Scientific Martyrs, Life Beyond Our Planet & More! | Cosmic Queries | Universe

Hinzugefügt: 2026-05-26

[00:00:00]This was Giordano Bruno's argument.

[00:00:02]>> Who was that? I never talked about Bruno. We've never talked about Bruno.

[00:00:04]He had just read Copernicus' book.

[00:00:06]God-fearing man said, "If the Sun has planets, maybe the stars in the night sky are just like our Sun. And if they are, maybe they have planets. And if they have planets, maybe [music] they have >> uh life.

[00:00:19]>> life. Heretical. Oh, they killed him.

[00:00:21]They killed [laughter] him.

[00:00:23]You know what one of his last words were? LET ME GUESS.

[00:00:36]THIS IS STARTALK. Neil deGrasse Tyson, your personal astrophysicist. Chuck, you're the grab bag man.

[00:00:43]>> I'm the man with the bag.

[00:00:45]>> [laughter] >> This is Youssef Kaswani, who says, "Greetings, StarTalkers. Youssef from Damascus, Syria, here. Damascus? That's right.

[00:00:54]>> Whoa. That's right. Ancient ancient >> Oh. city, Damascus. I found your podcast recently and I joined the club.

[00:01:02]>> Go. Welcome aboard, my friend. Here's my question. You often mention pro photons travel at the speed of light at all times.

[00:01:09]>> Yep.

[00:01:10]Working as an optics engineer and dealing with TIRF microscopes, I wonder how evanescent waves during total internal reflection, TIR, is thought of from a particle physics perspective. Are the photons moving at the speed of light but somehow without propagating? Or the photons don't exist at all. But then, what is interacting with the sample on my microscope?

[00:01:44]Thank you. I love your work. PS, Chuck, you surely deserve an honorary PhD by now, my brother.

[00:01:50]>> Oh. Oh.

[00:01:51]>> Look at that. My brother.

[00:01:53]>> My brother.

[00:01:53]>> [laughter] >> Optics is a field >> Yes. that does very important work on a lot of frontiers.

[00:02:04]>> Okay. Optics is what do you do with electromagnetic waves? Mhm. Do you bend them? Do you reflect them? Do you trap them? Do What Do you heat What do What do you do with them? Mhm. An entire branch of physics and engineering addresses those questions. So, I don't know how specific the example is that he's giving and how that would lend itself to my explanation.

[00:02:35]Okay.

[00:02:35]>> Okay. So, what I will otherwise say is the speed of light is not just a good idea.

[00:02:42]It's not just a good idea, it's the law.

[00:02:45]>> law. Thank you.

[00:02:46]>> [laughter] >> That's a That's a dated reference to uh 55 miles an hour speed limit when we went out and said we're not going to go fast anymore.

[00:02:56]>> Right.

[00:02:56]Uh so, that doesn't mean light always travels at that speed.

[00:03:01]Exactly.

[00:03:02]It means it will never travel faster than that speed.

[00:03:05]>> Right, cuz you can slow it down.

[00:03:07]>> So, that's That's how you do that. Okay, turns out you sort of can slow it down. Right. I got you. So, the medium itself can slow the travel. Yes. However, >> How Okay, but the way it slows it down >> Mhm. is fascinating. Interesting.

[00:03:28]>> Okay. Okay. Okay. So, I'm a beam of light Just going on about my business.

[00:03:32]>> Going at the speed of light. Nothing could be faster.

[00:03:36]>> Nothing could be faster. Then you hit the air or you hit a piece of glass or a piece of water. This is for visible light going through what we would say are transparent object. Okay? If you're transparent, it means the light stays coherent as it goes through. Okay. So that the wave form maintains its structure. If it does not maintain its structure, light can still get through, but you would we would not call it transparent.

[00:04:05]>> Right. Yes. Do you know the word we have for that? Translucent? Translucent. Yes.

[00:04:09]And lucent means light in in in um Latin.

[00:04:14]>> Latin, yeah. Luce luce is light. Luce.

[00:04:17]So the light comes up to the boundary.

[00:04:20]Mhm.

[00:04:21]Some light will get reflected.

[00:04:23]Yes.

[00:04:23]>> And optics people know and understand that, okay? That will happen no matter you can't do anything about that. You can try to minimize it by having what are called these coatings that will delete any attempt for the light to reflect back. Right. Yes. And you know it's it's fun the way they do that. You have a coating that's half the wavelength of the light that you're using. So then the light goes through and by the time it wants to reflect back, the light that's coming in is out of phase with it. Oh, so it creates a disruption.

[00:04:53]>> And it flattens out and flattens the light. Look at that. I never Isn't that brilliant? God, PEOPLE ARE SMART.

[00:04:59]>> [laughter] >> YEAH, SO A COATED LENS prevents the the reflections off of surfaces.

[00:05:06]>> Interesting.

[00:05:07]>> Okay? And cameras, especially zoom lenses and other big industrial cameras, they have many many lenses in them.

[00:05:13]>> Yes, they do. You can't have light reflecting off of shiny surfaces at every time there's a surface.

[00:05:19]>> Yeah. Okay? You just end up with a blob at the end. It's just a blob at the end and all the light would be scattered everywhere and you got nothing. Okay.

[00:05:25]And when I say it reflects because light will reflect off of practically any surface whether or not it's a mirror. That's what I'm saying.

[00:05:32]>> Okay. As a matter of fact, in in in photography they have something called a bounce board and it's just a stark stark white. I forget the color of white >> the light that comes back to you. Right.

[00:05:43]And that's all it does.

[00:05:44]>> Otherwise a flash can be very harsh.

[00:05:46]>> So you bounce it off of there and you get the you get the light without the harshness.

[00:05:49]>> Without the harshness. So, now you took care of that. Mhm. Now, the light enters the medium between molecules. Okay.

[00:05:58]Light is moving at the speed of light.

[00:06:00]Got you. But, it hits a molecule. I got I got to deal with the molecule. I got to go in and come out.

[00:06:05]>> it. Yeah. Uh excuse me. Pardon me.

[00:06:08]>> [laughter] >> Pardon me. Excuse me.

[00:06:09]>> Excuse me. I'm so sorry.

[00:06:11]>> Pardon me. Now, I'm speed of light again until I hit the next molecule. Right.

