Daniel and Kelly’s Extraordinary Universe - Black Hole Questions!

Episode Date: October 14, 2021

Daniel and Jorge answer listener questions about black holes Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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We'd love to have them on the podcast. Hey, Jorge, why do you think we get so many questions about black holes? Well, you know, it's the mystery. You know, they're so inscrutable. They're like the reclusive celebrities of the universe. Exactly, right? Like, the more they avoid the paparazzi, the more people want to know about them. That could be true, but I was actually wondering if it might be the exact opposite.

What do you mean? Well, what if black holes are like the car crash of the universe? They're like a cosmic disaster that you can't drive by without slowing down to check it out. They're saying physicists are just rubberneckers, cosmic rubberneckers? That sounds kind of dangerous. Like, you might cause another accident by not watching where you were driving your space. Exactly. That's the gravitational runaway effects of the black hole. Slow down to check it out, get sucked in, make a bigger black hole. That's how I feel about driving in Los Angeles. It's like an infinite black hole that you will never escape. the comics. Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, but I almost

never go up to Los Angeles. Really? Do you avoid it like a black hole? If it was a black hole, it would suck me in. So yeah, I'm trying to stay in orbit around Los Angeles instead of falling into the singularity. Yes, where time slows down through plastic surgery, apparently. But, yeah, I mean, you're kind of famous now, Daniel. You don't get calls from Hollywood these days? I screen my call, so if they're calling, I'm just not picking them up. You look for the area code. If it's your local area code, it's spam. If it's 310, then it's someone from Hollywood, like Jorge, so you just hang up.

Also, you know, there's famous, and then there's Los Angeles famous. You can be, like, super famous in Orange County and be nobody in Los Angeles. But anyways, welcome to our podcast, Daniel and Jorge Explain the Universe, a production of IHeard Radio. In which we ask all the biggest and famous and most time dilated questions of the universe. We ask all of them about where it came from, where it's going, what it's made out of, and how it all works. We dive deep into the questions about black holes and neutron stars

and galaxies and tiny particles and quasars and everything in between because we think it's possible to download all of that into your amazing brain and hold for a moment an understanding

of the entire universe. Yeah, because it is a pretty famous universe. Everyone seems to know about it. Everyone's fan, I would hope. You know, it's everywhere you go you can't get away from this universe. And it's pretty fascinating.

Even it's black sheep. know, everyone wants to know about the black sheep of the celebrities. Yes, have you been checking out the universe's reviews on Yelp? Yes, I think it has about infinite stars and also infinite thumbs, but, you know, it's about 50-50 up and down. That's right. And, you know, nobody has any other alternatives. It's not like people like, hey, I was in this other university the other day and they have better chips. So, you know, this is basically all we got. Learn to love it, people. Maybe you just need to get out more, Daniel. You might find other universes if you just, you know, get out of your Orange County bubble. L.A. does seem like another universe sometimes,

not just because it's weird, but because it takes forever to get there. Definitely an alternate reality, for sure. But anyways, yeah, people are curious not just about the universe, but about the things in it, especially the things that are extra mysterious. And those are the things that drive physics. We look around in the universe and we say,

do we understand how this works? Does that bit over there make sense? And if it doesn't, then we focus our brains on and try to understand how could that possibly work? How could that make sense? How could that be consistent with what we know about the nature of space and time and energy? And so the weirdest things are also the best opportunities to learn something about the universe. Yeah, because when you look around, I guess it's all pretty bright and beautiful and majestic and cosmic.

But every once in a while when you look out into the universe, there is basically a big hole, like a big hole in our knowledge. And also literally, figuratively, and in all the ways, there are actual holes in the universe. There are holes in the universe. And, you know, to answer the question of our intro, I think one reason that they're fascinating is because they are so different from what we experience, you know? It's not just like, hey, there's a banana out there in space. Like, we know bananas. We eat bananas.

We're familiar with bananas. You know, it's something out there in space, which is so different from our everyday experience, so bizarre that we just sort of like want to see it. Yeah. So today on the podcast, we'll be tackling. Unanswered questions. about black holes. Now, Daniel, I assume it's not just bananas out there. We don't know.

You know, maybe bananas are the fundamental element of the universe, and it is just all bananas all the way down. That's a viable theory. Sounds like a slippery slope there. We just got to peel back the layers of reality until we reveal the banana inside. But yeah, black holes. A lot of people have questions about black holes,

and you were asking me earlier why they're so mysterious, It's like everyone, you get a lot of questions about black holes, right? Yeah, I say like a third of all the questions we get are about black holes. What happens if you fall in them? What would they look like if you did this? What would happen if you shoot two black holes at each other? All sorts of questions. People love to think about black holes.

Interesting. A third of the questions. That's amazing. It's like it's on black hole in your inbox. It does make my inbox pretty dense. But I love it. I love thinking about black holes just as much as our listeners do for the same reasons, you know? And the cool thing about black holes.

holes is that we all understand them about as well. I love that we can bring our listeners to the very forefront of knowledge because in the case of black holes, it's not that far away. We just don't understand very much about these weird mysterious objects. I think that's why they're so fascinating to physicists because they represent such a great opportunity to learn something new and shocking about the universe. Yeah. So today we're answering questions that we've gotten about black holes from listeners, just like you. And we've got three pretty interesting questions. one of them about the mass of a black hole, about mini black holes, and also about whether or not black holes can explain dark matter.

