SPEAKER_1: Coming up on StarTalk, Cosmic Query's Grab Bag Edition, from right here at my office, the Hayden Planetarium, the American Museum of Natural History.
SPEAKER_1: Your questions this time touched on all kinds of wacky, weird things, like what happens in a black hole, out of a black hole, quantum entanglement, this universe, other universes, the shape of the universe, all of the above and more.
SPEAKER_1: Welcome to StarTalk, your place in the universe where science and pop culture collide.
SPEAKER_1: StarTalk begins right now.
SPEAKER_1: This is StarTalk.
SPEAKER_1: Neil deGrasse Tyson here, your personal astrophysicist.
SPEAKER_1: Today, it's gonna be Cosmic Query's Grab Bag.
SPEAKER_1: Chuck.
SPEAKER_1: You the grab bag man.
SPEAKER_3: No, I'm just part of the bag.
SPEAKER_3: I'm not really much of the grab.
SPEAKER_3: I'm part of the bag.
SPEAKER_1: And we got Gary O'Reilly joining us here.
SPEAKER_1: And apparently, in previous grab bags, I was insufficient to serve the needs of the questions.
SPEAKER_4: Oh, you got that email.
SPEAKER_1: So y'all went out and got one of my colleagues.
SPEAKER_4: Well, of course.
SPEAKER_4: It's all about sharing care.
SPEAKER_1: Oh, sharing care, so Charles Liu, our returning champion, and still champion.
SPEAKER_1: Charles Liu, friend and colleague, and we go back.
SPEAKER_2: A long way.
SPEAKER_1: Almost 30 years now.
SPEAKER_2: What a pleasure.
SPEAKER_1: Yeah, so thanks for all you bring to StarTalk.
SPEAKER_2: Always happy to be here.
SPEAKER_2: Happy to see you.
SPEAKER_1: And you're still our geek in chief.
SPEAKER_2: Thank you.
SPEAKER_1: And you are the evidence that the geek spectrum is infinite in all directions.
SPEAKER_1: Because however geeky I am, one need not be impressed by that when they see the geekier person than me.
SPEAKER_2: I would not presume.
SPEAKER_2: But thank you so much.
SPEAKER_2: It's very kind.
SPEAKER_2: I'm really happy to be here.
SPEAKER_1: So you guys got the questions from our Patreon supporters?
SPEAKER_4: All right, I'll kick us off.
SPEAKER_1: All right, let's do that, Gary.
SPEAKER_4: These are exclusive questions from our Patreon contributors, so thank you very much.
SPEAKER_4: Go on, you want to jump in, Chuck?
SPEAKER_3: Here we go.
SPEAKER_3: This is Laz, and Laz says, hey, Neil and Chuck, he's talking about Chuck.
SPEAKER_2: Thanks, Chuck.
SPEAKER_3: And he says, this is Justin from Houston, Texas.
SPEAKER_3: I was wondering.
SPEAKER_2: Wait, I thought it was Laz.
SPEAKER_3: Well, he goes by Laz.
SPEAKER_3: Laz since his handle.
SPEAKER_1: Yeah, that's his name.
SPEAKER_1: That's because his handle doesn't have to be your name, dude.
SPEAKER_1: Get with the century.
SPEAKER_4: We're having another nerd fight.
SPEAKER_3: That was rather aggressive.
SPEAKER_3: It's all right.
SPEAKER_3: He says, I was wondering the other week, if gravity affects the flow of time and black holes are concentrated gravity, would the age of the universe be different based on the size of your nearest black hole?
SPEAKER_3: Side question.
SPEAKER_3: If I were to make a theoretical cloak of black holes around my body, would time cease to exist for me or would it change the rate of time inside the cloak at all?
SPEAKER_1: Yeah, so he's feeling Harry Potter there.
SPEAKER_3: He really is.
SPEAKER_3: The invisibility cloak of Harry Potter.
SPEAKER_1: But it's a time cloak.
SPEAKER_3: It's a time cloak, right?
SPEAKER_2: Yes.
SPEAKER_2: To answer the cloak question first, you can't make a cloak of theoretical black holes because you create basically one big black hole as a result.
SPEAKER_3: Right.
SPEAKER_2: And the stuff on the inside, time could stand still, but you've created essentially an event horizon around the interior of this cloak.
SPEAKER_2: So time could stand still for you if you were keeping time still at that point.
SPEAKER_3: So could you make like a Lagrange point of black holes where all the black holes are in a stable little, you know, environment and each event horizon is touching just enough where it doesn't tug and then you're just perfectly perched right in that middle of that.
SPEAKER_2: That is not-
SPEAKER_5: Listen to him talking about Lagrange points.
SPEAKER_2: It's great.
SPEAKER_2: It's wonderful.
SPEAKER_2: No, this is a very serious and valuable question.
SPEAKER_2: In fact-
SPEAKER_3: I learned it from watching you.
SPEAKER_2: Oh, that was from that wonderful drug commercial.
SPEAKER_2: Back in the day.
SPEAKER_2: Kids, yeah.
SPEAKER_3: Kids, parents.
SPEAKER_3: He was like, you're doing drugs.
SPEAKER_3: Where'd you learn this?
SPEAKER_3: And he says to his dad, I learned it from watching you, okay?
SPEAKER_2: Parents who do drugs have kids.
SPEAKER_5: Kids who do drugs.
SPEAKER_2: Yes.
SPEAKER_3: Go ahead.
SPEAKER_1: Did you guys grow up together?
SPEAKER_3: All right, go ahead.
SPEAKER_4: There's no way I could have done with you.
