Daniel and Kelly’s Extraordinary Universe - What Is A Tachyon?

Episode Date: April 23, 2019

Are Tachyons real or just the stuff of science fiction? Thanks to Prof. Flip Tanedo (UC Riverside) for scientific review.  Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nielbornet and I discuss flight anxiety. What is not a norm is to a lot. allow it to prevent you from doing the things that you want to do, the things that you were meant to do. Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Hey, Daniel, do particle physicists ever make mistakes?

Oh yeah, all the time. One time I ordered licorice ice cream, big mistake. I once had garlic ice cream. That was probably a bigger mistake. Do you know they make garlic ice cream? Yeah, they have pretty experimental flavors sometimes with ice creams. What I mean is, have physicists ever written papers, like scientific papers, that turn out to be wrong? You know, it does happen.

The most famous example comes from maybe the opera experiment, which in 2011 claimed to have measured neutrinos going faster than the speed of light. Wow. Turns out they just had a cable loose, and when they jiggle it, all the numbers go. got back in the sink and everything with traveling happily less than the speed of light. Oh, man. Particles can't travel faster than light? Probably not. But you know, if particles could travel fast than the speed of light,

physicists are already set up with an awesome name for them. Oh, yeah, they have a good name for this far faster than light particles. They call the garlicino or the Likorons. Likron. Sounds like a terrible pun. Like a not-safe-for-work pun. Hi, I'm Jorge. And I'm Daniel. And welcome to our podcast, Daniel and Jorge Explain the Universe, a production of IHeart Radio.

In which we take the universe and explain everything in it to you, including things which might not be possible. That's right. Things that are tasteful and nice and things that are maybe a little tacky. Things which stretch the boundaries of understanding. Things which might even break the laws of physics themselves. Today on the program, we're going to talk about... Takions. Are they real? What are they? Are they really tacky? What are they on? Who taught them their sense of style?

Exactly. Tachyons are a fascinating concept because, first of all, from a theoretical physics point of view, they're interesting. Like, the idea for a tachyon is a particle that travels faster than the speed of light. And so that already is, like, immediately arresting. Like, is it possible? How would that work? What would it mean? Right.

But they also exist in science fiction. So this is a particle that exists in the minds of physicists, but we don't know if it exists in the real world. Yeah, exactly. And it's a really interesting history sort of of. the idea. There was a short story written by somebody in which they had particles going fast in the speed of light. So it started in

science fiction. And then there was a physicist that read that story and thought, hmm, could you do that? Would that be possible? And sat down and sort of worked out the mathematics of it and then gave it a name called it a tachion. And then more science fiction writers heard about that and thought, oh,

well, this must be a real thing now. And now it's like everywhere in science fiction. And you hear tackyons everywhere. It's like cosmic bad case of telephone exactly exactly just sort of an idea of bouncing around and you know there must be something really to it if it's really resonating in the minds

of physicists and science fiction authors you know it's something tantalizing something exciting something people want to be true right yeah because it would expand our kind of what's possible in the universe right yeah or it would expand the plot options available to science fiction authors right if you can send

particles fast in the speed of light and backwards in time and all sorts of stuff then there's lots of things you can do with your plots. That's right. If you follow the laws of physics, all science fiction would be pretty boring, right? That's right. You know everything in the first scene,

you can predict the whole story, right? Actually, I feel like a lot of science fiction is like that. You read one chapter, you know the whole story. You know the whole story, yeah. Did this writer come up with the name for the Tachyon, or was it the physicist who read the story? No, it was the physicist. So the story was written by a guy named Blish,

And the story is called beep It involves like messages from aliens That come in at the end of every message There's a beep And it turns out that the beep Encodes like all future messages or whatever Oops, I just spoiled the story for everybody Anyway

Because parts of the message travel fast in the speed of light And so then the physicist read the story And came up with it in a 1967 paper This physicist named Gerald Feinberg And so he coined the name Tachian as far as I understood But you know now it's everywhere It's in pop culture everywhere you turn.

Yeah, he should have named after the author, the Blicheon. I don't think that would catch on quite as much, or the beepies. No, but, you know, I read about Takions because they're part of the, integral part of the plot of one of my favorite comic books, and in fact, one of the most famous comic books of all time. Oh, wait, what is Jorge's favorite comic book? I'm dying to know. It's one of my favorites.