So let's jump into our first question right away here, and it comes from Levi from the Ukraine. Hi, Daniel, Jorge. I'm Levi in Hebrew, Ukraine. And I had two questions about my favorite topic, which is black holes. First, how is the mass of a black hole calculated? And second, is there any way to know? when an event horizon of a black hole begins, if I were to, say, take a rocket ship to the black hole in the center of our galaxy, is there any way that I could know when I need to

turn that thing around before it becomes spaghetti? Thank you. Interesting question. Now, was he allowed two questions? I feel like he's not getting an extra question in. His question imploded into a black hole because of its density. Yeah, it multiplied, it seems. See, you just can't stop asking questions. Once you start thinking about black holes, the questions just proliferate. What do you think it's captured the imagination

of not just our listeners, but it seems like everyone out there has questions about black holes. I think it's just the opportunity to see something hidden, to learn something new. You know, the thing that captivates me about the black hole

is knowing that one of the greatest mysteries in modern physics, how to reconcile crazy intense gravity and quantum little particles, how to bring those together into one idea, is out there and it's hidden inside a black hole. So if we could only peek

inside, we could learn the very nature of space and time. There's so much we could know by the universe if only we could see inside a black hole and yet it's hidden from us. So it's sort of like somebody saying, I have the secrets you want and they're written on this envelope and I'm going to earn it. I'm going to throw it in the fire instead of opening it to you. That would kill you. Oh man, it'd be so frustrating. To know the answers are out there and to not be able to get them, that's very frustrating. These throw a big red button into that envelope that would drive you Doubly crazy. But all right, let's jump into Levi's questions here.

The first one is how do you calculate the mass of a black hole? Now, I'm guessing, Dan, there are not gigantic scales we can use to measure the mass of a black hole. Sort of we can, yeah. Scales work by using gravity, right? If you put something on a scale, you're measuring its weight, and its weight is the force of gravity on it, which is determined by its mass. And so to measure the mass of something, you can use the strength of the gravitational pull. on it, which depends on the object's mass. Now, out there in space, you're right,

there's not some, like, massive scale we can put it on, but we can see how the black hole tugs on things around it, which are visible, and that's one way we can measure its mass. I see you can see the effects of its mass on the things around it. I guess kind of like our sun, right? Like if our sun was a different mass, like if it was bigger or smaller, then our orbit around it would be different, right? Like, you could tell what the mass of the sun is maybe from our orbit.

Yeah, if you measure just the velocity and location of the Earth as it moved around the sun, you can deduce exactly the mass of the sun because you could tell what gravitational force is necessary to move the Earth in that path. And that would tell you how much mass you need to provide that gravitational force. So, yeah, the Earth is like a little scale that's measuring the Sun all the time. But what do you need to know the mass of the Earth too, pretty accurately? Yes, absolutely. You need to know the mass of the Earth. And don't say you just use the Sun because now we're in a circular argument.

No, you need to use the mass of the Earth, absolutely. The mass of the Earth you can get using, like, your knowledge of what it's made out of and its volume. So if you know the radius of the Earth, like its size and you're understanding roughly what it's made out of, then you can tell its mass. Or you can bootstrap. You can say, well, I'm going to look at the moon and see how the moon moves around the Earth. And that's going to tell me the mass of the Earth, if, again, you know the mass of the moon. Yeah, and so on and so on. I guess at some point, maybe the question is, at some point, when do you have to guess, right?

Because at some point you have to guess what the moon is made out of or even the Earth, you kind of have to guess. I mean, we have some measurements, but ultimately you're sort of guessing what's inside the earth. Yeah, in the end, you do need to know the mass of one of the objects to measure the mass the other. But there's also some constraints there. Like what you really need to know is the product of the two masses, right? Mass 1 times mass 2. So if you make enough measurements of pairs of objects, then you can narrow that down. You get like enough systems of equations that you can constrain it.

But yeah, you also do need to say something about what they are made out of to get some information about how much mass one of them has. You can also measure the mass of the earth by flipping that around and saying, here I have an object whose mass I know, and I can measure the gravitational effect on it. And from that, I can measure the mass of the earth. So you build like a calibration object, like a test object, like a one kilogram pound of platinum or something. Yeah, you can see how much it pulls on like a known weight. And then that's how you would estimate the mass of the earth. And that's just sort of definitional. You say, like, this is the definition of a kilogram, this object.

And from that, you can measure essentially the ratio of its mass to the mass of the earth. You can say, how massive is the earth in terms of this object I'm defining to be one kilogram? And then you can bootstrap your way up to the sun and basically everything else in the universe. Right. You can strap your boot. You can boot your strap. But what about for like a black hole? I mean, they're so far away. We've barely seen one directly. You know, we can see the things flying around it. But how do we know what those things are? I mean, they're just like bright little pinpoints, right?

Yeah, so one way we can see the black holes exist is by seeing their gravitational effect on stuff nearby, because black holes, of course, are black. They don't emit any radiation directly, or if they're emitting hawking radiation, then we can't see it. It's too faint. So you're right, we need to know the mass of the objects nearby. And so, for example, the black hole, the center of our galaxy has some stars whizzing very close by to it.

And we can measure the mass of those stars by looking. at the light they emit because we have a pretty good model for how the brightness of a star is related to its mass. So we did a whole episode on how you measure the mass of stars. And that's not perfect. It's not exact, but it's pretty good. Right. It's based on like models and some observations. And so just from the light that you get from the stars around the black hole, you can say, oh, that's a stage so-and-so star weighs about, they usually wait about this much. And so therefore, and it's curving around the black hole this much. So therefore, that black hole is probably this many kilograms.

