Latest / Daniel and Kelly’s Extraordinary Universe / Physics of the Internet

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Physics of the Internet · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, do you think we could do physics without
• 0:10
  Speaker 1: the Internet.
• 0:11
  Speaker 2: Well, I mean there was a lot of physics done
• 0:13
  Speaker 2: before the internet. So yeah.
• 0:17
  Speaker 1: Do you think the Internet distracts you or helps you?
• 0:19
  Speaker 2: I'm sure it distracts me, but also lets me look
• 0:21
  Speaker 2: stuff up.
• 0:22
  Speaker 1: When you can do physics by just looking stuff up.
• 0:25
  Speaker 2: Sometimes you got to know the mass of the electron
• 0:27
  Speaker 2: and who remembers that stuff? Anyway?
• 0:30
  Speaker 1: Don't you think maybe like Newton would have done a
• 0:33
  Speaker 1: better job if he had the Internet available at the time,
• 0:37
  Speaker 1: or would have been just stug watching cat videos.
• 0:41
  Speaker 2: I think watching cats fall out of trees might have
• 0:44
  Speaker 2: inspired his ideas in gravity even earlier.
• 0:46
  Speaker 1: Oh boy, like he had the original cat video. But
• 0:49
  Speaker 1: I wonder if you would be more popular if we
• 0:50
  Speaker 1: had more cat episodes.
• 0:53
  Speaker 2: I'll drop one cat per episode, I promise, Yes, we
• 0:56
  Speaker 2: need new categories.
• 1:12
  Speaker 1: Hi. I'm morehem and cartoonist and the author of Oliver's
• 1:15
  Speaker 1: Great Big Universe.
• 1:16
  Speaker 2: Hi I'm Daniel. I'm a particle physicist, professor at UC Irvine,
• 1:19
  Speaker 2: and I really wish I had cats.
• 1:22
  Speaker 1: You wish you had cats?
• 1:23
  Speaker 2: I do?
• 1:24
  Speaker 1: Why did you just get some cats?
• 1:25
  Speaker 2: I have kids and they are allergic to cats. Unfortunately,
• 1:28
  Speaker 2: I used to have cats before I had kids. That's
• 1:30
  Speaker 2: easily remedied, Daniel, I'm terrified. Just depends how much you
• 1:36
  Speaker 2: want the cats. You know, well, the kids also want cats,
• 1:39
  Speaker 2: so they're actually taking algae shots in hopes that we
• 1:42
  Speaker 2: can one day have a cat.
• 1:43
  Speaker 1: Uh like those treatments where you get exposed a little
• 1:46
  Speaker 1: bit at a time. M exactly like one cat air
• 1:48
  Speaker 1: at a time.
• 1:49
  Speaker 2: M hmm, just like this podcast is exposing everybody to
• 1:52
  Speaker 2: physics a little bit at a time, inoculating them against
• 1:55
  Speaker 2: the disease.
• 1:57
  Speaker 1: So if you go too strong on this podcast, get
• 2:00
  Speaker 1: the hives.
• 2:00
  Speaker 2: You could get a reaction, but choke, I've seen that reaction.
• 2:04
  Speaker 2: Not pretty.
• 2:04
  Speaker 1: No, yeah, it just makes you sleepy.
• 2:06
  Speaker 2: I guess their mental immune system rises up in defense.
• 2:10
  Speaker 1: It just makes people pass out. We go too deep
• 2:13
  Speaker 1: into particle physics, it acts like Benadrul and just knocks
• 2:19
  Speaker 1: people out. But anyways, welcome to our podcast, Daniel and
• 2:22
  Speaker 1: Jorge Explain the Universe, a production of iHeartRadio.
• 2:25
  Speaker 2: In which we go as deep as we can into
• 2:27
  Speaker 2: particle physics and cosmology and astrophysics and astronomy and all
• 2:31
  Speaker 2: the different kinds of physics that help explain this amazing, beautiful,
• 2:35
  Speaker 2: bonkers universe that we live in. We think it all
• 2:38
  Speaker 2: makes sense, and we want it all to make sense
• 2:40
  Speaker 2: to you.
• 2:41
  Speaker 1: That's why we try to be the hives of curiosity
• 2:43
  Speaker 1: and try to inoculate you against the mysteries of the
• 2:46
  Speaker 1: universe by talking about all of the things that we
• 2:48
  Speaker 1: know and maybe don't know about.
• 2:50
  Speaker 2: The cosmos and physics has always relied on conversation, people
• 2:54
  Speaker 2: talking about how things work, people brainstorming together, people writing
• 2:57
  Speaker 2: elaborate letters to each other about what or it's what
• 3:00
  Speaker 2: in the solar system. Communication has always been an inherent
• 3:03
  Speaker 2: part of physics, and physics has always enabled communication.
• 3:07
  Speaker 1: I guess also, it's not just physics. It's kind of
• 3:09
  Speaker 1: this mix of individual thought and pondering, but also this
• 3:14
  Speaker 1: mix of talking to your peers and sharing your ideas
• 3:17
  Speaker 1: and where you're at.
• 3:18
  Speaker 2: Right, Yeah, exactly. Brainstorming is such an essential part of it.
• 3:22
  Speaker 2: I can't count the number of times I've had a
• 3:23
  Speaker 2: bad idea, suggested it to somebody and it's inspired a
• 3:27
  Speaker 2: better idea in them.
• 3:28
  Speaker 3: Yeah.
• 3:28
  Speaker 1: I guess we all need that person to like check
• 3:30
  Speaker 1: our ideas, right.
• 3:33
  Speaker 2: Yeah, we all need that person have a good idea
• 3:35
  Speaker 2: in response to our dumb idea.
• 3:36
  Speaker 1: That's why I see and then becomes your idea.
• 3:41
  Speaker 2: Then becomes our idea.
• 3:43
  Speaker 1: Did you just reveal your whole plot here for how
• 3:45
  Speaker 1: to exploit graduate students and steal the ideas?
• 3:49
  Speaker 2: Collaborating with graduate students is not a well kept secret.
• 3:53
  Speaker 1: I see you call it collaborating.
• 3:54
  Speaker 2: Got its collaborative.
• 3:56
  Speaker 1: That's a safe word.
• 3:58
  Speaker 2: They get to be first Author's true.
• 4:02
  Speaker 1: But yeah, as you said, it's all about communication, and
• 4:05
  Speaker 1: it seems like communication just for the entire human race
• 4:08
  Speaker 1: has sort of accelerated at lightning speed with the advent
• 4:11
  Speaker 1: of the Internet.
• 4:12
  Speaker 2: Exactly because communication facilitates physics, but also physics discoveries help
• 4:17
  Speaker 2: us find new ways to communicate even faster. More cat
• 4:21
  Speaker 2: videos all day long.
• 4:23
  Speaker 1: I guess even in the old days, like if you
• 4:25
  Speaker 1: sent a letter across the Atlantic, you relied on physics
• 4:28
  Speaker 1: to you know, keep the wagon rolling down to the coast,
• 4:32
  Speaker 1: and then you need physics to keep the boats afloat
• 4:34
  Speaker 1: right as it crosses and takes your letter across the Atlantic.
• 4:38
  Speaker 1: Couldn't you just say everything is physics, like my cereal
• 4:41
  Speaker 1: is physics. It's also chemistry, maybe math.
• 4:46
  Speaker 2: That's right, but physics is also the reason why we're
• 4:48
  Speaker 2: not using wagons in boats anymore. You know, development of
• 4:52
  Speaker 2: electronics meant we could send telegraphs to each other. Cathode
• 4:55
  Speaker 2: raid tubes meant we can invent screens to look at stuff.
• 4:58
  Speaker 2: Radio waves allowed for wireless communication around the planet. Physics
• 5:02
  Speaker 2: has helped change how we communicate.
• 5:04
  Speaker 1: Or I think you just said it. Electronics help change everything,
• 5:07
  Speaker 1: and for that we are thankful to electronic engineers.
• 5:11
  Speaker 2: Perhaps absolutely the Internet relies on engineers, but the principles
• 5:16
  Speaker 2: of physics are what created these new opportunities.
• 5:19
  Speaker 1: Well, I guess I wonder if that's debatable, or maybe
• 5:23
  Speaker 1: it depends on a case by case bases. Like sometimes
• 5:25
  Speaker 1: we like engineers or anyone, discovers an effect and they
• 5:30
  Speaker 1: figure how to use it, and then they discover what's
• 5:32
  Speaker 1: going on behind it. Right, you need to give you an example, No,
• 5:35
  Speaker 1: I can't give you an example.
• 5:38
  Speaker 2: Very persuasive.
• 5:39
  Speaker 1: Yeah, if I ask you for an example, yeah, sure.
