeah, well, there's another fine line there, which is sometimes
• 4:12
  Speaker 1: you want to make jokes to lighten the mood, right.
• 4:15
  Speaker 1: I remember in our first book, we talked about what
• 4:17
  Speaker 1: space can do, and I'd written this space can bend,
• 4:21
  Speaker 1: it can expand, it can ripple, and Jorge drew a
• 4:25
  Speaker 1: hilarious little doodle of space bending and expanding and rippling,
• 4:28
  Speaker 1: and then he added a fourth one of like space breakdancing,
• 4:31
  Speaker 1: and you always got to wonder like, okay, is that
• 4:35
  Speaker 1: ridiculous enough that people get Okay, that's obviously a joke
• 4:38
  Speaker 1: to lighten the mood, or somebody out there being like, well,
• 4:41
  Speaker 1: I don't know if space can ripple and expand maybe
• 4:43
  Speaker 1: it could breakdance.
• 4:44
  Speaker 3: What does that mean?
• 4:45
  Speaker 1: We are the equations of breakdancing.
• 4:47
  Speaker 2: Yep.
• 4:47
  Speaker 1: So you always gott to walk that fine line.
• 4:49
  Speaker 2: Zach and I have had so many of those conversations
• 4:51
  Speaker 2: where he's like, people are going to get it's a joke,
• 4:53
  Speaker 2: and I was like, maybe they won't. There are humorless
• 4:56
  Speaker 2: people out there who will be confused.
• 4:59
  Speaker 1: And sometimes the reality is so ridiculous people might think
• 5:02
  Speaker 1: you're making a joke. In our latest book about what
• 5:04
  Speaker 1: science Aliens Might do, we talk about how people tried
• 5:07
  Speaker 1: to communicate with aliens, and there's a guy who wrote
• 5:10
  Speaker 1: letters in the sand and set them on fire hoping
• 5:13
  Speaker 1: that Martians would read them. And that sounds like I'm
• 5:16
  Speaker 1: made up ridiculous example. So I remember adding a footnote
• 5:19
  Speaker 1: being like, I know, we make a ridiculous example sometimes
• 5:22
  Speaker 1: for humor. This is not one of those cases.
• 5:25
  Speaker 2: Yes, everyone while humans are just so crazy you need
• 5:27
  Speaker 2: to be like, no, this isn't a joke. I'm not
• 5:30
  Speaker 2: going into fiction here.
• 5:31
  Speaker 1: Amazing And if anybody's interested in that book, it's coming
• 5:34
  Speaker 1: out in November. It's called Do Aliens Speak Physics? By
• 5:38
  Speaker 1: it anywhere you get books, and.
• 5:39
  Speaker 2: I read an early copy and I can tell you
• 5:41
  Speaker 2: it's amazing.
• 5:42
  Speaker 3: And we're gonna be talking about it a lot until
• 5:44
  Speaker 3: it comes out.
• 5:44
  Speaker 2: Yep. Yeah, nice to have a platform. You know what
• 5:47
  Speaker 2: else is awesome?
• 5:48
  Speaker 3: What's that?
• 5:49
  Speaker 2: Our listeners, they are so awesome and they ask such
• 5:53
  Speaker 2: amazing questions. And we've got like a question from kids
• 5:56
  Speaker 2: theme going on today, and so let's start with our
• 5:59
  Speaker 2: first ques question from Ryan and thirteen year old Grace
• 6:02
  Speaker 2: from the best states in these United States.
• 6:07
  Speaker 1: I'm confused, they're not from California.
• 6:09
  Speaker 3: What are you.
• 6:09
  Speaker 2: Talking about, oh, Daniel.
• 6:12
  Speaker 1: Despite their coming from Virginia, Let's hear about Grace's question.
• 6:15
  Speaker 4: Hey, Daniel and Kelly. My name is Ryan and I
• 6:18
  Speaker 4: have my thirteen year old daughter, Grace here with me.
• 6:20
  Speaker 4: We live in Virginia, and she came up with an
• 6:22
  Speaker 4: interesting question after we discussed your episode on particles and
• 6:25
  Speaker 4: the current understanding that they are ripples in fields?
• 6:28
  Speaker 5: Hi, this is Grace, and here's my question. I don't
• 6:32
  Speaker 5: understand how ripples make things. For instance, how do a
• 6:34
  Speaker 5: bunch of ripples in a field somehow all add up
• 6:37
  Speaker 5: to make a person or banana or sloth? Thanks for
• 6:40
  Speaker 5: taking my question. We love the podcast all.
• 6:42
  Speaker 2: Right, Daniel, As someone who is a huge fan of sloths,
• 6:45
  Speaker 2: I now desperately want to understand how ripples help make
• 6:49
  Speaker 2: up a sloth.
• 6:50
  Speaker 1: I love this question because this is the whole point
• 6:53
  Speaker 1: of physics, to take our everyday experience and explain it
• 6:56
  Speaker 1: in terms of the microscopic stuff that's happening. To like
• 6:59
  Speaker 1: pull back the veil and say what's really going on underneath?
• 7:03
  Speaker 1: And it's cool to say, oh, what's going on underneath?
• 7:05
  Speaker 1: Is this complicated thing with fields and particles and waves
• 7:08
  Speaker 1: and whatever. But Grace is exactly right that the second
• 7:10
  Speaker 1: part of that is to weave it together so that
• 7:13
  Speaker 1: it does explain our everyday experience. You've got to give
• 7:16
  Speaker 1: a path sort of like an intellectual ladder, from the
• 7:19
  Speaker 1: microscopic explanation back to the macroscopic to show how they
• 7:23
  Speaker 1: come together. So thank you Grace for asking this question.
• 7:25
  Speaker 2: It's a fantastic question, and I love that both banana's
• 7:28
  Speaker 2: and sloughts got featured exactly because what good is physics
• 7:32
  Speaker 2: if it's not explaining biology.
• 7:36
  Speaker 1: And maybe there's a banana sloth out there, oh that
• 7:39
  Speaker 1: we could explain.
• 7:39
  Speaker 2: One day, delicious and easy to catch.
• 7:46
  Speaker 3: Probably why they went extinct.
• 7:47
  Speaker 1: So let's get to particles and ripples and quantum fields
• 7:50
  Speaker 1: and all that. Grace's question is how ripples make things.
• 7:54
  Speaker 1: So let's zoom all the way back down to ripples,
• 7:56
  Speaker 1: and then let's walk our way back up to the
• 7:58
  Speaker 1: macroscopics to the sloth in the banana. So like one
• 8:01
  Speaker 1: hundred years ago, we were trying to understand what stuff
• 8:03
  Speaker 1: is made out of. We started taking stuff apart, and
• 8:05
  Speaker 1: we realized it's made out of elements, and those elements
• 8:07
  Speaker 1: are made out of atoms, and eventually we had little
• 8:10
  Speaker 1: particles protons and neutrons and electrons, and back then, I
• 8:12
  Speaker 1: think people were still thinking that those were little bits
• 8:16
  Speaker 1: of stuff that you could like pack together like legos
• 8:18
  Speaker 1: to make bigger stuff that was the sort of microscopic
• 8:21
  Speaker 1: to macroscopic, Like the legos were super duper tiny, almost
• 8:25
  Speaker 1: incomprehensibly tiny, and there were so many of them. You know,
• 8:28
  Speaker 1: Avogado's number is a big number. But if you click
• 8:31
  Speaker 1: them all together, you made macroscopic stuff. And that was
• 8:33
  Speaker 1: our understanding, right.
• 8:34
  Speaker 2: And on the plus side, you can step on them
• 8:36
  Speaker 2: and it doesn't hurt.
• 8:40
  Speaker 3: The a particle legos.
• 8:41
  Speaker 1: Yes, But then we learned, oh, they're not really little
• 8:44
  Speaker 1: bits of stuff. Actually, they're like waves. And quantum mechanics
• 8:49
  Speaker 1: came around and told us that they don't have specific
• 8:51
  Speaker 1: locations and maybe these particles are actually tiny zero volume points.
• 8:56
  Speaker 1: And then quantum mechanics grew up and said, those waves
• 8:59
  Speaker 1: are actually even more important because the particles themselves are
• 9:02
  Speaker 1: just waves and quantum fields.