Exactly. And those models are pretty good and we validate them using binary star systems where we can see two stars. We can measure their brightness and we can see how they move around each other. And so we can really validate those models pretty well. I mean, there are uncertainties. But we can trust those because remember, there are a lot of binary star systems out there in the universe, many more than you might expect.

So that lets us measure the mass of the stars and from that to deuce the mass of the black hole. Because remember, black holes don't emit any information from there inside except for the total mass of the black hole, which can be deduced by its gravitational effect. That's the only information that comes out other than the black holes spin and charge. And also do you have to account for like the camera adding 10 pounds? Like does a telescope add you know 10 million kilograms? No, the black hole's agent is very particular by the cameras we use to take their pictures. I see. It uses doubles when it's taking naked pictures. I said take the profile above the accretion disc. That's when it looks good. All right. And there's also sort of a different way to measure the mass of a black hole,

which is by looking at its size. Like if we ever do get better pictures of a black hole, you might be able to tell how heavy it is by just seeing its size, right? Because the size of the event horizon depends on the mass of the black hole. Yeah, they're very closely connected. As the black hole eats more and gets more mass,

then it is gaining in size. The size of the event horizon is growing. And so if you could measure the event horizon, then you could deduce its mass. Measuring the event horizon is tricky, though, because you need to see photons like whizzing around it. So you need a direct picture. And we've done that for one, maybe two black holes now, but it's much harder, obviously.

And so that brings us to the second question Levi had, which is like, if I'm trying to check out a black hole, like, could I tell where the actual event horizon is? Like, at what point do you want to make sure you turn around before you get sucked in forever? Well, I would say turn around now. Do not take that trip to the black hole. It's not a good idea. Don't even buy the tickets. That's when you should turn around. Right. So it is a good idea to think about where a black hole begins, where its event horizon is,

so that if you are a billionaire scientist entrepreneur and you do take that trip to the center of the Milky Way to study the black hole, you know when to turn around. And one thing you could do if you know the mass of the black hole is you could just calculate it. You could say, well, I know how massive it is. So I know the point of no return. I can calculate the event horizon. So yeah, there's a point at a distance from the center of the black hole at which not even. light can escape, right? I think maybe that's what Levi is asking, like, what's the point where not even light can escape? That's the event horizon. And from a distance, you can sort of see it, right? Like, it's sort of where, when you look at a black hole, and we've looked at one, it looks like a big black circle. And so that's generally where the event horizon is,

although it's not exact, right? That's right. The black circle you see when you look at a black hole is actually bigger than the event horizon, because you can't see photons that, like, fly just above the event horizon from behind the black hole. Those will get curved and fall into the black hole. So there's the event horizon itself and then there's like a shadow that the black hole makes that's even larger than the event horizon. You can get closer than the shadow you see. It looks bigger than it actually is. And as you get closer and closer to the black hole, that shadow grows. And it grows to take over more and more of your view. So if you're very close to the black hole, for example, then it might appear to take up like half of your entire view. Right. That's the kind of

the tricky thing about black holes is that there's so much distortion around them that, you know, from afar, they look like a nice, clean circle. But as you get closer, everything gets distorted and kind of blown out of proportion. And so it's going to be really hard to tell when you've reached the actual event horizon, right? Because like you're saying, the black hole's going to start taking about more and more of your field of view. And you're going to be like, am I in or am I out? I don't know. Yeah, exactly. And so this is very dangerous, not to be recommended or endorsed. But as you get closer and closer to black hole, the image of it grows larger and larger. And as you say, what you're seeing is not anymore a good representation of what's actually there. Like when you

look around yourself in your room, the stuff you see is the stuff that's there because the light is moving in a straight line from whatever it is to your eyes. And so you can look around and say, oh, that's over there and this is over here. But if there are like lenses around you that bend the light, then you get distorted images. Imagine you're in a fun house mirror. What you see is not what's actually there. And that's what's happening with the black hole. Light is no longer following straight lines. So what you see is a distortion. And it's really interesting as you get closer and closer to the black hole,

then the shadow of the black hole, this big black image of the event horizon, gets larger and larger. Eventually it becomes more than just half of your view. It like takes up most of your view and the rest of the universe is squeezed down into a smaller and smaller circle. And you can get a clue about when you're about to cross the event horizon. Because when you cross the event horizon, that circle that is the rest of the universe is now shrinking down to a tiny little dot. And once you fall inside the event horizon, then the rest of the universe is now

exactly one tiny little point where light from the universe can still reach you. Yeah, it's a pretty trippy experience and pretty extreme. And actually, if you want to know more about this, it's conveniently a question we answer in our new book, right, Daniel? Frequently asked questions about the universe. That's right. This is a frequently asked question.

What would it be like to fall into a black hole? And the book is a lot of fun. It's out on November 2nd, 21. You can check it out at universefaq.com. It's filled with answers and a bunch of really awesome cartoons at Jorge Drew. They give you a sense for what it would look like to fall into a black hole. Yeah, order a copy for yourself, for your nieces and nephews, uncles, and best friends. But we do sort of go into a lot of details because there are a lot of details about going into the black hole. And I'm not sure we can cover all of them. So please check out the book if you are actually that curious.