Is it Banana Man? He can throw banana peels from the table. tips of his fingers, make anybody slip? It's a licorice lady. Lickrish lady. Wow, there's so many not-safe-for-work jokes I can make about the licorice lady. Yeah, they'll need to be beeped out. Exactly.

So tell me, what is your favorite comic book? One of my favorite comic books, and that is one of the most famous comic books of all time, is Watchmen. Have you seen the comic book, or the graphic novel, or the movie? read the graphic novel, and I have seen all 11 hours of the movie. All different versions. Exactly. All the slow motion scenes that Zach Snyder added.

Yeah, yeah. No, I love, what is it, Mr. Atomic, who can basically do anything at the end of the movie, so all plots can just be resolved by Mr. Atomic, if necessary. Is it that the doctor, no, Dr. Manhattan? What's his name? Dr. Manhattan? Professor Atomic? I like your version better.

Mr. Atomic. That sounds better. That sounds better. No, it's Dr. Manhattan. Dr. Manhattan, there you go. Or Mr. Manhattan. I think Dr. Manhattan. And, yeah, so he can see Takianz.

So that's kind of how he can. And he sort of exists in this kind of quantum, you know, uncertainty, space-time kind of mindset. So he can see the future, see the past. He sees it all sort of at the same time. And so that's how the villain in the comic book, I'm not going to spoil it, kind of gets around this. He confuses Dr. Manhattan by,

adding a lot of tachyon interference and so he can't predict the future and he doesn't know what's going to happen. Very clever, yes. Very clever. You also see tachions a lot in Star Trek, I noticed. There's like tachyonic pulses and tachyonic fields and all sorts of stuff.

Anytime they need to go back in time or send messages back in time or whatever, they're always using tachyons. Right. They just always sort of forget to say that these things are not real. Well, you know, they're real in the Star Trek universe. I suppose. They don't really play with all the consequences.

You know, if you really did have tachyons, a lot of things would break about modern physics. Right. You know, I had a bit of a tachyonic experience today, actually. That just reminds me. I went to file some paperwork for my student who just defended his PhD, and he wasn't in town, so he couldn't file it himself.

So I went to this office in the basement and turned in these forms. And the woman at the desk must have thought that it was my PhD. Because when I turned the form, she reached out, she said, congratulations, doctor. As if I was getting my PhD at this moment.

And I thought, wow, all right, maybe I went back in time and now I look like I'm 27 again. Or maybe she wasn't wearing her glasses. That's another possibility. It was a pretty dark basement, so I can excuse her, yeah. It's always in the basement. It's always in the basement. But his thesis was not on Tachian, so.

Oh. But actually, we don't know if they're real or not, right? It's a theoretical possibility, but we have no confirmation. Do we have confirmation that they can exist? we do not know that they cannot exist right but that's a pretty broad caveat because in general it's really hard to prove the non-existence of something and you can always say with an asterisk like if all we know about physics turns out to be wrong or a special case of the part of the universe we're living in then anything could happen right so in general it's pretty hard to say with absolute certainty something cannot exist but you can say and we'll get into this more more deeply that it'd be pretty hard to full tact eons into our modern understanding of physics. Right. Maybe harder than choking down a whole scoop of licorice ice cream.

More unpleasant. Then you really wish you could go back in time. You know, the joke is my wife actually loves licorice ice cream. And one time we went to an ice cream place and she ordered two scoops of licorice ice cream. And I saw her eating her deliciously. She didn't tell me what it was. And I tried to take a bite out of it. And it literally like jumped out of my mouth.

It was so impulsive. Wow. ejected itself from my mouth. That's like your kryptonite or your Tachyon interference. Yeah, it turns out actually there's lots of things can defeat me, but one of them

on the long list is a licorice ice cream, yes. One of them upsets your stomach. Yeah, or my tongue. Well, Tachions is kind of a cool name, first of all, takions, and we know it's in

science fiction a lot. It's in comic books, in science fiction in science fiction but we were wondering how many people out there knew what it means and what it refers to it. So I went around the UC Irvine campus and I costed random students and said, hey, would you answer a random science question? And

all of them said yes and so I asked them about tachions and here's what they had to say. Have you ever heard of a tachion? Do you know what a tachian is? No. What's your best guess? It's a particle which gets emitted from a black hole. Is that it? No.