• 5:43
  Speaker 2: Well you know, cathode rays we're definitely discovered not by physicists,
• 5:47
  Speaker 2: but then understood by physicists, and then the application of
• 5:50
  Speaker 2: them to developing screens relied on that physics understanding. So
• 5:54
  Speaker 2: cathoid ray tubes, for example, were in sideshows and demonstrations
• 5:57
  Speaker 2: and even like circuses well before JG. Thompson understood that
• 6:01
  Speaker 2: they were electrons.
• 6:02
  Speaker 1: Mmm, so it sort of starts with non physicists, then
• 6:05
  Speaker 1: physicists jump in, we understand it a little bit better,
• 6:08
  Speaker 1: and then we understand it a little bit better enough
• 6:11
  Speaker 1: to use it for things.
• 6:12
  Speaker 2: Yeah, exactly. Or you know, the foundation of modern computing
• 6:16
  Speaker 2: our transistors, and without quantum mechanics, we definitely wouldn't understand
• 6:20
  Speaker 2: all the energy levels and the electron flows and be
• 6:22
  Speaker 2: able to build such miniaturize little switches that definitely run
• 6:25
  Speaker 2: the Internet. So physics is essential there as well.
• 6:28
  Speaker 1: Yeah, so it seems like there's physics in our everyday
• 6:30
  Speaker 1: lives and in our everyday surfing of the web as well.
• 6:34
  Speaker 1: So to the O, the proium will be taging the
• 6:36
  Speaker 1: question what physics is behind the Internet? Wait, there's something
• 6:45
  Speaker 1: behind the Internet. There's a secret cabal, there's death through
• 6:48
  Speaker 1: the Internet.
• 6:50
  Speaker 2: You can only see the surface layer, but us physicists
• 6:52
  Speaker 2: have access to the next dimension of the Internet.
• 6:55
  Speaker 1: WHOA, you make it sound like it's the matrix neo,
• 7:01
  Speaker 1: Is that what this is all about?
• 7:03
  Speaker 2: Yes? This is a secret council of physicists that run
• 7:05
  Speaker 2: the Internet and decide what you see every day.
• 7:09
  Speaker 1: Totally all right, So it seems like that we're going
• 7:12
  Speaker 1: to be talking about some of the physics effects or
• 7:16
  Speaker 1: principles then power the Internet or that make the Internet possible.
• 7:20
  Speaker 2: Yeah, exactly what physics do you have to know if
• 7:22
  Speaker 2: your civilization and you want to build an Internet?
• 7:25
  Speaker 1: Well, as usually, we were wondering how many people out
• 7:27
  Speaker 1: there had thought about this question.
• 7:28
  Speaker 2: Thanks everybody who volunteers, and if you would like to
• 7:31
  Speaker 2: join this group, please don't be shy. Write to me
• 7:33
  Speaker 2: two questions at Daniel and Jorge dot com. We really
• 7:36
  Speaker 2: do want to hear your voice.
• 7:38
  Speaker 1: So think about it for a second. How many physics
• 7:40
  Speaker 1: principles can you name in the use of the Internet.
• 7:44
  Speaker 1: Here's what people have to say.
• 7:46
  Speaker 4: Particle or nuclear physics as World Wide Web was designed
• 7:51
  Speaker 4: for and within SIR at the time. Other than that, well,
• 7:55
  Speaker 4: forty all radio communications to satellze through Wi Fi, all
• 7:59
  Speaker 4: electromagnetics them and for the five cables, all the photone
• 8:03
  Speaker 4: and the crystal stuff, and then the routers and everything.
• 8:08
  Speaker 4: Just all electromagnetism. But there are a lot of solid
• 8:11
  Speaker 4: state physics too, with the storage running the Internet and
• 8:14
  Speaker 4: so on so on.
• 8:16
  Speaker 2: So I think this is all about electrons moving around
• 8:19
  Speaker 2: back and forth to communicate and create ones and zero
• 8:22
  Speaker 2: so that we can transmit information.
• 8:25
  Speaker 5: When I think about the physics behind the Internet, I
• 8:27
  Speaker 5: think of, first off, the power requirements to run all
• 8:30
  Speaker 5: of the data centers and servers and our computers and
• 8:34
  Speaker 5: our desks, And then you think about the infrastructure that
• 8:37
  Speaker 5: supports it, from undersea cables to data cables and fiber
• 8:42
  Speaker 5: optic lines and all of the infrastructure built just to
• 8:46
  Speaker 5: transmit information.
• 8:48
  Speaker 2: Is that physics, Well, physics went into building or designing it.
• 8:52
  Speaker 2: But that's the first thing I think of.
• 8:54
  Speaker 3: There's got to be a whole lot because there's so
• 8:55
  Speaker 3: many elements of the Internet. From the actual signals that
• 8:58
  Speaker 3: we pass, whate that'd be electric or optical or radio
• 9:02
  Speaker 3: or microwave. The actual devices that process backets have micro
• 9:07
  Speaker 3: controllers and storage devices, and I think they need to
• 9:10
  Speaker 3: worry about quantum effects on dot scale. And then we
• 9:14
  Speaker 3: have satellites in orbit that probably need to do corrections
• 9:17
  Speaker 3: for general relativity. So a whole lot of physics.
• 9:20
  Speaker 1: All right, A lot of interesting answers here I feel
• 9:23
  Speaker 1: like at some point that isn't physics behind everything, and
• 9:26
  Speaker 1: isn't mad behind all the physics, etcetera, etcetera. Like you
• 9:30
  Speaker 1: could say, what are the physics behind cereals or herbology.
• 9:37
  Speaker 2: In principle, you might be able to tear the universe
• 9:40
  Speaker 2: apart down to its tiniest little bits, understand those rules,
• 9:43
  Speaker 2: and put it back together to make sense of everything.
• 9:46
  Speaker 2: But in practice that's not the way we do science.
• 9:48
  Speaker 2: To do science at various different layers where things emerge
• 9:52
  Speaker 2: and we discover the rules that guide them. So you know,
• 9:54
  Speaker 2: we have like fluid mechanics, and we have chemistry, and
• 9:57
  Speaker 2: we have economics, and we could in principle say why
• 10:01
  Speaker 2: people buy sneakers is physics, but really it's a different
• 10:03
  Speaker 2: kind of science, government by different kinds of rules. So
• 10:06
  Speaker 2: I don't think it's fair to say everything is physics.
• 10:08
  Speaker 1: Well, these days it seems like the Internet is everything,
• 10:11
  Speaker 1: and say we're going to be talking about some of
• 10:13
  Speaker 1: the technologies behind the Internet and what physics there is
• 10:17
  Speaker 1: behind those technologies exactly.
• 10:20
  Speaker 2: And there are lots of bits of the Internet that
• 10:22
  Speaker 2: really do rely on physics, where understanding of how things
• 10:26
  Speaker 2: work at the smallest scale or revolutions in that understanding
• 10:30
  Speaker 2: have allowed us to do all the great awesome stuff
• 10:32
  Speaker 2: we do online.
• 10:33
  Speaker 1: All right, well, let's start maybe at the beginning of
• 10:36
  Speaker 1: the internet. The Internet, you need computers for that.
• 10:39
  Speaker 2: Yeah, that's right. The Internet is a big connected set
• 10:41
  Speaker 2: of computers. And you're absolutely right. Unique computers in order
• 10:44
  Speaker 2: to have an Internet, and computers actually come out of
• 10:47
  Speaker 2: mechanical engineering, you know, like Ada Lovelass and Charles Babbage
• 10:51
  Speaker 2: back before we had electronics. All modern computers, of course,
• 10:55
  Speaker 2: are digital and electrical, and so you have to understand
• 10:58
  Speaker 2: something about electricity in order to build a modern computer.
• 11:01
  Speaker 1: Well, this kind of raises an interesting question, like what
• 11:03
  Speaker 1: exactly do you call the Internet? Like we all use
• 11:06
  Speaker 1: the word, we all use the internet, but like if
• 11:10
  Speaker 1: you had to define what the Internet is, what would
• 11:13
  Speaker 1: you say it is?
• 11:14
  Speaker 2: I would say the Internet is a bunch of computers
• 11:17
  Speaker 2: all connected on a network with a very specific protocol.
• 11:21
  Speaker 2: The way we send messages back and forth is a
• 11:23
  Speaker 2: very specific algorithm for how to get information from one
• 11:26
  Speaker 2: side of the world to another. So that's what I
• 11:29
  Speaker 2: would call the Internet. You can have other kinds of networks,
• 11:32
  Speaker 2: but this is one specific way to connect everything.
• 11:34
  Speaker 1: It's like the infrastructure that enables you to just plug
• 11:38
  Speaker 1: your computer into the wall so they can talk to
• 11:40
  Speaker 1: other computers. But it's also sort of like the Like
• 11:42
  Speaker 1: you said, the protocol is the software and the standards
• 11:46
  Speaker 1: that everyone agrees to. Like if I want to send
• 11:49
  Speaker 1: a message to someone in Russia, you have to go
• 11:52
  Speaker 1: use certain protocols about how do you call that address?