Because there are a lot of complications. Like not only does the black hole take up your whole field of you but also like it's possible for you to get inside a black hole without getting stretched into spaghetti it sort of all depends on these details about the mass of the black hole right that's right so if you're interested in that dig into that copy that book and let us know if you have any follow up questions all right so the basic answers for levi is uh you can calculate the mass of a black hole by how the things around it are moving and also when do you need to turn around when you visit a black hole before you visit a black hole is when you need to turn around right right Exactly. Before you start searching Airbnb for black hole opportunities.

Yeah, don't believe those pictures. They distort the space inside of the Airbnbs. All right, let's get into our two other listener questions about black holes. One of them is about mini black holes. And the other one is about dark matter. But first, let's take a quick break. Imagine that you're on an airplane and all of a sudden you hear this. Action passengers, the pilot is having an emergency, and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control.

And they're saying like, okay, pull this, until this. Do this. I can do it my eyes close. I'm Mani. I'm Noah. This is Devon. And on our new show, no such thing. We get to the bottom of questions like these.

Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then as we try the whole thing out for real. Wait, what? Oh, that's the run right. I'm looking at this thing. Listen to no such thing on the Iheart radio app, Apple Podcasts, or wherever you get your podcasts.

Hey, sis. What if I could promise you you never had to listen to a condescending finance, tell you how to manage your money again. Welcome to Brown Ambition. This is the hard part when you pay down those credit cards. If you haven't gotten to the bottom of why you were racking up credit or turning to credit cards, you may just recreate the same problem a year from now. When you do feel like you are bleeding from these high interest rates, I would start shopping for a debt consolidation loan, starting with your local credit union, shopping around online, looking for some online lenders because they tend to have fewer fees and be more affordable. Listen, I am not here to do. judge. It is so expensive in these streets. I 100% can see how in just a few months you can have this much credit card debt when it weighs on you. It's really easy to just like stick your head in the sand. It's nice and dark in the sand. Even if it's scary, it's not going to go away just because you're avoiding it. And in fact, it may get even worse. For more judgment-free money advice, listen to Brown Ambition on the IHeart Radio app, Apple Podcast, or wherever you get your podcast.

Your entire identity has been fabricated. Your beloved brother goes to missing without a trace. You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your life, impacting your very legacy. Hi, I'm Danny Shapiro. And these are just a few of the profound and powerful stories I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you,

stories of tangled up identities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me and my extraordinary guests for this new season of Family Secrets. Listen to Family Secrets

Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hello, it's Honey German, and my podcast, Grasasas Come Again, is back. This season, we're going even deeper into the world of music and entertainment with raw and honest conversations with some of your favorite Latin artists and celebrities. You didn't have to audition?

No, I didn't audition. I haven't audition in, like, over 25 years. Oh, wow. That's a real G-talk right there. Oh, yeah. We've got some of the biggest actors, musicians, content creators, and culture shifters sharing their real stories of failure and success. You were destined to be a start.

We talk all about what's viral and trending with a little bit of chisement, a lot of laughs, and those amazing vivas you've come to expect. And of course, we'll explore deeper topics dealing with identity, struggles, and all the issues affecting our Latin community. You feel like you get a little whitewash because you have to do the code switching? I won't say whitewash because at the end of the day, you know, I'm me. But the whole pretending and code, you know, it takes a toll on you. Listen to the new season of Grasasas Come Again as part of My Cultura Podcast Network on the IHartRadio app, Apple Podcasts, or wherever you get your podcast. All right, we're answering questions about black holes from listeners, and you get a lot of questions about black holes. I do. I have a lot of questions about black holes. I read a lot about black holes, and we get lots of questions from the listeners.

about black holes because everybody wants to know what's going on. I see. And what proportion of the questions you get do you actually know the answer? Well, I have a wonderful backup, which is if I don't know the answer, I just send them a link to our book. We have no idea. And say, that's the answer. Go buy a copy of the book.

Oh, boy. You're plugging away today. I'm plugging away. But also, I think people like to hear that the question they've asked is not one that has an answer. Of course, people would like to know the answer, but it's also satisfying to feel like, oh, I'm at the forefront of human knowledge. I have questions just like Kip Thorne has questions

or just like Barry Barish has questions, these Nobel Prize winners who also don't understand what's going on inside a black hole. Welcome to the club. Curious about Blackholes Club. All right, so our second question is from Tim and he has a question about mini black holes. Hello, Daniel, Jorge, and Katie.

I've got a question about mini black holes. If you were to have some super large Hadron Collider and create miniature black holes that immediately disappear with hawking radiation, how would you detect that hawking radiation? And what would you learn? Since all the information other than the mass of the black hole is essentially destroyed. Curious about the answer. Cheers.

All right. Awesome question here. There's a lot in this question. There's the idea of mini black holes. There's the idea of hawking radiation. And he asked about quantum information. I know so many good questions and so many fun opportunities to learn about black holes by creating them at particle colliders. All right, so let's dig into it. Daniel, what is a mini black hole? I guess it's just a small black hole. Are those possible? How do you make them?

Yeah, black holes can come in almost any size. There is an absolute minimum size to a black hole, but it's pretty small. You can make a black hole. That's the size of the galaxy. You can make a black hole. That's like, you know, the size of a particle almost. The crucial thing is not the mass. It's the density. If you compact enough stuff into a small enough space, then you can create a black hole. It's this combination of mass and radius. You know, for example, if you took the Earth, you could compact it into a peanut and that would be a black hole. So the mass of the Earth is enough to make a black hole. It's just not dense enough. And so you can make mini black holes by pouring enough energy or enough mass into a small enough space. And that's what you do at the Large Hadron Collider, right?

