Radiolab - Little Black Holes Everywhere

Episode Date: July 28, 2023

In 1908, on a sunny, clear, quiet morning in Siberia, witnesses recall seeing a blinding light streak across the sky, and then… the earth shook, a forest was flattened, fish were thrown from streams..., and roofs were blown off houses. The “Tunguska event,” as it came to be known, was one of the largest extraterrestrial impact events in Earth’s history. But what kind of impact—what exactly struck the earth in the middle of Siberia?—is still up for debate. Producer Annie McEwen dives into one idea that suggests a culprit so mysterious, so powerful, so… tiny, you won’t believe your ears. And stranger still, it may be in you right now. Or, according to Senior Correspondent Molly Webster, it could be You.EPISODE CREDITS Reported by - Annie McEwen and Molly WebsterProduced by - Annie McEwen and Becca Bresslerwith help from - Matt KieltyOriginal music and sound design contributed by - Jeremy Bloom, Annie McEwen, Matt KieltyMixing by - Jeremy Bloomwith dialogue mixing by - Arianne WackFact-checking by - Diane Kellyand edited by  - Alex Neason GUESTS Matt O’Dowd (https://www.mattodowd.space/)Special Thanks:  Special thanks to, Matthew E. Caplan, Brian Greene, Priyamvada Natarajan, Almog Yalinewich EPISODE CITATIONS Videos: Watch “PBS Space Time,” (https://zpr.io/GNhVAWDday49) the groovy show and side-gig of physicist and episode guest Matt O’Dowd Articles: Read more (https://zpr.io/J4cKYG5uTgNf) about the Tunguska impact event! Check out the paper (https://zpr.io/vZxkKtGQczBL), which considers the shape of the crater a primordial black hole would make, should it hit earth: “Crater Morphology of Primordial Black Hole Impacts”Curious to learn more about black holes possibly being dark matter? You can in the paper (https://zpr.io/sPpuSwhGFkDJ), “Exploring the high-redshift PBH- ΛCDM Universe: early black hole seeding, the first stars and cosmic radiation backgrounds”   Books:  Get your glow on – Senior Correspondent Molly Webster has a new kids book, a fictional tale about a lonely Little Black Hole (https://zpr.io/e8EKrM7YF32T) Our newsletter comes out every Wednesday. It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing radiolab@wnyc.org. Leadership support for Radiolab’s science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a Simons Foundation Initiative, and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Transcript
Discussion (0)
Starting point is 00:00:00 Wait, you're listening to Radio Lab from WNYC. Hey, I'm Molly Webster. I'm Lula Miller and this is Radio Lab. And today we have two very different stories from two very different reporters, one of whom is you Molly. Yeah. Who each got pulled down into the same very strange
Starting point is 00:00:34 and very dark place. All right. Okay. Thank you for joining me. And we're gonna begin with producer Annie McEwan. Yeah, yeah, yeah. Well, where do you want to start? Where do I want to start?
Starting point is 00:00:47 I want to start in Siberia. Okay, okay. So the year is 1908. It is June. It is a bright sunny morning. And in this remote part of Russia, it's mostly forest, swamp, bugs, reindeer. The few people in the area are waking up, stretching their legs, making breakfast, and
Starting point is 00:01:10 everything's cool, okay? It is promising to be just a beautiful day. But that is all about to change, because just after 7 a.m., something appears low in the sky as bright as a second sun. Hmm. From oral histories gathered years later, people reported looking up and seeing this thing rocketing towards Earth faster than a bullet. It quickly grows into a giant ball of fire, dragging behind at this tail of blue and white light.
Starting point is 00:01:42 Whoa. It arks across the sky, disappearing over the horizon. And then, a shockwave pulses through the forest, flattening trees, shattering windows, throwing people to the ground. The earth shakes, boats are tossed from rivers. Some people reported a hot blast of wind, others reported a colossal amount of smoke and fire.
Starting point is 00:02:09 And luckily, because it's such a remote region, despite the fact that 800 square miles of forest were flattened, only somewhere between zero and three people are killed. Huh. Wow. And I don't know, either have you heard of this before? It's called the Tunguska event.