• 9:04
  Speaker 3: And so that's where.
• 9:05
  Speaker 1: We are now that we understand that all the matter
• 9:07
  Speaker 1: that's out there, the electron, the quarks inside the proton
• 9:10
  Speaker 1: and the neutron, all these things are actually just ripples
• 9:12
  Speaker 1: in quantum.
• 9:13
  Speaker 3: Fields, all right.
• 9:14
  Speaker 2: And there are a bunch of different kinds of fields.
• 9:16
  Speaker 2: We've talked about those before, right, And so are we
• 9:20
  Speaker 2: talking about a very particular kind of field that makes
• 9:23
  Speaker 2: up bananas and slots or are all the fields relevant?
• 9:25
  Speaker 1: So you're right, there are lots of different kinds of fields.
• 9:27
  Speaker 1: Every particle has a field. So the electron is a field,
• 9:30
  Speaker 1: the muon has a field, the cow has a field,
• 9:32
  Speaker 1: the top qrk has a field. Every different kind of
• 9:35
  Speaker 1: particle has a field. We don't understand why there are
• 9:37
  Speaker 1: so many. There're dozens of these fields. Every bit of
• 9:40
  Speaker 1: space that's out there has all these fields sitting on
• 9:42
  Speaker 1: top of each other in the same chunk of space.
• 9:45
  Speaker 1: It's kind of hard to wrap your mind around because
• 9:47
  Speaker 1: if you're thinking of like blankets, you know, blankets you
• 9:50
  Speaker 1: stack because they can't be in the same location. But
• 9:52
  Speaker 1: these fields are all in the same place, and they
• 9:55
  Speaker 1: can all oscillate independently. And you asked, which fields are
• 9:58
  Speaker 1: we talking about in this case, we're talking mostly about
• 10:01
  Speaker 1: the fields that make up us, which are electron fields,
• 10:04
  Speaker 1: and two of the cork fields, the upfield in the downfield.
• 10:07
  Speaker 1: So there are dozens of those fields out there, and
• 10:09
  Speaker 1: there's like big fundamental questions about what that means and
• 10:11
  Speaker 1: how do we unify them, and it can be simplified,
• 10:13
  Speaker 1: et cetera. But most of the matter in the universe
• 10:15
  Speaker 1: is made out of particles which are oscillations in three
• 10:18
  Speaker 1: of those fields, the electron field and then the up
• 10:20
  Speaker 1: and down cork fields which make the proton and the neutron.
• 10:24
  Speaker 1: And how do you understand like a particle being an
• 10:26
  Speaker 1: oscillation of a field, what does that really mean?
• 10:28
  Speaker 3: What are we talking about?
• 10:29
  Speaker 1: Well, when we say an oscillation of a field, we
• 10:32
  Speaker 1: really mean that it's vibrating, like the value of the
• 10:34
  Speaker 1: field is going up and down, and so because it's moving,
• 10:37
  Speaker 1: it can have kinetic energy. And as it has different values,
• 10:40
  Speaker 1: it can have potential energy. The way they like a
• 10:42
  Speaker 1: book on a shelf has a different potential energy if
• 10:45
  Speaker 1: it's on a high point of the shelf or a
• 10:46
  Speaker 1: low point on the shelf. Right, you like store energy
• 10:49
  Speaker 1: in a book by moving to the top of the shelf,
• 10:52
  Speaker 1: you release energy from the book when it falls off
• 10:54
  Speaker 1: the shelf. The same way these fields oscillate. They go
• 10:57
  Speaker 1: up and they go down, They slosh back and forth
• 10:59
  Speaker 1: between tential and kinetic energy, and so there's energy stored
• 11:03
  Speaker 1: in the field. So you should think of the particles
• 11:05
  Speaker 1: as like not a little dot of stuff, but instead
• 11:08
  Speaker 1: a little vibrating blob of energy in the field.
• 11:11
  Speaker 2: Oh way, already, like where this is going, I'm a
• 11:13
  Speaker 2: vibrating field of energy or made up of vibrating fields
• 11:16
  Speaker 2: of energy, and If so, why are the sloths so slow?
• 11:20
  Speaker 3: Exactly, they are filled with energy.
• 11:22
  Speaker 2: They should be all right.
• 11:24
  Speaker 1: So now we have these little vibrating fields of energy.
• 11:26
  Speaker 1: Grace's question is how do you put that together to
• 11:28
  Speaker 1: make a banana.
• 11:29
  Speaker 3: Or a sloth?
• 11:30
  Speaker 1: Basically, these things are super duper tiny, but they're not
• 11:33
  Speaker 1: like little volume cubes like legos. How do you put
• 11:36
  Speaker 1: them together to make something big?
• 11:38
  Speaker 3: Right?
• 11:39
  Speaker 1: Well, here's the crucial insight. You need the volume that
• 11:42
  Speaker 1: we experience. The reason things take up space is not
• 11:46
  Speaker 1: from the stuff that they make, but from their interactions
• 11:49
  Speaker 1: with each other. So it's not like you have two
• 11:52
  Speaker 1: particles and they have surfaces and those surfaces click together,
• 11:55
  Speaker 1: or even that they're like two tennis balls that you're
• 11:57
  Speaker 1: packing into a space and their surfaces are particles have
• 12:01
  Speaker 1: interactions with each other. They exchange energy. This energy we
• 12:04
  Speaker 1: were talking about slashing in the electron field or slashing
• 12:07
  Speaker 1: in the quarkfield. That energy can slide from one field
• 12:10
  Speaker 1: to another. That's when an interaction is so. For example,
• 12:13
  Speaker 1: an electron moving through space will also make ripples in
• 12:16
  Speaker 1: the electromagnetic field the photons field because those two fields interact.
• 12:21
  Speaker 1: There's a connection between those two fields and the ripples
• 12:24
  Speaker 1: in the electromagnetic field will then push or pull on
• 12:27
  Speaker 1: other electrons. So how do two electrons interact with each other?
• 12:30
  Speaker 1: Why do they repel? Because they are both making ripples
• 12:33
  Speaker 1: in the electromagnetic field, which has the capacity to affect
• 12:36
  Speaker 1: other electrons.
• 12:38
  Speaker 2: So I'm going to try to tie this back to biology.
• 12:39
  Speaker 2: So I'm thinking, you know, Christmas has ended and I'm
• 12:42
  Speaker 2: feeling like my body could do with fewer interactions. Is
• 12:46
  Speaker 2: there is there a way to think about it, like
• 12:49
  Speaker 2: as you go into calorie deficit, can you think about
• 12:52
  Speaker 2: it as like electrons sort of leaving the electric field?
• 12:55
  Speaker 2: Or am I just making this too complicated?
• 12:57
  Speaker 1: I think there's a Christmas analogy if we can do
• 12:59
  Speaker 1: use to understand here. Think about what happens at a
• 13:01
  Speaker 1: Christmas party. Right when you put people into a room
• 13:04
  Speaker 1: at a Christmas party, do they stack like sardines against
• 13:07
  Speaker 1: the wall or like physically phase on top of each
• 13:09
  Speaker 1: other and occupy the same space. No, they talk to
• 13:12
  Speaker 1: each other and they get like a comfortable distance from
• 13:15
  Speaker 1: each other. Right, So you're at a party, people are
• 13:17
  Speaker 1: sort of scattered.
• 13:18
  Speaker 3: Through a room.
• 13:19
  Speaker 1: You're all sipping your Christmas cocktails or whatever, and they're
• 13:22
  Speaker 1: not squeezed and touching each other. Right, there's this comfortable
• 13:25
  Speaker 1: distance because people are talking to each other and they
• 13:27
  Speaker 1: respect each other's personal space. The reason that we can
• 13:30
  Speaker 1: generate volume in a banana from a bunch of tiny
• 13:32
  Speaker 1: little particles, which are actually ripples in the fields, is
• 13:35
  Speaker 1: for the same reason that they have their own little
• 13:37
  Speaker 1: personal space. Their interactions keep them apart, and so like
• 13:41
  Speaker 1: inside your banana, are a bunch of little ripples that
• 13:45
  Speaker 1: are keeping their space between them because of their interactions.