SPEAKER_1: Yeah, yeah, yeah.
SPEAKER_1: Just stay out of that one.
SPEAKER_2: You cannot put black holes just so they barely touch by event horizon and keep them stable.
SPEAKER_2: The quantum mechanical effects of gravitational radiation will inevitably cause them to crash into one another.
SPEAKER_2: Because they're not that way.
SPEAKER_2: However, Bowden Paczynski, who is an astronomer from a long, long time ago, or maybe Andrej Paholczyk, one of those two guys, maybe decades ago suggested that the centers of galaxies might contain configurations of black holes that were indeed kind of buzzing around a common center of gravity, like bees swarming around.
SPEAKER_2: Now, the problem in the end is going to be the gravitational radiation that comes from that.
SPEAKER_2: They will eventually collapse.
SPEAKER_2: If they're that close, they just can't stay in a stable configuration purely gravitationally.
SPEAKER_2: They need something else to keep them apart.
SPEAKER_2: Otherwise, they coalesce, they release gravitational waves, we see it at LIGO, and we can find out what that is.
SPEAKER_1: Yeah, but we don't have to be that exotic.
SPEAKER_1: Just put them on a planet orbiting very close to the black hole.
SPEAKER_1: As we saw in the film Interstellar, if you're really close to a black hole, your time takes way more slowly than everybody else.
SPEAKER_1: So is that all you need to solve his question?
SPEAKER_1: His question?
SPEAKER_5: Well, yeah.
SPEAKER_2: If you get close to the black hole, time for you runs more slowly, but the rest of the universe.
SPEAKER_1: We see your time runs slowly.
SPEAKER_1: No, time for you runs normal.
SPEAKER_2: For me, what I felt like was a second or two, it doesn't change anything, but you guys see me, right, having only been one second while you guys experience decades of life.
SPEAKER_2: So that particular question is hard to answer specifically that way, but the answer is, like you said, we solve the problem.
SPEAKER_1: In fact, the New York Times science journalist from the 60s and 70s, Walter Sullivan, wrote a book called Frozen Star back in the early days of black holes, where if you see someone about to fall in, they're basically frozen relative to you.
SPEAKER_1: You'll just see them just sort of pause.
SPEAKER_2: Yeah, and that's been used in a number of places.
SPEAKER_2: There was a TV show called Andromeda starring Kevin Sorbo, where he in fact was in the ship and was caught almost falling in.
SPEAKER_2: And during that moment when he was kind of caught, he didn't age at all, but other people did, and 300 years later, using more advanced technology, someone salvages his ship.
SPEAKER_2: And so now he's like fish out of water, a guy who's 300 years older than everybody else, and somehow he still can save the universe.
SPEAKER_3: So the first part of this question, which was if gravity affects the flow of time, are black holes concentrated gravity?
SPEAKER_3: So is a black hole, is the gravitational effects of a black hole the result of the black hole, its density, or is it actually gravity itself concentrated?
SPEAKER_2: Well, gravity, Neil, tell me if I'm explaining this okay, is essentially the curvature of space-time caused by mass.
SPEAKER_2: Okay, so yeah, and mass and energy.
SPEAKER_2: So if a black hole is sitting there, we don't necessarily think of it as a concentrated point of gravity, but rather as an object that happens to warp space and time so significantly that it has an event horizon around it.
SPEAKER_2: So to answer that question, I think, is to express it.
SPEAKER_1: Yeah, I don't know if it's semantic at that level, because Newton was, there's an object and there's a gravitational field, all right?
SPEAKER_1: Einstein is, there's an object and space-time is warped in the presence of that object, and everything you do and how you move is influenced by this curvature of space-time, and you measure that curvature to be gravity.
SPEAKER_1: So it turns out that might sound semantic, but that Einsteinian description is way more accurate in predicting phenomenon in the universe.
SPEAKER_1: And so, but to quibble over what happens to the time, yes, time slows down for you.
SPEAKER_1: After that, I don't know what more interesting there is to talk about.
SPEAKER_2: And there's, of course, one of the most important parts of the general theory of relativity is the equivalence principle, which means that at some point, you can't tell the difference between the curvature of space-time causing you to move differently and some sort of acceleration that's causing you to move differently.
SPEAKER_2: So, as far as the time changing and differing, I think Neil has the right idea on this one.
SPEAKER_1: Charles, aren't all parts of the general theory of relativity important?
SPEAKER_2: Yes.
SPEAKER_2: But some parts are more important.
SPEAKER_6: Thank Hello, I'm Finkie Baroque Allen, and I support StarTalk on Patreon.
SPEAKER_6: This is StarTalk with Neil deGrasse Tyson.
SPEAKER_1: All right, who's next up?
SPEAKER_4: All right, Bill Bailey.
SPEAKER_4: Hi, Bill.
SPEAKER_4: Says, Guardians of the Galactic Groove.
SPEAKER_4: My innocent bystander.
SPEAKER_4: Say I fall into a black hole, I cross the event horizon if, and we're back to Kevin Sorbo.
SPEAKER_4: If there really was a singularity in my future, not a point in space, would it take me till the end of time to reach it?
SPEAKER_4: Are you of the opinion that black holes are really places as opposed to objects?
SPEAKER_4: Bill Bailey hails from Ohio, so here we go.
SPEAKER_2: Our black holes places are objects.
SPEAKER_2: Black holes are definitely objects.
SPEAKER_2: They can move through space and time.
SPEAKER_4: There's no doubt.
SPEAKER_3: They can collide, so clearly.
SPEAKER_2: So they are objects.