You think you're making mini black holes or you know you're making mini black holes? We hope we're making many black holes. We haven't yet seen any. But that is exactly what we do at the Hadron Collider. And at every collider is that we pour a lot of energy into a very small space. And we let the universe decide what comes out. We take advantage of the quantum mechanical nature, the probabilistic nature of the rules of physics that say, if you have a little ball of energy there, it can basically turn into anything.

It might turn into some new particle you haven't seen before. It might turn into a black hole. Right. And so sometimes you get enough energy packed into such a small. space that you make a mini tiny black hole about the size of like a particle. And so those are actually black holes, just like the ones at the center of the galaxies. They're just really, really small. And something special happens to them, right? They don't last very long. That's right. And so to be clear, we have not, to our knowledge, made any of these black holes.

We have not seen any. It's a hypothetical. It's a theoretical idea that perhaps it's possible to make these black holes by colliding particles together. And so we are looking for them. And the thing you have to understand about many black holes is that they don't last. very long. Like big black holes can last for billions of years as they keep eating stuff, but all black holes emit radiation. They don't actually keep all their information inside. They leak a little bit of mass all the time. It's called hawking radiation. And this happens faster if you're a small black hole. So a big black hole hardly emits any hawking radiation. It can last for a long time. A little black hole will very rapidly evaporate by giving away all of its mass in

terms of hocking radiation. So the smaller the black hole is, the quicker it disappears, which is actually good because you want your black holes to evaporate rather than growing and gobbling up the earth. All right. So then the tiny black holes evaporate quickly. And the question, I guess, is can you detect that hawking radiation? And what would you learn from it? Yeah. So these black holes, if you made them, they would basically explode almost instantaneously. The kind we're talking about making it the Large Hadron Collider would last like 10 to the minus 27 seconds. And they would just emit a bunch of hawking radiation. But what? is that hawking radiation and how would you see it?

The cool thing about black holes is that they couple gravitationally, right? They're connected to everything that has mass. They don't care about things, electric charge or strong charge or weak charge. So they're sort of democratic. They turn into like all kinds of particles with basically equal probability. And so that means that what you would see is just a huge spray of a bunch of different particles, like a huge explosion at the center of your detector, with a lot more energy than you would typically see. I see.

But you're eagerly liked to see like an electron or a proton or a muon, kind of, right? I mean, depending on how much energy they have, they might be more probable. But there's no constraint about what particular particles you'll see. That's what you're saying. Yeah. And because the particles that feel the strong force, like quarks and gluons, have so many more varieties. Because, for example, for the upcork, there's the red upcork, the green upcork and the blue upcork. Whereas the electron doesn't feel that.

And so it only has one version. That means there are more versions of corks and gluons, so you're more likely going to get corks and gluons than electrons and muons, just because there are more of those, and black holes are democratic. So most likely what you're going to see is a big spray of corks and gluons that fly out. And corks and gluons, we don't see those directly because corks and gluons can't be by themselves. So instead, each one turns into its own stream of particles. So what does a black hole look like in our detector at CERN? it looks like seven or 10 streams of particles all coming out of the center of the collision. Well, I think the question that Tim had was like, could you learn or would you learn anything

from that stream of particles? And it sort of seems like you wouldn't, right? Because it'd just be a random spray of particles, right? Yeah, and there's a subtle point here because you can't look at an individual collision that has like 10 of these sprays of particles and say, that's a smoking gun signature of a black hole because there are other ways for that to happen. Sometimes two protons collide and you do get 10 quarks flying out. which make 10 of these streams of particles.

So that does happen. So we can't specifically say this was a black hole or that was a black hole. All we can do is say, look, we see more of these collisions that lead to 10 or 12 sprays of particles than we expected from non-black hole sources. So we can statistically say we think we're making black holes because we see more of these weird kind of events than we can explain otherwise. And this weird kind of event is just what we expected to see from black holes. So we can't definitively say a black hole is created on two.

day at 4 p.m. But we can't say over the last year, we think we made 10 of them. Well, I see. You can't study like a particular mini black hole. You can study kind of like a statistically what's going on in your collider. But I think Tim was sort of making the connection to this idea that we've talked about before, which is that inside of a black hole, quantum information is destroyed. So does that mean that when a mini black hole evaporates, there's no information in the hawking radiation? Yeah, and this is not something that we understand because we think that quantum information can't be destroyed. And so we wonder if somehow that hawking information does have encoded in it the quantum information that went into the black hole. And we had recently

a fun podcast episode where we talked about people who recently made a breakthrough about how this might work. It's super fascinating. But it's not something we understand very well. But the information that's being destroyed in a black hole is just about the particles that went into it, which is like the two protons you smashed together. So you don't really care that much about that quantum information. It's not like useful or interesting. But if you do make black holes, you can learn something much more interesting about the universe. You can gain like contextual information because you can learn something about quantum gravity. If we make black holes with a large Hadron Collider, it means that gravity is much stronger at very short distances than it is at long distances. Something

weird and different is going on when two particles get really close together, their gravity gets different. And that's a clue about maybe the whole nature of space, about how many dimensions there are to space itself. Oh, what do you mean? Like, you would shoot things together, create mini black holes, and then you would see how it interacts with the things around it? Like, can you actually get a sense of, you know,

what happens as you get that close to mini black holes? Or is it maybe hidden in the fact that you do or do not get mini black holes? Yeah, it's the fact that you make black holes and also their typical energy tells you something about how they are made. You can't study an individual black hole or like put things near it or anything like that. But one thing we are really curious. about is why gravity seems to be so weak. You know, gravity is so much weaker than all of the other forces. Like we say often, you can defeat the entire gravity of the earth by using a simple