Best guess? I would assume it hasn't to do with space. I'm a space. Okay. I have no idea. Okay. Not yet. I haven't heard of it.

I've also heard it in a TV show. I think it's in the flash. I think they talk about that, but I don't know what it is. This sounds cool. This sounds cool. No, I have no idea. Okay. No.

A Tachion, I don't know what it is, but it sounds like something chemical. something from Star Trek that's literally as far as my knowledge goes I'm not actually sure if it's even real or not it could be entirely from science fiction as far as I'm aware all right not a single positive answer not a single positive answer

a lot of people had heard of it right some people I'd never heard of it but some people heard of it in the context of science fiction or Star Trek or this kind of stuff oh and the Flash right I think they have it in the TV show The Flash yeah the Flash must have it right because he breaks all sorts of laws of physics. It's basically the

laws of physics break particle, right? Anytime you need to break physics, just insert some tachions. She's just called the plot holeions. It's the plot fictsions, right? The plot chush ions. It's like, yeah, it's like filling a pothole, right? Fill potholes with tachions.

Yeah, so it's not a common name that people are familiar with. So let's break it down, Daniel. But first, let's take a quick break. December 29th, 1971, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed.

There's been a bombing at the TWA terminal. Apparently, the explosion actually... impelled metal, glad. The injured were being loaded into ambulances, just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism.

Law and Order, Criminal Justice System is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order criminal justice system on the iHeart radio app apple podcasts or wherever you get your podcasts my boyfriend's professor is way too friendly and now i'm seriously suspicious oh wait a minute sam maybe her boyfriend's just looking for extra credit well dakota it's back to school week on the okay

story time podcast so we'll find out soon this person writes my boyfriend has been hanging out with his young professor a lot he doesn't think it's a problem but i don't trust her now he's insisting we get to know each other but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating.

He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. I don't write songs. God write songs. I take dictation. I didn't even know you've been a pastor for over 10 years. I think culture is any space that you live in that develops you.

On a recent episode of Culture Raises Us podcast, I sat down with Warren Campbell, Grammy-winning producer, pastor, and music executive to talk about the beats, the business, and the legacy behind some of the biggest names in gospel, R&B, and hip-hop. This is like watching Michael Jackson talk about thoroughly before it happened. Was there a particular moment where you realize just how, instrumental music culture was to shaping all of our global ecosystem. I was eight years old, and the Motown 25 special came on. And all the great Motown artists, Marvin, Stevie Wonder, Temptations, Diana Raw.

From Mary Mary to Jennifer Hudson, we get into the soul of the music and the purpose that drives it. Listen to Culture raises us on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Now, let's start with this. What is a tachyon? All right, so tachyon is a theoretical particle, right? It's an idea. It's a idea for a particle that can travel faster than the speed of light, right? And remember, in relativity, we say nothing can travel faster than the speed of light.

We say things that have mass can travel less than the speed of light, they can approach it. Things with no mass, like photons, they travel always at the speed of light, right? So there's the speed limit to the universe, the speed of light in a vacuum. Tacions are like, what if something could break that? What if something could move fast than the speed of light? How would that work? And what should we call it? So that's what a tacky on is.

I like how that's the second most important question about it, not how will this revolutionize our understanding and our ability to travel the cosmos? It's like, what are we going to call it? Oh, yeah. There's big fights over the names of stuff, right? You know, if you come up with a cool idea, you've got to name it. so it sticks, right? And you get the credit for it.

You know, this is that famous case in particle physics where two groups discovered the same particle on the same day and gave it different names, right? The same day. The same day, yeah. Oh, there's a whole lot of fun whisper stories about how maybe grad students in one group tipped off grad students in the other group.

Anyway, they named it on the same day, and they gave it two different names. So now we call that particle the J-Sai particle. We use both names because nobody can agree, right? Really, people, you guys have fun. writes about this? Like, I want it to be called J. No, I want it to be called Sai. Like, it's not, it's not even personal to them. Well, I think it is personal. The guy who called it J, he's Chinese, and I think J is, looks like the Chinese character for his name.