[00:06:14]>> And it's oh God, here we go.

[00:06:15]>> Here we go again. Right.

[00:06:16]>> walking in a New York City street behind [laughter] tourists.

[00:06:20]Yes.

[00:06:20]>> Yeah. Tourists are just in the way.

[00:06:22]>> Yeah. In the way that New Yorkers are not.

[00:06:24]>> That's right. And I figured I I analyzed that. I figured out why.

[00:06:27]>> Why? May I say may I go on?

[00:06:28]>> Please go ahead. I'll try to relate it to light going through a medium.

[00:06:31]>> Okay. Okay. Here's why. New Yorkers anticipate each other's trajectories because we've done this with each other before.

[00:06:41]>> It's a dance that we know. Yes, it's a dance we know. Whereas a tourist >> Mhm.

[00:06:45]they might step left unannounced.

[00:06:48]>> Mhm. Right. Who who No No nobody told you to step left cuz I'm about to pass you on the left.

[00:06:54]>> does that? Who Who does that?

[00:06:55]>> that? But, a tourist who's just ambling on looking looking up All right.

[00:06:59]ambling. Right. And so, you can't predict what their next move is, but for other New Yorkers you can.

[00:07:05]It's true.

[00:07:05]>> Not only that, there people who are I've walked perpendicular to people. They're on the sidewalk and I'm crossing the street. You time it. That's right.

[00:07:14]>> So, that you perfectly You know exactly.

[00:07:17]>> No, it's it's a dance. You got to live here to know the dance.

[00:07:20]>> Whereas the tourist will stop.

[00:07:21]>> Right. Well, now they just messed up my timing.

[00:07:23]>> Exactly. Okay, they'll look. They'll say, "Excuse me. Pardon me."

[00:07:26]>> Right. And you get people I'm trying to get in the subway.

[00:07:30]Okay?

[00:07:30]>> Mhm. And the train just lets out.

[00:07:33]>> Mhm. There people Tourists will wait for everyone to clear from the stair. No, you don't do that. YOU TIME IT.

[00:07:39]>> [laughter] >> YOU YOU MAKE YOUR PATH. YOU MAKE YOUR PATH. AND THEY KNOW you're coming down.

[00:07:43]They will move aside as they come down and you're going to right. Correctly.

[00:07:47]Just cuz it's a mass transit don't mean you just MADE ME MISS MY TRAIN. YOU KNOW THAT, RIGHT? That's what you did.

[00:07:52]Waiting in line to get on the damn stairs. WHAT THE HELL IS WRONG WITH YOU?

[00:07:56]I'M LATE FOR WORK.

[00:07:58]>> [laughter] >> AND BY THE WAY, STAND BACK FROM THE DOGGONE PLATFORM.

[00:08:02]NOT THAT I'M WORRIED ABOUT YOUR concerned about your safety, I'm late for work.

[00:08:06]YOU FALL ON THE DAMN TRACKS, GUESS WHAT?

[00:08:08]NOW I'M LATE.

[00:08:09]>> [laughter] >> OKAY, ANYWAY.

[00:08:13]I'LL GIVE NEW Yorkers a bad name.

[00:08:15]>> [laughter] >> Anyway, so the light in the medium is bumping into the molecules And in between It's going back at the speed it's traveling at the speed of Correct. So, the combination of getting through the molecule plus the speed of light between molecules on average slows down the propagation of light through the medium.

[00:08:37]Look at that. This is called the index of refraction. Ooh. It's and it's a beautiful mathematical construct.

[00:08:44]>> it. The index of refraction, yeah.

[00:08:48]Yeah, so Oh, I love it. And and I'll tell you how it works. The index of refraction, you can use that in a formula to tell you how much the light will bend coming in or out of that medium. That's how you make a lens at all, okay? But the index of refraction if you take the speed of light and divide by the index of refraction Go ahead. That's the speed of light in that medium. Ain't that something? That is really cool. Okay, so let's let's do the math. The index of refraction of diamond is 2.4.

[00:09:20]What is 1 / 2.4? 1 is like the speed of light / 2.4, what's the number?.4 something. Exactly, about.4. So, light in diamond is going 40% as fast as it goes in a vacuum.

[00:09:38]That's awesome. Isn't it? I love it so much.

[00:09:42]>> Yeah, yeah. And so diamond is is one of the hardest natural substances known.

[00:09:48]It's hard for light to get through as well. And even though it's transparent.

[00:09:52]>> Right. And before we get get all get all emotional about light trying to get through the medium.

[00:09:59]Visible light can't get through most mediums.

[00:10:02]Like a brick wall. Light's not going to go through it at all. Like, "Damn it."

[00:10:06]That's light trying to get through a brick wall.

[00:10:08]"Damn it."

[00:10:09]>> [laughter] >> If light If If light were given a voice >> Right.

[00:10:15]"Let's try the brick. Nope.

[00:10:17]Let's try the you know, the the steel.

[00:10:19]Nope. "Damn it."

[00:10:20]>> [laughter] >> "Damn it."

[00:10:24]But other wavelengths of light are transparent in these other substances as you know.

[00:10:29]So your cell phone works in here because the walls are transparent to microwaves.

[00:10:33]>> Microwaves. Right. Microwaves go Right on through.

[00:10:35]>> No problem.

[00:10:36]>> No problem. Uh they don't travel well through plaster, though.

[00:10:40]What are you talking about? Cuz my house, the walls are plaster. My house was built in 1898.

[00:10:45]>> there might be something else in your walls.

[00:10:47]Oh, you know what? You're right. It's a metal lathe.

[00:10:50]Metal lathe.

[00:10:52]Plus So here's what it is. It's plaster, then it's wood, then it's lathe, then it's metal.

[00:10:59]I bet there's a metal mesh to hold up the plaster.

[00:11:03]That's So you're in a Faraday cage, my son. Oh my god. Faraday cage.

[00:11:07]>> That's what it is.

[00:11:08]>> That's right. If you're surrounded by a metallic anything >> grid. Yeah. Okay, then the electrons in the metal will conspire to prevent electromagnetic energy from entering.

[00:11:20]That's why I can only hear the voices when I go outside. So that's [laughter] why. Don't blame the plaster.

[00:11:25]Damn. Plaster ain't nothing to do with this.

[00:11:28]That's Wow, look at that. Okay.