• 11:56
  Speaker 1: In what format you send stuff? Right, how those computers
• 11:59
  Speaker 1: shake hands and communicate with each other exactly.
• 12:01
  Speaker 2: You basically have to agree to participate in this huge
• 12:04
  Speaker 2: thing called the Internet. And when you plug into the Internet,
• 12:07
  Speaker 2: it's not like mail. It's not like you only get
• 12:09
  Speaker 2: stuff that was sent for you. You get a bunch of
• 12:12
  Speaker 2: stuff sent for other people and you agree to pass
• 12:14
  Speaker 2: it along towards them. So the Internet has this really
• 12:16
  Speaker 2: complex packet switching model for getting data from one side
• 12:20
  Speaker 2: of the world to the other, and everybody that connects
• 12:22
  Speaker 2: to it participates in it. So that's what the Internet is,
• 12:24
  Speaker 2: a bunch of computers connected, of course, but then also
• 12:27
  Speaker 2: the way that everybody agrees to participate.
• 12:30
  Speaker 1: There could be multiple internets for example, right just like
• 12:33
  Speaker 1: for example, there is the US Postal Service, and there's
• 12:35
  Speaker 1: also ups. There's also FedEx. There are like different networks
• 12:39
  Speaker 1: of things that let you move things around that The
• 12:42
  Speaker 1: Internet is one of those things.
• 12:43
  Speaker 2: Yeah, the Internet is one of those things. And back
• 12:45
  Speaker 2: in the day, there used to be multiple different networks,
• 12:48
  Speaker 2: you know, there were these building board services, there were
• 12:50
  Speaker 2: other little local networks. The Internet is really the growth
• 12:53
  Speaker 2: of the global network that ties them all together into
• 12:56
  Speaker 2: one meta network.
• 12:59
  Speaker 1: Well, I just said it requires computers and wires, and
• 13:02
  Speaker 1: some of that requires physics to understand what's going on
• 13:06
  Speaker 1: and also just to kind of squeeze as much data
• 13:09
  Speaker 1: out of these wires and connections as much as possible.
• 13:12
  Speaker 2: Yeah, and at their heart, computers these days are built
• 13:15
  Speaker 2: out of electrical wires and switches. So you have electrical
• 13:19
  Speaker 2: currents are sending information down the wires, and then you
• 13:22
  Speaker 2: have things like transistors that are flipping bits, turning things
• 13:25
  Speaker 2: on and off, making decisions, changing that dynamically. So you
• 13:29
  Speaker 2: don't just have like a fixed circuit that does the
• 13:31
  Speaker 2: same thing every time. You have a programmable circuit. They
• 13:33
  Speaker 2: can also adjust itself and change its own behavior. That's
• 13:37
  Speaker 2: what makes a computer so powerful is that it can
• 13:39
  Speaker 2: do any kind of calculation, not just one fixed kind
• 13:42
  Speaker 2: of calculation. It's like the difference between a piano and
• 13:46
  Speaker 2: a CD of somebody playing one song on the p
• 13:48
  Speaker 2: and o piano lets you play anything, the recording only
• 13:52
  Speaker 2: plays the one song.
• 13:54
  Speaker 1: So where would you say, is a physics in those
• 13:56
  Speaker 1: wires or like, how has physics helped us transmit information faster?
• 14:02
  Speaker 2: Yeah, so understanding electricity has helped us transmit information at
• 14:06
  Speaker 2: the speed of light all the way back to the telegraph,
• 14:09
  Speaker 2: which is definitely not part of the modern Internet, but
• 14:12
  Speaker 2: it's sort of part of the origins of it. That
• 14:14
  Speaker 2: was really a revolution understanding how you could send electrical
• 14:17
  Speaker 2: pulses down wires to wiggle something at the other end
• 14:21
  Speaker 2: using electromagnetism where you're turning magnets on and off to
• 14:24
  Speaker 2: shape this telegraph receiver. This allows us to transmit information
• 14:29
  Speaker 2: at what was effectively instantaneous speeds compared to you know,
• 14:32
  Speaker 2: letters and ponies and carrier pigeons and whatever else they
• 14:36
  Speaker 2: had just before the telegraph. So that really shrunk the
• 14:39
  Speaker 2: whole world. And it's the same principle that operates inside
• 14:42
  Speaker 2: your computer right now to transmit information around the computer
• 14:45
  Speaker 2: and then along the network and then along the cables
• 14:48
  Speaker 2: between the computers, so that understanding of electricity really changed
• 14:52
  Speaker 2: how rapidly we could communicate over long distances.
• 14:55
  Speaker 1: And I think these days it gets even more physics ly,
• 14:58
  Speaker 1: like basically the wires between here and Europe, they're not
• 15:02
  Speaker 1: electrical at this age, right, I think it's either optical
• 15:06
  Speaker 1: fibers or through satellites, right.
• 15:08
  Speaker 2: Yeah, absolutely, Optical fibers are a great way to send information,
• 15:12
  Speaker 2: and for that you don't need to understand electricity. But
• 15:14
  Speaker 2: you do have to understand light, which is of course
• 15:16
  Speaker 2: related to electricity, and you have to understand optics and
• 15:20
  Speaker 2: how to make long tubes of glass and all sorts
• 15:22
  Speaker 2: of stuff. The crucial physics concept of fiber optics is
• 15:26
  Speaker 2: called total internal reflection. But it's not that hard to understand.
• 15:30
  Speaker 2: When light hits a surface like air to glass or
• 15:32
  Speaker 2: air to water or whatever, the way it wiggles on.
• 15:35
  Speaker 2: The two substances on either side of that surface is
• 15:39
  Speaker 2: different because they're different substances. But at the surface in
• 15:43
  Speaker 2: between them, the interface, the electromagnetic field has to line
• 15:46
  Speaker 2: up and make both sides happy. That's why, for example,
• 15:50
  Speaker 2: light bends at an interface. It's the only way to
• 15:53
  Speaker 2: get both sides of the field on both sides of
• 15:56
  Speaker 2: the surface where the wavelengths are different. To line up nicely,
• 16:01
  Speaker 2: the light has to have a different angle on one
• 16:03
  Speaker 2: side of the surface than the other. But if the
• 16:05
  Speaker 2: angle on one side is just right and you pick
• 16:08
  Speaker 2: the materials carefully, then there's actually no way to get
• 16:11
  Speaker 2: the light waves to line up on both sides the
• 16:14
  Speaker 2: wavelength and the coding on a fiber optic cable is
• 16:17
  Speaker 2: too long to get any matches at that boundary. And
• 16:21
  Speaker 2: so because there's no way to have light in the coding,
• 16:24
  Speaker 2: you get total internal reflection because the light goes down
• 16:27
  Speaker 2: the fiber and none of it escapes. So that's some
• 16:30
  Speaker 2: crucial bit of physics for making fiber optics work, which
• 16:33
  Speaker 2: is an essential part of the Internet. And then satellite
• 16:36
  Speaker 2: networks of course rely on wireless technology, so there's physics
• 16:39
  Speaker 2: all over those networks.
• 16:41
  Speaker 1: Yeah, and how you transmit information. But also there's physics
• 16:44
  Speaker 1: in how you actually make computations, right, And like computers
• 16:48
  Speaker 1: are based on transistors and transistors they have their origin
• 16:52
  Speaker 1: in mechanical thinking and logical machines, but nowadays it's all
• 16:56
  Speaker 1: like semiconductors, right, and super super tight almost quantum size devices.
• 17:03
  Speaker 2: Yeah, the origin of them are pretty simple. They're just
• 17:06
  Speaker 2: like a mechanical switch. You want to turn something on,
• 17:09
  Speaker 2: you want to turn something off, You want to set
• 17:10
  Speaker 2: a value in the computer memory, or you want to
• 17:13
  Speaker 2: change how two things are connected to add numbers or
• 17:15
  Speaker 2: subtract numbers. And back in the day, you could build
• 17:18
  Speaker 2: these things using mechanical relays or other sorts of devices.
• 17:22
  Speaker 2: But these days, in order to have very fast computers
• 17:25
  Speaker 2: computers so they can do a lot of calculations, so
• 17:28
  Speaker 2: they can render that cat falling off the tree, or
• 17:30
  Speaker 2: they can support your latest video game or whatever, then
• 17:34
  Speaker 2: you got to miniaturize all those relays because a big
• 17:37
  Speaker 2: mechanical relay it takes time to switch because it's so big.