So I think he was basically naming it after himself. But no, these are like the kids of divorced parents, you know, end up with long, complicated names. Anyway, yes, so naming things very important. And as you and I have discussed many times in this podcast, physicists don't always do a great job of naming things. Like sometimes they don't even come up with a new name. They just like use a word that already exists in English that means something else to describe some physics thing, right? Like we have particles that have flavor and color and like particles don't have actual

flavor and color. So we should have come up with different words. So in this case, I think it's awesome that they actually came up with a new, cool sounding word. Yeah. I think if you discover a quark, Daniel, you should call it a new flavor, liquorice. The disgusting quarks, the revolting quarks, the vomit quarks. It turns out vomit is made out little vomiton particles.

Technically, that's true, yeah, if you write it in a physics paper. Right, but it's always fun theoretically to think about, like, how could this work? What would it mean? If we took the laws of special relativity and tried to use them to describe something going fast in the speed of light, what would happen? What exactly would break? How could it be tested? That's sort of the point of a tachia. So it starts with a hypothesis, like what if one of these particles could go faster than light?

What would it look like? Yes, exactly, exactly. What would it look like? How do we see it? Could you like break two things at once so that in the end it's not broken, right? Like sometimes you have to break one law of physics and that has a consequence somewhere else. And you're like, okay, well, maybe I'll just break that one also and then things will be honky-dory, right? And so sometimes you can make big discoveries by breaking two things.

things at once, right? You could reveal that there were two mistakes, two misunderstandings we had about the universe. That'd be like, two Nobel Prizes in one afternoon. Wow. Two wrongs making it right. Yeah. And so that actually sort of happens here. And so as you folks listening might know, the interesting idea in relativity, one of the core ideas in relativity is that you can have infinite amount of energy. There's no limit on the energy a particle can have. You can keep pouring energy into a particle. But there is a limit on speed. So, for example, at the Large Hadron Collider, we push particles using little waves, so they surf, and they get more and more energy. But then they approach the speed of light, and they never really get faster.

That doesn't limit us from adding more energy to the particles, right? It's kind of like an infinite bucket almost. Like you can keep pouring energy into it, but the speed just won't go over the speed of light. Yeah, and if you're a visual person, you can think of sort of a graph, right? our basic idea of the relationship between speed and energy is that they're directly connected, right? As you go faster, you get more energy. And that's true. But then as you approach the speed of light, it sort of bends over and it asymptotically approaches the speed of light.

So you can keep pouring energy in, but the speed never goes higher. And there's this mathematical relationship. You can write it down. You can look at it on Wikipedia. It involves this complicated expression. It's like energy is mass squared over the square root of one minus. is v squared over c squared. And that's mathematically how you get that expression.

The cool thing is you can say, all right, well, what happens if you just plug in velocity is twice the speed of light? What happens mathematically? What does that mean? Oh, I see. Like, what have you cross over that line? What have you assumed that you filled the bucket and went over? Yeah, exactly.

And, you know, it's just playing around. This is what theoretical physicists do for fun. They're like, let's poke these equations and see what happens. and so it does get interesting because on the bottom of the equation he gets the number inside the square root goes negative right so you have like square root of a negative number and you're probably thinking what you can't have the square root of a negative number right like what number when you multiply it by itself gives you negative 2

right well there's no real number you have to go to imaginary numbers which means that this particle is imaginary or it has imaginary mass Well, it means it has imaginary energy, right? Because the expression is energy is basically mass over this crazy velocity term. If that velocity term goes imaginary, then the energy goes imaginary. And you're like, what? What does that mean? So this is what I mean by breaking two things.

So then physicists thought, okay, well, what if we make the top part of the equation also imaginary? So we make the mass imaginary. Then you have velocity greater in the speed of light, imaginary mass, but real energy, like actual energy. So if you just say that this particle has imaginary mass, and let's get into what that means, but if you say that it has imaginary mass, then the laws of physics technically don't break, if this particle goes faster than light. Well, if, I don't know, that the laws of physics don't break. We can talk about that a little later. It turns out they break other things also, but this one equation does hold, right? This equation for the relationship, essentially,

between energy and speed does hold. But, yeah, it requires you to have imaginary mass. And it also means for other really weird things. For normal particles, as the velocity increases, the energy increases, right? Right. In this case, if you look at the equation, as the speed goes up, the energy actually goes to zero. So the faster it goes, the less energy it has. That's pretty weird. Yeah. Because everything in nature wants to have low energy. So that means this particle will just keep going faster and faster and faster to infinity. Exactly. So as it goes to zero energy, it has infinite speed. Like, what does that even mean, you know?