• 13:48
  Speaker 1: So the volume of the material comes from the bonds
• 13:50
  Speaker 1: between these particles, these little ripples, not from like the
• 13:54
  Speaker 1: inherent volume of them, as they're stacked together on top
• 13:56
  Speaker 1: of each other. So let's zoom all the way in
• 13:59
  Speaker 1: and then out again, just to make sure it all
• 14:00
  Speaker 1: makes sense. We zoom as far in as we understand
• 14:03
  Speaker 1: the nature of the universe. We have these little ripples
• 14:05
  Speaker 1: and fields which are just little buzzing blobs of energy. Right,
• 14:09
  Speaker 1: particles are not little scoops of universe stuff. They are
• 14:12
  Speaker 1: little blobs of buzzing energy in the field, and the
• 14:15
  Speaker 1: fields interact with each other. So buzzing energy in the
• 14:17
  Speaker 1: electron field also means buzzing in the electromagnetic field, and
• 14:20
  Speaker 1: also in the Higgs field and all sorts of other fields.
• 14:22
  Speaker 1: Whatever the electron interacts with and interactions between those fields
• 14:26
  Speaker 1: keep these little buzzing blobs in harmony and in balance
• 14:30
  Speaker 1: and allow you to build up bigger things. So they're
• 14:33
  Speaker 1: not little lego bricks that you click together, but they
• 14:35
  Speaker 1: little buzzing blobs sort of in balance with each other,
• 14:38
  Speaker 1: keeping their space. And that's where the volume comes from.
• 14:41
  Speaker 1: So you zoom all the way out and you look
• 14:42
  Speaker 1: at a banana, should think of it as like a
• 14:45
  Speaker 1: matrix of these buzzing blobs that are all somehow in
• 14:48
  Speaker 1: balance with each other because of their interactions.
• 14:51
  Speaker 2: It doesn't sound beautiful, but you know, I study dumb
• 14:53
  Speaker 2: trucks full of dead fists, so who are to judge?
• 14:57
  Speaker 1: No, but I think that is like peeling back a
• 14:59
  Speaker 1: layer of reality, like seeing the matrix and like, oh,
• 15:02
  Speaker 1: this is what makes up the banana. And you know,
• 15:04
  Speaker 1: what's a banana in your mind is your experience the banana,
• 15:08
  Speaker 1: poking on it, pushing on and tasting it, whatever, chasing
• 15:11
  Speaker 1: that sloth, all these experiences of what build your sort
• 15:14
  Speaker 1: of your mental construct of the banana. But it's nice
• 15:16
  Speaker 1: to know, like mathematically, how that comes from the littlest
• 15:20
  Speaker 1: bits it's made out of. So thank you Grace for
• 15:22
  Speaker 1: asking that question. And we're curious if this answered your
• 15:25
  Speaker 1: question and if you have follow ups, So we'll ship
• 15:28
  Speaker 1: this off to Grace and we'll hear what she.
• 15:30
  Speaker 3: Has to say.
• 15:31
  Speaker 2: I also don't think answers have to be beautiful, but
• 15:33
  Speaker 2: maybe that's because I'm a biologist. Our answers are rarely.
• 15:36
  Speaker 3: Beautiful, but often they're insightful.
• 15:38
  Speaker 2: Yeah, I wasn't implying they weren't, Daniel. I don't know
• 15:41
  Speaker 2: why you felt you needed to say that, well.
• 15:45
  Speaker 1: Because that's where the beauty comes from, right the inside. Like, oh, no,
• 15:48
  Speaker 1: I understand this in a way I didn't before. Yeah,
• 15:51
  Speaker 1: it can still be gooey, it's true.
• 15:53
  Speaker 5: Hi, Daniel Keilly, thank you so much for answering our question.
• 15:56
  Speaker 5: I'm still not sure I understand all of it, but
• 15:59
  Speaker 5: it was really helpful here you explain it.
• 16:01
  Speaker 6: I agree, it's clear I need to change my mental
• 16:04
  Speaker 6: model of ways and particles stecking up like lego bricks
• 16:07
  Speaker 6: to make things like sloths and instead think about blobs
• 16:10
  Speaker 6: of energy. Thank you for all that you both do
• 16:13
  Speaker 6: to help educate us and break down complex topics and
• 16:16
  Speaker 6: have fun while doing it. I rate your answer a
• 16:19
  Speaker 6: solid A plus.
• 16:21
  Speaker 5: Thank you so much.
• 16:22
  Speaker 7: Bye.
• 16:44
  Speaker 2: All right, we're back and the next question is from
• 16:46
  Speaker 2: a listener who, when they emailed us, was working through
• 16:49
  Speaker 2: a very miserable cold. I believe they're feeling better now.
• 16:52
  Speaker 2: But here is their question.
• 16:54
  Speaker 8: A common COLDE seems to have a lot of variants,
• 16:56
  Speaker 8: But how quickly does it mutate? Such as for the
• 16:59
  Speaker 8: common I'm suffering with at the moment, Is there a
• 17:02
  Speaker 8: quantifiable percentage of my sneezing and coughing that I accidentally
• 17:06
  Speaker 8: spew onto others noticeably different compared to my original infection?
• 17:12
  Speaker 8: Or are the variants pretty rare? But given the billions
• 17:16
  Speaker 8: of us who get a cold that can create variants,
• 17:19
  Speaker 8: a big number times a small percentage can have a
• 17:23
  Speaker 8: surprisingly noticeable number.
• 17:25
  Speaker 1: Help me out, all right, this is a great question,
• 17:28
  Speaker 1: and it's sort of similar in spirit to the previous one, Right,
• 17:30
  Speaker 1: getting a microscopic understanding of a common experience, in this case,
• 17:35
  Speaker 1: the common cold. So let's see if biology can provide
• 17:38
  Speaker 1: the insights to give you that sense of understanding, even
• 17:41
  Speaker 1: if we are talking about mucus.
• 17:43
  Speaker 2: Well, let's give it a shot, all right, So it
• 17:46
  Speaker 2: gets complicated right from the beginning. The common cold. According
• 17:50
  Speaker 2: to the Centers for Disease Control, this is defined as
• 17:53
  Speaker 2: a viral infection of the upper respiratory track. Okay, okay,
• 17:56
  Speaker 2: but it turns out it's not caused by just one
• 17:59
  Speaker 2: kind of virus. It's caused by something like over two
• 18:02
  Speaker 2: hundred different kinds of viruses. But depending on the time
• 18:06
  Speaker 2: of year, between fifty to eighty percent of the common
• 18:09
  Speaker 2: colds that people have are caused by a group of
• 18:11
  Speaker 2: viruses called the rhinoviruses. So we're going to answer Tim's
• 18:15
  Speaker 2: question based on data that we've gotten in labs that
• 18:18
  Speaker 2: have looked at rhinoviruses.
• 18:20
  Speaker 1: So this is like asking, why is my house infected
• 18:23
  Speaker 1: with insects? Well, it turns out there's lots of different
• 18:25
  Speaker 1: kind of insects that couldn't infest your house.
• 18:27
  Speaker 2: That's right, that's right. And so to answer your question
• 18:29
  Speaker 2: without taking too many lifetimes, we need to narrow down
• 18:33
  Speaker 2: on an example. So we're narrowing down on the rhinoviruses.
• 18:37
  Speaker 1: And so for those of us who are not biologists,
• 18:39
  Speaker 1: remind us, like, what is a virus and how does
• 18:41
  Speaker 1: it work?
• 18:42
  Speaker 3: What is its plan?
• 18:43
  Speaker 2: Yeah, So what viruses do is when they get inside
• 18:46
  Speaker 2: of you, they have this way of injecting themselves into
• 18:49
  Speaker 2: your cell. So they've got like some machinery that helps
• 18:51
  Speaker 2: them move around, and then when they get to a cell,
• 18:53
  Speaker 2: they clamp down and then they inject genetic material into
• 18:57
  Speaker 2: the cell.
• 18:58
  Speaker 1: This is amazing. It's empazing. It sounds so mechanical.