• 17:40
  Speaker 2: You know, you send the signal to complete the current
• 17:43
  Speaker 2: and the thing like slides over. You know, it takes milliseconds,
• 17:47
  Speaker 2: and that limits how fast you can do calculations. If
• 17:49
  Speaker 2: you need lots of those switches to flip, what you
• 17:52
  Speaker 2: want are small fast switches because the faster they switch,
• 17:55
  Speaker 2: the faster your computer is. And that's why you want
• 17:58
  Speaker 2: to shrink them down because then everything goes faster.
• 18:02
  Speaker 1: And sometimes I think the technology behind these computers of
• 18:07
  Speaker 1: suddenly changes like we went from vacuum tubes, which totally
• 18:11
  Speaker 1: different than how they work now, which is silicon.
• 18:13
  Speaker 2: Wafers exactly because we have new ideas for how to
• 18:16
  Speaker 2: support it. In the end, it's sort of philosophical, like
• 18:19
  Speaker 2: it's just representing information and how that information adjusts itself.
• 18:23
  Speaker 2: In principle, you could do that in lots of different media,
• 18:26
  Speaker 2: lots of different substrates could support computation. And we haven't
• 18:30
  Speaker 2: even gotten into you know, quantum computers, so they're not
• 18:32
  Speaker 2: really even part of the Internet yet. But silicon is
• 18:35
  Speaker 2: a really nice way to do it, but it requires
• 18:37
  Speaker 2: a bunch of techniques all coming together. One is like
• 18:40
  Speaker 2: how to actually build those transistors, and those transistors are
• 18:44
  Speaker 2: built on the principle of semiconductors, like understanding how electrons
• 18:49
  Speaker 2: flow through some materials and don't flow through other materials,
• 18:51
  Speaker 2: and how you can change that by applying voltages on them.
• 18:55
  Speaker 1: Back in the day, they had mechanical computers, right, like
• 18:57
  Speaker 1: you can use machines like leversanical machines to do these computations.
• 19:02
  Speaker 2: Yeah, and principle, you could build a computer out of anything,
• 19:04
  Speaker 2: you know, tubes of plasma in the sun or whatever,
• 19:07
  Speaker 2: as long as you can control it, you can develop
• 19:09
  Speaker 2: logic based on it. The semiconductors are a really nice
• 19:12
  Speaker 2: way to do it because we can miniaturize them because
• 19:14
  Speaker 2: we have the technology from making these very thin wafers
• 19:18
  Speaker 2: of silicon for printing the circuits onto them. And so
• 19:20
  Speaker 2: it's been decades we've been making these things smaller and
• 19:23
  Speaker 2: smaller and smaller. And the way that the transistors actually
• 19:26
  Speaker 2: work relies on a really subtle bit of physics, which
• 19:29
  Speaker 2: in the end is quantum mechanical. Like if we hadn't
• 19:31
  Speaker 2: discovered quantum mechanics, we would not be able to build
• 19:34
  Speaker 2: transistors out of semiconductors.
• 19:36
  Speaker 1: All right, let's get into how quantum physics is maybe
• 19:40
  Speaker 1: changing computers and competitions, and then let's talk about some
• 19:44
  Speaker 1: of the other ways that physics figures into the Internet.
• 19:47
  Speaker 1: But first let's take out a quick break. All right,
• 20:02
  Speaker 1: we're talking about the physics of cat videos. Now, Daniel,
• 20:05
  Speaker 1: is there a physical way to quantify the cuteness of
• 20:07
  Speaker 1: a kitten?
• 20:09
  Speaker 2: See, that's not physics at all, that's sociology or psychology.
• 20:13
  Speaker 2: There are sciences.
• 20:14
  Speaker 1: You know, I feel like you're cherry picking, Like if
• 20:17
  Speaker 1: you want to take credit for it, you call it physics.
• 20:18
  Speaker 1: If you don't want to take credit for it, you
• 20:20
  Speaker 1: call it something else. There's this very suspicious strategy you
• 20:23
  Speaker 1: got here.
• 20:24
  Speaker 2: No, no, no, I would love to take credit for why
• 20:27
  Speaker 2: cats are cute. I would love to be able to
• 20:29
  Speaker 2: explain to you because the weak force works in this way.
• 20:31
  Speaker 2: Therefore your brain thinks cats are cute. But I can't
• 20:34
  Speaker 2: do that. There's no way I can connect particle physics
• 20:37
  Speaker 2: to cats are cute's brain chemistry.
• 20:40
  Speaker 1: There, I see, I see. Well, can you connect particle
• 20:44
  Speaker 1: physics to IP addresses?
• 20:46
  Speaker 2: No, but I can connect particle physics to the World
• 20:48
  Speaker 2: Wide Web. We'll get there eventually.
• 20:50
  Speaker 1: Hmmm, all right, we'll get to that in a minute.
• 20:53
  Speaker 1: But we were talking about quantum mechanics and how they
• 20:56
  Speaker 1: figure into the sort of super tiny transistors that are
• 21:00
  Speaker 1: made out of silicon. But looking a little bit into
• 21:02
  Speaker 1: the future, they might also just totally revolutionize computers with
• 21:06
  Speaker 1: the advent of quantum computers as well. Right in those cases,
• 21:10
  Speaker 1: you're not using silicon transistors, are you.
• 21:13
  Speaker 2: Yeah. Quantum computers can be based on lots of different technologies.
• 21:16
  Speaker 2: They're not fundamentally based on bits the way we think
• 21:19
  Speaker 2: about them. For normal computers, which are these little transistors
• 21:23
  Speaker 2: that can be in the state of zero or one,
• 21:25
  Speaker 2: but they're based on cube bits and a cubit is
• 21:28
  Speaker 2: kind of like a generalization of a classical bit, but
• 21:31
  Speaker 2: it's not necessarily in a state of zero or one.
• 21:33
  Speaker 2: It has probabilities to be in various states, So it's
• 21:36
  Speaker 2: a different kind of computation, like the way that we
• 21:39
  Speaker 2: think about logic and manipulating information. That's one kind of computation,
• 21:44
  Speaker 2: but there are other kinds of computation, ways to take
• 21:47
  Speaker 2: advantage of what the physical world is doing. To extract
• 21:51
  Speaker 2: an answer to.
• 21:51
  Speaker 1: Your question, but do you think all computers will eventually
• 21:54
  Speaker 1: be quantum computers or do you think quantum computers will
• 21:57
  Speaker 1: only be useful in certain applications.
• 22:00
  Speaker 2: There's nothing a quantum computer can do that a classical
• 22:02
  Speaker 2: computer cannot do. It's just a question of can they
• 22:06
  Speaker 2: do it more efficiently. And there are a few examples
• 22:08
  Speaker 2: where people think if you build a large error correct
• 22:11
  Speaker 2: and quantum computer, you can do those calculations faster on
• 22:15
  Speaker 2: quantum computers than normal computers. But they're really very narrow
• 22:18
  Speaker 2: and limited. So even though there's a huge amount of
• 22:21
  Speaker 2: hype about quantum computers. I haven't seen a whole lot
• 22:24
  Speaker 2: of persuasive arguments that quantum computers are anywhere in the
• 22:27
  Speaker 2: near future are going to revolutionize like what we call
• 22:30
  Speaker 2: computing and the kind of problems we can solve. But
• 22:32
  Speaker 2: of course it's naive to say we know everything quantum
• 22:35
  Speaker 2: computers could ever do. It's always exciting to have a
• 22:38
  Speaker 2: new kind of thing, a new kind of computer, and
• 22:40
  Speaker 2: the kinds of things people will do with them aren't
• 22:43
  Speaker 2: things we can imagine right now, so it's definitely valuable research.
• 22:47
  Speaker 2: I just think it's actually more exciting to not know
• 22:50
  Speaker 2: what they're going to be useful for. But right now
• 22:52
  Speaker 2: people feel the need to sell them with a specific
• 22:54
  Speaker 2: killer app, which I think is sometimes a bit overdone.
• 22:58
  Speaker 1: But in terms of making computer smaller and smaller, we
• 23:00
  Speaker 1: are sort of starting to get into the quantum realm, right,
• 23:03
  Speaker 1: Like some of these transistors now that you can fit
• 23:05
  Speaker 1: like billions, bazillions of transistors into a tiny microtschip, Like,
• 23:10
  Speaker 1: the size of these transistors are now getting to the
• 23:12
  Speaker 1: point where you do kind of have to start thinking
• 23:14
  Speaker 1: about the quantum mechanics of it, right, You.
• 23:17
  Speaker 2: Have to think about the quantum mechanics of it no
• 23:18
  Speaker 2: matter the size of your transistor. Like there's quantum mechanics
• 23:22
  Speaker 2: and the basic principles of a transistor, and it all
• 23:25
  Speaker 2: comes from the quantum mechanical understanding of how an atom works.