Now you have a particle with like infinite speed and imaginary mass, but no energy, right? It's a pretty weird thing. But technically maybe could exist. Technically maybe could exist, right? There's some causality issues we'll talk about a little later. But that's sort of the concept. Like, that's the idea of a tacky on.

And it's a fun thing to play with, theoretically. And, you know, this, before you think this is a waste of time, remember, this is how progress is made. This is how, for example, anti-particles were discovered. People were looking at the equations, and they were like, hmm, what if you flip the sign of this and flip the sign of that? It looks like this equation would also hold for opposite charge particles. I wonder if they exist. Let's go look. I see.

And they did exist. And they do exist, yeah. This is a rich source of searching around for the corners of the equations and seeing if they describe some actual physics that might be real that we just hadn't imagined. because there's a lot of crazy stuff out there in the universe that we haven't conceived of. Well, it's kind of a philosophical thing because you sort of saying that anything that can exist mathematically, so far we think has existed, right? Like if the equations say that this is possible and doesn't break everything else, then if you keep searching, you sort of, so far you sort of, you found it.

Yeah, it's a subtle point, right? Sometimes we have mathematical descriptions of things, and then we look at the mathematics. like, well, the math says that, but physics says no, right? Like, sometimes a mathematical equation will have two solutions, and one of them will be nonsense. And you say, oh, well, that's not physical, so we'll ignore it. But yeah, then you have to wonder, is it really, is that, are we doing science there?

Or are we just sort of like enforcing our prejudices, right? Should we be more open-minded and explore all the possibilities of the math? And sometimes the math is all we have. Like, look at quantum mechanics. You can't even apply your intuition. You just have to blindly follow the math and say, Well, quantum mechanics says a particle can appear on one side of the barrier and then appear on the other side of the barrier without passing through it. And then we do the experiments and it happens, right?

So sometimes you just have to follow the math. Yeah. You're saying sometimes you have to be kind of open-minded and say, hey, what if mass could be imaginary? And let's see what happens then. Yes, that's exactly. That's the whole point, right? That's why you poke these equations because it could just be our prejudice. It could be that the way we're thinking about the universe is determined by the way we have experienced it, which is we know.

not typical and not fundamental, right? So we don't want to have our eyes closed because of the biases of the way we have lived and grown up, right? So we want to keep our eyes open. And sometimes the math is a very helpful guide. Well, I have a great money-making scheme for you, Daniel. It's called the Takyan diet. It makes your math imaginary.

Gee, I imagined you were fat, but I guess I was wrong. You just had the wrong perspective in physics. Yeah, well, so what's the diet? Run fast in the speed of light. and you'll lose weight. I think it's go back in time and stop yourself from eating all that liquor's ice cream is.

You know, we're recording this podcast on pie day, so we should have done all these examples with pie instead of ice cream. Pie, liquor's pie. Liquorice pie. That sounds even more gross than liquorish ice cream, if that's even possible. Here, let's go back in time using tachions and start over.

And search and replace ice cream with pie. But hey, pie and ice cream go well together. So we'll start with ice cream and we'll switch over to pie. And then the episode would be like a la mode. Yeah, they go well together. So let's get into what they actually might look like. But first, let's take a quick break. December 29th, 1975, LaGuardia Airport.

The holiday rush. parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal glass. The injured were being loaded into ambulances. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, and it was here to stay.

Terrorism. Law and order criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon.

This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating.

He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Culture eats strategy for breakfast. I would love for you to share your breakdown on pivoting. We feel sometimes like we're leaving a part of us behind when we enter a new space, but we're just building.