SPEAKER_2: But the singularity that Bill is describing would be a place, possibly a place inside the black hole.
SPEAKER_2: Because singularities might not even have to exist.
SPEAKER_2: As long as something is inside an event horizon, we actually don't know how the material is structured inside it.
SPEAKER_2: So when you're falling, Bill, you actually are falling in toward the event horizon.
SPEAKER_2: You don't know if there's a singularity there.
SPEAKER_2: And in fact, it would take you a huge amount of time, possibly an infinite amount of time, to fall into the black hole as you.
SPEAKER_2: Because what happens is that the black hole's event horizon grows to meet you.
SPEAKER_2: And as you look in toward the event horizon, the things closer to the event horizon to you, you see their time going more slowly.
SPEAKER_2: But if you look backwards, then the time is going more fast or quickly and the other direction.
SPEAKER_2: So at the moment you are reaching the black hole's event horizon, you see the entire history of the entire universe of that location simultaneously.
SPEAKER_1: The entire future history of the universe behind you unfolding, right?
SPEAKER_1: Because you've slowed down.
SPEAKER_2: And the entire past.
SPEAKER_1: And the entire past.
SPEAKER_3: Because time has basically stopped for you.
SPEAKER_3: Yeah.
SPEAKER_5: That's so, I'm crazy!
SPEAKER_5: Insane!
SPEAKER_1: The universe is under no obligation to make sense to you.
SPEAKER_3: Well, it succeeded.
SPEAKER_3: It certainly succeeded.
SPEAKER_3: That is insane!
SPEAKER_2: In these big, huge concepts that we're talking about here about quantum versus general relativity versus space and time, it sometimes can be helpful to think of time as always existing, past, present and future.
SPEAKER_2: And you're just filling in that dimension as you happen to pass through it.
SPEAKER_1: We are prisoners of the present forever transitioning between our inaccessible past and our unknowable future.
SPEAKER_3: Oh, that's in the Bible.
SPEAKER_2: Prisoners sounds so depressing.
SPEAKER_2: Makes me feel like I'm Patrick McGuinn or number six.
SPEAKER_1: Don't put emotion in what I just said.
SPEAKER_1: It just is.
SPEAKER_2: Maybe we're not prisoners.
SPEAKER_2: Maybe we're privileged participants in the present.
SPEAKER_3: Oh, that sounds like a creepy prisoner to me.
SPEAKER_3: Don't worry, one day you'll be able to leave the basement.
SPEAKER_2: Not now.
SPEAKER_3: Not today.
SPEAKER_2: What do we say to the gods of prison?
SPEAKER_1: By the way, that me uttering that line was lifted by Beyonce for her international tour between songs.
SPEAKER_3: Are you serious?
SPEAKER_4: All right, so who is the author of that particular quote?
SPEAKER_3: That's him, man.
SPEAKER_1: It would be me.
SPEAKER_1: That's him.
SPEAKER_4: Thank you.
SPEAKER_4: I didn't know that before.
SPEAKER_4: That's why I asked.
SPEAKER_1: Oh, you didn't know?
SPEAKER_4: No sarcasm.
SPEAKER_1: Yeah, well, that's how.
SPEAKER_3: So wait a minute.
SPEAKER_3: Okay, now I'm derailing the show, but I gotta derail the show.
SPEAKER_3: I'm sorry.
SPEAKER_1: Because somebody mentioned Beyonce.
SPEAKER_5: Yes, exactly.
SPEAKER_1: You can't keep a focus.
SPEAKER_1: Stay focused.
SPEAKER_3: Come on.
SPEAKER_3: Come on, you mentioned Beyonce.
SPEAKER_3: I mean, it's a law.
SPEAKER_3: Whenever somebody mentions Beyonce, all things must stop.
SPEAKER_3: And we gotta talk about Beyonce now.
SPEAKER_2: Beyonce did do one of the greatest videos of all time.
SPEAKER_3: Which was?
SPEAKER_5: Of all time.
SPEAKER_3: Of all time.
SPEAKER_3: Oh, that's right.
SPEAKER_3: I'ma let you finish.
SPEAKER_5: I'ma let you finish.
SPEAKER_5: Please.
SPEAKER_2: What?
SPEAKER_3: What did Beyonce, how did Beyonce get this quote to say?
SPEAKER_1: I'm on the internet somewhere saying it.
SPEAKER_1: And her people, or she, saw it, said, that's cool.
SPEAKER_3: No, but what I'm saying is, did they use your voice?
SPEAKER_1: Yes.
SPEAKER_3: Okay, that's different.
SPEAKER_3: So here's what I'm thinking.
SPEAKER_1: Yeah.
SPEAKER_3: Okay, I'm thinking, you know, got me lookin so crazy right now.
SPEAKER_3: Thank you!
SPEAKER_3: We are all prisoners.
SPEAKER_3: Like, that's how I thought it went down.
SPEAKER_5: Yeah.
SPEAKER_3: But it's you, it's actually you saying it.
SPEAKER_1: It's my voice.
SPEAKER_5: We're all just prisoners here of our own lives.
SPEAKER_1: It wasn't for the domain, it was for the international tour.
SPEAKER_3: Okay, but I thought she was quoting you, but really what they were using you as a part of the actual concert.
SPEAKER_5: Yeah.
SPEAKER_3: That's still cool, that's really cool.
SPEAKER_3: That's, you know.
SPEAKER_4: We get back on the road.
SPEAKER_3: I mean.
SPEAKER_1: Oh, and people ask me, well, how much did they pay you?
SPEAKER_1: So I told them how much and they say, dude, you should have gotten Beyonce tickets.
