Listener Questions 69

00:00:08
Speaker 1: Hey, Daniel, would you rather live in the Star Wars or Star Trek universe?

00:00:14
Speaker 2: Oh? Man, I'm not sure.

00:00:16
Speaker 3: I guess I'd prefer to live in the one that's more scientific, you know, that follows actual laws.

00:00:22
Speaker 1: I think they use more particle names in Star Trek. They might be made up. I know in Star Wars they use Midi Chlorians, which are definitely not made up.

00:00:33
Speaker 3: Yeah, but I think Star Wars leans on the little magic aspect a bit too much. I think Star Trek is trying to sound more scientific at least.

00:00:41
Speaker 1: I mean, isn't that basically our jobs, right? We're always trying to sound more scientific.

00:00:49
Speaker 3: I mean I do my best to sound like a physics professor. I hope it's working.

00:00:53
Speaker 1: I yeah, I think you had me fooled there for.

00:00:56
Speaker 2: A minute, you and all the listeners.

00:00:58
Speaker 1: I hope the big reveal.

00:01:17
Speaker 3: Hi, I'm Daniel, I'm a particle physicist and a professor at UC Irvine.

00:01:20
Speaker 2: Really really, I promise I am.

00:01:23
Speaker 1: I'm Katie Golden. I'm none of those things, but you know, I do have an animal biology podcast, and I'm interested in physics, or.

00:01:32
Speaker 2: At least you can make it sound like you are.

00:01:35
Speaker 1: That's so interesting, Daniel.

00:01:38
Speaker 3: And Welcome to the podcast Daniel and Jorge Explain the Universe, a production of iHeartRadio in which we sound interested in the big questions of the universe, because we really really are interested. We want to know how everything works, where it all came from, how it all comes together to create our amazing, glittering, beautiful, mysterious cosmos, and we want to make sure that everybody out there understands things as well as we do and as well as we don't. Thanks very much Katie for joining me on today's episode.

00:02:09
Speaker 1: I'm super excited. I love to hear people's questions because usually they are something that I am also curious about, and I also don't know the answer to.

00:02:20
Speaker 2: That's right.

00:02:21
Speaker 3: Many of our episodes are us explaining a concept in physics to you, but we don't want this podcast to be a one directional lecture. We want it to be a conversation. We want to know what you are wondering about when those ideas don't click in your mind. We want to hear from you so we can help you understand. So please, if you have questions, right to me to questions at Danielandjorge dot com. Everybody gets an answer from a real live physics professor.

00:02:46
Speaker 2: They really really do.

00:02:48
Speaker 3: And sometimes I hear a question from listeners, I think, well, I bet a lot of people ask this question, or a lot of people would appreciate the answer, or that one would be fun to joke with Katie about. So let's do it on the podcast.

00:03:01
Speaker 1: No physicists were harmed in the making of this Listener Questions episode.

00:03:06
Speaker 2: Not yet, but I'll keep you up to date. We'll see if that changes.

00:03:11
Speaker 3: And so today on the podcast, we'll be answering Listener Questions, Episode number sixty nine.

00:03:22
Speaker 1: There's nothing funny about that number.

00:03:25
Speaker 3: Absolutely nothing. We have been counting down to Listener Question sixty nine ever since we've been doing Listener Questions and we realized we were going to get there.

00:03:33
Speaker 1: I get it. The six looks like a nine upside down. That's what's funny about it.

00:03:39
Speaker 3: Yeah, that's exactly what's funny about it. It reminds me a little bit of when comic Shoemaker Levy hit Jupiter. When it ran around the sun. The comment broke up into like twenty six pieces. So somebody in NASA was like, ooh, let's give the comet pieces names and we'll use letters because there's twenty six of them. So there was the A fragment, the B fragment, the C fragment, and then when the first piece hit Jupiter, they called it the A spot, and the next one when they hit they called it the B spot. And then when they got up to the F spot, they realized, uh oh, they had a problem with the next one because were they really going to write a scientific paper about Jupiter's G spot.

00:04:15
Speaker 1: I have no idea what you're talking about. That just sounds like numbers and words to me.

00:04:22
Speaker 3: So they ended up talking about the F spot and then the G impact site, and then the H spot.

00:04:27
Speaker 1: Somehow that sounds dirtier to me. I don't know impact site all right.