On a recent episode of Culture Raises Us, I was joined by Volusia Butterfield, media founder, political strategist, and tech powerhouse for a powerful conversation on storytelling, impact, and the intersections of culture and leadership. I am a free black woman who worked really hard to be able to say that. I'd love for you to break down. Why was so important for you to do, see you? You can't win as something you didn't create. From the Obama White House to Google to the Grammys,

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All right, Daniel, so that's a tacky. It's a theoretical particle with imaginary mass that can go faster than the speed of light. So what does that even look like? What would it at tachyon look like? What could we interact with it? Yeah, here's where it gets really fun is you start to think, how could we see tachions? What experiments could you build to detect them, right? And we think tachions, you know, they have mass, though it's imaginary, and we think we could interact with them.

We don't know what kind of interactions they might have. But imagine that they're visible, right? that they interact with light. Then you can think about, like, doing an experiment to look at a tachyon. This already gets really tricky because the tachions are moving faster than the light they might be emitting. So you know how, like, an airplane moving through the air creates a sonic boom because it's moving faster than the sound it makes, right? Right. That means that you can't hear the airplane coming, right?

If one of those airplanes is coming at you, then you're not going to hear it coming because the sound it's making is trailing behind it. Oh, so you, it would just magically appear to you. Yeah, so it's the same thing for a tachyon, right? If a tachian is moving and it's moving fast in the speed of light and it's coming right at you, you wouldn't see it until it's on top of you, right? Wow. It would just appear to you. That's just bad manners.

I mean, that's just tacky, you know? That's right. It's tacky and it's on you. That must have been how they got the name, right? I'm guessing, yeah. I got hit by Tachian. I spilled my licorice pie all over my suit. Let's just show up at this guy's house and be like,

is this why you came up with the name? Have some pie. Yeah, in fact, you would see the tackion, but even weirder than it just appearing all of a sudden is it would look like it's going away from you. What? Yeah. When you see something moving away from you,

what you're really seeing are a bunch of time slices, right? You see it's closer to you now. It's a little further away from you a moment later. It's a little further away from you a moment after that, right? Oh, I see. Well, that's the order of arrival of images from tachyons. You would first see the photons that it emitted when it was close to you before you saw the photons that it emitted when it was far from you.

Exactly, exactly. So if you play that movie, your brain's going to be like, oh, there's a tachion moving away from you, right? So a tachion, if you see a tachion moving away from you, it means you just got hit by a tachion. But you would see it, oh. So you would see it, hmm. You almost see it moving backwards in time, right? Yeah, exactly. You see it moving the reverse direction it's actually going.

So that's weird. That's pretty weird, right? It's weird for particles to look like they're going different speeds if they're coming towards you or going away from you, right? We're just not used to that. And that's because of this weird feature that they travel faster than the information that they're sending, right? Well, that's kind of one of the reasons why physicists don't think

you can even go faster than the speed flight, because it would just be so weird. Yeah, exactly. It would break a lot of rules. But, you know, sometimes things are weird, and being weird doesn't necessarily mean that they're wrong. You know, I think one of the really fascinating things is this question of imaginary mass that we mentioned earlier.

Yeah, I'm still hung up in there. What does that mean? Yeah, well, what does it mean, right? And you have to think for a moment about what we mean by a particle's mass. When we say, you know, electron has a certain mass, what we mean is that the particles is stable. It, like, exists. It could hang out for a little while.

and we just did that episode about what particles are and turns out particles are not like the building block of the universe at all they're just excited states of quantum fields right so what is a particle of a certain mass it's a stable excitation of a quantum field meaning there's this weird jelly out there that knows how to wiggle and it can wiggle in a certain way that sticks around for a while mass is kind of a marker of how stable the wiggles are

yeah exactly so if you talk about a particle with a imaginary mass, you're talking about strange wiggles going through these quantum field, right? These jellies wiggling in a weird way and not in a way that's stable, right? Imaginary mass does not mean it's a stable particle. It means it's something else

and you're trying to describe it in terms of a particle and so you get a weird answer. Oh, I see. It's like if you use the language of one thing to try to describe something else, it doesn't really make sense, you know? So it's almost like we have to stop using the word particle and just say,

it wiggles in a quantum field. And if you just stop calling it a particle and just call everything wiggles in a quantum field, then you could technically have a wiggle that has imaginary mass. Yeah, exactly, right. And it breaks your idea of what a particle is. But anyway, what your idea of a particle is is probably wrong anyway. So feel free to break it all, smash it all the heck, you know.