SPEAKER_5: It would have worked much more.
SPEAKER_1: It was like, no, but I'm not-
SPEAKER_3: Now we gotta get you in a Taylor Swift concert.
SPEAKER_1: All right, who's next?
SPEAKER_4: You wanna go, I'll go.
SPEAKER_3: No, you go.
SPEAKER_1: Do I think all's about black holes?
SPEAKER_3: These are all about black holes in the beginning.
SPEAKER_1: Well, I should have said that at the top.
SPEAKER_3: Oh no, not everything's about-
SPEAKER_1: Okay, okay, go.
SPEAKER_4: This one's from Matthew, again, these are all Patreon patrons that are contributing these questions, so thank you very much.
SPEAKER_4: I, Neil, Charles and Chuck, Matthew from Dallas, that'll be in Texas.
SPEAKER_4: Is there a way to transfer information-
SPEAKER_1: You said Dallas, Norway, yes.
SPEAKER_4: Yeah, no, it actually says Dallas TX, so I'm just in case there's like a Paris, Texas, as opposed to Paris, France.
SPEAKER_1: This is America, dude.
SPEAKER_1: We know where Dallas is.
SPEAKER_4: Do we?
SPEAKER_4: We're so happy for you.
SPEAKER_2: It's just south of Amarillo, right?
SPEAKER_4: Oh, here we go.
SPEAKER_5: Your record here.
SPEAKER_4: Is there a way to transfer information-
SPEAKER_4: He's giggling.
SPEAKER_4: Is there a way to transfer information with quantum entanglement?
SPEAKER_4: If so, can we instantaneous communication anywhere in the universe, no subspace required?
SPEAKER_2: At the moment, quantum entanglement could provide instantaneous information transfer, but we haven't been able to confirm it.
SPEAKER_2: There's no way yet for us to be able to conduct an experiment that can show that quantum entangled particles could transfer information faster than light.
SPEAKER_2: There's nothing mathematical that says that it can't, but there's nothing physical that says that it can.
SPEAKER_3: Okay, so he says no subspace required.
SPEAKER_3: Okay, what is subspace?
SPEAKER_3: Is there a subspace?
SPEAKER_2: Subspace-
SPEAKER_1: Are you really asking that?
SPEAKER_1: Are you asking that?
SPEAKER_4: I think Chuck's asking it on behalf of our audience.
SPEAKER_3: I am asking on behalf.
SPEAKER_2: Let's not be harsh on Chuck.
SPEAKER_2: Subspace was invented by Star Trek writers because it needed to find a way to move things faster than light from one point to another in our universe.
SPEAKER_2: And so-
SPEAKER_1: Not just things, but communication.
SPEAKER_2: Yes, subspace communications are even more amazing than actual traveling through subspace.
SPEAKER_2: But what you do is your warp nacelles create a warp bubble around you, which puts you out of our universe and into subspace, which then allows you to squirt forward like a little bubble through space time at faster than light.
SPEAKER_2: So warp 10 is an infinite speed, and you get, it's a logarithmic scale, warp nine and not warm 9.9 and warp 9.99 and so on and so on.
SPEAKER_2: Just gets you faster and faster and faster.
SPEAKER_1: That's where the engines really can't take it.
SPEAKER_1: I can't take it.
SPEAKER_2: That's right.
SPEAKER_3: She's breaking up, Cap'n.
SPEAKER_3: She can't take it, Cap'n, I can't do any more.
SPEAKER_2: The USS Voyager.
SPEAKER_1: Scotty and Shrek were the same.
SPEAKER_3: Yeah, Scotty and Shrek were the same, you know.
SPEAKER_2: The Star Trek Enterprise D could go around, could go around warp 9.4 at a sustained period of time.
SPEAKER_2: But Star Trek Voyager had 17 decks and had a nominal cruising speed of warp 9.975.
SPEAKER_2: So it was a speedy little ship.
SPEAKER_1: Okay, so subspace allows, because with regard to communication, if they're just having banter with, you know, home base, what the United-
SPEAKER_2: Starbase, Starfleet, San Francisco.
SPEAKER_1: Starfleet Command.
SPEAKER_1: If they're just having conversation back and forth, that's not really possible if it's moving at the speed of light.
SPEAKER_2: So all those conversations in Star Trek or through really any space show had to be going through some medium other than regular space.
SPEAKER_1: Right.
SPEAKER_4: We're nowhere near that right now, are we?
SPEAKER_2: Not anywhere close.
SPEAKER_4: We're nowhere.
SPEAKER_2: Next question.
SPEAKER_3: All right.
SPEAKER_3: This is Windy Sue and Windy says, hi Dr.
SPEAKER_3: Tyson, Dr.
SPEAKER_3: Liu, Mr.
SPEAKER_3: Nice, the glue that holds everything together.
SPEAKER_3: I'm from Shanghai, China.
SPEAKER_3: I didn't know Shanghai in China was the glue that holds everything together.
SPEAKER_3: If gravity is the curvature of space time, say if two celestial objects were to stay completely still relative to each other, they would feel zero effect from each other's gravity because they are not moving through the fabrics.
SPEAKER_3: Thanks for bringing back the joys of learning.
SPEAKER_3: I don't think, I missed the question.
SPEAKER_3: If gravity is the curvature of space time, say if two celestial objects were to stay completely relative to each other, they would feel zero effect from each other's gravity.
SPEAKER_2: They would.
SPEAKER_3: I guess the question is, is that the case?
SPEAKER_2: It turns out that no, they would still feel the effects.
SPEAKER_2: You see, because gravity, say you have object A, it has a gravitational field, it distorts space time around it.