kitchen magnet to pull on a screw, for example. So why is gravity so weak? It's not something we understand. One possible explanation is that maybe gravity is so weak because it's leaking out. It's like getting diluted because there are other ways that you can move through space other than the three we're familiar with. So these are called extra dimensions. like maybe space doesn't have just three dimensions, maybe it has 11 or 26, but only gravity can feel those. And so when you're far away from something, you're not really feeling its true gravity because most of it's leaked out into these other dimensions. But these other dimensions might be really, really small and compact. So if you get really close to something, you might feel

it's like true strength of its gravity. So the idea is if you smash two protons together and you bring them really close together with enough energy, then they might feel that strong gravity enough to make a black hole. So the fact that you made the black hole would tip you off that gravity is getting strong at short distances and maybe reveal something about the existence of those other dimensions of space and time. So you're saying that if you do make black holes

at the Large Hadron Collider, then maybe that points to the existence of extra dimensions. Yes, exactly. So we can't learn that much from one black hole, but if we can prove that we have been making them, then that suggests that there must be extra dimensions of space and time, and the pattern in which they appear,

like the energy that they come with and how often we make them can give us a clue as to like how many dimensions are there and what radius do they have because these aren't dimensions like the ones we're familiar with like x y and z that we move around in these are like little looped dimensions they're like move in a little circle or they're only like a centimeter wide they're really weird and strange dimensions but lots of theories of physics actually insist on having more dimensions like string theory yeah and conveniently that's another topic we cover in our book But it sort of sounds like the answer for Tim here is that we haven't detected any mini black holes in the colliders. But if you do create them, A, you would see this big shower of sort of random particles, maybe mostly quarks.

And B, it would point to the existence of extra dimensions. That's right. That's one explanation. There are other theories that also predict the creation of black holes. And so if we did see them, the theorists would go crazy coming up with new ideas to explain our data. It would be very, very exciting. And for those of you nervous about the safety aspect of this, don't worry, we've done all the calculations and we're confident and we can't make black holes big enough to eat the earth.

That's good to know. Always reassuring that you've done the calculations and that you never make mistakes, right? That's right. We've never ever made a mistake that destroyed the Earth, right? That's a pretty good track record. Yeah, yeah. So far, zero for zero.

All right, well, let's get into our last question about black holes from a listener, and this one has to do with dark matter. But first, let's take another quick break. Imagine that you're on an airplane, and all of a sudden you hear this. Attention passengers, the pilot is having an emergency, and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control. And they're saying like, okay, pull this, until this.

Do this, pull that, turn this. It's just... I can do it my eyes close. I'm Mani. I'm Noah. This is Devin. And on our new show, No Such Thing, we get to the bottom of questions like these.

Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then, as we try the whole thing out for real. Wait, what? Oh, that's the run right. I'm looking at this thing. See?

Listen to No Such Thing on the IHeart Radio app. Apple Podcast. or wherever you get your podcasts. Hola, it's Honey German. And my podcast, Grasias Come Again, is back. This season, we're going even deeper into the world of music and entertainment with raw and honest conversations

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It takes a toll on you. Listen to the new season of Grasasas Come Again as part of my Cultura podcast network on the IHartRadio app, Apple Podcasts, or wherever you get your podcast. Your entire identity has been fabricated. Your beloved brother goes missing without a trace. You discover the depths of your mother's illness, the way it has echoed and reverberated throughout your life, impacting your very legacy. Hi, I'm Danny Shapiro.

And these are just a few of the profound. and powerful stories, I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue to be moved and inspired by our guests and their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of tangled up identities, concealed truths, and the way in which family secrets almost always need to be told. I hope you'll join me and my extraordinary guests for for this new season of Family Secrets. Listen to Family Secrets Season 12 on the IHeart Radio app,

Apple Podcasts, or wherever you get your podcasts. Hey, sis, what if I could promise you you never had to listen to a condescending finance, bro, tell you how to manage your money again. Welcome to Brown Ambition. This is the hard part when you pay down those credit cards. If you haven't gotten to the bottom of why you were racking up credit or turning to credit cards,

you may just recreate the same problem a year from now. when you do feel like you are bleeding from these high interest rates, I would start shopping for a debt consolidation loan, starting with your local credit union, shopping around online, looking for some online lenders because they tend to have fewer fees and be more affordable. Listen, I am not here to judge.

It is so expensive in these streets. I 100% can see how in just a few months you can have this much credit card debt when it weighs on you. It's really easy to just like stick your head in the sand. It's nice and dark in the sand. Even if it's scary, it's not going to go away just because you're avoiding it. And in fact, it may get even worse.

For more judgment-free money advice, listen to Brown Ambition on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. All right, we're answering questions from listeners about black holes because they're so cool and mysterious and dark. And our last question comes from Juan, who has a question about whether, black holes can explain a little bit of missing mass.

If there is missing gravity in the galaxy, why can't we attribute it to the black hole in the center of it since we don't know its mass? Interesting question. First of all, we're missing mass? Like, did we misplace some mass in the galaxy? Oops, I thought you were going to bring it home. Where is it? Did the galaxy go on a quick diet or something?