[00:11:29]>> Yeah, back then they would put up the mesh and and and they put the plaster to hold the plaster up cuz all of the the little the grid of the metal. So, if you have multiple internal reflections, that's the light just going back and forth. Oh, by the way, by the way, check this out.

[00:11:46]Check this out. Are you ready? What?

[00:11:47]Okay. So, if I have two media Okay. two media with different indices of refraction, okay? So, I have light coming up from one, it crosses the border and it bends. Anytime you go between two media the path of light bends. It will bend, okay? Right. That's why sunset happened 5 minutes ago.

[00:12:08]Right.

[00:12:08]>> Because the light bent going from vacuum of space to our atmosphere and it gave us an extra 5 minutes of sunlight because it refracted around the your horizon.

[00:12:20]>> Nice.

[00:12:21]>> Okay. So, it will bend. Now, watch this.

[00:12:23]It comes up and it bends. Right.

[00:12:27]Yes. Suppose I take >> the angle of the light and make it steeper like this.

[00:12:35]Then that will keep this come further and further down. There is an angle at which the light never enters the next medium.

[00:12:45]Oh.

[00:12:46]>> Because this bend now takes it backwards into the medium itself and it's called total internal reflection. Oh, wow.

[00:12:54]That's something I avoid at all costs.

[00:12:56]>> [laughter] >> That's why I can't sleep at night.

[00:13:00]So, here's So, that's that angle.

[00:13:01]It's It's still in the other medium.

[00:13:03]Right. Bam! Now it's total internal reflection.

[00:13:06]>> That's pretty cool, man.

[00:13:07]>> It's very cool.

[00:13:07]>> That's I love that.

[00:13:08]>> It's And And you can know exactly what that angle is, what the what they how to do that. And so, if you have an optical system where the light is just bouncing back and forth it is within the parameters of in Or you can have just a reflective surface as well.

[00:13:23]>> Right. Just a mirror would do that, right? But anyhow what you do inside your medium is your business. Yeah. [laughter] And what that then does to a beam of light. But, yeah.

[00:13:34]Interesting.

[00:13:34]>> is. That's all I can That's the all I can do to illuminate. See what I did there?

[00:13:40]>> Mhm. To illuminate that question. There may be other places to go in the physics of optics that I would not have known to touch. Very cool, man. That was a What a great question, and thanks, Youssef. And welcome to the club. Today's episode is sponsored by Delete Me, a service I use to take back control of my personal online data. You know I've been on the internet a long time, and for years I thought the worst thing that could happen to me was reading the comment section. Well, I was wrong. With the advent of AI, data breaches, and data brokers, your digital footprint isn't just a history, it's a target. You know the old saying, if you're not paying for the product, you are the product? That means that every free service you've used for the past decade or more has been collecting your personal information.

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[00:15:50]And we never had this conversation. You know what I'm saying.

[00:15:53]All right, this is Vic G. He says, "Hey there, Lord Nice, Dr. Tyson. Vic G here from California with a question for each of you. Are there any cosmic mysteries that you are most looking forward to knowing their resolutions, but sadly may not be resolved in our lifetimes? Bonus points if you can name mysteries that we are so close to resolving, but is probably just beyond our reach." Okay, you go first.

[00:16:22]Well, see, my mine is the easiest because I just want to know um what exactly is causing the acceleration and the expansion of the universe.

[00:16:34]You're like everybody else, wants to know that.

[00:16:35]>> Because that's everybody else, but but the reason is because I believe that it's a pressure from outside of our universe that bleeds through. That's what I think it is, and I just >> there's a puppet master? No, well, I don't I won't not going to call it a puppet master. I think there's a bleeding. That's what I'll call it.

[00:16:57]>> An injured puppet.

[00:16:58]>> An injured puppet master. [laughter] Leakage.

[00:17:02]>> A leakage, leakage of pressure.

[00:17:03]>> Because what that If we were to find that out, now we have to explore the leak. And that means we're looking at a whole 'nother universe, [singing] and to me, that's fascinating. That's interesting.

[00:17:17]>> Yeah. Yeah. You have to then explore the leak.

[00:17:21]>> leak now. Okay. So, I can't I can't top that. That's good.

[00:17:26]>> [laughter] >> No, I would say I don't think we're going to know Mhm. for sure if there's life in the universe in my lifetime. Woah.

[00:17:38]>> Intelligent life in the universe.

[00:17:39]>> you you you win the bonus points because that is something we are very, very close to.

[00:17:45]But, it's very possible we may not find it in our lifetime.

[00:17:48]>> Yeah, I don't think in my lifetime we will know that. What we will know in our lifetime is if there's any life at all outside >> in our own solar system.

[00:17:57]>> system. In our own solar system.

[00:17:58]>> Okay, cuz we're looking at Europa.

[00:17:59]Right. We did a whole episode. We we went to JPL.

[00:18:04]>> Right. Jet Propulsion Lab, NASA in Pasadena.

[00:18:07]>> That's right. Talked to the the the Europa Clipper people.

[00:18:09]>> That's right.

[00:18:10]>> Talking about what are they going to do, what are they going to measure it, what's beneath the ice. So, we will know whether or not Yeah. there has ever been or is currently life in our solar system other than on Earth. Yes.

[00:18:25]>> I think that will happen. But, it would be sad if there is no life other than life on Earth. You know, you know what has been said? Mhm.

[00:18:34]How profound it would be if we discovered intelligent life in the universe.

[00:18:41]But, how more profound it would be if we discovered that we're alone.

[00:18:48]Listen, the second one is far scarier >> It's a little scarier, isn't it?

[00:18:53]>> cuz that means >> of want neighbors, don't you?

[00:18:55]>> all of this was a mistake.

[00:18:58]>> [laughter] >> No, it would feed many religious thinking that the whole universe is just for us.

[00:19:06]>> [laughter] >> That That's Okay. That's what I said.

[00:19:13]Some some branches of Christianity, and perhaps other religions as well, require that life on Earth be the sole object of God's creation.

[00:19:23]>> Okay, I'm just going to say it, and please don't judge me here. I'm being logical, and I'm thinking like God.

[00:19:33]All right.

[00:19:34]>> [laughter] >> That's the dumbest crap I ever heard, and here's why it's stupid. I don't need to do all this, okay? I don't need to do all this.