SPEAKER_2: Object B is over here.
SPEAKER_2: It distorts space time around it.
SPEAKER_2: Even if they're still with one another, they still feel the distortions.
SPEAKER_2: The distortions do not change with time if they're exactly apart, but they still feel each other.
SPEAKER_2: So they may not accelerate toward each other, but they feel that force.
SPEAKER_2: They should accelerate toward each other if no other forces or accelerations are present.
SPEAKER_2: That would have to be the case if the two of them are staying absolutely still with respect to one another.
SPEAKER_2: The only way that they would not feel each other's gravity is if they didn't have any gravity at all.
SPEAKER_1: I will quote John Archibald Wheeler.
SPEAKER_1: Will you?
SPEAKER_1: He's dead.
SPEAKER_2: He's dead, Gary.
SPEAKER_1: Is it final?
SPEAKER_1: Go on.
SPEAKER_1: Mass tells space how to curve.
SPEAKER_1: Space tells mass how to move.
SPEAKER_2: Ooh.
SPEAKER_1: Okay, so in this case, we have two objects that have curved space-time in their vicinity.
SPEAKER_1: That's all the instructions they need to fall towards one another or towards each other.
SPEAKER_1: Because they're following the path that they can't help following.
SPEAKER_3: I love how specific how you differentiated one another from each other.
SPEAKER_1: Each other is just between two people.
SPEAKER_2: So if they're staying...
SPEAKER_1: Your mama.
SPEAKER_1: I was going to make your mama proud.
SPEAKER_1: She taught English.
SPEAKER_3: I was the one who said it incorrectly, so she's proud of you.
SPEAKER_2: So if they're perfectly still with respect to one another, they are experiencing something else that's keeping them perfectly still with respect to one another.
SPEAKER_2: Otherwise, they would be accelerating toward one another.
SPEAKER_1: I have an addendum to this, if I may.
SPEAKER_2: Please.
SPEAKER_1: One of the most realistic scenarios to deflect an asteroid that might be headed our way is to take a spaceship, park it near the asteroid in perfect path with it.
SPEAKER_1: So park it...
SPEAKER_1: It's a moving asteroid.
SPEAKER_3: I know what you mean.
SPEAKER_3: It's a moving asteroid, so it's just moving alongside of it.
SPEAKER_1: So it moves alongside of it.
SPEAKER_1: And they want to move towards each other.
SPEAKER_1: But you have little retro rockets on your spacecraft that prevent that.
SPEAKER_3: So every time it tries to move towards, the retro rockets fire, and it's just like, I'm just going to move over here.
SPEAKER_2: And it's like, where you going, baby?
SPEAKER_1: So the meteor, the asteroid, the comet, ends up getting pulled towards the spaceship through the gravitational field.
SPEAKER_1: So in a way, it's like a gravitational tractor beam.
SPEAKER_2: Don't stand so close to me.
SPEAKER_3: Very nice.
SPEAKER_4: So you don't need much of a deflection.
SPEAKER_1: If you get it early enough, tiny deflection is all you need.
SPEAKER_3: Right.
SPEAKER_1: That also has the benefit that some asteroids, comets, we think they're not very tightly held together.
SPEAKER_1: Some might be just piles of rubble moving in unison.
SPEAKER_1: Whereas if you just go in and bust it up, who knows what that's going to look like.
SPEAKER_1: But gravitationally, that will affect all the particles together.
SPEAKER_1: And so you're good.
SPEAKER_4: Two in one.
SPEAKER_4: All right.
SPEAKER_4: This question, next question, is Javier Ortega.
SPEAKER_4: Javier.
SPEAKER_4: Javier Ortega.
SPEAKER_4: I'm an engineer from Panama.
SPEAKER_5: Panama.
SPEAKER_2: The spirit moved me.
SPEAKER_5: I know.
SPEAKER_4: And it's great.
SPEAKER_4: Okay.
SPEAKER_4: The question is, the light of the stars travels away from it in an infinitely dense sphere of photons.
SPEAKER_4: Will every unobstructed object in the distance receive its photons?
SPEAKER_4: How can this be if in the far distance, the rays will spread apart from the star?
SPEAKER_4: I know we can be talking about quantum waves instead of photons, but even in that case, I can't figure out how this light can maintain its density through the distance and size greetings from the past.
SPEAKER_4: Love your show.
SPEAKER_2: You're welcome.
SPEAKER_2: I think I understand the question.
SPEAKER_2: In this sense, imagine a star, and the rays come in every direction.
SPEAKER_2: Those rays start spreading farther and farther apart so that they'll not intersect some stars, whereas they will intersect others.
SPEAKER_1: Does every single sight line on to a star from every single distance receive light?
SPEAKER_1: And how could the star be giving off that much light?
SPEAKER_1: That's a great question.
SPEAKER_3: That's a great question, but how could it not?
SPEAKER_3: I mean, seriously, I mean, because no matter where you are and whatever vantage point, you will see light.
SPEAKER_1: Here's what I want to check.
SPEAKER_1: Just check me out on this.
SPEAKER_1: I'm thinking just in real time because I didn't have the answer ready made for this.
SPEAKER_1: No, no, here's what I want to…
SPEAKER_4: That's the whole idea of this.
SPEAKER_1: Here's what I wonder.
SPEAKER_1: As your distance gets greater and greater from the star, the energy density of the light diminishes.
SPEAKER_2: Correct.
SPEAKER_1: So the intensity drops and drops and drops and drops.
SPEAKER_1: And so there will be a point where it's below your ability to detect it.