Just, yeah. Stop using the word particle. Yeah, well, it's true. You know, particles are not fundamental, right? They are an emergent phenomena. They come from how quantum fields wiggle. And we don't know quantum fields are fundamental either, or there's something else that makes them.

But we do know the particles themselves are not fundamental because they know they can be created and disappear. So tachyons are like a weird, different way for quantum fields to wiggle. And that's what imaginary mass is. It's sort of a breakdown of trying to describe quantum fields in terms of particles, right? It's saying you should look at this in a different way. But it could technically exist? like what these fields could wiggle in that way?

I don't think so. And the reason is that if you had tachyons, then these fields could wiggle in a way that breaks causality, right? And so this is physics, right? The math says it's fine. The math says there's no problem with it. You can incorporate this into special relativity. You get these weird things like zero energy and infinite speed,

but, you know, the math is happy with it. Physics says no. Physics says, but we have these other rules, these other rules like, Causes happen before effects. You know, messages have to arrive after they're sent, not before, right? You have to be born after your grandfather, not before, this kind of stuff. We impose these requirements on the universe and on the laws of physics separately.

Right. But why does the universe have to follow causality? Couldn't we, like you said, be open-minded and imagine a universe that is not causal? Yeah, I suppose we could, but it's sort of hard to logically argue for a non-concern. causal universe because logic requires causality, right? Well, I feel like you're saying logic requires logic, but what if maybe the universe is not logical? Yeah, so you're saying, like, could we describe, could we have laws of physics to describe

a universe that doesn't have laws? I don't know how to do that. It's so fundamental to the way we think. It's a fundamental to the way humanity thinks, not even just about physics, you know. I think that we are storytellers. We weave all of our experiences into stories, and that's how we remember things and forget things and communicate to each other. That's how we build models of the world

that's outside our head. And stories are causal, right? They're a narrative. I did this and then this happened. I shot this laser beam and then, you know, the wall burned down or whatever. I licorice ice cream and then I threw up, right? This cause and effect. So you can write stories

I mean, science fiction, you can write stories that have tachions in them. Do you know what I mean? Like you can, if you can imagine it and tell a story. It breaks the story, right? it's a huge plot hole that's why I hate time travel in science fiction because it breaks causality right it doesn't make any sense

okay well let's break it down what does it mean like if this particle existed and it can go faster than light what are some of the cool things you could do with it right so in special relativity if you have something that goes faster than light what it means is you can break causality

you can kind of go backwards in time Now, remember, we talked about Special Relativity in another episode, and something we talked about is how there's no universal description of how things happen, right? For example, if I shoot two laser beams, one to the left and one to the right, and I'm just looking at both, I can say, okay, the two laser beams hit the targets at the same time because the targets are the same distance away. Somebody else with a different speed might see those events happening at different times. they might say, oh, laser beam one hit before laser beam two. And somebody else at a different speed might see laser beam two happen before laser beam one, right? So if you can change, so you can change the order in which you see things happening based on your speed. That just tells you there's no absolute truth to the universe, right?

Right. Okay. Okay. But those things are not causally linked, right? It doesn't really matter if laser beam one hits or laser beam two hits. Okay. But what if you just had the one laser beam and you press the buzzer? button, right? Can the laser beam arrive before it leaves? Can the laser beam hit the target

before you've pressed the button? Those two things are causally linked, right? It seems impossible for it to get there before you press the button. Well, it's causally linked if you go backwards in time. Do you know what I mean? Like, it arrived because in the future, I'm going to press a button. Yeah, but what if it arrives and then you change your mind? You're like, you know what? I'm not going to hit that laser beam button right now, but it's already arrived. But if you change your mind, that means you didn't see it. I feel like this is a, like you can pick a different movie

to go with your theory. Like there's, there are the movies that... Movies are not lost of physics, man. All right, fine. Graphic novels. Let's go with common. No, like, seriously, the laser beam arrives,

and if later you still have a choice to make about whether to press that button, then you could choose not to fire the laser beam, right? And then, but the laser beam's already arrived, so how does that work? Anyway, the point is... Multiverse. The point is, relativity covers that.