[00:19:43]>> I'm God right now. I don't need to do all this to show you that you're the only thing necessary, and uh good, and my central and crowning creation. As a matter of fact, all I really need is the sun and the Earth. Because that's our That's the energy system that makes all of this happen.

[00:20:10]>> else matters.

[00:20:11]>> Nothing else matters. So, if the sun, like a hydrogen atom, had just the Earth going around it, then I would say, "There is a God, and he made this just for us."

[00:20:27]But, when you look at the vastness of the universe, and the trillions of galaxies, all of which containing stars, billions and billions of stars in each galaxy, to a a place where we can't even fathom the number of celestial bodies that are out there, then what you're saying to me is I'm stupid, and I like to waste my time.

[00:20:57]I like to waste my time. That's what I'm doing.

[00:21:00]>> So, God is an inefficient manufacturer of Exactly. And that's it. I'm Right, it doesn't make any sense. So, either there's a lot more of us out there, not meaning us, but life, all over the place.

[00:21:09]>> This was Giordano Bruno's argument.

[00:21:12]>> Who is that? You know who Giordano Bruno I never talked about him.

[00:21:14]>> we never talked about Bruno.

[00:21:15]>> Bruno? Who's Bruno? He's a monk.

[00:21:18]I'm sorry. That just sounds funny. But go ahead.

[00:21:20]>> He's a 16th-century monk.

[00:21:21]>> No, really?

[00:21:22]>> Yeah. Yeah. He had just He had just read Copernicus' book Mhm. De revolutionibus, which is puts the sun back in the I say back cuz the Greeks knew this, but it got lost in the Dark Ages. But the sun back in the middle of the known universe.

[00:21:38]>> Okay. He, religious man, Okay.

[00:21:41]God-fearing man, said, "Hm, if the sun is in the middle and not Earth, that means Earth is a planet going around the sun like Jupiter and Mercury and Mars and Venus. If the sun has planets and we're life on a planet, maybe these stars in the night sky are just like our sun. And if they are, maybe they have planets. And if they have planets, maybe they have Uh life.

[00:22:09]>> Life. Right. Heretical. Oh, they killed him. THEY KILLED [laughter] BECAUSE that meant Earth was not the object of God's creation.

[00:22:19]>> There you go. So, they put him on trial, sentenced him to death, >> Oh my god. burnt him upside down, naked, in the Campo de' Fiori, uh the the Piazza in Rome, >> Right.

[00:22:35]>> and I think that's in Rome, not Florence. And they drove a stake into his mouth to shut his ass up. So that even in the afterlife, he would not be preaching heresies.

[00:22:50]>> [sighs] >> We don't Okay. Okay. We do not deserve to be a species who makes things. Okay.

[00:22:56]You know what his one of his last words were? UH LET ME GUESS.

[00:22:59]>> [screaming] >> STOP.

[00:23:02]STOP.

[00:23:03]>> [laughter] >> OKAY, BEFORE THAT.

[00:23:10]>> OKAY.

[00:23:11]>> [laughter] >> HE SAYS he had a few good last words. My favorite among them was "Your god is too small." Yes. Ooh. Way to go out. Way to go out.

[00:23:25]>> Way to go out, man. Your god is too small.

[00:23:29]>> Too small. You got just Earth and the Sun?

[00:23:31]>> Yes.

[00:23:32]Yeah. So, anyhow.

[00:23:33]>> Oh my god. Okay, first of all, I'm going to read up on this guy. Bruno is his name, huh? Giordano Bruno. Cool name, too. So, check this out. Um, you know, some people know my background, but uh, one of my last words before I left my other life, my religious life, uh, was over this whole idea of homosexuality. I never understood it. I still don't understand it. Like, why people have a problem with it and why would god have a problem with it. I couldn't get around it. As I'm studying to become, you know, a a minister. Right. So, it's cuz it's in Leviticus. Yeah, but Leviticus is full of [ __ ] anyway.

[00:24:11]I mean, honestly, you know how many people have read Leviticus? Me being one. Okay.

[00:24:16]>> [laughter] >> So, anyway, um, so I my one of my last >> someone told me, Jewish person told me, "Leviticus are just suggestions."

[00:24:25]Kind of. If they were important enough, they would have been a commandment.

[00:24:27]>> been commandments. Right. Mhm. No, seriously. The Levitical law, and by the way, it's a Levitical law for the priest. Okay, anyway.

[00:24:34]Anyway, um, I said, a a a god that needs me to fight this battle for him is not a god I want to serve.

[00:24:46]Ooh. If god needs me to fight this battle The homosexuality and then what?

[00:24:52]If that's the battle that I got to fight. Interesting.

[00:24:54]>> I I to be worried about two dudes doing it. Like that's what my god is all about. Two consenting dudes doing it.

[00:25:01]Like that's what I GOT TO WORRY ABOUT? I I can't serve that. I I got to be out.

[00:25:05]Anyway, so I love this Bruno dude and I'm going to Yeah, check him out. I'm going to check him out.

[00:25:09]>> All right. Awesome. Oh, by the way, there's a there's a memorial to him in the square.

[00:25:13]>> [laughter] >> I'm sorry. Looking very [snorts] A little late.

[00:25:18]>> [laughter] >> Sorry.

[00:25:21]He's there he's he's got his monk robe on and he's very solemn Mhm. there.

[00:25:26]Giordano Bruno. Yeah. Ooh, I can't wait.

[00:25:28]I think it was 1601, something like that. Yeah. That's amazing. Wow, what a great great story.

[00:25:35]I love it. Okay, this is Keith Koenigsberg. Koenig Koenigsberg.

[00:25:41]Koenigsberg. Yes. It was a K. It's a K.

[00:25:43]Yeah, yeah. Um Keith says, "Hello Team StarTalk. This is Keith here writing from New York, New York, big city of dreams."

[00:25:50]Uh here's a question I've been wrestling >> first one we've gotten from New York, New York.

[00:25:54]>> That's so true. We don't get a lot of New York New York We're right here in my office in the Hayden Planetarium and and we we're getting from Syria Right.

[00:26:02]Pakistan Pakistan all kinds of Chile.

[00:26:05]That's cool.

[00:26:05]He says this, "LIGO has used light waves to detect the shrinking and expanding of space caused by passing gravitational waves. But wouldn't the waves be in and out of the material of space?