• 19:02
  Speaker 2: It does. Yeah, I know, sometimes biology is just as
• 19:04
  Speaker 2: good as Sci Fi, maybe better. So they hijack the
• 19:10
  Speaker 2: cell's machinery and they get the cell to start replicating
• 19:13
  Speaker 2: the virus. And this is part of where Tim's question
• 19:16
  Speaker 2: comes in. As the virus replicates, sometimes mistakes are made,
• 19:21
  Speaker 2: and cold viruses tend to not correct these genetic mistakes
• 19:24
  Speaker 2: very often, and so we're going to get to that
• 19:26
  Speaker 2: in a little bit more detail layered. So the host
• 19:28
  Speaker 2: cell replicates the virus many times, and then the virus
• 19:32
  Speaker 2: breaks out of the cell and goes and completes that
• 19:34
  Speaker 2: cycle again.
• 19:35
  Speaker 1: So the element of the cell that is taking over
• 19:37
  Speaker 1: is the bit where it replicates the genetic material. That's
• 19:39
  Speaker 1: what the virus can't do for itself. Yes, so this
• 19:42
  Speaker 1: is like a hacker breaking into a publishing house. And
• 19:45
  Speaker 1: getting it to print his personal manifesto instead of whatever
• 19:48
  Speaker 1: it was going to print otherwise.
• 19:49
  Speaker 2: That's right, yep. Print it's pamphlets over and over and
• 19:51
  Speaker 2: over again. And then through some mechanism that sort of
• 19:55
  Speaker 2: breaks the metaphor, it sneaks into another publishing house and
• 19:58
  Speaker 2: does the same thing over and over and over again
• 20:01
  Speaker 2: until you stop sneezing. So anyway, so it goes through
• 20:06
  Speaker 2: this process, and it is finding cells in particular in
• 20:09
  Speaker 2: like your nasal passage and your lungs, and it's replicating
• 20:13
  Speaker 2: in there. And as it replicates, your immune system sort
• 20:16
  Speaker 2: of amps up and starts attacking it. And this cold
• 20:19
  Speaker 2: process can last for about a week, and so you
• 20:21
  Speaker 2: get a build up of virus particles and then your
• 20:24
  Speaker 2: immune system starts to get it in control, and the
• 20:27
  Speaker 2: density of virus goes down over time.
• 20:29
  Speaker 1: And so if I've had the common cold and my
• 20:31
  Speaker 1: immune system has figured out how to combat it, why
• 20:34
  Speaker 1: do I then get the common cold again the next
• 20:36
  Speaker 1: year or three weeks later when my kids come back
• 20:38
  Speaker 1: with a different one.
• 20:39
  Speaker 2: Well, that great question brings me to mutation rates. So,
• 20:43
  Speaker 2: as I mentioned, the virus doesn't correct mistakes as often
• 20:47
  Speaker 2: as for example, human cells do. And so the question
• 20:50
  Speaker 2: that we want to ask here to really address Tim's
• 20:53
  Speaker 2: question is how many mutations do you tend to get
• 20:55
  Speaker 2: and how much do they build up? So I found
• 20:58
  Speaker 2: estimates that the mutation rate is you get something like
• 21:02
  Speaker 2: ten to the negative three to ten to the negative
• 21:05
  Speaker 2: five mutations, and ten to the negative three is one
• 21:08
  Speaker 2: in a thousand, one in a thousand. Yeah, per nucleotide,
• 21:11
  Speaker 2: per genome replication event. Don't worry about all of those numbers.
• 21:15
  Speaker 2: The point is that a virus is about seven two
• 21:19
  Speaker 2: hundred pieces long, and each time it replicates, you usually
• 21:22
  Speaker 2: end up with about one mutation on average in that
• 21:25
  Speaker 2: genetic code.
• 21:26
  Speaker 1: So it's getting the cell to replicate it, but it's
• 21:28
  Speaker 1: not a perfect copy.
• 21:30
  Speaker 2: That's right, and then it doesn't get corrected, and so
• 21:32
  Speaker 2: that error goes on to the next cell and that
• 21:35
  Speaker 2: gets replicated over and over again.
• 21:37
  Speaker 1: So already the initial virus that infected Tim, all of
• 21:40
  Speaker 1: its little babies likely are different than it was by
• 21:44
  Speaker 1: one nucleotide.
• 21:45
  Speaker 2: That's right. And so then the question you want to
• 21:47
  Speaker 2: ask yourself is does that matter? And I think a
• 21:49
  Speaker 2: lot of the time it's not going to matter. So
• 21:51
  Speaker 2: a lot of mutations don't change the kind of protein
• 21:54
  Speaker 2: that ends up getting made, or they don't have any
• 21:56
  Speaker 2: meaningful change based on this one little that flips to
• 22:01
  Speaker 2: a different value.
• 22:01
  Speaker 3: Right.
• 22:02
  Speaker 1: It's not like the common cold suddenly becomes a completely
• 22:04
  Speaker 1: different disease measles all of a sudden with one slip
• 22:07
  Speaker 1: or something.
• 22:07
  Speaker 2: Right. But you know, as Tim noted in his question,
• 22:10
  Speaker 2: if this is happening many many times in your body,
• 22:13
  Speaker 2: and then it's happening to many many people, these changes
• 22:15
  Speaker 2: can add up over time. Amazingly. This all seems to
• 22:18
  Speaker 2: also be temperature dependent. And I have a lot of
• 22:21
  Speaker 2: friends who will say things like, oh, don't go outside
• 22:23
  Speaker 2: without a coat on. It's cold out, and then you're
• 22:26
  Speaker 2: gonna get sick. And that's not quite how it works.
• 22:28
  Speaker 2: But there is some evidence that at colder temperatures, cold
• 22:33
  Speaker 2: viruses do replicate more quickly in mice. I don't think
• 22:36
  Speaker 2: this has been done in humans. It's always in mice.
• 22:39
  Speaker 2: But it's not because that's better for the virus in
• 22:41
  Speaker 2: some way, which I think is implied when they're like, oh,
• 22:44
  Speaker 2: don't go outside without your coat on. It's because the
• 22:46
  Speaker 2: immune systems in mice seem to react less strongly at
• 22:50
  Speaker 2: low temperatures. So these replication rates that we're talking about here,
• 22:54
  Speaker 2: they're all a little bit handwavy, and they depend on
• 22:56
  Speaker 2: what temperature you're at, and so Tim, I hope you're
• 22:58
  Speaker 2: staying nice and warm. Yeah, So what do we know
• 23:01
  Speaker 2: about how much the cell replicates inside of a host?
• 23:05
  Speaker 2: And the answer is well as complicated. So at a
• 23:09
  Speaker 2: lot of our data come from what I think of
• 23:11
  Speaker 2: as the wrong kinds of cells in the lab. And
• 23:14
  Speaker 2: so the cells that are often used in these experiments
• 23:16
  Speaker 2: are HeLa cells. So these are I think ovarian cells
• 23:19
  Speaker 2: collected from a woman named Henriette Lex a long time ago.
• 23:23
  Speaker 2: They were collected without her permission.
• 23:24
  Speaker 1: Bad bad biologists.
• 23:26
  Speaker 3: Bad.
• 23:27
  Speaker 2: Yeah, yeah, no, bad biologists. You're right, I'll take that one.
• 23:31
  Speaker 1: I mean, we've never gotten consent from any of the
• 23:33
  Speaker 1: protons we've destroyed, but I don't think they are the
• 23:35
  Speaker 1: same rights.
• 23:35
  Speaker 2: Yeah, no, it's you're right. This was not a bright
• 23:38
  Speaker 2: spot in the history of biology. So we stole those cells.
• 23:42
  Speaker 2: There's a whole very interesting book on that which I
• 23:44
  Speaker 2: recommend people check out. But anyway, so these cells are
• 23:47
  Speaker 2: really great at surviving in the lab, and so we
• 23:49
  Speaker 2: will infect them with cold viruses and see how they replicate.
• 23:52
  Speaker 2: But the problem is they're ovarian cells. They're not like
• 23:54
  Speaker 2: nasal passage cells, and the body is complicated. So just
• 23:58
  Speaker 2: because something happens in a petri dish, does it I
• 24:00
  Speaker 2: mean it would happen the same in a body. So
• 24:02
  Speaker 2: when a cell explodes, how many baby viruses are made?