Starting point is 00:02:29 No, I've never heard of it. Tunguska. Tunguska. That's the town. That's the nearby river. Okay. And today, this is still considered the largest impact event in recorded human history.
Starting point is 00:02:41 So like an impact. So there's a something that like hit us. Yes. Well, maybe. Hmm. Hmm. Okay. So a bunch of scientists go plunging into the forest to try to figure out what the heck just happened.
Starting point is 00:02:56 This gamble over fallen log after fallen log through dense bog after dense bog for miles and miles until finally they realize they have no idea what happened out here. Okay. Really? Yeah, they can't find any evidence of what caused this huge explosion. Wait, what?
Starting point is 00:03:19 Like they sort of figured this must have been an asteroid. So they thought they'd find debris from an asteroid, like space rock. They don't find a single bit of space rock in this whole area. Weird. And not only that, an asteroid that would have caused this much destruction should have left probably something like a three quarter mile long impact crater
Starting point is 00:03:40 and they don't find any crater whatsoever. That's kind of spooky. In 800 square miles of destruction, there was like nothing from space. Yeah, not even a hole. This is why people think UFOs exist. Yeah, and I think that that's what the scientists were like, well, we have to find what obviously should be there.
Starting point is 00:04:03 And so all kinds of ideas cropped up. Some people thought it was maybe a natural gas bubble that bursts from beneath Earth's crust. But that doesn't explain the bright light in the sky. Some people thought maybe it was a strange volcanic eruption. But again, doesn't really explain the light moving through the sky. One guy for a while thought that he had found the crater,
Starting point is 00:04:24 and it was a lake. but then the locals were like, yo, that lake was here, it's been here forever. So they were trying for many, many years to figure out what the heck it was. But so the main theory and the one that holds strongest today is that it was an asteroid, a really big one. Estimates put it at 120 feet across,
Starting point is 00:04:43 220 million pounds. Oh my gosh. Like it's like an office building, or like an apartment building headed toward planet Earth. Right, and the theory is that it came into Earth's atmosphere at kind of a weird angle, and so it stayed in the atmosphere and started to overheat. And it got so hot that eventually it just went boom.
Starting point is 00:05:00 Wait, but then are there some chunks or it's just dust and fire and energy? That's the thing. Like, that's a real question. Like, should it there be some pieces of this, like, somewhere out there, like, some sort of evidence? Yeah. And that's the part that is still a little... weird. What do you think of that?
Starting point is 00:05:23 That does seem strange, doesn't it? I think it does. Yeah. But, you know, it's pretty plausibly an atmospheric explosion. And I think, you know, most scientists have sort of dusted their hands off and moved on to the next question with regards to Tungaska. It's not a cold case. It's not like, oh, on the shelf, isn't it? Well, I think it's some people's minds it is.
Starting point is 00:05:48 Hmm. Some still believe it wasn't an asteroid. This is astrophysicist Matt O'Dowd. Professor at the City University of New York, Lehman College. And I reached out to Matt because I had recently seen him on his side gig. Have you ever asked, what is beyond the edge of the universe? It's really awesome physics YouTube show. What would it take to build a Starship, which
Starting point is 00:06:09 she's called PBS Space Time? Talking about this really wild, absolutely. Alternate theory of what could have caused the Tunguska event of 1908. Which is the black hole. Wait. which is the black hole. Wait, that's... What?
Starting point is 00:06:31 That's different. Like a black hole, like a space black hole. Did this? Like how? I don't know, radiated a death wave toward planet Earth? No. Matt's talking about a black hole actually hitting Earth. Exactly. What?
Starting point is 00:06:51 Which sounds impossible, because usually when we're talking black holes. I, God, right out of dentist inferno. We're talking about these big, terrifying, churning places in space where gravity is just so strong that not even light can escape it. It's a monster, right? They eat stars and planets and gas, and they have all these almost supernatural qualities like they warp the space around them, change the flow of time, and all of that awesome
Starting point is 00:07:18 stuff that comes out of general relativity. But if one of these black holes approached Earth, its gravitational pull would be so strong that Earth would be, they call it, big gettify, the entire planet would begin to stretch towards the black hole and then as it punched in, Earth would essentially follow it through the hole that it made. So you should imagine kind of Earth just folding in afterwards and it would probably follow the black hole in this kind of stream of super hot stuff. Until all of Earth, everything on it, everything in it is ripped apart into individual atoms and Earth is devoured.