[00:26:19]If space expands, don't your light waves stretch along with it? Uh and any other measuring rod, as Einstein would say, and cancel out the change?

[00:26:34]So >> Yes. Yes. Okay. Explain to me What the hell he was saying [laughter] just now? He's really asking.

[00:26:42]Cuz I'm confused.

[00:26:43]>> What he's saying is we we have a laser that bounces back and forth. Okay?

[00:26:48]We measure the trip of that laser with very high precision.

[00:26:51]>> Very high precision.

[00:26:51]>> What he's asking is if a gravitational wave washes over the measuring device, >> Mhm.

[00:26:58]how's the measuring device going to know if everything about it moves with it?

[00:27:04]I got you.

[00:27:05]Okay.

[00:27:07]Okay.

[00:27:08]>> Mhm. So, if I'm measuring your height, how how tall are you? I'm 5 10. You lying now? No, I'm 5 10.

[00:27:17]Okay. I'll give you five I'll I'll give you 5 9. That's it. Okay.

[00:27:21]So, you're 5 9 and I have a 5 9 uh tape measure and you look at it it says 5 9, right?

[00:27:28]Okay.

[00:27:29]Then we stretch both you and the tape measure.

[00:27:33]You're still 5 9.

[00:27:34]True.

[00:27:36]Unless you have some other way to measure what just happened. Uh they're called Ronda Santos heels.

[00:27:41]>> [laughter] >> Anyway, sorry. Go ahead. Okay.

[00:27:46]This is like a news item from the 8 years ago.

[00:27:47]>> Uh last year, but okay. It feels like it.

[00:27:50]Yeah, it does.

[00:27:52]So, you're absolutely right. If I stretch you and the tape measure, you're still 5 9.

[00:27:56]>> Right. But we're talking about something washing over the measurement system.

[00:28:00]>> but if but if So, now watch.

[00:28:02]It's because of that fact that LIGO, Laser Interferometer Gravitational Wave Observatory, has two lasers Ah. at right angles to each other. Oh.

[00:28:17]So, if one of them stretch, moving that way, it's not stretching the other one.

[00:28:22]>> way.

[00:28:23]And it's those two path lengths that we compare with each other. Got you. That's how we know if a gravitational wave washed over us.

[00:28:32]So, you got smart people designing this.

[00:28:34]That, first of all, is a brilliant question and secondly, those people they deserve the money.

[00:28:40]What money? Whatever money we gave them to make LIGO. Oh, oh, oh, the the the funding.

[00:28:45]>> Yeah. Whatever That's was, they deserve a foundation. They deserve that cuz that First of all, what a simple simple little answer to what could be um you know, altered results.

[00:28:57]>> Right. Right. Right.

[00:28:59]>> Interesting. I love it. So, 1915 Right.

[00:29:02]>> Albert Einstein puts forth the general theory of relativity.

[00:29:05]>> Okay. A year later, he uses the general theory of relativity to break predict the existence of gravitational waves.

[00:29:13]Right. But he doesn't think we'll ever detect them. Of course.

[00:29:16]>> energy level's so low and how's how would you detect It's 1916 for goodness sake. Okay? That same year he publishes a paper on the stimulated emission of radiation. Mhm. Which is the foundation for the laser.

[00:29:31]>> Right. 100 years later in 2016 >> Mhm. Or was it 2015? 99 or 100 years later All right. we discover gravitational waves using lasers. Damn.

[00:29:48]Bro, Einstein was gangster. Gangster. He was gangster.

[00:29:52]>> Gangster. Okay? Gangster.

[00:29:54]>> That's like a chicken laying a egg so you can discover a egg.

[00:30:00]OKAY.

[00:30:01]>> [laughter] >> I I YOU MADE IT WAY LESS PROFOUND. It [laughter] started out Normally, you would digest it into something more profound.

[00:30:11]>> and poetic.

[00:30:11]>> And poetic, but that was worse in all counts. It probably is, yeah.

[00:30:15]>> [laughter] >> Hey.

[00:30:16]That's Einstein. He was gangster.

[00:30:17]>> Gangster. Oh, yeah. That's Mhm. That's dope.

[00:30:20]>> All right. That's really Mhm.

[00:30:22]God. If you See, this is You don't love science.

[00:30:26]>> [laughter] >> Don't get angry with people. IF THIS DOES NOT MAKE YOU LOVE SCIENCE >> [laughter] >> I SWEAR.

[00:30:34]I'M GOING TO GO KICK YOUR ASS.

[00:30:35]>> YOU SHOULD YOU KNOW WHAT? You should go You should get a like a a dumbass poker. Fact. Right up.

[00:30:42]That's what they a big poker that's [snorts] brands Anyway, God help me.

[00:30:48]So good. That is so good. I'm Okay.

[00:30:51]Scott uh Jarboe says this. Mhm. Hello dynamic duo. My name is Scott Jarboe from Seattle, Washington and you mentioned, I believe, recently that we cannot gather data from sending a probe into a black hole as we would have no way to transmit any data collected because it could not escape the gravity of the black hole. Okay? So, my question is understanding we can't at this time, if we quantum entangle the instrumentation of the probe with a twin probe that was kept external, could we not record that data that way? And in fact, in general, would that not be a feasible mechanism for interstellar communication in faster-than-light speed? The state of each should instantaneously mirror. Is that correct?

[00:31:40]Quantum entangle I'm not a black hole entangled expert.

[00:31:44]>> Okay. So, it feels plausible that you should be able to entangle particles even though you lose one of them into the black hole. Right.

[00:31:54]>> It feels like you should be able to do >> know what the other particle is doing even though it's inside of a black hole.

[00:32:01]>> It should.

[00:32:03]But, and so someone interacts with the particle that just went into the black hole, Mhm. which then triggers the the measurement of your the one outside the black hole.

[00:32:16]>> outside of the black hole.

[00:32:17]>> And that way you knew something happened in the black hole. Right.

[00:32:20]I don't see why that wouldn't be possible. I I don't know what to say.

[00:32:25]>> I don't You know I don't know what to say.

[00:32:27]>> [laughter] >> You don't know what to say.

[00:32:30]I don't see why not.

[00:32:33]Okay.