• 24:06
  Speaker 2: And the answer is probably something like one hundred thousand,
• 24:09
  Speaker 2: maybe even more than that. And then how long is
• 24:12
  Speaker 2: the cycle of infection before you get an explosion? And
• 24:16
  Speaker 2: you know, we don't really know. It's probably longer than minutes,
• 24:20
  Speaker 2: but less than weeks, which is a pretty big timeframe.
• 24:22
  Speaker 2: And thank you so much to Katrina Whitson for giving
• 24:25
  Speaker 2: us this information, because I was having trouble sort of
• 24:28
  Speaker 2: narrowing down the numbers to use for this question, and I.
• 24:31
  Speaker 1: Think Coatinia would probably want me to emphasize that these
• 24:33
  Speaker 1: are very fuzzy numbers because it's a research question. Nobody
• 24:36
  Speaker 1: knows the answer to these things, which is sort of
• 24:39
  Speaker 1: shocking and amazing, but it's hard to measure. And she
• 24:42
  Speaker 1: was also telling me that sometimes a virus wants to
• 24:44
  Speaker 1: slow down how long the process takes because it wants
• 24:47
  Speaker 1: the cell to get like stronger and fatter before it explodes.
• 24:50
  Speaker 1: So sometimes they like beef up the cell, sort of
• 24:52
  Speaker 1: like fattening a calf before you kill it.
• 24:54
  Speaker 2: That's right, And so as a group effort, I would
• 24:56
  Speaker 2: say the Whitesn Research Institute plus adjunct faculty member or
• 25:00
  Speaker 2: Kelly Wiener Smith decided that the virus that you sneeze
• 25:04
  Speaker 2: out sort of towards the end of your cold probably
• 25:07
  Speaker 2: has something like twenty mutations and is about one percent
• 25:10
  Speaker 2: different than the virus that you were infected by GO team.
• 25:15
  Speaker 2: But Tim wanted to know if it was noticeably variable,
• 25:18
  Speaker 2: and we've mentioned that it really depends where those mutations
• 25:20
  Speaker 2: are happening. But over time this is adding up. The
• 25:24
  Speaker 2: cold virus does end up being noticeably variable enough that
• 25:27
  Speaker 2: it's really hard to make a vaccine for the cold.
• 25:31
  Speaker 2: And this is for a couple reasons. So one, we've
• 25:33
  Speaker 2: already mentioned that there's like something like two hundred different
• 25:35
  Speaker 2: kinds of viruses that can cause colds. Additionally, each strain
• 25:39
  Speaker 2: of the cold virus is replicating pretty rapidly, so from
• 25:42
  Speaker 2: one season to another it might be different enough that
• 25:44
  Speaker 2: the vaccine wouldn't work. And additionally, colds don't tend to
• 25:47
  Speaker 2: be as serious as something like the flu, So there's
• 25:50
  Speaker 2: not a lot of impetus to try to create a vaccine,
• 25:53
  Speaker 2: even though I sure would love to have not spent
• 25:56
  Speaker 2: oh my gosh, when my kids started elementary school, I
• 25:59
  Speaker 2: think I spent like sixty percent of my time at
• 26:01
  Speaker 2: home with a cold. I would have loved to have
• 26:03
  Speaker 2: had that time back. But what are you gonna do?
• 26:06
  Speaker 1: And that's interesting because colds are varying constantly and it's
• 26:10
  Speaker 1: hard to maintain immunity against them. Yet they mostly feel
• 26:13
  Speaker 1: the same, right, Yeah, yeah, you got a head cold
• 26:15
  Speaker 1: or a chest cold or whatever. But it's not like,
• 26:17
  Speaker 1: oh wow, this one makes my head green, or now
• 26:20
  Speaker 1: my thumb is swollen or something. It's basically the same disease,
• 26:23
  Speaker 1: it feels like to me.
• 26:24
  Speaker 2: Yeah, no, it feels that way to me as well.
• 26:26
  Speaker 2: And just to be clear, the flu viruses are also
• 26:28
  Speaker 2: doing quite a bit of mutating, but I think they
• 26:31
  Speaker 2: mutate a little bit less. But every year, the reason
• 26:33
  Speaker 2: you get a new flu vaccine is because that vaccine
• 26:36
  Speaker 2: is meant to replicate the strains of the flu that
• 26:38
  Speaker 2: we think are going to be most common in a
• 26:39
  Speaker 2: given year, Given like mutations that we've seen in those
• 26:42
  Speaker 2: flu virus strains in the past.
• 26:45
  Speaker 1: Yeah, And I think there's a lot of detective work
• 26:47
  Speaker 1: and guesswork that goes into the flu. Right, they're like
• 26:49
  Speaker 1: thinking about what it might be because they obviously don't
• 26:51
  Speaker 1: have the examples for the flu that's gonna come.
• 26:54
  Speaker 3: In the future.
• 26:54
  Speaker 2: Yep, exactly. I mean they're making their guests based on
• 26:57
  Speaker 2: years of data, looking at trends and how this stuff
• 26:59
  Speaker 2: plays out. But you're right, at the end of the day,
• 27:01
  Speaker 2: you just need to guess which flu strains are going
• 27:03
  Speaker 2: to be the most important ones to make vaccines against.
• 27:06
  Speaker 2: And I hope you got it.
• 27:07
  Speaker 1: Right thanks to folks working on the front lines of
• 27:10
  Speaker 1: public health.
• 27:11
  Speaker 2: Yes, oh my gosh, they're the best. All right, Tim,
• 27:13
  Speaker 2: We hope you're feeling better, and let's find out if
• 27:16
  Speaker 2: we were able to answer your question.
• 27:18
  Speaker 9: Yes, that answer my question. And wow, that is rather
• 27:21
  Speaker 9: terrifying that two hundred variants out there make up the
• 27:24
  Speaker 9: cold virus. I don't know if I'm going to sleep
• 27:27
  Speaker 9: well at night knowing that fact on top of all
• 27:29
  Speaker 9: the other mutation rates. But luckily we feel a little
• 27:33
  Speaker 9: bit on the safe side.
• 27:54
  Speaker 3: All right.
• 27:55
  Speaker 1: And our last question comes from Mark in Newcastle, who
• 27:58
  Speaker 1: asks a very heavy question about something very ephemeral.
• 28:02
  Speaker 10: Hi guys, it's Markia from Newcastle upon Tyne in the UK,
• 28:06
  Speaker 10: and I've got a question for you about data. I
• 28:09
  Speaker 10: was recently working on a project with my orduino writing
• 28:11
  Speaker 10: to some SD cards and of course when you switch
• 28:15
  Speaker 10: off the power and switch it back on, the data
• 28:16
  Speaker 10: is retained. So these cards do store something. This storing
• 28:21
  Speaker 10: charge and charge is electrons. Electrons have mass, So does
• 28:26
  Speaker 10: data have mass? Would an SD card full of data
• 28:30
  Speaker 10: way more than an SD card that didn't I guess
• 28:33
  Speaker 10: this is an extra opulation of this question, how much
• 28:36
  Speaker 10: does the Internet Way? Book pops for another day.
• 28:39
  Speaker 2: This is such a great question because, well, for a
• 28:41
  Speaker 2: variety of reasons. But I love this question because in
• 28:44
  Speaker 2: the past on this show you have said that when
• 28:46
  Speaker 2: a Tesla battery is charged, it weighs more than when
• 28:50
  Speaker 2: it's not charged, And that makes sense now, but at
• 28:54
  Speaker 2: the moment it totally surprised me and I didn't expect that.
• 28:56
  Speaker 2: And so, yeah, how much does the Internet Way.
• 28:59
  Speaker 3: Daniel seven at weighs seven?
• 29:02
  Speaker 2: Oh good, I was going to guess forty two.
• 29:04
  Speaker 1: Yeah, remember that mass as a measure of internal stored energy,
• 29:08
  Speaker 1: So if you increase the internal stored energy of an object,
• 29:11
  Speaker 1: then you are increasing its mass.
• 29:13
  Speaker 3: Like if you have a.