Starting point is 00:07:58 Um, alright, so no, not- That's so awesome. Not like happened. But you would also notice, you know, you know. Wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, wait, not what happened, but you would also notice, you know, we would all agree today Exactly. That was black hole exactly right. Okay, so this obviously is not a very plausible explanation for the tongue guska event No, no, certainly not, but that's because there's one very important difference between these black holes And the one that potentially destroyed 800 square miles of Siberian forest, which is that rather than being this giant monster, the Tunguska black hole
Starting point is 00:08:35 would have been a really, really teeny tiny monster. Very small. Wait, if black holes can be little? Yeah, like really small. Like how small? Like very tiny, like itty bitty. So small. Wait, if black hole is gonna be little? Yeah, like really small. Like how small? Like very tiny, like itty bitty. So small. I mean, could it fit on my hand? Yeah, I mean. Are we talking like a peanut?
Starting point is 00:08:52 Uh, we're talking like the size of a hide shrewd atom. Oh, an atom. Yeah. Oh my goodness! That is very small for black hole, okay. Now, so these tiny little black holes are special black holes because typically a black hole gets made after a star explodes.
Starting point is 00:09:10 But these tiny little black holes, they got made in this one particular explosion. 13.5 billion years ago, the Big Bang. Which was a very great day for existence. Yeah, exactly awesome. But a very upsetting day for gravity. Yeah, exactly awesome. But a very upsetting day for gravity. Because like the Big Bang was the explosion outward where things became free of gravity in a way.
Starting point is 00:09:32 Yes, everything had been packed together in this really tight dense ball. And then this little dense ball was this rapidly expanding ocean of hot hydrogen and helium. These bright swirling gases. Glowing. And gravity was like, oh my god, I was just, oh, I have to get all of it back in that tiny little hole again.
Starting point is 00:09:54 Exactly. For one minute I fell asleep. Seriously? It's a gravity stress. Gravity is stressed and immediately begins trying to turn the whole universe into a black hole Trying to grab everything and pull it back together which is Not possible. Mostly it fails, you know, happily because the expansion of the Big Bang is just too powerful
Starting point is 00:10:17 But everything is still so hot and so dense and so compacted together the gravity is able to grab some of this stuff Crashed it together, to create... What we call primordial black holes. Black holes from the beginning of time. And the idea is that these black holes have been just out there all this time, spinning through the universe, doing their thing devouring stars and planets and other black holes. But over time, as the universe expands and things start to spread out more and more, space
Starting point is 00:10:57 starts to get, well, pretty empty. And there's this weird thing about black holes, which is while they eat things up and they can, they are also very slowly spitting stuff out, which means if they spend long enough moving around in empty space, they will slowly over billions and billions of years shrink, even down to the size of an atom. Exactly. So these primordial black holes are PBHs, which would do you prefer? PBHs. Really?
Starting point is 00:11:31 No, no, yeah, PBH, it sounds like PBS, but yeah. I know, or it's like a condiment. Yeah, exactly, PBHs. Yeah, primordial black hole is good. It's really good. I'm happy to go with primordial black hole. Yeah, okay, okay, I didn't know if it was too much every time, but no, let's really good. I'm happy to go with Primordial black hole. It's a two-match every time, but no, it's good. I'll try to say it fast.
Starting point is 00:11:49 Great. All right, so. Matt explained that even though these primordial black holes could be as small as an atom. Still, they could be very massive. There is still a huge amount of stuff packed into that small space. So.
Starting point is 00:12:01 It's an atom, but with the mass of... An asteroid asteroid basically. And the other thing is that super big black holes they usually sit in the middle of a galaxy with everything spinning around them. These little primordial black holes they're kind of like un-tethered and since everything in the universe is swirling and spinning and moving around. They do have to cross the orbits of other objects. Other objects like planet Earth, for instance. Exactly.
Starting point is 00:12:32 And it's possible, or so the theory goes, that on a beautiful June morning in 1908, one of these primordial black holes, a particularly small one, about the size of a hydrogen atom, but with a mass equal to an office building size rock. Zooming along at 62 miles a second, about to make a direct hit with a certain patch of Siberian forest. Okay, we're back.