[00:32:34]>> I Now, now, but they want to talk about faster than light communication. The problem is you're not your your thing has the information already built into it.

[00:32:43]Right.

[00:32:44]You can't after the fact change that information.

[00:32:46]>> Now that we know. That so this normally communication happens where oh, turn left instead of right. All right.

[00:32:54]All right. And if it's already built in, I can't do that. All right. And so there's still some jury that's out on how we will fully exploit quantum entanglement as a communication mechanism going forward.

[00:33:08]And from what I have read it's less favorable than you want to believe it is. Okay.

[00:33:14]>> For these reasons. All right. Okay. All right. All right. This is James Peterson. Hello to my personal astrophysicist and personal science comedian. My name is James Peterson from Lacey, Washington. Here are my scenarios and related questions. Two man spacecraft are approaching each other at a constant rate within a huge cosmic void. Neither one is accelerating or decelerating. They are no there are no other visible or detectable objects within this cosmic void. Just the blackness of the vacuum of space.

[00:33:46]Neither of them knows if they are moving or stationary. They only know that they are approaching each other at roughly 20% the speed of light. What would be the reference point for each of them to determine their individual velocities assuming that they could compare rates of time on their clocks as they passed?

[00:34:05]Could the relative speed of their clocks be used to determine their individual velocities and individual velocities relative to what? Everything is relative, you know?

[00:34:17]Do all these people have jobs?

[00:34:19]>> [laughter] >> To have the time to come up with questions like this?

[00:34:25]>> I know. It's just like this guy, weren't you satisfied with two trains leave the station at the same time. One in Chicago, one in DC.

[00:34:33][laughter] He didn't stop there.

[00:34:35]>> stop there.

[00:34:37]So. So, what he is not getting right in the question, the simple point is each of them does not know if they're moving. As far as they are concerned, they're stationary.

[00:34:50]>> Right. So, he's saying, "Well, they approach each other." I don't know that.

[00:34:55]As far as I'm concerned, I am still in a void. Mhm. And I see this other craft coming towards me. Right. There it is.

[00:35:01]That's That's the only thing that matters.

[00:35:03]>> That's it. That's it. And so, I will measure how fast it's moving. Right.

[00:35:07]There there'll be uh time dilation relative to me Mhm. as a function of how fast it's going.

[00:35:12]>> Mhm. It There's It's not more complicated than that.

[00:35:15]>> That's it.

[00:35:16]>> We don't have to do a double calculation >> Nothing. or anything. Right. We will each measure exactly the same thing about each other.

[00:35:22]>> Right. Because it's relative to the observer.

[00:35:24]>> It's relative to them. Correct.

[00:35:25]>> each one of us will see the other ship coming. We will measure that.

[00:35:29]>> will think we are not moving.

[00:35:30]>> And we're going to still stay stationary as far as we're concerned.

[00:35:32]>> Correct.

[00:35:33]>> And when the when the ship goes by, it's like, "Whoa, did you see that?" And that's going to be the end of it.

[00:35:36]>> That's it. Beginning and end of it.

[00:35:38]>> Right. And there were jokes back in 1905 when Einstein came out with this for the first time, special relativity.

[00:35:45]Uh they tried to egg him on. See, "Hey Einstein, when does Grand Central Station arrive at the next train?"

[00:35:51]>> [laughter] >> That's actually kind of funny.

[00:35:58]Damn.

[00:35:59]>> So. Boy, haters no MATTER WHAT. JUST HATERS no matter what.

[00:36:02]>> I know.

[00:36:02]>> Even Einstein had haters. Look at that.

[00:36:05]All right. So, this is Vexonnar who says, "Greetings, Dr. Tyson Who is who?

[00:36:08]Vexonnar. Vexonnar, okay.

[00:36:10]>> Vexonnar who says, "Greetings, Dr. Tyson and Lord Nice. What are you putting in your time capsule for the next generation to open?" Ooh, so.

[00:36:17]>> Interesting.

[00:36:18]>> So. So.

[00:36:20]Yeah. Yeah. Yeah. So. Go ahead.

[00:36:23]>> [laughter] >> I just got to say this. Okay? Mhm.

[00:36:28]and there's a book written on this. I forgot the name of it. Forgive me. I don't remember the author.

[00:36:32]But, there's nothing less interesting to a subsequent generation than an earlier generation's time capsule.

[00:36:41]Wow.

[00:36:42]And the evidence of this is nobody remembers where any of these time capsules [laughter] are buried.

[00:36:48]Hold their ceremony. There's there's and and there's a mayor speaks and then it's and then as things move on and culture advances and technology advances, no one cares what your sorry ass from 40 years ago thought was modern.

[00:37:06]And well, look at this, A PHONOGRAPH.

[00:37:10]>> [laughter] >> I WAS in Flushing Meadow near the Unisphere. Okay. Tell everybody what the Unisphere is. It's the thing outside of the old World's Fair stadium.

[00:37:23]It's a big giant globe, right?

[00:37:24]>> Yeah, yeah. It's the one that it's what anyone thinks of when they think of the Flushing Park. Okay? It's Earth. US Steel created this for the World's Fair.

[00:37:34]And then these three rings around it Right.

[00:37:36]>> evocative of John Glenn's three orbits around the Earth. I did not know that.

[00:37:40]I'm just saying. Just saying. So, there I am. This is maybe 15 years ago. I'm just sitting on a bench. I forgot why I was there. It's where I had to go I don't remember. Forgive me. I don't remember why I was sitting on a bench in Flushing Meadow. Okay.

[00:37:55]>> don't live in Queens. I usually I'm just driving through Queens. But, I'm sitting there and I look down and under the the under the brush I part of it Here is the time capsule from 1965. It was like a a time capsule buried in that spot.

[00:38:14]No one cares.

[00:38:15]>> put a bench on top of it. No one cares.

[00:38:17]>> Nobody gave a damn. There's no sound There's no memorial around it. No ceremony. Nothing. We have a time capsule for the Rose Center here.

[00:38:25]And they asked me, "What do I want to put in the time capsule?" So, I thought about it. I said, "Okay, I I'll tell you what I put in it. I put a MetroCard in it." Oh. And guess what? That's a good thing to put in it cuz they don't exist anymore.

[00:38:36]>> [laughter] >> So, you were ahead of your time.