• 29:14
  Speaker 1: Rock and use zapp it with a photon and it
• 29:16
  Speaker 1: gets hotter, it also has more mass. Now, so when
• 29:19
  Speaker 1: you charge your Tesla battery, you're giving it more energy,
• 29:23
  Speaker 1: not because you're adding more electrons, you know, like physically
• 29:25
  Speaker 1: adding more scoops of universe stuff. Just giving more energy
• 29:29
  Speaker 1: to that configuration does increase the mass of the battery.
• 29:32
  Speaker 1: Since equals mc squared and C squared is a really
• 29:35
  Speaker 1: big number, you need an enormous amount of energy to
• 29:37
  Speaker 1: make a tiny increase in mass. So nobody really notices this,
• 29:41
  Speaker 1: and that's why. But Mark's question is sort of related.
• 29:44
  Speaker 1: He's asking about whether the arrangements to configuration of information
• 29:49
  Speaker 1: on his SD card or on your hard drive or
• 29:52
  Speaker 1: in your brain also has mass, which is a really
• 29:55
  Speaker 1: fascinating question and touches on deep concepts about information and entropy.
• 30:00
  Speaker 2: And we luckily have someone who is part computer scientist,
• 30:04
  Speaker 2: part physicists who is absolutely prepared to answer this question
• 30:08
  Speaker 2: for us.
• 30:09
  Speaker 1: Yeah, so information is really fascinating. It's hard to think
• 30:12
  Speaker 1: about like whether information has mass because information seems sort
• 30:16
  Speaker 1: of subjective, right, like, if you have a hard drive
• 30:20
  Speaker 1: and it has just random ones and zeros on it,
• 30:23
  Speaker 1: does it have more or less information than if you
• 30:25
  Speaker 1: put a picture of your dog on the hard drive? Well,
• 30:28
  Speaker 1: it depends, like do you consider the picture of your
• 30:31
  Speaker 1: dog to be useful or information in some way?
• 30:33
  Speaker 3: Right?
• 30:34
  Speaker 1: Or like did you encrypt the picture of your dog?
• 30:37
  Speaker 1: Because the best encryption algorithms make data that's valuable it
• 30:41
  Speaker 1: has some information look like random noise. So you can
• 30:44
  Speaker 1: imagine a scenario where you, like, you take a picture
• 30:46
  Speaker 1: of your dog, you put it on the hard drive,
• 30:47
  Speaker 1: looks like your dog, then you encrypt it. Somebody else
• 30:50
  Speaker 1: coming along is like, no, that's just random noise. There's
• 30:53
  Speaker 1: no information. And what if you, like, lose the password,
• 30:56
  Speaker 1: has the information decreased? And so information turns out to
• 30:59
  Speaker 1: be a fascinatingly subjective concept, which makes it very hard
• 31:03
  Speaker 1: to link to masks because mass is something physical and
• 31:05
  Speaker 1: invariant that everybody agrees on that you can like measure
• 31:08
  Speaker 1: without knowing about dogs or passwords?
• 31:10
  Speaker 2: Should I be thinking about information differently than I think
• 31:14
  Speaker 2: about like you know, before I put my PowerPoint presentation
• 31:17
  Speaker 2: on my SD card, it has fifty megabytes of data
• 31:21
  Speaker 2: and after the PowerPoint presentation is on there, it has
• 31:23
  Speaker 2: one thy fifty. So how is information different than megabytes?
• 31:29
  Speaker 1: Yeah, if you have an empty disc and then you
• 31:31
  Speaker 1: put files on there, it's counting, like how much of
• 31:34
  Speaker 1: the drive has information you've put on there. There could
• 31:38
  Speaker 1: also be information on the other bits that it's not counting,
• 31:41
  Speaker 1: maybe somebody else put it on there, but then you
• 31:43
  Speaker 1: format it the drive, so you consider it to be empty.
• 31:45
  Speaker 1: So it's a different question of like when you're filling
• 31:48
  Speaker 1: up the drive, right, because it's just like using some
• 31:50
  Speaker 1: of the bits for this rather than considering them unused.
• 31:53
  Speaker 1: But the question of information is subtle, and we're going
• 31:56
  Speaker 1: to have to dip into our understanding of entropy in
• 31:58
  Speaker 1: order to understand it, because it's turns out these two
• 32:00
  Speaker 1: concepts are closely related.
• 32:02
  Speaker 2: So okay, So just to clarify, then, information is not
• 32:06
  Speaker 2: how much stuff is on a card, it's how informative
• 32:11
  Speaker 2: is the thing?
• 32:12
  Speaker 1: Yeah, Because you could take a card and just fill
• 32:14
  Speaker 1: it with random ones and zeros, right, there's no information
• 32:17
  Speaker 1: there for you. So just because you put a big
• 32:19
  Speaker 1: file in your hard drive doesn't mean you add a
• 32:21
  Speaker 1: lot of information. It's about the contents and this seems
• 32:23
  Speaker 1: really subjective, and physics is all about equations and crisp definitions.
• 32:27
  Speaker 1: So how do we think about information from the point
• 32:30
  Speaker 1: of view of science and physics. So Claude Shannon defined
• 32:33
  Speaker 1: this in the middle of the last century. He was
• 32:35
  Speaker 1: thinking about this and he came up with something of
• 32:37
  Speaker 1: an arbitrary but very useful definition of information, and he
• 32:40
  Speaker 1: defines it as how much you have learned, how much
• 32:43
  Speaker 1: surprising information you have gained. So he was imagining like,
• 32:47
  Speaker 1: I'm communicating to you by sending you symbols across some
• 32:50
  Speaker 1: channel ones and zero's on a hard drive or you know,
• 32:53
  Speaker 1: text on a phone or whatever, and you want to
• 32:56
  Speaker 1: measure how much information is in these messages from Daniel
• 32:59
  Speaker 1: and to his definition, if when you learn something surprising,
• 33:03
  Speaker 1: that's high information. If you learn something you already know,
• 33:06
  Speaker 1: that's low information. So for example, let's say every day
• 33:09
  Speaker 1: I text you and I say, hey, Kelly, the earth
• 33:11
  Speaker 1: didn't explode last nightew every day you look at it
• 33:14
  Speaker 1: and you're like, Okay, that's not a surprise, right, this
• 33:17
  Speaker 1: has happened every day so far in my life.
• 33:19
  Speaker 2: I'm changing my phone number. Leave me alone, Daniel.
• 33:23
  Speaker 1: Why a physicists text me about the planet's exploding.
• 33:26
  Speaker 3: What did I do wrong?
• 33:27
  Speaker 2: Low information?
• 33:28
  Speaker 1: Low information exactly because it's something you expected to happen.
• 33:32
  Speaker 1: So the fact that it happened you didn't really learn much.
• 33:35
  Speaker 1: If one day I texted you I was like, by
• 33:36
  Speaker 1: the way, at two am, the Earth exploded, you'd be like, wow,
• 33:39
  Speaker 1: that's news to me, right, this is big information.
• 33:41
  Speaker 2: But wouldn't that also be low information because I would
• 33:44
  Speaker 2: have been exploded and I would have also been like,
• 33:46
  Speaker 2: thanks for being late to the party, Daniel.
• 33:48
  Speaker 1: Don't use the practical details of my analogy to confuse you, audience.
• 33:53
  Speaker 2: Okay, whoa, Oh no, I didn't know that, Daniel.
• 33:56
  Speaker 1: You're living in a city on Mars in this example.
• 33:58
  Speaker 1: All right, So let's put Kelly on Mars. She and
• 34:01
  Speaker 1: her cute babies in their baby spacesuits, and her and
• 34:04
  Speaker 1: the girl Scout troop are camping up there on Mars awesome.
• 34:07
  Speaker 1: And every day I wake up and my job is
• 34:09
  Speaker 1: to text you about whether the Earth exploded. So the
• 34:12
  Speaker 1: day that you get a text that the Earth exploded,
• 34:14
  Speaker 1: that's big news. Why because it was unlikely and so
• 34:17
  Speaker 1: the fact that it happened is a lot of information.
• 34:20
  Speaker 2: Major bummer.
• 34:22
  Speaker 1: So This is fascinating because it means a bits of
• 34:24
  Speaker 1: information like did the Earth explode?
• 34:26
  Speaker 3: Yes and no.