Starting point is 00:12:59 We're back. You ready for your impact? Oh my God, yeah. All right, let's do it. Mm-hmm. Okay, now? Now my god, yeah. Alright, let's do it. Hmm. Okay, now. Now. Okay.
Starting point is 00:13:06 Alright, so... This primordial black hole punches through the atmosphere... Like a tiny needle of gravity. And stuff gets pulled towards that gravitational field. Stuff like nitrogen molecules, carbon dioxide, oxygen molecules. And this tiny little black hole... begins... to eat.
Starting point is 00:13:26 It devours molecule after molecule after molecule and each one of those molecules as it fill into the black hole becomes hotter than the surface of a star radiating An enormous amount of heat and energy And with all that energy around the black hole, this halo begins to form, and it's not very big, but it is shining with the power of several Hiroshis. Several atomic bombs. Oh my God. In that moment, if you've been standing
Starting point is 00:13:55 in the Siberian forest, looking up at the sky, this would have looked exactly like a second sun rocketing through the sky, pulling behind it a tail of blue and white light. As it got closer and closer to the surface of the earth, it would suck stuff from the atmosphere into it, and that would actually create enough heat and energy to be equivalent in energy to an asteroid exploding.
Starting point is 00:14:20 Which meant this tiny, primordial black hole was creating these enormous... Shockwaves. And what did that sound like? Um, I imagine a ginormous... Kaboom... Cool. That would flatten as far as... Knock people over, throw a bozette of rivers,
Starting point is 00:14:36 shatter windows... And then it would hit the ground, and it should actually leave a crater. Oh! But this one would be much smaller... Sort of a column. Thinner, definitely not what the scientists have been looking for. And it would have been harder to find.
Starting point is 00:14:49 It would also be very deep, because while an asteroid stops when it hits the Earth... The black hole... Doesn't even slow down. What? And is it plummet severe? Through its whole passage. It would be generating these seismic waves. These rings of earthquake expanding from around this bullet shooting through the earth.
Starting point is 00:15:09 And the earthquakes wouldn't be strong, but that would be global. Meaning every single person, plant, animal, and earth, everyone would just be like... Good? What? The heck? Tell you the earthquake? Hmm. Anyway. What? What? The hook. Tell you the earthquake. Hmm. Hmm.
Starting point is 00:15:25 Anyway. As this little black hole rips through Earth, it would be eating or burning all the molecules of rock or dirt that it hit. And some stuff does follow the black hole, but some stuff just gets super hot. Leaving behind this trail that it would at first molten, and then it would slidify into this column of solid glass. Oh, like a glass lightsaber all the way through earth. Yes.
Starting point is 00:15:55 Yeah. Topped it. This long tunnel of altered material. Wow. And then it comes out somewhere. And then yeah, there would have to be an exit wound. Wait, where would the exit wound be? Well, it depends on what angle it came in at.
Starting point is 00:16:10 The angle? Yeah, like if it had been a perfect shot directly through the middle of the earth. It would be in Chile somewhere, but... Back in 1908, it could have easily been in the ocean somewhere and we probably wouldn't have noticed. If you were on a boat or standing nearby, would you be like, oh my goodness, that was,
Starting point is 00:16:30 that was something that came up through the floor of the planet and it made a boom and then there was a bright light. It would be like a shooting star coming out of the ground. That's so crazy! Right. That whole journey through the Earth would have taken this little back hole about two minutes And then it would continue on making its way through the universe and As it goes forward on the rest of its journey, is there a little bit of
Starting point is 00:17:17 1908 forest floor Siberia inside it In some very altered form, yes. But okay, I am wondering, like how many people think or how likely is it that this is what happened? Or is this like a pretty thought exercise? Well, this is a kind of a pretty thought exercise, but it doesn't mean that it's never happened or it's never going to happen.
Starting point is 00:17:48 Tunguska just gives you kind of like a case study for like, okay, well, is it possible that it could have been? And the scientist found out, yes, it is possible. And statistically, something like this either has happened in Earth's history or truly might happen in Earth's future. Well, now that we know there are little black holes out there everywhere, Black holes out there everywhere. When we come back from a short break, we are going to meet one up close, personal, intimately. Stick with us.