00:04:32
Speaker 3: Anyway, we've got to do our best to extract humor from science. But on today's episode, we are not just making jokes about the number sixty nine. We were answering questions from listeners like you, and today's episode is discussion of a question from Dale from Washington. Here is Dale's question.

00:04:49
Speaker 4: Hello, Daniel and Jorge, This is Dale from Chattarroy, Washington. I was watching Star Trek the other day and it occurred to me that when the Enterprise D is cruising a speed of warp six and the stars were all speeding by, they maybe shouldn't have been able to see them due to blue shift. Would the light be shifted all the way into ultraviolet or maybe even X rays or even further down? Is that even possible at a large percentage of the speed of light? Anyways, thanks for listening to my question.

00:05:24
Speaker 3: All right, Katie, are you a Star Trek fan? Have you wondered about this yourself?

00:05:27
Speaker 1: So? I have watched a good amount of Star Trek, and I I'm always kind of I don't know. I guess I kind of gloss over the weird engineering babble. It doesn't it's like we got to put the transoperitors or interopertors on the warp schism. I don't really know. And like I'm also a little bit confused about the concept of the warp drive. I know there are different like warp speeds, but like the idea, I guess is that what you're like ending space and making the ship go across. I don't know. Do you know if they ever did like an explanation of warp drive.

00:06:09
Speaker 3: Well, one of the funny things about Star Trek is that it's not really science fiction. I mean, they don't actually have any sort of explanation for what they're doing. It's exactly as you described. It's like particle babble.

00:06:21
Speaker 2: It's sort of like.

00:06:22
Speaker 3: The way jen Ai is. You know, you ask chat gbt to generate an answer to physics question and it'll generate a bunch of words which sound like an answer, and Star Trek is kind of like that. It's like, here's a convincing number of words which sort of sound like an explanation for the science, but it's really nonsense, you know. And I gotta love that about Star Trek. They're not really trying to be hard sci fi. They sort of make fun of themselves a little bit. They don't take themselves too seriously. The science of Star Trek is not like crisply thought out and click together into some coherent explanation, as you'll see when we dig into what a warp drive is in Star Trek and what it should look like when you look out right.

00:07:01
Speaker 1: But the idea being that you're going really really fast, like is the idea that you're going at the speed of light.

00:07:09
Speaker 3: The idea of a warp drive in physics aside from star trek is an attempt to move faster than the speed of light. So we have this frustrating limitation on all motion in the universe that nothing can move faster than the speed of light through space. So if you want to fly to Alpha Centari and it's three light years away, it's going to take you at least three years to get there because you can't even go at the speed of light. Nothing with mass can move even at the speed of light, and nothing at all can move faster than the speed of light. And the speed of light is really really fast, you know, one hundred and eighty six thousand miles per second is incredibly fast, But distances in space are incredibly vast, and so stars are far apart even compared to the speed of light. So our galaxy, for example, is one hundred thousand light years across. You wanted to go from here to the other side of it and back, we're talking two hundred thousand years even if you're a photon. So it's incredibly hard to get around the universe because the speed of light is actually very very slow. And in science fiction universes people often want to have like galaxy spanning empires or civilizations that go from star to star, and it's kind of hard to make that work unless you have faster than light travel. So a warp drive in physics is a way to try to circumvent use loopholes in special relativity to make it possible to go from here to there in less time than a photon would take.

00:08:32
Speaker 1: Okay, so it's some kind of magic.

00:08:37
Speaker 3: Well, there really is a concept in physics of a warp drive, and it doesn't break special relativity. The law in special relativity says you can't move through space faster than light does. But a warp drive doesn't move through space. It actually compresses space. Because what we've learned in the last one hundred years or so is that space is not just like an empty backdrop on which the things in the universe happen. It's actually like a thing. It has features, It can bend and curve and ripple and expand. And so if, for example, you could compress the space between here and a distant star so that it's not actually as far, then you could just move a lower than the speed of light but still get there very very quickly. That's the basic idea of a warp drive, and people want to know more about the physics of a warp drive and is it possible. Can check out some of the episodes that we have about warp drives. But that's actually a possibility. We don't know how to make it work. We don't have to build one, but the laws of general relativity say it might be possible. And we're talking about in our real universe. In Star Trek, their warp drive is a little bit different.