• 23:29
  Speaker 2: In an individual atom, we know electrons have energy levels.
• 23:32
  Speaker 2: Like the classical picture is you have a proton the
• 23:35
  Speaker 2: nucleus of a hydrogen atom, for example, and electrons exist
• 23:38
  Speaker 2: in various states around it. But the electron has to
• 23:40
  Speaker 2: be in one of these states. It's like specific energy
• 23:43
  Speaker 2: levels that solve all the equations of quantum mechanics. The
• 23:46
  Speaker 2: electron can just have an arbitrary energy. It's like a
• 23:49
  Speaker 2: ladder there. So that's a single atom. It's sort of
• 23:51
  Speaker 2: a simple picture. As you bring a bunch of atoms
• 23:54
  Speaker 2: together to make like a blob of stuff, you know,
• 23:57
  Speaker 2: like silicon or geranium or something else, energy levels get
• 24:00
  Speaker 2: a little fuzzier because now your electrons are interacting with
• 24:03
  Speaker 2: more than one nucleus. So instead of having the same
• 24:06
  Speaker 2: crisp energy levels from a single atom, now you have
• 24:09
  Speaker 2: these bands of energy levels the electrons can live in,
• 24:12
  Speaker 2: like more energy levels with finer steps between them, but
• 24:15
  Speaker 2: then also groups of them like lower energy levels, and
• 24:18
  Speaker 2: then a band of higher energy levels. Those bands of
• 24:21
  Speaker 2: energy levels, rather than just some simple tomic spacing, is
• 24:24
  Speaker 2: the physics behind why some materials are conductors and some
• 24:27
  Speaker 2: are insulators. The lower bands are usually full, so electrons
• 24:31
  Speaker 2: can't move like if you're packed into a totally full elevator.
• 24:34
  Speaker 2: To move as an electron, you have to jump into
• 24:37
  Speaker 2: an empty upper band. So insulators tend to have a
• 24:39
  Speaker 2: big gap between the bands, so electrons are mostly stuck
• 24:43
  Speaker 2: in the lower bands and can't move around in the
• 24:45
  Speaker 2: empty bands above. Conductors have a small gap, so it's
• 24:48
  Speaker 2: easy for the electrons to jump up and move freely.
• 24:51
  Speaker 2: Semiconductors have an intermediate gap that can be tweaked and
• 24:54
  Speaker 2: tuned by adding various materials to the silicon, so that
• 24:57
  Speaker 2: lets you do clever material engineering to make things like
• 25:00
  Speaker 2: one way path for electrons from one sized gap to another.
• 25:04
  Speaker 2: That's what a diode is. You can put the diodes
• 25:06
  Speaker 2: together and the materials together in more complex ways, and
• 25:09
  Speaker 2: you get like a transistor, which is basically a quantum
• 25:12
  Speaker 2: mechanical switch, and that's the basis of all modern computing
• 25:16
  Speaker 2: right right.
• 25:17
  Speaker 1: But I wonder if that's more in a classical physics side.
• 25:20
  Speaker 1: I mean, I know you need quantum mechanics to understand
• 25:22
  Speaker 1: in that, but like you don't need to know the
• 25:24
  Speaker 1: Heisenberg uncertainty principle to make a vacuum tube work.
• 25:27
  Speaker 2: For example, you don't need to know the Heisenberg and
• 25:29
  Speaker 2: certain principle to make a vacuum tube work. That's true.
• 25:31
  Speaker 2: You can build switches without quantum mechanics, but if you
• 25:33
  Speaker 2: want to build them out of transistors, which is crucial
• 25:35
  Speaker 2: for making them really really small, then you got to
• 25:38
  Speaker 2: know the quantum mechanics. You got to understand how to
• 25:40
  Speaker 2: make a conductor, an insulate, or a semiconductor, all these
• 25:44
  Speaker 2: kind of things. These are are the foundation of modern
• 25:46
  Speaker 2: transistors right.
• 25:47
  Speaker 1: Right, But like to make one work, like the early transistors,
• 25:51
  Speaker 1: you didn't really need to be thinking about wave functions
• 25:54
  Speaker 1: or probabilities to make them work and use them.
• 25:59
  Speaker 2: The first solid state transistors which are built out of
• 26:01
  Speaker 2: semic conductors, you absolutely did. The previous ones that are
• 26:04
  Speaker 2: not solid state, that are like mechanical, those you don't
• 26:07
  Speaker 2: need to understand quantum mechanics.
• 26:09
  Speaker 1: Yeah, you need physics to understand everything, Daniel, like to
• 26:14
  Speaker 1: use them like it might be first computers or even
• 26:17
  Speaker 1: like my phone today doesn't really take into account things
• 26:22
  Speaker 1: like the wave functions of the atoms and the transistors.
• 26:25
  Speaker 2: Do they Your phone has transistors which are based on semiconductors,
• 26:29
  Speaker 2: and understanding the energy level of semiconductors requires quantu mechanics. Absolutely.
• 26:33
  Speaker 2: You can't do that with classical physics.
• 26:35
  Speaker 1: Understanding them, yes, but to make them work. And what
• 26:37
  Speaker 1: I'm saying is we haven't needed to really dig into
• 26:42
  Speaker 1: the quantum mechanics. But as these transitionors get even smaller,
• 26:45
  Speaker 1: they are going to be even more important to know
• 26:48
  Speaker 1: that the quantum mechanics that are happening.
• 26:50
  Speaker 2: Yeah, I think quantum mechanics is going to continue to
• 26:52
  Speaker 2: be vital. I think the issue for getting them even
• 26:54
  Speaker 2: smaller is the technology of just making them smaller, Like
• 26:58
  Speaker 2: can you physically build these things, like actually assemble this
• 27:00
  Speaker 2: device that has like a single row of atoms here
• 27:03
  Speaker 2: in a single row of atoms there. I think the
• 27:05
  Speaker 2: quantum mechanics actually becomes a little simpler as they get smaller,
• 27:09
  Speaker 2: because you have fewer atoms to deal with.
• 27:13
  Speaker 1: All right, Well, so then that's the physical substrate on
• 27:17
  Speaker 1: which the Internet is based on. I think you're also
• 27:20
  Speaker 1: trying to make the argument that the communication. Part of
• 27:24
  Speaker 1: it also depends on physics.
• 27:26
  Speaker 2: Yeah, once you have these computers and they're cranking along
• 27:28
  Speaker 2: and they're doing their calculations on their silicon chips, then
• 27:31
  Speaker 2: you want to stick them together. Right, it's not on
• 27:33
  Speaker 2: the Internet if they're not stuck together. And the way
• 27:35
  Speaker 2: you connect them is with these wires or the fiber
• 27:38
  Speaker 2: optics or the satellites, and that's sending information. And all
• 27:42
  Speaker 2: of those technologies, even just electrical pulses, fiber optics, satellite technology,
• 27:48
  Speaker 2: all that relies on some understanding of physics. In each case,
• 27:52
  Speaker 2: it was a breakthrough in physics that allowed us to
• 27:55
  Speaker 2: create some new technology to connect our computers together. What well,
• 28:00
  Speaker 2: let's talk about fiber optics. As you say, fiber optics
• 28:02
  Speaker 2: are crucial for sending information across the oceans or even
• 28:06
  Speaker 2: just around your neighborhood. Like in my neighborhood, it's all
• 28:08
  Speaker 2: fiber optics that connects houses to houses and to those backbones.
• 28:13
  Speaker 2: And that's because it's very robust. Having fiber optics requires
• 28:16
  Speaker 2: optics and then also requires lasers to send pulses down
• 28:20
  Speaker 2: those fiber optics, you need like tiny little mini lasers,
• 28:23
  Speaker 2: which rely again on quantum mechanical principles to send those
• 28:27
  Speaker 2: pulses down these crazy glass tubes. And that's where lasers
• 28:31
  Speaker 2: are super important. The physics of lasers is also fundamentally
• 28:34
  Speaker 2: quantum mechanical. Again, you have some kind of atom with
• 28:37
  Speaker 2: specific energy levels. That's quantum mechanics, and these atoms can
• 28:42
  Speaker 2: emit and absorb specific frequencies of light. And then if
• 28:45
  Speaker 2: you add a pumping source that can excite the atoms
• 28:48
  Speaker 2: to some high energy state, so they emit that light
• 28:51
  Speaker 2: and put the whole thing in a cavity that has
• 28:53
  Speaker 2: a resonance at that frequency of light. Then you get
• 28:56
  Speaker 2: the laser effect self oscillating because of all that optical feedback.
• 29:00
  Speaker 2: That's super cool because you can get a coherent beam
• 29:03
  Speaker 2: of light, one that has only one frequency and is
• 29:07
  Speaker 2: super collimated. That's perfect for optical communications.
• 29:11
  Speaker 5: Yeah.