• 34:27
  Speaker 1: It feels like one bit like either value should be
• 34:29
  Speaker 1: equal amounts of information, but they're not because information depends
• 34:33
  Speaker 1: on context, so bits of information are not created equally.
• 34:37
  Speaker 1: And so Shannon said, let's define the amount of information
• 34:41
  Speaker 1: to be the inverse of the probability for that to happen. Right,
• 34:45
  Speaker 1: so if a high probability of it happens, one over
• 34:47
  Speaker 1: that number is a small number, so it's a small
• 34:49
  Speaker 1: amount of information. And if a very unlikely thing happened,
• 34:52
  Speaker 1: then one over that number is a very big number,
• 34:55
  Speaker 1: so that's a lot of information. And he called this surprisal.
• 34:59
  Speaker 2: That's cute.
• 34:59
  Speaker 1: And to make it well, behave we have the logarithm
• 35:01
  Speaker 1: of it. So he defines information as log of one
• 35:05
  Speaker 1: over the probability for something to happen, which just means
• 35:08
  Speaker 1: that like more probable, lower information, less probable, more information.
• 35:13
  Speaker 1: So now we have like a definition of information. And
• 35:15
  Speaker 1: again this is just something Claude Shannon made up, but
• 35:18
  Speaker 1: we're gonna see in a moment that actually connects with
• 35:21
  Speaker 1: other concepts in physics.
• 35:23
  Speaker 2: Would you be like taking the expected value of surprisal
• 35:27
  Speaker 2: after accounting for the fact that people might differ in
• 35:29
  Speaker 2: how surprised they are about some like would you have
• 35:33
  Speaker 2: to average different people's surprisal to really get a good
• 35:36
  Speaker 2: sense of the information.
• 35:38
  Speaker 3: That's really cool.
• 35:39
  Speaker 1: Yeah, so something might be information to me but not
• 35:41
  Speaker 1: to you, right Like, what if I'm the one who
• 35:43
  Speaker 1: destroyed the earth and then somebody texts me like the
• 35:46
  Speaker 1: earth blew up today, I'm like, yeah, dude, I know.
• 35:49
  Speaker 1: Then that's not information to me because I already knew happened,
• 35:52
  Speaker 1: but it is information to you. And that kind of
• 35:54
  Speaker 1: makes sense, right, Like, the same bit is not the
• 35:56
  Speaker 1: same amount of information for everybody, depending on what they
• 35:59
  Speaker 1: already knew. God, But there is a concept of expected
• 36:02
  Speaker 1: a surprisal. So if you take the kind of surprise
• 36:05
  Speaker 1: you might get from all the different messages you might
• 36:07
  Speaker 1: get from Daniel, and you average them over how likely
• 36:10
  Speaker 1: you are to get those messages, you get this other formula.
• 36:13
  Speaker 1: And this formula is fascinating because it looks just like
• 36:16
  Speaker 1: the formula we have in physics for calculating entropy.
• 36:20
  Speaker 3: Remember a few.
• 36:21
  Speaker 1: Episodes ago, we talked about what does entropy mean? And
• 36:24
  Speaker 1: we said that entropy was a ratio between basically how
• 36:27
  Speaker 1: much you know and how much you don't know. How
• 36:30
  Speaker 1: many ways can you configure the micro states of a
• 36:32
  Speaker 1: system to be consistent with the macro state you see,
• 36:35
  Speaker 1: So you see that there's particles in a box at
• 36:37
  Speaker 1: a certain temperature. How many ways can you arrange the
• 36:39
  Speaker 1: particles inside? How many different configurations can there be that
• 36:43
  Speaker 1: are consistent with the measurement that you made. And the
• 36:46
  Speaker 1: relationship between the micro states and the macro states is
• 36:49
  Speaker 1: also related by the formula with exactly the same structure
• 36:52
  Speaker 1: as Shannon's formula for average surprisal. So Shannon showed this
• 36:57
  Speaker 1: formula to John von Neumann, famous physicist and mathematics, and
• 37:00
  Speaker 1: he said, oh, you should call this information entropy for
• 37:03
  Speaker 1: two reasons. One because the formula looks the same. It
• 37:06
  Speaker 1: looks like the formula for entropy, and it's conceptually sort
• 37:09
  Speaker 1: of similar. And two because nobody really knows what entropy means,
• 37:12
  Speaker 1: and so they can't argue with you.
• 37:15
  Speaker 2: I like that anything that makes it impossible for people
• 37:19
  Speaker 2: to argue with me, I'm down for exactly.
• 37:22
  Speaker 1: And so in Shannon's information entropy, low information means low entropy.
• 37:28
  Speaker 1: So if you're getting a bunch of signals from Earth,
• 37:30
  Speaker 1: and you're always getting the same high probability message, like
• 37:34
  Speaker 1: the Earth didn't explode today, The Earth didn't explode today.
• 37:37
  Speaker 1: That's low information entropy. You're always getting the same one.
• 37:40
  Speaker 1: But if you're always getting a different message, like maybe
• 37:43
  Speaker 1: instead of getting texts from Daniel about whether the Earth exploded,
• 37:45
  Speaker 1: you're getting pictures from probes that landed on exoplanets, And
• 37:49
  Speaker 1: every time you open one of those, you're like, I
• 37:51
  Speaker 1: have no idea what to expect. Anything I see is
• 37:54
  Speaker 1: going to be new to me, right, and like this
• 37:56
  Speaker 1: one has rocks, and that one has like lava, and
• 37:58
  Speaker 1: that one has aliens on it, and like what is
• 38:00
  Speaker 1: this over here? Oh my gosh, the way like every
• 38:02
  Speaker 1: time we turn on a new telescope we see something
• 38:04
  Speaker 1: weird and surprising in the universe. Right, that's very high
• 38:08
  Speaker 1: information content because there's lots of different possible outcomes, each
• 38:12
  Speaker 1: of which are equally likely, instead of there being like
• 38:15
  Speaker 1: one very likely outcome. So that's high information entropy.
• 38:19
  Speaker 2: Okay, so now let's try to connect to mass. So
• 38:21
  Speaker 2: I'm wondering if an internet made of cat memes, which
• 38:25
  Speaker 2: would be low information, would weigh less than an Internet
• 38:29
  Speaker 2: that reconciles relativity with quantum mechanics, which would be a
• 38:33
  Speaker 2: high information internet. How do you compare those?
• 38:38
  Speaker 1: Yeah, so now we have a definition of information, right,
• 38:42
  Speaker 1: we know how to measure information into something that's low
• 38:44
  Speaker 1: information or high information.
• 38:45
  Speaker 3: And you're right.
• 38:46
  Speaker 1: If you get on the Internet and you see the
• 38:47
  Speaker 1: same cat memes you're always seeing, then that's low information.
• 38:50
  Speaker 1: If somebody says something really new and clever and surprise
• 38:52
  Speaker 1: and you're like, whoa, my gosh, that's high information. That's
• 38:55
  Speaker 1: more entropy. And we're talking about in terms of entropy
• 38:58
  Speaker 1: because we're trying to get a graph on the physical
• 39:01
  Speaker 1: nature of this and the consequences for it.
• 39:03
  Speaker 3: Like does it have mass?
• 39:04
  Speaker 1: Because we know entropy is connected to energy, right, and
• 39:08
  Speaker 1: energy is connected to mass. So can we somehow draw
• 39:10
  Speaker 1: a dotted line between information, cat memes and the weight
• 39:14
  Speaker 1: of the Internet. No, unfortunately not, because increasing the information
• 39:20
  Speaker 1: doesn't increase the mass or the energy of the system.
• 39:23
  Speaker 1: The information content is relative to what you already know,
• 39:26
  Speaker 1: depends on the context. You can arrange a set of
• 39:29
  Speaker 1: sticks or bits on the hard drive to mean one
• 39:31
  Speaker 1: thing or another. It doesn't change the mass or the energy.
• 39:35
  Speaker 1: So it has to do with how you interpret the
• 39:36
  Speaker 1: arrangement of the system and what you already know. It
• 39:39
  Speaker 1: does require some mass and some energy to store that information.