00:09:40
Speaker 1: Okay, so how does the Star Trek warp drive quote unquote work.

00:09:46
Speaker 3: So the basic principle is the same, is that you're going faster than the speed of light. And they have these warped levels, so like warp one, warp two, warp three, each of those goes faster and faster, and for example, and warp nine point nine is the maximum that they could have do. And if they ever go warp nine point nine, you can really see it straining their ship.

00:10:07
Speaker 1: That seems like airplane or boat logic right where it's still the idea that you are like moving in a way where there is some kind of like resistance against your ship, and then if you're going faster, there's more strain on the ship. But if this is about scrunching space time. It doesn't seem like that would have the same kind of effects as say, like a jet plane trying to a sound barrier.

00:10:33
Speaker 3: Yeah, exactly, But the warp drive on Star Trek isn't a general relativistic squeezing space creating a warp bubble kind of situation. They don't explain at all how it works. It's just sort of like, we can go faster than the speed of light.

00:10:45
Speaker 2: We have a warp drive.

00:10:46
Speaker 1: Right, Okay, so part of the question was about blue ships. So the idea is like, so, okay, you have one of these warp drives where you can go faster than the speed of light, and there is the obvious question of what would like look like to you? But can you explain what the question asker means when they talk about blueshift?

00:11:09
Speaker 3: Yeah, I think basically he's wondering, what does it look like out the window when you are doing the warp drive?

00:11:15
Speaker 2: Right?

00:11:15
Speaker 3: And this is one of my favorite parts of science fiction is thinking about the consequences, like you've created this new technology or discovered this new bit of science, what does that mean? Not just for like what is it like to be human? In that universe, but what are the experiences like.

00:11:29
Speaker 2: Of using it? And the best science fiction.

00:11:31
Speaker 3: Are the ones that have really thought this through and come up with creative or interesting or surprising results.

00:11:36
Speaker 1: It's like in a B movie, the science fiction B movie where it asks if bees were sentient and all went on strike, would that be good or bad for the planet. But we were talking about some of the best science fiction movies, so of course I thought of B movie, but going.

00:11:53
Speaker 3: Absolutely yeah, definitely a high point in the science fiction movie canon.

00:11:58
Speaker 2: But in this case they're wondering.

00:11:59
Speaker 3: Like, well, it look like if you looked out the window while you were going faster than the speed of light, which is a really cool question. And the writers on these TV shows, or the visualization artists or wherever it's responsible for this, typically do this by making the stars streak by right like you see this in Star Wars the stars go from points to these lines, and on Star Trek they have this particular visualization where the stars aren't completely solid lines, they sort of zoom by, so it looks like you're whizzing through the universe and seeing the stars go by really fast. And the question is like, would you really be able to see the stars, because wouldn't their frequency be shifted by the Doppler effect, so they'd be so blue that you couldn't see them. The Doppler effect being that if something is moving relative to you, the light it emits changes frequencies. So, for example, stars from other distant galaxies are all moving away from us as the universe is expanding, and so the light from those stars is shifted red because the stars are moving away from us, Galaxies like Andromeda are moving towards us, so light from Andromeda is shifted blue. So if you were right next to Andromeda and not moving relative to it.

00:13:08
Speaker 2: You would see it's pure light as it's actually emitted.

00:13:11
Speaker 3: We see that light at higher frequencies it's blue shifted more towards ultraviolet and X ray then it would be if we weren't moving relative to Andromeda. It's actually a really powerful way to measure the velocity of distant stuff by measuring its red shift or its blue shift. So the question is asking, like, wouldn't the stars out the window be so blue shifted that they would be invisible?

00:13:32
Speaker 1: I see right, Because if you're moving away or towards something, it's like the wavelength of that light that would be hitting your eye is going to change.

00:13:41
Speaker 2: Yeah, exactly.

00:13:42
Speaker 3: It's basic physics of the Doppler effect. It's like when a police siren is coming towards you, it sounds one way, and when it's moving away from you, it sounds another way. It's the same effect but applied to sound.

00:13:51
Speaker 1: Yeah, it sounds like we woo we woo, and it goes like wee woo woo woo.

00:13:57
Speaker 2: Yeah exactly.