Did it go keto? You're looking great these days, Milky Way. Maybe it's like only 2% Milky Way or like low-fat Milky Way. Skim, Milky Way. All right, so there is a missing mass in the galaxy, right? I know this one. It's like if you measure how the stars in the galaxy are spinning around, they are spinning around faster than they would be

if there was only stars and planets in the galaxy, right? There's something else missing from the mass of how we see the galaxy spinning. Exactly. Just like we were talking about, you can deduce the mass that the sun has to be to explain the Earth's motion. You can do the same thing with the whole galaxy. measure the motion of the stars, and from that deduce the mass of all the stuff that has to be pulling on those stars to keep them moving in a circle. It's exactly the same strategy. Right.

And this is kind of how people first started thinking about dark matter, which is that they saw that the galaxies were spinning faster than they would be if the stars were to stay in the galaxy. And so they hypothesized like, hey, maybe there's some invisible mass, we'll call it dark matter. And that's what's keeping all the stars in the galaxy. I usually think about it the other direction they measure the velocity of the stars and then they ask how much gravity do you need to explain that motion to keep the stars from flying on and then they couldn't

find that much mass. They looked at all the stars and all the dust and all the things they could see and it just didn't add up it wasn't even close so that was a big puzzle for decades right and so the idea of a lot of invisible mass out there in the universe is kind of crazy so a lot of people are like are you sure that sounds crazy

How do you know that maybe the black hole at the center of the galaxy isn't just heavier than you think it is? Maybe that would explain why the stars are not flying off into space. Yeah, it's a great question because it points to like our uncertainty. Like how do you know how massive those stars are and how do you know the other things in the galaxy? How well do you know their mass? And so it's just like pointing at, you know, other places we could be making mistakes, which is a great scientific exercise, like to go back and think maybe we just misestimated the number of stars or maybe we misestimated their mass or maybe it's all. hiding at the center of the galaxy inside that black hole?

Yeah. So the question is, like, could a bigger black hole at the center of the galaxy explain how all the stars are moving around the galaxy? Or does it have to be something like dark matter? So there's sort of three answers, two noes and then a maybe yes. So the first no is that we actually kind of do know the mass of the black hole at the center of the galaxy. It's not just some huge cosmic knob that we can turn up and down and say, nobody knows,

so we can just set it to anything. As we talked about just a few minutes ago, we can measure the mass of black holes by looking at the movement of stars near it. And the one near the center of our Milky Way is actually super awesome because there's a star that gets really, really close to it. It whizzes right by it.

It ends up going super fast and allows us to make a pretty precise measurement of the mass of the black holes of the center of the Milky Way. I see. So there isn't like a mysterious black hole at the center of the galaxy. There's one that we can measure.

Yeah, we've measured its mass pretty well. And there's a bunch of stars moving around it. And this really awesome video you should watch, it took like decades to make of them observing the black hole and seeing the motion of the stars around it. And you can watch it in time lapse. You know, it took them 20 years, but you can watch the whole thing in 20 seconds.

And you can see these stars moving around some obvious invisible object. Like they're bending their path around what seems to be nothing and therefore must be something. Right. And it's pretty massive, I imagine, right? It's a pretty massive black hole at the center of our galaxy. Yeah, it's pretty heavy. It has 4.1 million times the mass of our star.

So it's pretty hefty. And I just want to make a plug for UCLA that won the Nobel Prize for these observations very recently. So go check out that video. It's pretty cool. But it's a pretty massive black hole. But it can't explain all of the dark matter. Number one, because we know it's mass. But number two, also it's in the wrong place to explain the dark matter.

Right. Like even if we didn't know the mass of the black hole at the center of the. galaxy, like even if we were wrong, one giant mass at the center of the galaxy wouldn't explain how all the stars are moving. That's exactly right, because even if you increase the mass of the black hole to account for all the missing stuff, it wouldn't give you stars moving the way our stars are moving. And that's because we can look at the velocity of stars very close to the center of the galaxy and the velocity of stars further away from the center of the galaxy. So what we need is dark matter to explain all of those different velocities, stars closer to the center and stars further

from the center. And every star, its motion, tells you about how much mass is sort of in a sphere that's closer to the center of the galaxy than it. Like stars are not affected by stuff that's further away from them, only by stuff that's closer to them. So as you look at stars as a function of their distance, you notice that you need a distribution of mass that sort of spread out through the galaxy. If you only put a huge blob of mass at the very center, it would make the stars near the core of the galaxy move way too fast, for example. Right, right. Because, That's kind of an interesting property of mass. It's like, you know, if you're really far away from it,

you might as well treat it as a like a dot. But if you're really close to it, then it does matter whether or not it's like diffused in a little tiny ball in the middle or in a giant cloud that this actually sort of engulfs you, right? Yeah. If you're inside of it, then you're only sensitive to the parts of it that are closer to the center. Just like if you drill the hole inside the earth and jumped inside,

the force of gravity on you would decrease as you are, closer and closer because a lot of the stuff would now be outside of your shell. You could ignore it. And when you get to the very center, there would be no force of gravity. So you can no longer treat the Earth as like just a point particle with the mass of the Earth. And so it's the same thing with the galaxy. In order to explain the velocity of stars, we have to distribute the mass in just the right way to make these stars go fast, these stars go a little slower. So the cool thing about this velocity measurement is that we're not only sensitive to the overall amount of missing mass, but also how it's distributed through the

galaxy. Right. I like that analogy about the earth because if you fall to the center of the earth and you're at the center of the earth, basically the earth is all around you and it's pulling you in every direction. So you're basically weightless, right, in the middle of the earth. Yeah, there's no force of gravity at the center of the earth. Yeah. And so the same would be with a galaxy. Like if you're at the center of the galaxy and you would feel the dark matter pulling all around you so you wouldn't feel this mass. But if you were out in the edge of the galaxy, you would feel the mass of the dark matter like it was a point in the middle. Yeah, exactly. So imagine now a star that's very close to the center of the galaxy.