SPEAKER_1: Maybe that's this point in practice for what it is you're talking about.
SPEAKER_2: In practice, there is a detection threshold.
SPEAKER_2: And therefore, for any detector, any real world, in mathematical reality, you actually can in fact, eventually receive light from every single object in the universe.
SPEAKER_2: This is the basis of Olbers paradox.
SPEAKER_2: Why is the sky dark at night?
SPEAKER_2: If there are enough stars out there, every line of sight should get some light from it somehow.
SPEAKER_2: And you eventually wind up filling the entire night sky with stars or star light one way or another, no matter what.
SPEAKER_2: So why is the star?
SPEAKER_2: Why is the sky ever dark?
SPEAKER_2: And part of the answer, one way to think of the answer is that light travels at a finite speed.
SPEAKER_2: And therefore, not every spot actually has a light source where the light has had time to reach your eye yet.
SPEAKER_2: Another point...
SPEAKER_1: An object can be so far away, in the time it has turned on, there's not enough time for the universe to reach it.
SPEAKER_1: There's like one of three ways.
SPEAKER_2: There are different ways out of this thing.
SPEAKER_2: But that's one way that you can think about it.
SPEAKER_2: Another way is this detection limit.
SPEAKER_2: Your eyes can't see them even though it's there.
SPEAKER_2: Right now, one of the famous things that we do in science is to try to find cosmic background radiation, right?
SPEAKER_2: Microwave radiation is famous from the Big Bang, but also there's cosmic infrared radiation background, there's cosmic visible light background.
SPEAKER_2: Like exactly how much is it?
SPEAKER_2: Spaces that we looked years ago that were completely blank, had nothing in there, we stare at it with the Hubble Space Telescope or JWST, and thousands of galaxies appear.
SPEAKER_2: It's all a matter of detection.
SPEAKER_2: So hopefully that answers the question there.
SPEAKER_2: And if we're talking about like the light from the Big Bang, where the entire universe is being filled with all of this light that existed at the moment that the universe began, what's going on there is that the entire spectrum of that background light is being stretched as space is expanding.
SPEAKER_2: So that's why that light, which used to be a gamma rays, is now microwaves.
SPEAKER_2: And so you can fill the space.
SPEAKER_2: So you can fill the space with the same amount of energy, just each spot in space has much less of it.
SPEAKER_3: So there you go.
SPEAKER_2: Deep significant question.
SPEAKER_4: Yeah, some great questions.
SPEAKER_3: People have been on point today, man.
SPEAKER_2: Guys, we've got like five minutes left.
SPEAKER_1: So, Charles, you and I have to tighten our game here, okay?
SPEAKER_1: Charles, you pulled out your stopwatch, what's up?
SPEAKER_3: So, I figure if we gotta get through these quickly, then we'll just do a time limit on each question.
SPEAKER_3: And then you guys have to determine whether or not you can answer it in that.
SPEAKER_3: So, what do we say, 30 seconds?
SPEAKER_3: I think that's a good round number.
SPEAKER_1: All right.
SPEAKER_2: 30.
SPEAKER_1: That's sound bite.
SPEAKER_3: That's a long time.
SPEAKER_1: Even the news finds you on the street.
SPEAKER_2: Make it 10.
SPEAKER_1: 10 seconds?
SPEAKER_3: No, that's too much.
SPEAKER_3: That's too short.
SPEAKER_4: You're the Usain Bolt of science.
SPEAKER_3: You don't have to use the whole 30 seconds.
SPEAKER_3: I'm just saying that the most of it can be.
SPEAKER_1: If you can do it in 10, do it in 10.
SPEAKER_3: If you can do it in 10, do it in 10.
SPEAKER_3: But 30 seconds, time is up.
SPEAKER_1: I don't want to take five minutes explaining why we're only going to take 30 seconds.
SPEAKER_3: All right, here we go.
SPEAKER_1: Go.
SPEAKER_3: This is Jamie Wilson.
SPEAKER_3: Greetings, Dr.
SPEAKER_3: Tyson and honored guest, Charles Liu.
SPEAKER_3: If you could time travel to any point in human scientific history, which time period would you choose and why, Jasmine, from Santa Rosa, California?
SPEAKER_2: Whoa.
SPEAKER_2: Trinity, first nuclear explosion.
SPEAKER_1: I would time travel back to the collision of Thea and Earth, which made the moon.
SPEAKER_1: I want to see that in the night sky.
SPEAKER_2: Dang.
SPEAKER_3: I would time travel forward to a place where black people are doing okay.
SPEAKER_1: He, he, he.
SPEAKER_1: So, Thea would be now four and a half billion years ago, right?
SPEAKER_1: And Trinity would now be 70 years ago, 80 years ago.
SPEAKER_2: 1945.
SPEAKER_1: Yeah, okay.
SPEAKER_4: All right, next question.
SPEAKER_4: Frederick Deschamps, Fred's from UP, Michigan, and would like to know if you, Charles, have read the Discworld books.
SPEAKER_2: Ah, yes, by Terry Pratchett.
SPEAKER_4: Yes, indeed.
SPEAKER_4: What kind of fun physics can you think of taking place on a magical land such as?
SPEAKER_2: Well-
SPEAKER_1: Did he also ask for Easter eggs that we might have missed?
SPEAKER_4: No, he said there's sons of physics Easter eggs in it.
SPEAKER_2: Terry tells all kinds of cute physics jokes because this world is literally a disc, but it sits on elephants, and then there's a turtle that the elephants are standing on, and it just kind of swims through the universe.
SPEAKER_2: So it's a-
SPEAKER_1: So it's not turtles all the way down.