Starting point is 00:18:44 Lulu, Molly, radio lab, beholes, black holes. So this next one comes to us from you, Molly, Radio Lab, Beholds, Black holes. So this next one comes to us from you, Molly. Indeed. So what do you got? So when Annie came to our pitch meeting, and she was like, have I got a story for you guys, it's about tiny black holes, I was like, whoa, Annie, rolling up with your little black holes pitch. I've got one too, rolling up with your little black hole's pitch.
Starting point is 00:19:05 Like, I've got one, too. And mine is a little black hole story that just took me in a completely different direction than the one that I or the show normally does. And it came out of this conversation that I had with a physicist, Brian Green, who's like a popular science dude. And we were just having a chat one day, and he told me about this mystery that consumed physicists for decades,
Starting point is 00:19:30 which is that when things fall into black holes, they seem to just vanish. No one's ever been inside a black hole. We don't know how to look inside of a black hole. So seemingly from our perspective, like matter disappears. But physicists were like, how can that be? Because the first law of thermodynamics says that nothing can be created or destroyed.
Starting point is 00:19:52 So what happens to the stuff after it falls into the black hole? It's like a star goes in. A star goes in. Don't know. And you don't know, like, did the star get crushed? Is the star through a wormhole out somewhere else? Did the star burn crushed? Is the star, through a wormhole, out somewhere else? Did the star burn up?
Starting point is 00:20:07 Like, there are guesses, there are theories, but at the time, no one knew. I mean, talk about a black box, you know? It was one of the biggest mysteries. Hmm. And then Stephen Hawking came along and proposed a solution, which is that even if we can't see what's happening inside of a black hole,
Starting point is 00:20:27 the way that matter works is that occasionally particles are just shot out of things into the universe, right? That particle could come off of you, a particle could come off a chair, a particle could be spit out of a black hole. And so he came up with this idea, which we now call Hawking Radiation, that is supported by math, which is a statement I don't fully understand. But came up with this idea that if you got to the surface of a black hole, the black hole would be spitting out
Starting point is 00:21:02 particles that contained information about what was inside of it. Oh Inter so wait so it's like the particles would come out and they might have little clues about like the interiority of a black hole Yeah, they would be like hey, I'm a particle and I'm telling you that there is a brown rock in here Like it would give you a hint of what the black hole has gobbled Or what the black hole has gobbled or what the black hole has seen or intersected with. Okay. And the thought is, is that all of these particles that are shot out of the black hole kind of gather on its surface and create a glow. Yeah, which I just thought was so beautiful. It's like, somewhat beastly object
Starting point is 00:21:46 that none of us understands is revealing parts of itself to the rest of the universe. Mm. So I learn about all this stuff. I'm like, oh, that would be a really cool story. And normally what I do is I do a lot of like reporting and then I put a bunch of voices together and we put it on air
Starting point is 00:22:06 But but the idea of a glowing black hole never stuck with me in kind of like a science reporting way it more Started just to remind me of people and I just thought oh little black hole would be a great children's book character And so I made it one. I wrote it into a kid's book. Indeed you did. I have it right here in front of me. Yay. It is called Little Black Hole.
Starting point is 00:22:33 Okay. And will you, will you, will you flip to the first page of the story and just read us, uh, the first couple of pages of the story? Okay. A couple pages of the story. Okay. There once was a little black hole who loved everything in the universe. The stars, the planets, the space rocks and the space fox,
Starting point is 00:22:57 even the flying astronauts. The little black hole loved her friends. One day a star came by. The Little Black Hole built a space castle with her. La la la la, they sang as they built in sword. The Little Black Hole was having so much fun. She couldn't wait to show the star more of the galaxy. Maybe they could even watch one of the moon's rise together.
Starting point is 00:23:33 Okay, so what happens is there's a little black hole and she is at the center of her galaxy and she has a bunch of friends, there's even a fox, but basically there's like a repeated cycle of those friends leaving. Like a star comes around and she's excited and they're hanging out and then the star goes away and then she's like all alone and this just keeps happening and she just feels super sad. And yes she is eating her friends. It's subtle but it's there. We all eat our friends. And then the little black hole meets a big black hole, another black hole, and the big black hole tells the little black hole to take a deep breath and to close your eyes and to think about the things she loves. And what the little black hole sees is essentially she sees herself glowing.