• 29:11
  Speaker 1: Interesting, Although as an engineer, Daniel, I just feel like
• 29:16
  Speaker 1: I have to plug think the plug for engineers, Like,
• 29:19
  Speaker 1: I wonder if you dig into the history of it
• 29:21
  Speaker 1: like that, maybe the person who first started using lasers
• 29:24
  Speaker 1: for communications, or the person to figure out you can
• 29:27
  Speaker 1: make fiber optics, Like I wonder if you can actually
• 29:30
  Speaker 1: drill down and say, oh, the person who came up
• 29:32
  Speaker 1: with that idea was an optical engineer, not actually a physicist,
• 29:36
  Speaker 1: or like a materials engineer, not actually a physicist, although
• 29:39
  Speaker 1: obviously engineers are all trained in physics to some degree.
• 29:44
  Speaker 2: Yeah, you know, I'm not a big fan of drawing
• 29:46
  Speaker 2: dotted lines between groups of people and putting labels on them.
• 29:49
  Speaker 2: In the end, it's just smart people being curious and
• 29:52
  Speaker 2: trying to make new stuff. In the case of the laser,
• 29:55
  Speaker 2: I think it really was driven by physicists. You know,
• 29:57
  Speaker 2: It's like Charles Towns thought about that a mazer first,
• 30:01
  Speaker 2: and then later on people developed into a laser. And
• 30:04
  Speaker 2: this is all research down at Bell Labs and at Berkeley,
• 30:07
  Speaker 2: and these are academic physicists that invented these ideas for
• 30:11
  Speaker 2: the laser. At least in the case of fiber optics,
• 30:13
  Speaker 2: I think there's definitely a lot of engineering that goes
• 30:16
  Speaker 2: into that. You know, you might have the basic principle
• 30:18
  Speaker 2: from physics, but then actually making these fibers that like
• 30:22
  Speaker 2: go for miles and miles without losses is really pretty
• 30:25
  Speaker 2: impressive amount of engineering. So it's definitely you know, a
• 30:28
  Speaker 2: beautiful duet of skills.
• 30:30
  Speaker 1: All right. Yeah, so, like you said, lasers and optics.
• 30:33
  Speaker 1: There's also like radio ways, right, we use radio ways
• 30:35
  Speaker 1: to communicate as well.
• 30:36
  Speaker 2: Yeah, most people who are listening to us right now
• 30:38
  Speaker 2: are probably receiving that information not through wired communications but
• 30:43
  Speaker 2: wireless communication. And back in the day, radio was the
• 30:47
  Speaker 2: breakthrough that allowed us to communicate across oceans and to
• 30:50
  Speaker 2: receive music in your house in your radio. But these
• 30:53
  Speaker 2: days even just Wi fi is essentially an extension of radio.
• 30:57
  Speaker 2: We're sending information via electromagnet radiation.
• 31:01
  Speaker 1: Yeah, it's pretty wild, right, Like Wi fi is such
• 31:03
  Speaker 1: a common household word. My kids use it all the time.
• 31:07
  Speaker 1: But really you're talking about radio waves being shot everywhere
• 31:10
  Speaker 1: on all around.
• 31:11
  Speaker 2: This yeah, exactly. And to orient you radio waves on
• 31:14
  Speaker 2: your FM dial, for example, those are like eighty eight
• 31:18
  Speaker 2: or up to like rockin one o eight or whatever.
• 31:20
  Speaker 2: Those are all megahertz frequencies. So you know, ninety three
• 31:23
  Speaker 2: point seven means ninety three point seven megahertz. That's the
• 31:26
  Speaker 2: frequency of the radio wave that's being used to transmit
• 31:30
  Speaker 2: you information. But that's just the frequency of the light.
• 31:33
  Speaker 2: If the frequency was in another range, it would be
• 31:35
  Speaker 2: visible light that you could see it. If it was
• 31:38
  Speaker 2: in a different range, it would be Wi Fi. So
• 31:40
  Speaker 2: Wi Fi is in like two and a half gigahertz
• 31:43
  Speaker 2: or these days the five gene networks or five gigaherts,
• 31:46
  Speaker 2: so much higher frequency, but still basically radio waves.
• 31:50
  Speaker 1: Yeah, I always wonder, like what if our eyes could
• 31:52
  Speaker 1: somehow see radio waves or see like a different range
• 31:56
  Speaker 1: of frequencies of light, Like wou would just be walking
• 31:58
  Speaker 1: around with like bright lights and pulsing lights everywhere all
• 32:02
  Speaker 1: around this.
• 32:03
  Speaker 2: It's sort of amazing. We can only see a tiny
• 32:05
  Speaker 2: slice of the spectrum. Of course, the slice that we
• 32:07
  Speaker 2: can see happens to be also the most common kind
• 32:10
  Speaker 2: of light. Our ability to see light peaks where the
• 32:13
  Speaker 2: sun is the brightest, so that's not a coincidence. But
• 32:16
  Speaker 2: there are other species out there with the capacity to
• 32:19
  Speaker 2: see light into the UV or down into the infrared.
• 32:22
  Speaker 2: So it's not like only humans that can see things obviously.
• 32:25
  Speaker 1: Yeah, but like if you could see light in that frequency,
• 32:28
  Speaker 1: you would hold up your phone and sometimes it would
• 32:30
  Speaker 1: glow a little bit more or start pulsing a little
• 32:33
  Speaker 1: bit more than when it's sending these signals out exactly.
• 32:36
  Speaker 2: And when we look out into the universe, we have
• 32:38
  Speaker 2: infrared telescopes, we have X ray telescopes, we have UV telescopes.
• 32:42
  Speaker 2: They all see different things out there in the night sky.
• 32:45
  Speaker 2: The night sky looks very different in the infrared as
• 32:48
  Speaker 2: it does invisible light, or it does in the UV.
• 32:51
  Speaker 2: So if we have the ability to see those things,
• 32:53
  Speaker 2: we would see lots of other stuff going on all
• 32:55
  Speaker 2: the time, and then we might give a second thought
• 32:57
  Speaker 2: to like filling our world with these waves. We wouldn't
• 33:01
  Speaker 2: build a communication system that relied on flashing visible light everywhere.
• 33:06
  Speaker 2: That would just drive people crazy. So it's sort of
• 33:08
  Speaker 2: an advantage that it's not visible to us, because then
• 33:10
  Speaker 2: we can use it to invisibly send information.
• 33:13
  Speaker 1: Yeah, I guess if you had the idea to make
• 33:15
  Speaker 1: your cell phone work using visible light, it would be
• 33:18
  Speaker 1: kind of a terrible idea. I mean, you'd be basically
• 33:23
  Speaker 1: doing like a morph code between ships.
• 33:26
  Speaker 2: But there's also a lot of clever engineering in making
• 33:29
  Speaker 2: like cellular phones work. Wi Fi is one thing, it's
• 33:32
  Speaker 2: a certain band of information, but cell phones work and
• 33:35
  Speaker 2: different frequencies, and there's a lot of really clever ideas
• 33:38
  Speaker 2: to making your cell phone work.
• 33:40
  Speaker 1: Well, maybe can you talk about how the antenna in
• 33:44
  Speaker 1: my cell phone works? Like, is it like a little
• 33:46
  Speaker 1: tiny flashlight that just emits light at a certain frequency.
• 33:49
  Speaker 1: Or is it more like the traditional radio antennas.
• 33:52
  Speaker 2: It's more like a traditional radio antenna. Basically, the way
• 33:55
  Speaker 2: you emit electromagnetic radiation hasn't changed. You take a bunch
• 33:59
  Speaker 2: of electrons, you wiggle them back and forth, and wiggling
• 34:02
  Speaker 2: electrons makes wiggles in the electromagnetic field. Because information takes
• 34:07
  Speaker 2: time to propagate. You move an electron up, the field changes,
• 34:10
  Speaker 2: but not instantly at a distance. So you move it
• 34:13
  Speaker 2: up and down, up and down, up and down. Then
• 34:15
  Speaker 2: the electric field is changing and is changing up and down,
• 34:19
  Speaker 2: up and down, up and down. And so that's basically
• 34:21
  Speaker 2: how you create electromagnetic radiation. You wiggle it a fast frequency,
• 34:25
  Speaker 2: you get high frequency radiation. You wiggle it slowly, you
• 34:28
  Speaker 2: get low frequency radiation. That's the way you generate electromagnetic
• 34:33
  Speaker 2: radiation in your antenna. That's also the way you can
• 34:35
  Speaker 2: receive it. You got electrons in the antenna, they are
• 34:38
  Speaker 2: wiggled by incoming radiation. You detect that and you pick
• 34:41
  Speaker 2: up the signal.
• 34:43
  Speaker 1: It seems almost very primitive, right.
• 34:45
  Speaker 2: Yes, it's sort of old school.