00:13:59
Speaker 3: And that also for light, because light is a wave in the electromagnetic field. And so he's asking about that, and so I did a little bit of digging into the physics of star trek warp drives, and I was wondering also, like why are we seeing stars whoosh by? Like is that realistic?

00:14:15
Speaker 1: Right?

00:14:16
Speaker 3: Because warp nine is pretty fast, but it's not actually that fast. Like I said, it takes two days to go like ten light years. But if you look at the window of the enterprise, you see stars whoshing by all the time. The thing is that stars are way too far apart for that to happen. Yeah, I mean stars are typically like three four five light years apart. So if you're only going ten light years every two days, then you should see like a star whoosh by like every twenty four hours. But if you look at the window of the enterprise, it's like ten stars a second. So they've taken some real liberties in that visualization.

00:14:50
Speaker 1: I mean one way, I know that Star Trek is sort of not going with the we are scrunching up space. But if you were scrunching up space, I could see an argument for there being some kind of weird optical effect. Not necessarily stars wooshing by, but you know, I remember in an episode where we talked about your point of view from a black hole, where it's like if you have a very dense point where it would suck in light. So maybe if you're scrunching space, you could I don't know exactly how this would work. I'm now beyond my understanding, but I guess there could be some kind of weird optical effect.

00:15:32
Speaker 3: I think that kind of creativity in science should get you a spot as physics consultation on Star Trek.

00:15:39
Speaker 1: Sweet so I can just say, uh, oh, the gasorp azorp drive went down.

00:15:46
Speaker 3: No, I think there's a lot of room for like, how could we make this work? What would you have to do is there any explanation in science? But anyway, let's take the star trek warp drive and just say somehow it makes you be able to move faster than the speed of light. Physics is spended or we've discovered if the special relativity is wrong or whatever. We're moving faster than the speed of light. What would it look like out the window, the front window, the side window, the back window. And Dale's totally right that the Doppler effect is a big effect. You're moving very fast relative to these stars, which is the same thing as saying they're moving fast relative to you. So, for example, if you look out the back window of the Enterprise, you're moving faster than the speed of light. Number one, all of the light from those stars is really really red shifted. It's red shifted so far that you wouldn't be able to see it like our sun amids light in the visual spectrum. But if you're moving away from the Sun super duper fast, then its light is going to be red shifted so far that you'd need like a special infrared camera to even pick it up.

00:16:44
Speaker 1: I see, yeah, because our eyes can only detect certain wavelengths, like if something's too I guess wide of a wavelength or too short of a wavelength, we are not going to be able to see it.

00:16:56
Speaker 2: Yeah exactly.

00:16:57
Speaker 3: And in addition, you're now moving faster than those photons somehow, right, we suspended physics, and so you're out running the photons, so you're not going to be able to see anything behind you.

00:17:08
Speaker 2: Yeah exactly.

00:17:10
Speaker 3: So it's like I'm trying to throw a baseball at you, but you're in your ferrari and you're going much faster, Like my baseball is not going to get to you. So you're just not going to see anything out the back window. If you're actually moving faster than the speed of light. But then what about your front window? Right, you're moving towards all these stars faster than the speed of light.

00:17:28
Speaker 2: What should you see?

00:17:29
Speaker 1: Right?

00:17:29
Speaker 3: This is actually also quite counterintuitive what you would actually see. And instead of imagining ourselves moving towards the stars, imagine the equivalent scenario of the star moving towards us. Because in our universe velocity is relative, it doesn't really matter who's moving.

00:17:44
Speaker 2: It's actually the same thing.

00:17:45
Speaker 3: Think about what it would look like if a star is moving towards you faster than the speed of.

00:17:49
Speaker 1: Light scary, you actually be very scary.

00:17:54
Speaker 2: Now.

00:17:54
Speaker 3: That means that the star is moving faster than the light that it emits, right, right, So it's like leaving the light behind, which means again you can't see it, right because you arrive at the star before the light that it emitted along the way it gets to you.

00:18:10
Speaker 1: Ah my brain.

00:18:13
Speaker 2: Yeah right.

00:18:14
Speaker 3: And so imagine the star is far away, it emits a photon, but the star gets to you before the photon, right, So you don't see that photon until the star has already passed you. So what happens is as the star passes you, that's when you see it, and you actually see it twice. You still go past you, and now it's emitting photons as it goes past you, and those photons are coming towards you, and you also start to receive the photons that it emitted while it was on its way to you. Those now start arriving, but they arrive in reverse order, right, because the images it's sent later arrived before the images it's sent earlier when it was further away.