Starting point is 00:24:25 She sees her hawking radiation. Huh, like she thought the star had left and the comet had left and the space fox and the space rocks and all these things from the millions of years of this little black hole living. And she realizes that her friends are all with her and that makes her feel a little more ready to like go on an adventure and play,
Starting point is 00:24:48 or just to look out into the vastness and be okay. Oh, yeah. I know that this is based on like rigorous astrophysics, but then journey that this little black hole character is on, it does ring so true for loss in life. Like when friends disappear, when people go away, when you look up blinking and no one's left, that's, it's a hard feeling that I think everybody and kids for sure, but everybody like for sure, but everybody has, but authentically, really, really just loved the realization that the memories, the almost companionship in your mind, it doesn't have to go, it
Starting point is 00:25:35 can, but it doesn't have to. It's interesting that you say that because I had a lot of trouble with the ending because I was like, I don't in any way want to imply to kids that just because you realize you have some memories inside of you, like the world's a lot better. Like, it's a little bit better. And so that was interesting because I just dug from a space of like having this memory of a feeling of almost like left behindness. Once I started to write the book, I'm like, oh, I'm the little black hole. You know,
Starting point is 00:26:12 I'm the youngest of four sisters. And growing up, I felt like they were constantly leaving, especially as they each got older and like went off into the world. And then, you know, it was just me. And then I was just like, I just wanted them to come back into my orbit again. Yeah. Did I say the word orbit when I was a kid? No, but I was always just like,
Starting point is 00:26:33 why are you leaving when are you coming back and feeling this sense of loss? And I've had that feeling again and again with other relationships as people come and go. And that kind of echoey solitude is like something that I've always contended with and has been like a daily part of my life. And then at one point I just have this feeling which was like, even if people aren't with me, these people are out there and they love me and they know me and they believe in me.
Starting point is 00:27:06 And that somehow makes charging through the world like more doable. And so for the little black hole when she glows and sees her friends, she realizes like there is a support network somewhere around her in her with her and that just helps her look to the next thing. Okay, so can I tell you one more thing or really quickly? Please. Okay. Yes. Okay. So when I was fact checking the book with Brian, he was saying that, you know, as black holes do this Hawking radiation thing, giving away bits and pieces of themselves,
Starting point is 00:27:52 you know, they actually become smaller and smaller, which is what Annie talked about. That's how primordial black holes get so tiny. But the thing he told me was is that they give away so much of themselves that they end up evaporating. What? And so I don't know, they disappear in the end, they die. Brian was like, good luck making that into a kid's book. So take that as you will. Oh, I've got something for you. Oh, whoa.
Starting point is 00:28:18 Hi, Annie. Hello. Where did you come from? Oh, I've actually never left. I've just quietly been here. Okay, cool. Very creepy, but cool. Anyway, so the reason I'm budding in is because of something that Matt told me.
Starting point is 00:28:33 So these are maybe my current favorite thing. As we were wrapping up our interview. Okay, so we've been talking about Hawking radiation, black holes evaporating, all that good stuff. But then he told me about some current thinking. There is one theory, a number of very reasonable scientists think that once the black hole is very small. Like when it evaporates, basically all of itself away and is now...
Starting point is 00:28:56 Down to around the plank scale. Which is so impossibly teeny tiny that a rough way of understanding it is, if the earth was a size of an atom, then one of these small things, these plank units, would be smaller than an atom on that atom-sized earth. Whoa. And when the black hole has evaporated down to this inconceivably tiny size, the thought is that... There is no transition that lets it give up its last little
Starting point is 00:29:26 bit of mass. So it's stuck. Oh, whoa. So that means that it can't die, that it just won't. If that's true, then there are cigilions of skeletons of black holes all over the universe. Yes. What? And the wildest part of all this is that there is this mystery in the universe.
Starting point is 00:29:41 You may have heard of the question of dark matter. Oh, yeah. Yes. So that's the idea that there's 80% of matter in the universe, that we don't know what it is, but it is heavy, dark, and impossible to detect. Right. And the theory goes that black holes actually can't totally disappear, but instead get locked at that last teeny tiny, invisible size. That sounds exactly like dark matter. Perfect.