[00:38:39]So, I put in a MetroCard. I think I put in a a a um an iPod. Okay. Okay. And and interesting.

[00:38:48]This is modern stuff. Right. At the time.

[00:38:52]We're all excited about it.

[00:38:54]But who cares? Right.

[00:38:57]Because like both of those things are nonexistent now. They're nonexistent and no one wants one.

[00:39:01]>> wants one. No one cares about them. No one wants one. We moved on. Right. So, I for me, time capsules, though they mean well, Mhm. I think are one of the greatest misplaced investment of our attempt to communicate with the future.

[00:39:16]>> Okay.

[00:39:17]That's very cool. I don't want to be victim of that.

[00:39:20]>> I don't Right. So, no, I'm putting I'm putting nothing in it.

[00:39:23]I'm putting um the transcript of every speech given by President Trump.

[00:39:28]Just the transcript. No No audio and no Just the transcript.

[00:39:32]>> Just the words.

[00:39:33]>> Just the words. Okay. So, that they could read it and go, "What the >> [laughter] >> What the Words of the most powerful person in the world.

[00:39:42]>> The most powerful man in the world said these words. [laughter] Okay. Let's see it. Thomas says this.

[00:39:49]>> [snorts] >> Uh Dr. Tyson, Lord and I send greetings from Hungary.

[00:39:53]>> Hungary, like >> Yeah, way to go. In an earlier episode, Dr. Tyson said, uh that mathematically the horizon of the universe has all the same properties as the event horizon of a black hole. That got me thinking, if our universe would be a black hole, knowing that gravity has no limits on range, could the continuous falling in of matter into our black hole universe explain accelerating expansion of our universe. And if that would be the case, is there any possible way to detect such matter since it would be at the edge of our known universe? Thank you for your work.

[00:40:31]>> That would be true. Good question. That would be true if if we were not expanding exponentially.

[00:40:40]Okay, so the fabric of the universe is expanding and because of that there's nothing falling in. Right. It it's taking it with it out to the edges.

[00:40:49]>> Yes. So if we were not that way and we just had our horizon, an object moving could just kind of cross our horizon and show up.

[00:40:59]And it'll just show up.

[00:41:02]Okay? If it moves in in that way. Or you wait enough time I should I should say that differently. Wait enough time that horizon washes over the next set of galaxies that are sitting there waiting to be seen by you. Because right now the horizon's 14 billion light years away.

[00:41:18]Wait a billion years.

[00:41:20]Then it's 15 billion. That's a whole extra universe that's in your horizon.

[00:41:24]>> Right. You know the the scariest day of them all will be? What? You wait another billion years and there's no new galaxies to reveal themselves.

[00:41:34]It meant you reached the actual edge of the universe.

[00:41:39]>> Yes. Not just the observable universe, but the edge.

[00:41:43]>> Of the whole universe [snorts] itself.

[00:41:46]That's a scary day right there. That's That's kind of a cool day though.

[00:41:49]>> It's kind of cool. Yeah.

[00:41:50]>> But it also means cosmology will evaporate because at that distance we're seeing things that are that old getting born, but if there's nothing there then the galaxies that a billion years ago were just born, they're now a billion years old. Right. In another billion years they're 2 billion years old.

[00:42:09]There's nobody new coming in that's just being born.

[00:42:11]>> Mhm. Gone is cosmology. Look at that.

[00:42:14]Yeah. Wow, that is a scary day. I have it on my calendar.

[00:42:18]>> [laughter] >> All right, this is Bill.

[00:42:21]>> This might be the last question, I think.

[00:42:23]>> Okay, last question. Look, Bill gets the last question. Bill says, "Hi Dr. Tyson Lord nice.

[00:42:28]Um this is Bill. I made it easy for Chuck to say shut up, Bill."

[00:42:32]>> [laughter] >> This is how you pronounce Bill.

[00:42:37]Uh he says from Ban- uh Ban- nock uh Ban- nock Scotland and he says, "I need some cheering up considering the state of the Earth in a few hundred years, maybe sooner if he whose name we shall not mention gets his way.

[00:42:54]Uh from now when humankind has finally turned Mother Earth against us, which species that exist just now would you imagine will pick up the cloak of dominance that we humans held for a few thousand years? Will they have Will they be land-based, sky or sea-based, or even amphibious? What is it about the species that leads you to that conclusion, or do you see a bright future for us and what that future would look like in the event we are still here in 25 25? Mhm. Ooh, a a a a question that is um I'll say laced with hope, but yet very dark. [laughter] Very dark and daunting.

[00:43:42]>> Yes, yes, it's both hopeful and darkful.

[00:43:45]Yes. So I have some important replies to that.

[00:43:49]>> Go ahead.

[00:43:50]>> there's a book written forgive me, I don't remember the author. It's called After Man. After Man?

[00:43:56]>> Something like that. Okay. Okay? And is that like What it does is it renders humans extinct and it looks at other animals to see what to see what would become of them.

[00:44:09]Oh, I thought it was a woman who left her husband for a lesbian relationship.

[00:44:14]After [laughter] man.

[00:44:16]I am so much happier, I can't tell you.

[00:44:19]How much better it is with no man.

[00:44:22]>> [laughter] >> Which by the way seems to be the consensus by the way. But apparently, anyway. So, so After man.

[00:44:30]>> And so I looked it over. I didn't read every word, but there's it's highly illustrated. It's intriguing. It is.

[00:44:36]Okay.

[00:44:37]>> Okay. Now Cuz who would have bet on us? Consider.

[00:44:41]What's the largest animal there ever was? Um from what I understand, it is the blue whale.

[00:44:49]>> And it is alive today.

[00:44:50]>> It's alive today.

[00:44:50]>> And what kind of animal is it? It is a mammal.

[00:44:52]>> Mammal. Yes.

[00:44:53]>> Okay.

[00:44:54]Uh do you know the size of the smallest mammal? Um I don't, but I think it's pretty small.

[00:45:00]>> It can fit inside of a like a teacup.

[00:45:01]Yeah. It's like this big. Yeah.

[00:45:03]>> I think and some marsupial.

[00:45:06]>> Yeah, it's like a little shrew or something like that.

[00:45:08]>> Marsupials Marsupials are mammals.

[00:45:10]>> it's some little thing.

[00:45:11]>> Yeah. Okay, this big and the whale.