• 39:43
  Speaker 1: You want to put bits on a hard drive, you
• 39:45
  Speaker 1: want to write numbers in the sahara and filled them
• 39:47
  Speaker 1: with kerosene. That definitely costs energy, right, And all stored
• 39:51
  Speaker 1: energy does have some mass, But increasing the information on
• 39:55
  Speaker 1: something doesn't increase its mass. So connecting back to Mark's question,
• 39:58
  Speaker 1: he's asking does data have mass? And data does not
• 40:01
  Speaker 1: have mass? Right, And remember that when you're putting a
• 40:03
  Speaker 1: picture of your dog onto the SD card, you're not
• 40:06
  Speaker 1: like downloading electrons and not flowing onto there. You're just
• 40:08
  Speaker 1: moving electrons up or down. You're just flipping switches on
• 40:12
  Speaker 1: that card, so you're not adding matter to it in
• 40:14
  Speaker 1: any way. You're not changing the energy of the card.
• 40:17
  Speaker 1: You're just flipping a switch, which doesn't require any more
• 40:20
  Speaker 1: or less energy. It requires energy to build a card,
• 40:22
  Speaker 1: and it requires energy to change things on the card.
• 40:25
  Speaker 1: But the card is not heavier because you put a
• 40:27
  Speaker 1: picture of a dog rather than a picture of the
• 40:29
  Speaker 1: Earth or a picture of an exoplanet, or like the
• 40:32
  Speaker 1: equations of quantum gravity, which wuld be very surprising that
• 40:35
  Speaker 1: anybody to find have a lot of information but wouldn't
• 40:38
  Speaker 1: have any more mass than any other arrangement of those
• 40:41
  Speaker 1: electrons or bits or sticks or flaming letters in.
• 40:45
  Speaker 3: The Sahara course lots.
• 40:46
  Speaker 1: But there is one other fascinating connection between information and
• 40:50
  Speaker 1: mass which people may have heard about. It's called the
• 40:53
  Speaker 1: beckensteam bound, which talks about the amount of information you
• 40:57
  Speaker 1: can have in a space, because it turns out there
• 41:00
  Speaker 1: is a limit to how much information you can put
• 41:02
  Speaker 1: in a volume of space, and it turns out that's
• 41:05
  Speaker 1: a black hole. Right, The most information dense arrangement of
• 41:09
  Speaker 1: matter or energy is a black hole. So black holes
• 41:13
  Speaker 1: have the maximum amount of information. It's called the Beckenstein bound.
• 41:17
  Speaker 1: Beckenstein is a student who work with Stephen Hawking. Doesn't
• 41:20
  Speaker 1: get enough credit for hawking radiation and all the black
• 41:22
  Speaker 1: hole work that he did with Hawking, but super genius guy. Now,
• 41:26
  Speaker 1: this doesn't mean, as you often hear in popular science,
• 41:29
  Speaker 1: that if you have too much information something will collapse
• 41:31
  Speaker 1: into a black hole. Like if you download enough amazing
• 41:35
  Speaker 1: pictures of dogs under your computer, it's going to turn
• 41:37
  Speaker 1: into a black hole. That's not the problem. It means
• 41:40
  Speaker 1: that if you need to store a huge amount of information,
• 41:43
  Speaker 1: the only way to do it is a black hole.
• 41:45
  Speaker 1: A black hole is like the most information dense system
• 41:49
  Speaker 1: you can have.
• 41:49
  Speaker 3: So if you need to.
• 41:50
  Speaker 1: Increase the amount of information you're storing, you might need
• 41:53
  Speaker 1: to increase the mass of your system so much so
• 41:55
  Speaker 1: that you get a black hole.
• 41:57
  Speaker 2: Well, you know, DNA is also supposed to be very
• 42:00
  Speaker 2: information dents, and there are people who are arguing that
• 42:02
  Speaker 2: when we can easily print DNA sequences, we might want
• 42:05
  Speaker 2: to start storing data in DNA and sticking it in freezers.
• 42:09
  Speaker 2: That sounds complicated to me, but we'll see what the
• 42:12
  Speaker 2: future holds.
• 42:12
  Speaker 1: Yeah, but DNA is an amazing storage system because it
• 42:15
  Speaker 1: lasts for a long long time compared to hard drives.
• 42:17
  Speaker 1: You put something on a hard drive, you think, oh,
• 42:19
  Speaker 1: it's there, but five years later you come back, it
• 42:21
  Speaker 1: could be totally degraded. So if you have like really
• 42:24
  Speaker 1: valuable information the secrets to quantum gravity are on a
• 42:27
  Speaker 1: hard drive in your closet, make sure you're upgrading those
• 42:30
  Speaker 1: every couple of years because that stuff fades.
• 42:32
  Speaker 2: You are making me very nervous about the videos from
• 42:35
  Speaker 2: my PhD that are still sitting in the closet a
• 42:37
  Speaker 2: decade on that need to be analystt We.
• 42:40
  Speaker 1: Have a real problem with digital storage. People think it's
• 42:42
  Speaker 1: forever because it's ones and zeros, but it's not, and
• 42:45
  Speaker 1: actually a lot of the old analog systems we have
• 42:47
  Speaker 1: last longer. Like my favorite story is computer punch cards.
• 42:51
  Speaker 1: My dad did his graduate thesis on the computer using
• 42:54
  Speaker 1: punch cards. I remember being in the computer room as
• 42:56
  Speaker 1: he would like insert them and pick them up.
• 42:58
  Speaker 3: And the cool thing about punch cards is totally resilient.
• 43:00
  Speaker 1: They'll last a long long time, right, yea, So he
• 43:04
  Speaker 1: still has like stacks of punch cards that you could
• 43:06
  Speaker 1: still run if the computer was around. But nobody has
• 43:09
  Speaker 1: a hard drive from like nineteen eighty four that still works.
• 43:12
  Speaker 1: So back up all your stuff, folks, and don't create
• 43:15
  Speaker 1: black holes. The Mark, you can keep adding pictures of
• 43:17
  Speaker 1: your dog to your SD card without making it heavier.
• 43:21
  Speaker 1: So let's check in with Mark see if that answered
• 43:23
  Speaker 1: his question.
• 43:24
  Speaker 10: Thanks for answering my question, guys. I think I'm fundamentally
• 43:27
  Speaker 10: more enlightened now. I found it interesting how the view
• 43:30
  Speaker 10: on data and mass extended into information value and information
• 43:35
  Speaker 10: entropy and also information density. Pops Bekenstein can have a
• 43:40
  Speaker 10: side hustle selling high density branded SD codes. Anyway, Thanks
• 43:46
  Speaker 10: again and keep up with the good work.
• 43:48
  Speaker 2: All right, everyone, thanks for listening today. If you have
• 43:51
  Speaker 2: a question you want to ask us right to us
• 43:53
  Speaker 2: at Questions at Daniel and Kelly dot org. We answer
• 43:55
  Speaker 2: every question we get, some of them end up on
• 43:58
  Speaker 2: the show, and we'd love to know what you're thinking about.
• 44:00
  Speaker 1: We really do, because it's not just our curiosity it
• 44:03
  Speaker 1: fuels this show. It's your curiosity, your desire, your deep
• 44:06
  Speaker 1: need to understand the nature of this extraordinary universe. So
• 44:10
  Speaker 1: right to us two questions at Daniel and Kelly dot org.
• 44:20
  Speaker 2: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We
• 44:23
  Speaker 2: would love to hear from you, We really would.
• 44:26
  Speaker 1: We want to know what questions you have about this
• 44:29
  Speaker 1: extraordinary universe.
• 44:31
  Speaker 2: We want to know your thoughts on recent shows, suggestions
• 44:34
  Speaker 2: for future shows. If you contact us, we will get
• 44:37
  Speaker 2: back to you.
• 44:38
  Speaker 1: We really mean it. We answer every message. Email us
• 44:41
  Speaker 1: at Questions at danieland Kelly.
• 44:43
  Speaker 2: Dot org, or you can find us on social media.
• 44:46
  Speaker 2: We have accounts on x, Instagram, Blue Sky and on
• 44:49
  Speaker 2: all of those platforms. You can find us at d
• 44:52
  Speaker 2: and Kuniverse.
• 44:54
  Speaker 3: Don't be shy, write to us.