• 34:47
  Speaker 1: All right, Well, let's get into some of the other
• 34:49
  Speaker 1: technologies in your cell phone and how those depend and
• 34:53
  Speaker 1: maybe not depend on physics and or engineers. So it's
• 34:57
  Speaker 1: to that. But first let's take a quick break. All right,
• 35:12
  Speaker 1: we're talking about the physics of the Internet and now
• 35:15
  Speaker 1: specifically about the physics in your cell phone. And we
• 35:17
  Speaker 1: talked about the antennas and how Wi Fi works, but
• 35:21
  Speaker 1: there's also other interesting physics in other parts of your
• 35:24
  Speaker 1: cell phone.
• 35:25
  Speaker 2: Yeah. Wi Fi is a certain frequency, and you know
• 35:27
  Speaker 2: how your phone can be connected to your house Wi
• 35:29
  Speaker 2: Fi and you get all sorts of good stuff at
• 35:32
  Speaker 2: very high speeds. But then when you're out and about
• 35:34
  Speaker 2: and there isn't Wi Fi, you can connect to your
• 35:36
  Speaker 2: cell phone data network and it's a completely different way
• 35:40
  Speaker 2: to receive information that relies on the same physical principles.
• 35:43
  Speaker 2: It's still basically radio packets, though it's at a different frequency.
• 35:47
  Speaker 2: So whereas Wi Fi is like two and a half
• 35:49
  Speaker 2: or five gigaherts, cell phones receive data like nine hundred
• 35:53
  Speaker 2: megahertz ish. But as you're walking around they do something
• 35:56
  Speaker 2: that seems kind of magical, Like you walk down the street,
• 35:59
  Speaker 2: you try to with your friend, You're getting further and
• 36:01
  Speaker 2: further away from that antenna that's sending you information and
• 36:04
  Speaker 2: receiving information. All of a sudden you're closer to another
• 36:07
  Speaker 2: antenna and you don't even notice, you don't even care,
• 36:10
  Speaker 2: you're watching that cat video or talking to your friend.
• 36:12
  Speaker 2: It just is all smooth and seamless. That's accomplished through
• 36:15
  Speaker 2: a lot of really clever engineering to hand that call
• 36:18
  Speaker 2: off from one tower to the next tower.
• 36:21
  Speaker 1: Now, can you explain, Daniel, what in these cell phone
• 36:24
  Speaker 1: companies what they mean by like five G, seven G LTE.
• 36:28
  Speaker 1: Is that all different physical technologies like higher, faster, more accurate,
• 36:33
  Speaker 1: or is it just like the protocols are getting more sophisticated.
• 36:37
  Speaker 2: Five G means fifth generation and so in some senses,
• 36:40
  Speaker 2: like a change in the underlying technology that we're using.
• 36:43
  Speaker 2: It's a change in the frequency of that radiation we're
• 36:46
  Speaker 2: using to go from like three D to four G
• 36:49
  Speaker 2: or LTE, is a change in the protocols, like how
• 36:52
  Speaker 2: they're handing them off from one to the other, how
• 36:54
  Speaker 2: they're building that information into the packets that get sent
• 36:57
  Speaker 2: back and forth between the phone and the tower. That's
• 37:00
  Speaker 2: all engineering.
• 37:01
  Speaker 1: Well, it's all engineering. It's not just then a sort
• 37:06
  Speaker 1: of our antenna and our radio ways there's also other
• 37:08
  Speaker 1: interesting physics in your phone, like even just like how
• 37:12
  Speaker 1: your phone knows which way you're holding it.
• 37:14
  Speaker 2: Yeah, your phone can do something pretty cool, which is
• 37:16
  Speaker 2: can measure your location. But it could also, for example,
• 37:19
  Speaker 2: measure your acceleration. So there's two things there that your
• 37:22
  Speaker 2: phone can do. One is it can sense its direction.
• 37:25
  Speaker 2: It's got like a little tiny gyroscope in it. But
• 37:27
  Speaker 2: also it's got an accelerometer, so it can measure basically
• 37:31
  Speaker 2: whether you are speeding up or slowing down. You know, fundamentally,
• 37:34
  Speaker 2: the principle of relativity says you can't measure your velocity.
• 37:38
  Speaker 2: There's no absolute velocity. So if you're on a train,
• 37:41
  Speaker 2: or if you're standing on the ground, or if you're
• 37:43
  Speaker 2: an airplane, your phone can't tell I mean other than
• 37:46
  Speaker 2: like measuring your location using GPS. But just on the phone,
• 37:50
  Speaker 2: it can tell if you're accelerating. It can tell if
• 37:52
  Speaker 2: you're speeding up. You can tell if you're slowing down.
• 37:54
  Speaker 2: It can tell if you're like crashed, because that's a
• 37:56
  Speaker 2: moment of severe deceleration. And to do that, he uses
• 38:00
  Speaker 2: a very old school kind of physics sensor.
• 38:03
  Speaker 1: Right, it's just basically like a weight at the end
• 38:05
  Speaker 1: of a spring.
• 38:06
  Speaker 2: Yeah, exactly. Like if you were in the back of
• 38:08
  Speaker 2: a pickup truck and you had a bowling ball, you
• 38:10
  Speaker 2: could tell when the person hit the gas because the
• 38:12
  Speaker 2: bowling ball would roll towards the back of the truck,
• 38:14
  Speaker 2: And you could tell when they hit the brake because
• 38:16
  Speaker 2: the bowling ball would roll towards the front of the truck.
• 38:18
  Speaker 2: So all you need is some sort of mass and
• 38:21
  Speaker 2: for it to be not connected to the rest of
• 38:23
  Speaker 2: the truck or in this case of the phone. So
• 38:26
  Speaker 2: inside your phone they have something that's kind of like that.
• 38:28
  Speaker 2: It's not a bowling ball, but it's a big blob
• 38:30
  Speaker 2: of metal. It's basically balanced on a very fragile spring,
• 38:34
  Speaker 2: and when you accelerate your phone, that metal is like
• 38:37
  Speaker 2: left behind a little bit, and when you break, that
• 38:40
  Speaker 2: metal keeps going a little bit. And inside the accelerometer,
• 38:44
  Speaker 2: it measures the position of this slab of metal relative
• 38:47
  Speaker 2: to the rest of the circuit board, and so it
• 38:48
  Speaker 2: can tell when you're accelerating it. So if you like
• 38:51
  Speaker 2: shake your phone, it can tell that you're shaking your
• 38:53
  Speaker 2: phone in frustration.
• 38:55
  Speaker 1: Right, but it's not just shaking like dun't. Cellphones also
• 38:57
  Speaker 1: use excelerometers to measure the direction of gravity and to
• 39:00
  Speaker 1: tell which ways up and down and whether you're holding
• 39:03
  Speaker 1: your phone like horizontally or vertically. They use excelometis for that.
• 39:06
  Speaker 2: Right Yeah, And principle, you could measure the gravity of
• 39:08
  Speaker 2: the Earth because that's basically an accelerometer. If you jumped
• 39:12
  Speaker 2: off a building, you'd be in free fall. There's no
• 39:13
  Speaker 2: gravity for you to measure. You just naturally following the
• 39:16
  Speaker 2: curvature or space and time. But if you're standing on
• 39:19
  Speaker 2: the Earth, the Earth is pushing you up against your
• 39:22
  Speaker 2: natural inclination to follow that curvature, and that's acceleration. And
• 39:27
  Speaker 2: so what you actually measure as gravity on the surface
• 39:29
  Speaker 2: of the Earth is really the acceleration of the surface
• 39:32
  Speaker 2: of the Earth relative to the natural motion in curved space.
• 39:37
  Speaker 1: Pretty cool. And you also made me think of your
• 39:39
  Speaker 1: GPS and your phone also requires basically a special or
• 39:43
  Speaker 1: general relativity to make that work, right.
• 39:45
  Speaker 2: Yeah. The network of satellites that tell you where you
• 39:48
  Speaker 2: are and where you can go to get your boba
• 39:50
  Speaker 2: or whatever. Those are very precise locations. You get messages
• 39:54
  Speaker 2: from those satellites, and your phone reconstructs your location based
• 39:57
  Speaker 2: on like the pulses and the information those satellites, and
• 40:00
  Speaker 2: they have to be very, very precise in order for
• 40:03
  Speaker 2: you to have precise timing information. And those things are
• 40:06
  Speaker 2: moving far above the surface of the Earth where time
• 40:10
  Speaker 2: flows differently because space is not as curved in their
• 40:13
  Speaker 2: orbits as it is down here on Earth. If you
• 40:16
  Speaker 2: don't account for that in all of your calculations, then
• 40:18
  Speaker 2: all the clocks get out of sync and you don't
• 40:20
  Speaker 2: make it to your Bobas store before it closes.