Starting point is 00:30:04 Exactly. Perfect. Exactly, perfect. And Matt says, if that's the case, then there must be an unthinkably large number of them out there. And in fact, they must be passing through the earth constantly, if that's the case. Really? I mean, there probably aren't any in the room
Starting point is 00:30:19 with you right now. OK. But over the course of your life, you might be hit by one. Okay. They will, of course, kill you. Pass straight through your body. And what happened? And they are so small, you know, you would leave absolutely no sign. Would you be like, what's it? No. No. No, I don't think so. I'm sorry. You wouldn't be like... I mean, the thing is, atoms are mostly empty space, so they would zip between your electrons.
Starting point is 00:30:50 Okay. And I'm pretty sure even if they passed through the nucleus, they would just pass through the nucleus like it's empty space. I think that would need to have like a head on with a quark or something. And then maybe. Okay. Then maybe like, ow. Yeah, and even well, yeah.
Starting point is 00:31:06 What? Yeah. Exactly. It's like this trail of stuff. It would be pulling behind it. Yeah, exactly. And that would be essentially what happens to most of the stuff because, yeah, because it's so small, the amount that actually has a different contact with it,
Starting point is 00:31:28 I can feel some heat, so I'm not sure if I can handle it, but it's only whatever. This episode was reported by Annie McEwen and Molly Webster. It was produced by Annie McEwen and Becca Bressler with help from Matt Kilti, fact checked by Diane Kelly and edited by Alex Nieson. Sound Design by Matt Kilti and Annie McEwen, Jeremy Bloom, mixing by Jeremy Bloom and Dialog Mix by Arian Wack. Special thanks to Matt Kaplan, a physicist at Illinois State University who worked on a team whose recent paper taught us what the impact crater left
Starting point is 00:32:21 behind by a primordial black hole would actually look like. also want to thank Bram but on not Roger and Brian Green and We dedicate this episode to our newest favorite littleest black hole Animacune's baby boy and then finally a reminder that Molly's children's book is now out everywhere you can find it online You can find in bookshops It is called Little Black Hole. It's illustrated by Alex Wilmore, and it is full of heart and beauty and darkness, and it's all based on science.
Starting point is 00:32:53 Before we go, Maul, do you have any last BHFs? Black Hole facts? BHFs? Black Hole fun facts, to share? I do, I do always. Did you know most black holes generally have a best friend? Who? A star.
Starting point is 00:33:10 Wait, what do you mean? It's just like always nearby, like like like like what's is near the flounder and the little mermaid? Exactly. Exactly. Wait, wait, in what way for real? The star orbits the black hole, sort of floating in space together and then depending on how close they are, they may
Starting point is 00:33:29 eat it all at some point my door is so wide right now or they may just you know grab up little bits of it and hug it pretty close that is wonderful I'm so happy to know that. All right well thanks so much for listening. Enjoy all the little black holes hitting you soon. Bye! Radio Levels created by Chad Abham Rod and is edited by Soren Wheeler. Lulu Miller and
Starting point is 00:33:59 Lottop Nasser are our co-hosts. Don't keep the director of sound design. Our staff includes Simon Adler, Jeremy Bloom, backup wrestler, Rachel Kusik, the Kedi Foster Keys, W. Hayforthuna, David Gabel, Maria Pasco Theatres, Sinden Yannas and Bandung, Matt Kilti, Annie McEwan, Alex Niesen, Sarah Curry, Anna Vascoidbuzz, Sarah Sandback, Aaron Wack, Pat Walters, and Molly Webster, with help from Sajikita G. Momoki. Our fact checkers are Diane Kelly, Emily Creaver, and Natalie Middleton.
Starting point is 00:34:31 Hi, my name is Michael Smith. I'm calling from Penn H. Indus Jersey. Leadership Support for Radio Lab Science Programming is provided by the Gordon and Betty Moore Foundation. Science Sandbox, the Simon's Foundation Initiative, and the John Templeton Foundation. Conditional Support for Radio Lab was provided by the Alfred P. Sloan Foundation.

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