00:18:51
Speaker 1: Oh yeah, Because you are moving so fast that you will approach the star and have those close by photons you faster than the ones that hit you from when the star was further away. Yeah, that's wild. You'd see like an after image of the star before from before.

00:19:13
Speaker 3: Yes, exactly, So you'd see nothing, and then when the star passes you, you'd suddenly see two stars.

00:19:18
Speaker 2: One going behind you and one going ahead of you.

00:19:21
Speaker 3: It would look like going backwards in time, right, you would see it in reverse order.

00:19:26
Speaker 2: Very bizarre effect.

00:19:27
Speaker 3: And I've never seen this displayed in science fiction. I would love to see somebody actually make this work. If you were writing a new show about people with warp drives, email me and I will help you get this right.

00:19:38
Speaker 1: Well, I'm going to keep that in mind for my new show Hot Alien Babes on Neptune.

00:19:45
Speaker 3: Dale's actual question is about the light, and he's right that the light is also going to be blue shifted, and so if it was like originally a red dwarf that emitted in the longer wavelengths, it would be shifted into the higher frequencies. The exact shift depends on the velocity, but he's right that that might also be invisible. It might be that is shifted up way past the ultraviolet, so that you need like X ray sensors or gamma ray sensors to be able to detect it. In principle, there's nothing that's actually invisible, Like if we have enough particle detectors, we can sense those very very high frequency photons. For example, orbiting the Earth, we have the Fermi Lat telescope, which you can measure photons at very very high energies. So in principle you imagine that these spaceships are probably equipped with sensors to be able to detect super high frequency photons, but you wouldn't see them with the naked eye, okay, but you might see something else. You know that the universe is filled with the cosmic microwave background photons, photons left over from a very early universe plasma, and these are very long wavelength because they've been stretched to very very infrared by the expansion of the universe. But if you're flying through the universe faster than the speed of light, those are all going to.

00:20:56
Speaker 2: Get blue shifted.

00:20:57
Speaker 1: It hits crunched up.

00:20:58
Speaker 2: Yeah, they might.

00:20:59
Speaker 3: Get blue shifted all all the way into the visible spectrum. So you might be able to see the CMB with your naked eyes, meaning that the whole universe would be filled with this fog.

00:21:09
Speaker 1: Oh whoa, it might maybe you would get some kind of weird spaceship Aura.

00:21:14
Speaker 2: Yeah, would be super cool.

00:21:17
Speaker 3: Anyway, Dale is totally right that the way they describe it on Star Trek is not really accurate from the physics point of view, and the engine they have anyway doesn't really make any sense. But it's a lot of fun. I don't mean that in a way to criticize Star Trek. I know what they're going for is not hard sci fi. There's definitely a niche there, and I love it big fans Star Trek.

00:21:35
Speaker 1: I hope one of those writers were fired for that blunder is my opinion.

00:21:40
Speaker 3: No, no, no fire any writers or pro writer. But please do reach out to us. We would love to help you get the physics right. And thank you to Dale for reaching out to us with your question about the physics of Star Trek. I love that Dale, that is doing this physics in his mind, he's being a physicist. He's wondering what would this actually look like? How does that work? Why not this one that's being a physicist. All you people out there who are wondering how the universe works, you're all physicists too sweet.

00:22:07
Speaker 1: Did we get a badge?

00:22:09
Speaker 2: I'll send you all a sticker.

00:22:10
Speaker 3: Yes, digital we get a badge, all right, so please don't be shy right to us with your questions to questions Aunt Daniel and Jorge dot com. Everybody gets an answer, because everybody deserves an explanation. Thanks Katie very much for joining me on today's special listener Questions sixty nine episode.

00:22:28
Speaker 1: All right, back to work on my hot babes from Neptune script.

00:22:32
Speaker 3: Can't wait to see that one on the screen. All right, everyone, Thanks very much. Tune in next time for more science and curiosity. Come find us on social media where we answer questions and post videos. We're on Twitter, disc Org, Instant and now TikTok. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the Heart Radio, Apple Apple Podcasts, or wherever you listen to your favorite shows.