[00:45:13]So, mammals have the capacity to not only occupy practically any size range, but practically any place on Earth. They can figure out how to live there.

[00:45:24]>> And we are on every place on Earth.

[00:45:26]>> Basically. That's it. We're even We're bacteria, but but I'm just talking animals.

[00:45:30]>> We're a different kind of bacteria.

[00:45:31]We're more like a virus.

[00:45:32]>> [laughter] >> I'm talking human beings.

[00:45:35]So, unlike reptiles and other cold-blooded creatures, they can't exist Right.

[00:45:41]>> in in cold climates.

[00:45:42]>> Right. Right? Cuz they would just freeze [clears throat] and die. But we maintain our body temperature no matter where we are. All right. The reason why I'm saying this is this book said, "If that's the case, what's limiting the size of rats?" Um I don't know.

[00:45:57]>> But I'll tell you, ready? Go ahead. I could be wrong, but just just put it out there.

[00:46:01]>> Cats?

[00:46:02]>> [laughter] >> THE SIZE OF NOT NEW York rats. Yeah.

[00:46:07]The size of the hole they will run into so that you don't harm them. Really?

[00:46:12]Okay. Just think about that.

[00:46:13]>> Yeah. Go look in the subway. You see rats? Yeah. They'll They'll crawl and there's a hole they go into.

[00:46:17]>> There absolutely There always is.

[00:46:19]>> is.

[00:46:19]>> No matter what rat you're talking about.

[00:46:20]>> is.

[00:46:21]>> Right.

[00:46:21]>> There's a hole. Yeah. Okay.

[00:46:23]If humans aren't here, they don't need the hole. Oof.

[00:46:27]Which is why you get some They're not rats, but they are part of Rodentia in certain parts of the world where they're as big as like Like a capybara.

[00:46:37]>> Like a capybara.

[00:46:38]>> rodent is is like Like a small horse.

[00:46:40][laughter] So, rodents, which are one of the most successful branches in the tree of life, >> Yeah. for how many they are and how many species there are, >> Mhm. okay? How many species are there in the branch called Homo? I don't know. I would have one. It's Homo sapiens. Homo sapiens. We're the only ones left. Left.

[00:47:02]>> Correct. Cuz when you say how many species, I was I was trying to think of We're the only ones left. Homo sapiens That makes us quite fragile Right. on the tree of life.

[00:47:09]>> Yeah. Rodents, so many of us. So many of them. Okay, so this book foresees that basically rodents take over.

[00:47:19]And they become huge.

[00:47:21]Like people sized.

[00:47:22]>> Oh.

[00:47:24]Like rats that are people sized.

[00:47:25]>> That's scary. And they not There's nothing there And nothing to stop them.

[00:47:29]>> Nothing to stop them. Nothing to stop them.

[00:47:31]>> You dirty rat.

[00:47:32]>> [laughter] >> And it talks about uh uh aquatic creatures. Right. What is it?

[00:47:38]The penguin gets really large or something.

[00:47:40]>> Right. The So, when you take away a predator, Right.

[00:47:45]>> There's no longer a limit on the size of what it is. Okay. So, Earth after humans, uh I picture a natural history museum.

[00:47:55]With a bunch of giant rats walking through. Walking through. Looking at us.

[00:47:59]I know. And it's all, "Mommy and Daddy, what's that?" And there's like human skeletons there and say, "Oh, those were CALLED DUMB ASSES.

[00:48:07]>> [laughter] >> THEY USED to run the earth at one point, sweetie. And then let's let's talk about the dinosaurs. They They ruled the earth.

[00:48:16]Yeah, yeah. So, these dumb asses, what they like to do was burn stuff. Dig it out of the ground and burn it, sweetie.

[00:48:22]And and they would burn it and it would release something called carbon into the atmosphere and then they all died and now we run this >> they kill each other for any reason at all?

[00:48:30]>> they also like to kill each other.

[00:48:32]>> [laughter] >> You know?

[00:48:34]So, So, that's the future of earth because earth and other life forms are going to survive us, for sure. Exactly. All right. So, don't do this all stuff about this green movement, "Save earth." No.

[00:48:46]Earth's going to be fine. Save your ass.

[00:48:49]>> [laughter] >> That's what you need to do. Earth's going to be fine. SAVE YOUR ASS.

[00:48:54]>> [laughter] >> THAT MAKES A LESSER [snorts] POSTER IN THE IN THE MARCH.

[00:49:01]Save your ass. Save your [laughter] ass.

[00:49:03]Okay. All right. So, but in terms of hope, In terms of hope, Here's the hope.

[00:49:09]Mhm. I I boy here's from Scotland.

[00:49:12]That's right. I gave a public talk a few nights ago. Someone asked me what was my favorite song ever.

[00:49:17]Really?

[00:49:17]>> And you know what I told them? What?

[00:49:19]Amazing grace. Okay. I think that's the song of the millennium.

[00:49:25]Amazing grace.

[00:49:26]>> song.

[00:49:26]>> It's a beautiful song. And you know how it's most beautifulest?

[00:49:30]Okay. No.

[00:49:32]In bagpipes.

[00:49:33]Okay.

[00:49:35]I'm not a fan of bagpipes.

[00:49:37]You would be if you heard it and play amazing grace.

[00:49:41]You know, >> That's all I'm saying.

[00:49:42]>> Okay. I'm not And bagpipes, that's a Scottish thing.

[00:49:45]>> It really is.

[00:49:46]>> So, what I'm saying is, when life and the world gets us down, we should hear chorus of bagpipes performing Amazing Grace. [snorts] How sweet the sound.

[00:49:59]Let's say the wretch like me.

[00:50:01]>> Cuz we're all wretches and we need saving. It's true. From each other. So, Scotland may may be the savior of us all. Well, look at that. All right. We got to go.

[00:50:12]>> to go, right?

[00:50:13]>> That was fun. That was so much fun.

[00:50:15]>> All right. This has been yet another Cosmic Queries. What kind of edition?

[00:50:18]This is Cosmic Queries grab bag.

[00:50:21]>> Grab bag with Chuck Nice, of course.

[00:50:24]Neil deGrasse Tyson here, your personal astrophysicist. Always good to have you, Chuck.

[00:50:28]>> Always a pleasure.

[00:50:29]>> As always. Keep looking up.