SPEAKER_4: Right.
SPEAKER_1: It's just turtles one layer deep.
SPEAKER_2: Yes.
SPEAKER_1: Okay.
SPEAKER_2: So it's almost like a giant disc-shaped spaceship that's going through the universe.
SPEAKER_2: That's what it is.
SPEAKER_2: And it-
SPEAKER_2: Yeah, are you guys feeling any flat earth trauma going on here?
SPEAKER_2: This is rough.
SPEAKER_1: It's disguised.
SPEAKER_2: But Terry was one of those folks that always told good jokes about science.
SPEAKER_1: I stole five of a second.
SPEAKER_2: It's all good.
SPEAKER_2: Now, his humorous physics Easter eggs were good enough for me.
SPEAKER_2: I have yet to speculate, aside from this very good point, that you're basically seeing new constellations all the time.
SPEAKER_2: Yeah.
SPEAKER_2: All right, go ahead.
SPEAKER_4: This question's from Logical Hillbilly from wonderful West Virginia.
SPEAKER_4: I have a question about white holes.
SPEAKER_4: Here we go.
SPEAKER_4: Although Einstein's equations show that mathematically they can exist, nothing has been found that fits the description.
SPEAKER_4: Is it possible that there was only one white hole and it was, as what we know as the Big Bang?
SPEAKER_4: Thank you for all the awesome information.
SPEAKER_2: Last note, the white hole idea and what we have seen about the Big Bang are not compatible.
SPEAKER_3: Well, that only took nine seconds.
SPEAKER_4: World record.
SPEAKER_2: I told you.
SPEAKER_1: Wait, will you yield 10 seconds to me?
SPEAKER_2: I yield 20 seconds.
SPEAKER_3: Yeah, because you.
SPEAKER_1: You'll yield 10 seconds to the gentleman from the Bronx.
SPEAKER_1: So when white holes were first put forth, we deeply wanted quasars to be white holes at the edge of the universe.
SPEAKER_1: So there was a very high concentration of energy coming out of them.
SPEAKER_1: And when you compared what you'd predict for a white hole with every known object in the universe, nothing matched.
SPEAKER_1: So the white hole remains mathematical speculation, unfortunately, because it'd be a really cool pairing with the universe's black holes.
SPEAKER_4: Okay.
SPEAKER_4: Ready, set up.
SPEAKER_3: That wasn't 20 seconds, so.
SPEAKER_3: We made it under 30 seconds.
SPEAKER_4: Chase Matthews writing from Ventura, California.
SPEAKER_4: Do we have the capability of creating a Dyson swarm with technology available today, or maybe a similar structure in low Earth orbit?
SPEAKER_4: Dyson swarm, explain, please.
SPEAKER_3: It's a bunch of vacuums that you put the Dyson swarm.
SPEAKER_4: I set them up, you know, come down.
SPEAKER_1: I don't know what a Dyson swarm is.
SPEAKER_1: I just know what a Dyson sphere is.
SPEAKER_2: Yeah, imagine just a whole bunch of satellites that kind of surround a thing.
SPEAKER_1: All right, so it's not a full solid structure.
SPEAKER_1: Yeah, I mean, a Dyson sphere swarm around Earth would be pointless.
SPEAKER_1: The only point of a Dyson sphere is to trap energy coming from the thing in the center of the sphere.
SPEAKER_1: So you would put it around the sun.
SPEAKER_1: You would put it around the galaxy.
SPEAKER_1: You would put it around a galaxy cluster or a cluster of stars.
SPEAKER_1: Time's up.
SPEAKER_2: And my nine second version is that you can create a constellation like that around the earth.
SPEAKER_2: In fact, some people might be trying to do that, like say Starlink or something.
SPEAKER_2: But it wouldn't get energy.
SPEAKER_1: Yeah.
SPEAKER_1: There you go.
SPEAKER_3: You guys did it.
SPEAKER_2: Thank you.
SPEAKER_1: All right.
SPEAKER_4: Next question's from Sam Green.
SPEAKER_4: I've read that aerogels are heat resistant to extreme temperatures, in some cases, 1,300 degrees Celsius.
SPEAKER_2: Wow.
SPEAKER_4: Yeah.
SPEAKER_4: But are very fragile.
SPEAKER_4: Are there any applications or apparatus that could be developed to harness this property to explore the inner earth or use in nuclear reactors?
SPEAKER_3: Oh, look at that.
SPEAKER_1: Oh.
SPEAKER_1: Well, one application I just learned in the Paris Fashion Week.
SPEAKER_1: There is a handbag made out of aerogel as a new fashion addition.
SPEAKER_4: Do you have one?
SPEAKER_1: No, I don't.
SPEAKER_1: But I do have my own aerogel on the shelf.
SPEAKER_4: Well, of course.
SPEAKER_1: Yeah, but what it means is new materials have always influenced the creativity of artists.
SPEAKER_1: And right up and down, whenever something new happens, creative artists say, hey, that's a new material with these properties.
SPEAKER_1: I'm going to do the XYZ with it.
SPEAKER_1: So, but in terms of probing earth, Charles, I don't know how...
SPEAKER_2: Aerogels have been used in spacecraft.
SPEAKER_2: You basically encase them in something, and then that forms a very interesting and useful thermal barrier between something you want to stay hot and something you want to stay cold.
SPEAKER_2: So you could do that down into the earth.
SPEAKER_2: Problem is with the earth going into the earth, the pressure...
SPEAKER_4: Yeah, in earth.
SPEAKER_2: The pressure is too strong, it will crush the aerogel.