If you took all the dark matter and you put it inside the black hole, that would mean that star is feeling all of that gravity, it would be moving really, really fast. If instead you took that dark matter and you spread it out through the galaxy, then most of it wouldn't affect that star near the core. Because as you say, it would all be balanced out. It would all be on the outside of it. It would be null. And so you can tell how it's distributed by looking at the velocity of stars that are close to the center and then a little further away and a little further away. A distributed mass of dark matter makes a very different prediction than dark matter concentrated all at the core of the galaxy. All right. So then

that's the answer. The answer is that a black hole cannot explain the missing mass in galaxies and the trajectory of stars. You kind of need something large and diffuse like how we think dark matter is. But there's also a possible yes, maybe to his answer, which is that we don't think that all of the dark matter is in the black hole the center of our galaxy, but remember that we don't know what dark matter is. And there's a possibility that dark matter, though it's spread out through the galaxy, might be a bunch of smaller black holes. Right, like primordial black holes, right?

Yes, black holes made in the very first few moments before there was even stuff and matter in the universe. They could still be around and they could account for the dark matter. It's one of the theories that are out there. It's maybe not the most common or highly. voted theory of dark matter, but it's still possible, it's still plausible, and we haven't figured out what dark matter is, so it could just

be a bunch of black holes spread out through the galaxy. Wow, that sounds a little horrifying to know that, like, if you were flying through space, it's like riddled with minds, kind of, right? You might be flying through space, and there's a hole, you're flying through a cloud of little tiny black holes. That wouldn't be good for your spaceship, right?

That would not be good for your spaceship, but you know, it's eaten zero Earth's so far, so it must be pretty safe. So far, zero out of zero. No, we've been flying through the galaxy for billions of years, right? And we have not yet run into a black hole. On the other hand, we don't know if there are other planets out there that have fallen into primordial black holes because if they had, we wouldn't see them.

So it's not really a great argument. All right. Well, then the answer is that a black hole at the center of the galaxy wouldn't explain dark matter, but maybe dark matter is explained by little tiny black holes everywhere. But it's great thinking, one, to try to come up with some other explanation for dark matter in terms of like the things we do know and our uncertainties about them. It's a great way to exercise your brain

and do physics and think about different hypotheses. So great idea. Cool. So those are three awesome questions about black holes. Daniel, do you think we've done our job here to fill the black hole of questions about black holes a little bit? Yeah, the problem is that the black hole questions

just grow. The more you feed them, the bigger it gets, the stronger it's pull. The more we want to know. It's just kind of like science that way. The more we ask questions and get answers, the more questions we have. Yeah, and hopefully we won't get stuck in them forever.

At some point, we'll get out of them. Or maybe inside the black hole is a really wonderful book filled with the secrets of the universe and a cozy reading nook to enjoy it in. Yeah, who doesn't love a good book about the universe titled Frequently Asked Questions About the Universe. That's right. Hypothetically at UniversefaQ.com.

You'll have to run an experiment to see if it's a real website. UniverseFaQ.com. You might find a black hole or you might find a lot of interesting knowledge. That's right. and funny cartoons. So go check it out. Go be a scientist. Those who write in asking,

how can we support the podcast? This is how you can support the podcast. Please go out there and check out our book. We put a lot of energy and a lot of fun and a lot of love into it, and we hope that you all enjoy it. Yeah, and more importantly, also those of you wondering,

like, how can I tell my friends or my cousin or my uncle or my mom, like how cool all of this stuff is, this book, I think it's a great way into these topics. Do you think it's going to convert the physics skeptics out there? Aren't all physicists, skeptics? I thought that was your thing.

That was your identifier. Yeah, but some people are skeptics about physicists. They're skeptic about skepticism. Meta-skeptics. All right, well, please go check it out, and please send us more of your questions. It was really fun to get and really fun to answer on the podcast. That's right. Please don't hesitate

write to us any questions you have about physics except, of course, humor problems to questions at Daniel and Jorge.com. We hope you enjoyed that. Thanks for joining us. See you next time. 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.

It's important that we just reassure people that they're not alone, and there is help out there. The Good Stuff podcast, Season 2, takes a deep look into One Tribe Foundation, a non-profit fighting suicide in the veteran community. September is National Suicide Prevention Month, so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission. One Tribe, save my life twice. Welcome to Season 2 of the Good Stuff. Listen to the Good Stuff podcast on the Iheart radio app, Apple Podcast, or wherever you get your podcast. I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast. Here's a clip from an upcoming conversation about how to be a better you.

When you think about emotion regulation, we're not going to choose an adaptive strategy which is more effortful to use unless you think there's a good outcome. Avoidance is easier. Ignoring is easier. Denials easier. Complex problem solving. It takes effort.

Listen to the psychology podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Do we really need another podcast with a condescending finance brof trying to tell us how to spend our own money? No, thank you. Instead, check out Brown Ambition. Each week, I, your host, Mandy Money, gives you real talk, real advice with a heavy dose of I feel uses. Like on Fridays when I take your questions for the BAQA. Whether you're trying to invest for your future, navigate a toxic workplace, I got you.

Listen to Brown Ambition on the IHeart Radio app, Apple Podcast, or wherever you get your podcast. This is an IHeart podcast.