Relativity says that for events that are not causally linked where one could happen before the other, you can travel fast enough if you want that you could see either one happen first. But for things that are causally connected where one has to happen before the other, like pressing a button on your laser and then hitting the target, there's no speed you can go to see the laser arrive

before you press the button. To do that, you would have to go faster than the speed of light to reverse the order of events and relativity says you can't but what if there wasn't the speed limit right what if you could shoot particles fast in the speed of light well then you could go fast enough so that messages could arrive before they're sent right

laser beams could hit the targets before you press the button if you go fast in the speed of light so it breaks causality if the light goes faster than the speed of light or if you send a message via tachyon if you send a message via tachions yeah Exactly. Okay. And so Tachyons, if they can travel fast on the speed of light, can sort of reverse the events, reverse orders of events

so that effects happen before causes, right? Which is pretty weird. Which is pretty cool. It would be pretty cool, sure, yeah. You know, like, hey, I already ate that pie. Now I'd like to go back in time and decide not to eat that pie. Then you could have eaten the pie and have decided not to eat the pie. And, yeah, it would break the universe, but, hey, at least you wouldn't gain

those five pounds. That would be kind of tacky though if you did that at a restaurant. Not if it's licorice pie, then I totally endorse breaking the universe to avoid eating it. So it's almost like an anti-telephone. It sends you your message before you even think about sending the message. Yes, exactly. And that's what it's called. It's called a tachyonic anti-telephone. Exactly. If you had tachyons, you could use them to build a telephone that sent messages back in time. Exactly that way. That's what I should tell my kids. It's not that I don't want. wanted to play with my phone. It's just that we're an anti-telephone household. It's an anti-telephone. Don't bring it near a telephone. It'll blow up. So you're basically saying that tachions are kind of impossible because it would break the logic

of the universe. Yeah. And I mean, if you hold causality to be a fundamental principle of the universe, which I do, then it's pretty hard to believe that anything could go fast in the speed of light. But the math says tachyons could exist, and it's possible that we're wrong about causality, that it's just, it's a prejudice that we've imposed on the universe because it's the way we think, and maybe the universe

doesn't operate the way we think. Totally possible. Happened lots of times in physics that we've upended our basic understanding of the universe, right? And I've been confronted by reality. Yeah. All right, well, that was cool to learn what a tachian is and how

it's an imaginary, or it has imaginary mass, and it's theoretically possible, but not likely. And Daniel, you had the idea of closing this episode with a limerick. Yeah, I was doing some research about tachians, and I found this hilarious physics

poem, right? It's not that often that you find physics and humor and poetry altogether. And so I thought, let's jump on the opportunity, right? Sub-sub-genre of science fiction. Yeah, not many authors specialize in this area, but there is one. This is by a gentleman named Reginald Buller, and it goes like this.

There was a young lady named Bright, whose speed was far faster than light. She went out one day, in a relative way, and returned the previous night. So there is your physics poetry. I noticed you didn't laugh. Well, I was just hung up on that first line. Her name is Bright. That sounds like a plot hole to me. I see.

Mr. The Universe Follows the Laws of Television Shows and Movies is now criticizing the physics poetry for not being accurate. Yeah, you know, how many people do you know are called Bright? Anyways. I'm actually a member of an organization called The Brights. I don't know what to do with that. Not joking. All right, so thanks, everyone, for listening to this non-Tackey episode about Tachions

for bending your mind a little bit. And remember that some of those crazy ideas that are in physicists, Ted, and science fiction authors are writing about, they could actually be real. And one day we might discover that the universe is far, far stranger than we ever imagined. Yeah. And if one day you do discover Tachions, why don't you send a message to yourself backwards in time and let us know? That's right. Hey, we could do a test right now, right? In the future, somebody discovers Tachians, send us a message to arrive right now.

Wait, hold on, I just got a call. Wait, here we go. Let me pick it up. Hold on. Is it from a lady named Bright? She's pissed at you for insulting her name. Ask her in the future if our podcast is a huge success. Okay, hold on.

Let me text her. Oh, wait, my phone doesn't send things. Oh, wait, it does send things into the future, so. Yeah, it does send things into the future, just not backwards. All right. Well, we hope you enjoyed that. See you next time, guys. Thanks for tuning in.

If you still have a question after listening to all these explanations, please drop us a line we'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge, that's one word, or email us at Feedback at Danielandhorpe.com. Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. luggage, kids gripping their new Christmas toys. Then everything changed.

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