SPEAKER_2: Right, and then in a nuclear situation, the radiation will alter the structure of the aerogel, unfortunately, over time, and therefore render it not as effective.
SPEAKER_1: That's a good point, I hadn't thought of that.
SPEAKER_1: So its thermal properties would be different.
SPEAKER_1: There's energy from 1000 degrees Celsius, of course, but targeted particle energy from nuclear reactions would have completely enough energy to break apart all those molecules.
SPEAKER_1: So you'd have a pile of dust at the end.
SPEAKER_2: Sadly.
SPEAKER_1: By my read.
SPEAKER_1: Yeah.
SPEAKER_4: And no handbag.
SPEAKER_1: And no handbag.
SPEAKER_3: Last question.
SPEAKER_1: Last question, okay.
SPEAKER_1: Charles and I have been doing okay with the-
SPEAKER_3: I gotta tell you, you guys have really been-
SPEAKER_1: With the yielding of the time?
SPEAKER_5: You've been knocking it out.
SPEAKER_3: Pretty cool.
SPEAKER_3: The last one, you both did about, I mean, well, Charles was 30.7 seconds and you were 33 seconds.
SPEAKER_1: Okay.
SPEAKER_3: Which for you was like three and a half seconds.
SPEAKER_4: If this was a child's coloring book, you just went over the edges.
SPEAKER_1: Yeah, I know, that's a good way to do it.
SPEAKER_3: Who stays in the lines?
SPEAKER_4: Anyway, right, Gabe Malek.
SPEAKER_4: I'm a high school student from Washington, DC.
SPEAKER_4: I'm writing, what is the most agreed upon geometrical nature of the universe, Euclidean or non-Euclidean?
SPEAKER_4: Or is it spherical?
SPEAKER_3: Oh, okay.
SPEAKER_2: It's Euclidean.
SPEAKER_1: Flat.
SPEAKER_2: Absolutely.
SPEAKER_2: It has been confirmed as a consensus almost completely by everyone.
SPEAKER_1: Yeah, no one is denying this.
SPEAKER_1: And we get that from the dark energy, which flattens out what would otherwise be a spherical shape or a saddle shape.
SPEAKER_1: The dark energy flattens that out.
SPEAKER_2: That is still a mathematical hypothesis.
SPEAKER_1: What is?
SPEAKER_2: We have measured the universe to be Euclidean and perfectly flat.
SPEAKER_2: And then we think that it is the dark energy that causes it to stay flat, like inflates it just enough.
SPEAKER_2: But we don't really know that.
SPEAKER_1: What do you think is making it flat?
SPEAKER_2: We don't know, but that is one hypothesis.
SPEAKER_1: I told you it was making it flat.
SPEAKER_2: You have to confirm that.
SPEAKER_2: There has not yet been an experiment confirmed.
SPEAKER_1: Is there something else out there that you think could be making it flat?
SPEAKER_2: Possibly.
SPEAKER_1: Like what?
SPEAKER_2: Something called quintessence, which is not exactly dark energy.
SPEAKER_2: There's also-
SPEAKER_2: Sounds like a fragrance.
SPEAKER_3: Quintessence.
SPEAKER_2: But the idea is that the geometry-
SPEAKER_2: I like it.
SPEAKER_3: Quintessence.
SPEAKER_1: Yeah, it's-
SPEAKER_2: By Cody.
SPEAKER_1: Flat.
SPEAKER_2: Yeah.
SPEAKER_1: Measured flat.
SPEAKER_1: And we good.
SPEAKER_4: Okay.
SPEAKER_2: So, why?
SPEAKER_2: We have more left to figure out.
SPEAKER_3: There you go.
SPEAKER_1: There you go.
SPEAKER_4: You're a young person, still in high school, so probably time on your side to work it out.
SPEAKER_1: Yeah, and let the print lab work it.
SPEAKER_3: You figure it out.
SPEAKER_3: That's right.
SPEAKER_4: Well, on you now, Guyp.
SPEAKER_1: Charles Liu, delighted to have you back.
SPEAKER_2: It is always a pleasure.
SPEAKER_2: We can take a tea chat.
SPEAKER_2: Fist bumps and handshakes all around.
SPEAKER_4: Way to go, guys.
SPEAKER_1: Oh, that's like Power Rangers.
SPEAKER_1: They all get together and they...
SPEAKER_4: The Mouseketeers, all for one and one for all.
SPEAKER_1: Oh.
SPEAKER_4: And the swords rooted in that.
SPEAKER_1: The Mouseketeers or the Mouseketeers?
SPEAKER_4: The Mouseketeers came later.
SPEAKER_2: Swiggle your ears.
SPEAKER_1: I swear he said Mouseketeer.
SPEAKER_1: All right, this has been another installment of StarTalk Cosmic Queries Grab Bag Edition, Leaning Black Hole, I must say, and Cosmology, but that made it that much sweeter.
SPEAKER_2: Black holes don't suck.
SPEAKER_1: Right, black holes don't suck.
SPEAKER_4: How long have you waited to say that?
SPEAKER_2: But if you fall in one, then that's your new home.
SPEAKER_2: In fact, this was composed by Harry Belafonte.
SPEAKER_2: Black holes don't suck.
SPEAKER_2: But if you fall in one, then that's your new home.
SPEAKER_2: No, they don't suck, they don't suck, they don't suck, they don't suck.
SPEAKER_2: No, they don't.
SPEAKER_3: I'm so glad he's dead right now.
SPEAKER_3: He did not have to hear that.
SPEAKER_5: It is time.
SPEAKER_1: Chuck, Gary, Charles, always good to have you guys.