• 40:22
  Speaker 1: Which I know is a primary concern of yours at
• 40:25
  Speaker 1: all times. And Daniel, you're always trying to get that Buba. Yeah,
• 40:30
  Speaker 1: it's like they try to make GPS work, but it
• 40:33
  Speaker 1: didn't work, and then they realize they needed to take
• 40:35
  Speaker 1: into account like the curvature of space around the Earth, right,
• 40:38
  Speaker 1: and the way that time slows down for things that
• 40:41
  Speaker 1: are closer to Earth and further away from Earth.
• 40:44
  Speaker 2: Right. Yeah, exactly, Clocks on the surface of the Earth
• 40:46
  Speaker 2: run more slowly because we are deeper in a gravitational well,
• 40:50
  Speaker 2: there's a greater curvature of space and time here on
• 40:53
  Speaker 2: the surface of the Earth than there is up in
• 40:55
  Speaker 2: orbit in space where the curvature is less, and so
• 40:58
  Speaker 2: time runs more naturally it runs faster, so you got
• 41:01
  Speaker 2: to take that into account.
• 41:02
  Speaker 1: Yeah, and then I guess the last category is sort
• 41:04
  Speaker 1: of like a power in your cell phone that also
• 41:07
  Speaker 1: requires a lot of physics.
• 41:09
  Speaker 2: Yeah, if you build a computer, then it requires power.
• 41:12
  Speaker 2: You know, you got to plug it into the wall.
• 41:13
  Speaker 2: And if you're running a bitcoin farm somewhere, of course,
• 41:16
  Speaker 2: then you know it takes a significant amount of power
• 41:19
  Speaker 2: to do computation. And in the end, this comes down
• 41:23
  Speaker 2: to thermodynamics, which of course is a fundamental part of physics. Essentially,
• 41:28
  Speaker 2: if you have a computer, doing computation means changing the state.
• 41:32
  Speaker 2: You want to flip a bit from zero to one,
• 41:34
  Speaker 2: you want to change a circuit. Anytime you do that,
• 41:37
  Speaker 2: anytime you change the configuration of an object that's doing
• 41:41
  Speaker 2: work that requires moving something, it takes energy to flip
• 41:45
  Speaker 2: a bit, or to move those electrons to create the
• 41:47
  Speaker 2: conduction channels inside your transistor. All that stuff takes energy,
• 41:51
  Speaker 2: which means it's always, always, always going to generate waste heat.
• 41:56
  Speaker 2: That's what thron dynamics tells us that you can't do
• 41:58
  Speaker 2: anything without creating weight, heat and silicon awayfirst, when they're
• 42:02
  Speaker 2: doing computation, generate a lot of heat so you know,
• 42:05
  Speaker 2: like one hundred watts boils off of a silicon chip
• 42:08
  Speaker 2: as it's cook and as it's doing its thing, And
• 42:11
  Speaker 2: so it takes a lot of power to do computation.
• 42:15
  Speaker 2: And one thing that the Internet has enabled specifically is
• 42:18
  Speaker 2: not just putting a bunch of computers on the Internet,
• 42:20
  Speaker 2: so you can send stuff back and forth to each other,
• 42:22
  Speaker 2: but you can do computing remotely. If I have a
• 42:25
  Speaker 2: calculation I want to do, I don't need to do
• 42:27
  Speaker 2: it on my computer. I can send it to a
• 42:29
  Speaker 2: bunch of computers up at Berkeley or down at Livermore
• 42:32
  Speaker 2: or somewhere else. Basically cloud computing. Amazon has these huge
• 42:36
  Speaker 2: data centers filled with computers that people can use at
• 42:40
  Speaker 2: a moment's notice because the Internet basically means that they're
• 42:43
  Speaker 2: right there with us. That also means that it's simpler
• 42:45
  Speaker 2: to have access to vast quantities of computing. You don't
• 42:48
  Speaker 2: have to build your own computing center to have a
• 42:51
  Speaker 2: lot of computing power, and that's become very very popular.
• 42:54
  Speaker 2: I use it in my research all the time. Cern
• 42:57
  Speaker 2: for example, has an enormous set of computers all around
• 43:00
  Speaker 2: the world that work together to solve problems. But as
• 43:03
  Speaker 2: these computer centers get bigger and bigger, of course they
• 43:06
  Speaker 2: draw more and more power. Projections suggest that these data
• 43:10
  Speaker 2: centers are going to keep sucking energy and it's going
• 43:12
  Speaker 2: to keep growing. The networks, of course, also use energy.
• 43:16
  Speaker 2: It's not just like free to send information down the wire.
• 43:19
  Speaker 2: You've got to create a pulse. That's power that takes energy.
• 43:24
  Speaker 2: One projection I read suggested that by twenty thirty, more
• 43:27
  Speaker 2: than twenty percent of all electricity demand will come from
• 43:32
  Speaker 2: the internet, data centers, consumer devices. Production of these things,
• 43:36
  Speaker 2: like actually building these things takes energy, and then just
• 43:40
  Speaker 2: running the networks altogether, these things are going to take
• 43:43
  Speaker 2: more than twenty percent of our energy budget. It's dominated
• 43:46
  Speaker 2: by the networks and by the data centers. You also
• 43:50
  Speaker 2: got to spend energy to cool these things, like they
• 43:53
  Speaker 2: are generating waste heat, which means that they're using power.
• 43:56
  Speaker 2: But then you also need to keep them cool because
• 43:58
  Speaker 2: they melt themselves down. They're no long we're going to
• 44:00
  Speaker 2: be able to do any computation. So there's like air
• 44:03
  Speaker 2: cooling and water cooling, and that involves again more heat
• 44:07
  Speaker 2: transfer and more power, which takes more energy. So all
• 44:11
  Speaker 2: this stuff is not free. The internet costs a lot
• 44:14
  Speaker 2: of power, and as we move into a future where
• 44:17
  Speaker 2: using power has significant consequences for our climate and for
• 44:21
  Speaker 2: our globe, we got to make sure we're not just
• 44:23
  Speaker 2: like spending a huge amount of power to make cavideos.
• 44:25
  Speaker 2: So there's real consequences there. Power is a very important
• 44:29
  Speaker 2: part of the Internet, and understanding how that works in
• 44:32
  Speaker 2: the end comes down to the basic thermodynamics of how
• 44:35
  Speaker 2: computing really works.
• 44:37
  Speaker 1: All right, well, I guess that's another interesting reminder that
• 44:40
  Speaker 1: there's physics everywhere, including on the thing that probably most
• 44:43
  Speaker 1: humans use nowadays the most.
• 44:47
  Speaker 2: That's right, physics has enabled all of your goofing.
• 44:50
  Speaker 1: Off physics and engineering.
• 44:53
  Speaker 2: Physics has sort of shot itself in the foot. It's
• 44:55
  Speaker 2: so effective at building communication networks and new technology to
• 44:58
  Speaker 2: connect us than now we're all so distractable.
• 45:02
  Speaker 1: Although if you asked me, as some of you might know,
• 45:05
  Speaker 1: I am a big fan of distractions for a creative thinking,
• 45:08
  Speaker 1: So in a way, maybe the Internet has helped the creatuty.
• 45:13
  Speaker 2: Also, physics is powering your procrastination, that's what you're saying.
• 45:16
  Speaker 1: Yes, yes, I have physics to blame and engineering to think.
• 45:23
  Speaker 2: Would you say you're a procrastination engineer or procrastination artist.
• 45:28
  Speaker 1: I'm a procrastination engine artist. All right. Well again, just
• 45:34
  Speaker 1: a fun reminder to keep your eyes open because there
• 45:37
  Speaker 1: are interesting things to discover and to explore and to
• 45:42
  Speaker 1: find the science of in our everyday lives.
• 45:44
  Speaker 2: That's right. And remember that as we understand the universe
• 45:47
  Speaker 2: better and better, we can develop new technologies which then
• 45:50
  Speaker 2: help us understand the universe better and better. So physics
• 45:53
  Speaker 2: is cyclical.
• 45:55
  Speaker 1: Yep, as is engineering.
• 45:58
  Speaker 3: Right.
• 45:58
  Speaker 1: Well, we hope you enjoyed that. Thanks for joining thing
• 46:00
  Speaker 1: is See you next time.
• 46:06
  Speaker 2: For more science and curiosity, come find us on social
• 46:09
  Speaker 2: media where we answer questions and post videos. We're on Twitter, Discorg, Insta,
• 46:14
  Speaker 2: and now TikTok. Thanks for listening, and remember that Daniel
• 46:18
  Speaker 2: and Jorge Explain the Universe is a production of iHeartRadio.
• 46:22
  Speaker 2: For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
• 46:27
  Speaker 2: or wherever you listen to your favorite shows.